Growing Up in the Universe

Transcripts

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Episode 1: Waking Up in the Universe
Episode 2: Designed and Designoid Objects
Episode 3: Climbing Mount Improbable
Episode 4: The Ultraviolet Garden
Episode 5: The Genesis of Purpose

Episode 1: Waking up in the Universe

Professor Peter Day:

It’s an enormous pleasure for me to introduce to you the 162nd series of Royal Institution Christmas Lectures that have been given in this lecture theatre. And during this year, since the last series, we have, in the Royal Institution, celebrated the 200th birthday of the, what I believe and many other people believe, to have been the greatest experimental scientist who ever lived, Michael Faraday. So I think it’s also worth saying this afternoon that not only was he a great scientist but he was also the originator of these Christmas lectures, which he started in 1826, and which he himself gave no fewer than 19 times. And I thought I would read to you, very quickly, what he said at the beginning of one of those series of lectures, when he stood here, and I believe it was in 1854, and he said the following:

"Let us consider, for a little while, how wonderfully we stand upon the world. Here it is that we are born, and bred, and live. And yet we view these things with an almost entire absence of wonder to ourselves, respecting the way in which all this happens."

Now, that was the reason for the Christmas lectures in Faraday's mind, it was to awaken wonder. And we're going to take up that theme again this year because Doctor Richard Dawkins, the Reader in Zoology from Oxford University, is going to tell us how you and I stand upon this world, and how that all comes to happen. Because he’s going to explain to us how living creatures, many kinds of living creatures, including you and I, have evolved on the surface of Earth.

We are very happy, once again, at the Royal Institution to acknowledge the help that we have had in preparing these lectures from Shell UK and Shell International, who have given us valuable sponsorship, and I would also like to take the opportunity to say that we are organising again a competition this year, based on the content of the lectures, so if you would like to participate in the competition, you will find the address to send your entries to displayed at the end of the lecture. Now, it only remains for me to introduce to you Doctor Richard Dawkins, who is going to give the 1991 Christmas lectures of the Royal Institution on “Waking Up In the Universe”.

(music intro & applause)

Richard Dawkins:

Hello, thank you very much for coming. I’d like to begin by asking you to do something for me. Would you please put your hands to your head and very gently feel your own head. Now, that might seem like a very easy thing to do but I can assure you … okay, put them down now, I can assure you that a man-made instrument that did that would be a very, very difficult thing to make, it would be a very, very expensive thing to make.

As your arms go up there, precision instruments in your muscles are monitoring the exact position of all your muscles. Thousands of sensory endings in your fingers are feeling the exact texture of your hair, the shape of your ears, the shape of your skull. Your brain is measuring the width of your skull with the greatest of precision.

If a human factory were to manufacture an instrument, a robot arm capable of doing that, it would cost something in the region, I would think, of 100 million pounds. Now think about what is between your hands when you do that: your brain. The brain is a kind of computer but it’s a computer such as no human factory has ever turned out. If we ever do succeed in making a computer with the performance of a human brain, I would guess that the research and development costs would be in the region of thousands of millions of pounds. Yet heads like yours and hands like yours are manufactured daily, millions of times over. A woman can do it with no research and only nine months’ development, and only a little help from a friend (laughter).

Life makes the wonders of technology seem commonplace. So where does life come from? What is it? Why are we here? What are we for? What is the meaning of life? There’s a conventional wisdom which says that science has nothing to say about such questions. Well all I can say is that if science has nothing to say, it’s certain that no other discipline can say anything at all. But in fact, of course, science has a great deal to say about such questions. And that’s what these five lectures are going to be about. Life grows up in the Universe by gradual degrees: evolution. And we grow up in our understanding of our origins and our meaning.

Of all the world's societies, the majority have practised some form of ancestor worship. This a totem of one particular cult of ancestor worship. Now I’m not going to encourage you to worship your ancestors, I’m not going to encourage you to worship anything. But it is true that ancestors hold the key to understanding the meaning of life.

You might think it is easy enough to be an ancestor. It’s easy enough to reproduce, or relatively easy, but to become an ancestor you’ve got to have descendants, alive many generations hence. And that's more of a tall order. We can think about it by going back to one of the simplest sorts of animals, a bacterium, right back at the beginning of life. And think about how many bacteria there would be after, say, 50 generations of reproduction. We’re going to illustrate this by folding paper. Now I wonder if I could have two volunteers to fold the paper?

Right, there and … yes, there. Thank you.

Come down here please and take the paper from Bryson. Right, now, every time you fold the paper, that’s going to represent one generation of reproduction. So we start with one bacterium, that’s one thickness of paper. Now, fold it … yes, if you both go the same end, it might be easier. Now we've got two. That’s right … crease it down there, that’s right, fold it, and then fold it across this way, thank you, and just go on folding it until you've done it 50 times (laughter).

So what have you got to now? Four? Four bacteria? Right, eight … sixteen … thirty-two … what can’t you do any more? Right, that's probably it … alright, it looks as though they’re not going to make it. We’re going to have to resort to mathematics to calculate how thick that paper would be.

Okay, thank you very much, do sit down. (applause)

In every generation, of course, the thickness of the paper doubles. So we go 2, 4, 8, 16, 32, 64, and so on. We go on multiplying by two 50 times. After we’ve multiplied by two 50 times what have we got? We’ve got a very big number indeed. We've got in fact a thousand trillion – a one with 15 noughts after it. The sheet of paper is a tenth of a millimeter thick. If you multiply that by a thousand trillion, you end up with … I’ve got it written down here a hundred million kilometres. The thickness of the paper would take us out to the orbit of Mars. The number of bacteria, after a mere 50 generations, is that. But 50 generations is nothing to bacteria, they can get through 50 generations in a day. After about a week, bacteria … the number of bacteria would be more than a billion times the number of the atoms in the known Universe.

Well, that’s called exponential growth, what mathematicians call it exponential growth, we’ll come back to it. Needless to say it doesn’t happen, to the same extent at least. After a point, natural factors come to regulate the size of the population of bacteria. Our original assumption that it was easy to become an ancestor was wrong. Only an elite become ancestors. You can do the same sort of calculation, by the way, for ourselves, or for elephants, as Charles Darwin did, and it just takes a little bit longer, but the same idea is there. After a fairly short number of years, you’ll find that the entire Universe is filled with elephant flesh, or human flesh, or whatever it is. So, it follows that most organisms that are born must die without becoming ancestors, without becoming distant ancestors. Only an elite are destined to become ancestors.

Well, some people don't like the word elite but I just mean that it won’t be all luck which ones end up ancestors. The ones that are going to be ancestors will tend to be the ones that are good at it. They’ll tend to be the ones that have what it takes, have what it takes to survive, to get a mate, to reproduce, to avoid being eaten, to find food, to be good parents, and so on.

That’s really just a way of putting Darwin's Theory of Natural Selection. Because we that are left, we that survived, have … will have inherited the genes of a long line of successful ancestors. We’ll have inherited whatever it took to make them successful as ancestors.

But for the moment I want to emphasise something else, which is that we are lucky to be alive. We’re lucky to be alive because it would've been so easy for our ancestors not to have been here. It would've been so astronomically probable that somebody else would have been here, rather than us. And we’re lucky to be alive for another reason. Think about it this way, the Universe is about 14 thousand million years old. That's 140 million centuries. Some 60 million centuries from now, the Sun will become a Red Giant, and engulf the Earth. So there are about 200 million centuries from the origin of the Universe to the end of the world.

Now, of the 140 million centuries since time began, every one of them was once the present century. And of the 60 million centuries to the end of the world, every one of them will be the present century. The present century is a tiny spotlight inching its way along a gigantic ruler of time. Everything before the spotlight is in the darkness of the dead past. Everything after the spotlight is in the darkness of the unknown future. We live in the spotlight. Of all the 200 million centuries along the ruler of time, 199 million 999 thousand 999 centuries are in darkness. Only one is lit up, and that’s the one in which we happen, by sheer luck, to be alive. The odds against our centuries happening to be the present century are the same as the odds against a penny tossed out at random on the road from London to Istanbul happening to fall on a particular ant.

Well, in spite of those odds, you may have noticed that we are, as a matter of fact, here, and it really … of course, it’s not surprising, we're here because we are the ones doing the calculation. If somebody has just done the calculation that we’ve just done, then that somebody, of course, has to be alive. Nevertheless, I do feel rather lucky to be alive and for another reason, too.

Now, the smoke going into the beam represent stars. Each particle of smoke represents one star. And you can think of the beam as a gigantic searchlight, beamed out from space and signalling from our planet, in the hope that somebody else on another world will pick up the message. We don’t know how likely it is that there is anybody up there. We can say that if our message does hit another planet then, almost certainly, it'll be so far away that if those people up there had a telescope looking back at us, then what they would be seeing is not us at all, but the dinosaurs that were here 65 million years ago. Or in other words, our message would reach people millions of years into the future.

People vary in their estimates of how much life there is likely to be, how likely there is to be life on other planets. Some people think that … some scientists think that as many as 10 million technologically-advanced civilisations are out there. Other people feel that this life, here, on this planet, is the only life that there is. But, even on the most extremely optimistic estimate, it’s still true that most of those worlds out there are going to be deserts. Most of them are not going to have any life on them at all, nor even any possibility of life on them, at all.

Now imagine a spaceship full of sleeping, perhaps deep-frozen, explorers, would-be colonists of another world. Perhaps they're the last population of Earth, despairing that Earth is about to be destroyed, sending out a colony to look for another planet anywhere, in order to carry on humanity.

Imagine that the spaceship turns out to be almost unthinkably lucky. It does chance to arrive at one of the very, very rare planets capable of sustaining our kind of life. A planet of the right temperature, with oxygen, and so on. The passengers wake up and stumble out into the light. And they see a beautiful world of waterfalls, green leaves, mountains, coloured animals and birdlike creatures flitting about.

Can you imagine how it would feel if you woke up, perhaps after a 100 million years of sleep in a spaceship, and found yourself on such a world? A whole new world, a world that you … such as you could live on, a beautiful world. You’d surely bless your luck in arriving on such a rare world, walk around in a daze, a trance, unable to believe the wonders that met your eyes and ears.

Well, this will almost certainly never happen to us. And yet, in a way, it's just what has happened to us. We have woken up after hundreds of millions of years of sleep. Admittedly, we didn’t arrive by a spaceship, we arrived by being born, but the wonder of the planet, the dazzling surprise of it, is the same, whether we arrived by spaceship or by birth canal. We are amazingly lucky to be here, privileged, and we must not waste that privilege. Here, it seems to me, lies the best answer to those narrowminded people who are always carping on about the use of science. The founder of these Christmas lectures, Michael Faraday, was once asked by the then prime minister, Sir Robert Peel, "what was the use of science?". "Sir", Faraday replied, "what is the use of a baby?"

What’s your name? She says her name’s Hannah.
Faraday said "what is the use of a baby?", and I’ve always thought that, what he meant by that, must be that a baby has such potential. It may not be able to do very much now, but it will be able to do a lot.
But it's also possible that what Faraday meant was that there’s no point in bringing a baby into the world, if all it’s going to do was work to go on living, to go on living, and work to go on living, again. If that's all point of life, then what are we here for? There’s got to be more to it than that.
Thank you very much.

Some of life must be devoted to living itself, some of life must be devoted to doing something worthwhile with one’s life, not just to perpetuating it. This is, of course, how people, quite rightly, justify spending taxpayers money on the arts and on conserving rare species. But sometimes, when we justify academic science on these grounds, people get rather philistine and say things like: "oh, so you think the government should spend the money on your scientific research because your research is fun for you, do you?"

“Fun” isn't really the right word, is it? After sleeping for 140 million centuries we have finally waken up in the Universe. We have opened our eyes on a wonderful planet, filled with color, teeming with life. Before very long, we shall have to close our eyes again. Finding out about the Universe in which we have woken up, answering questions like: What are we doing here? What is this Universe in which we’ve woken up? What is life, and what, if anything, is it for? - surely the enterprise that answers questions like that, science, deserves a better title than "fun".
Put like that, doesn’t science sound, to you, like about the most worthwhile way in which you could possibly spend your short time in the spotlight?

Now, of course, if you spent all your time wandering around the world, gasping at everything and saying "how wonderful, how amazing! I’ve woken up after a 100 million centuries, what a trip!", people would think you were a bit odd, and you might even get arrested. We do, of course, have an ordinary life to get on with, we do have a living to earn, we’ve got to earn our living being a solicitor, a lavatory cleaner or something like that. But, nevertheless, it is worthwhile, also, from time to time shaking off the anesthetic of familiarity, and awakening to the wonder that is really all around us all the time. So, how are we going to shake off the anesthetic?

We can't actually go to another planet, but fortunately we do not need to. Because we can go to regions of our own planet which are so unfamiliar that it almost might be another planet.
This is another planet. This is Jupiter. It’s a fantasy picture of Jupiter, conceived by the astronomer Carl Sagan, and he is imagining life forms that might live in the upper atmosphere of Jupiter, called "floaters". If there were life forms on Jupiter, they would be called Jovians. So let's use word Byjovians for creatures on this Earth that are so odd that they might almost be from another planet.

Here, for instance, is a deep sea fish. You would have to go on a long journey in a submarine in a diving suit, to see that fish. This is exactly the same species of fish. The only difference is that this has just had a meal and that hasn’t, that one is looking for a meal, as you can tell from its ravening jaws. These creatures look pretty monstrous to us. I suppose by their standards we might be thought monstrous.
This one is another deep sea fish, this has a luminous lure made by bacteria, luminous bacteria, and it uses it as a bait to lure prey into its vicinity and then slams its fishing rod down in the vicinity of its jaws, opens them and gulps in the prey. A very weird, Byjovian creature.

We don't even have to go to the deep sea, as a matter of fact, to see pretty weird creatures. I was once attending a lecture by a colleague who worked on octopuses, and he said the fascination with the octopuses is that these are the Martians. And he meant that, look at this, this creature could easily be from Mars, couldn't it? Watch the color charge; that creature, that cuttlefish – it’s not an octopus, it’s a cuttlefish – is changing color at will. Look at the waves of color falling over it. That’s not shadows falling over it from the outside. That’s internally controlled by the animal, by its own nervous system. It's registering emotion, signalling to other creatures, others of its own species. Byjovian creature.

We don't even have to go to the sea at all. These are all insects; they all have the same basic insect body plan, which they inherited from a common insect ancestor, which lived about 350 million years ago. They all look like insects, because they’ve inherited those attributes. They all have a head, a thorax, an abdomen, and, in this case, it’s enormously elongated, to look like a stick.

Here, the same body is flattened out in this bug, again the head, thorax, abdomen, three pairs of legs, antannae, wings. Here, butterflies – the same basic body plan, pulled and stretched, needed into different shapes. But, basically, the same shape. They’ve never quite shaken off their ancestral influence.
But, we were talking about shaking off our anesthetic of soporific familiarity. And, another way to achieve the illusion of waking up on a distant planet is to shrink ourselves, to go on a different kind of journey, to a much smaller scale than we’re used to.

This is a dust mite. It's the sort of thing that you’ve met often in the carpets of your own home, but didn't know it. It is hugely magnified by an instrument like this, which is a scanning electron microscope. And we can use the scanning electron microscope just as though it was a telescope pointing at some distant planet, so strange are the sights it shows us.
I think we have a volunteer there to work the electron microscope. Now, your name is?
Louise.
Do sit down, Louise. Now, on the screen at the moment we have what looks like a jungle, we can think of this as a jungle on another planet. Now, you know how to work the joystick and navigate around, you also know how to zoom out and in. What about zooming out, and seeing what this jungle really is?

Okay, let's go slowly, now. There are some curious rounded objects there. Go further. Two little patches of rounded objects. Go further. Go on. Right, now, I think what we’re seeing is the head of a mosquito. There are the compound eyes, lots of different facets of the compound eyes on either side. In the middle are the sockets of the antennae. Zoom out further. And again. And there’s the whole head; you can see the whole round head with sockets for the antennae and the rounded compound eyes, with all the different facets. Now, perhaps we could navigate to a different insect.
Yes, the machine has been pre-programmed to move to a different part of this strange landscape. And I hope we are going to see something else in a minute, what’s this here?

Looks like another jungle. So let's move around and explore what we think it is.
I can't see anything yet. Wait a minute, let's zoom out a bit, and see whether we can see better then. Again. Again. Oh, that’s looking like something. I think that’s a pair of wings, off to the left side, isn't it? So, I think that might be the thorax of an insect of some sort. Let's try moving that way and see what we see. Other way. And speed it up a little bit. That's right. Oh, that is the abdomen of a bee, I would think. Go on. More. Now, what’s that? There’s something curious poking out. Try to steer around so that’s in the middle. Other way. And then down a bit. Now zoom into it. Keep… I’ll keep steering, shall I? Right, zoom in. You need a bit of focus, I think. Can we do that? It looks to me like a head of something else. Zoom out again.

What that is, as a matter of fact, is a tiny parasite. Thank you very much indeed, Louise.
It’s a tiny insect parasite called a Strepsipteran, which is parasiting a bee, and what you saw was the Strepsipteran poking out below the armor plating of the bee, there. There’s its compound eyes, there’s its body, and that is one armor plate of the bee.
So we have been on a journey using the scanning electron microscope to the world of the very small, and that’s another way of capturing the strangeness of our own world. Yet another way is to go into our own bodies and look at the detailed structure of our own bodies.

For example, this is a picture of a human brain. And each of these black things is one brain cell. You can see how many they are – there are only a tiny fracture stained to be seen here – and the bewildering forest of interconnections between them. The total length of nerve cells in a human brain, if laid end-to-end, would stretch right round the circumference of the world; not just once, but 25 times. Well, that’s not in itself a very interesting fact – for one thing, if you actually did that, and you sent a message from one end of this vast, great nerve to the other – it would take about 6 years to get to the other end of the nerve.

What’s truly impressive about the nervous system is not the sheer number of elements but their connectedness. The complexity of the connections is truly awesome. Here is just 4 or 3 nerve cells and these are the connections between them. There are about 2000 wires connecting each nerve cell to each other nerve cell. So the total number of connections in the brain must be about 200 million million. To put that into perspective: if we assume that each of these connections is equivalent to one switching unit of a computer, this gives the brain about 10 million times as many switching elements as a typical desktop computer.

Brains are impressive because of the number and connections of their cells, but there are lots of other different kind of cells in the body, and they all have the same basic structure inside. This is a typical animal cell; a model of a typical animal cell, and it’s not just a bag of juice. It’s filled with membranes, it has got a structure, an internal structure. Each of these blue things here is a membrane. And every cell has them, in large amounts, such that the total area of membrane inside a typical human body is about 200 acres, that’s a good-sized farm. What are they all doing? Well, they are not just sort of stuffing or folded wadding. Those membranes, in many cases, are chemical factories – particularly the ones in these bodies, called mitochondria. The orange ones here.

They are made of membrane, and in those membranes, in every bit of those membranes, is going on chemistry. They are chemical factories. This here is a map of the chemical reactions in every cell. Mindbogglingly complicated, stupefyingly complicated. Every one of these arrows is one chemical reaction. Yet all of that, all of that is going on all the time inside the membranes of every mitochondrion in every cell in you. And, the number of mitochondria in which that is going on, all the time, is such that if you laid all your mitochondria end to end they would go round the world not once, not 25 times, but 2000 times.

In the nucleus of the cell, right in the center, is the DNA. The DNA, the magic molecule, the molecule of life, the most important molecule in the world. That molecule conveys the information from generation-to-generation about how to build a body. The total amount of information is such that, if you were to eat a steak, if you eat a steak, every time you do it your teeth are mangling, are shredding the equivalent of a billion copies of the Encyclopedia Britannica. That’s the kind of destructive work you can do with your teeth!

Haemoglobin is the molecule that carries oxygen in the blood; you can see it, the shape of it is complicated, it is very complicated. And what’s remarkable about it is that the same shape is going on all the time in all the different molecules. You can think of a hemoglobin molecule as rather like a truck for carrying oxygen. Each hemoglobin molecule drives around carrying oxygen from one part of the body to another. It’s a vehicle for carrying oxygen. But, I have just got six little trucks here. What's remarkable about hemoglobin is that the number of them in your bloodstream is not just six, it is six thousand million million million. And they’re are all very complicated, they all look like that, they all look exactly the same as each other. And they are all being destroyed and new ones being created, all the time in your blood, at a rate of 400 million million every second.

Another way to shake off the anesthetic of familiarity, another way to experience something a little bit like going to another planet, is to go on another kind of journey - backwards in time on our own planet. The best way to do this would be in a time machine, but even Bryson Gore and the Royal Institution can't lay on a time machine for us, so we have to use fossils.
One of the most difficult things to grasp about fossils like this Trilobite here, is how old they are. You can have no conception how old that animal is. In case that sounds patronising, let me rephrase it. I can have no conception how old it is. I can tell you in words how old it is: it’s about 500 million years old, perhaps a bit more. But to tell you in words and really to understand what that means, is another matter. Our brains have evolved to comprehend the timescales of our own lifetimes. We can understand seconds, minutes, days, weeks, years - even centuries we can understand.

When we come to millennia, thousands of years, our spines start to tingle. Epic myths, like Homer's Odyssey, tales of the Greek gods, Zeus and Apollo and the others, the Jewish heroes, Moses and Joshua and their god Yahwe, the ancient Egyptians and the Sun god, Raa, these all give us an eerie feeling of immense age. We feel that we are peering back into the mists of antiquity. Yet, on the time scale of this fossil, those mists of antiquity don't even count as yesterday.
This is a cuneiform tablet from Mesopotamia, somewhere around the 7th century BC. It's – let me see, my cuneiform’s a bit rusty – yes, this is a legal document on the sale of some land near Ninive. Yes, that's right.

This, here, is another thing that gives one the same feeling. This is a bronze age warrior's mask which was dug up in the last century by a famous 19th century archeologist, Schliemann. And he said: "1 have gazed upon the face of Agamemnon". As a matter of fact, it wasn’t the face of Agamemnon, but he thought it was. And, to him, that was his way of being awed, awed at the immense age of it. He was feeling himself going back through those mists of antiquity.
Let's try to get a feel how old things really are, and then try to fit our Trilobite onto the same scale.

I am going to take one pace to represent 1000 years, and I’m going to start at the time of the first Christmas. So, this little broach here dates from the time of the first Christmas, 0 BC. If I take one pace I am back at 1000 BC, about the time of the tablet that we have just been looking at, about the time of King David. Another pace, 2000 BC and this bronze age axe head. Another pace, 3000 BC, about the time just before the building of Egyptian pyramids. Another pace, this piece of pottery, 4000 BC, about the time when archbishop Usher calculated the beginning of the world and Adam and Eve. But we’ve hardly started yet. We’ve a long way to go.

Walking from one side of the green bench to the other, we’ve gone to 4000 BC. This is Homo Habilis. She, or someone very like her, is our direct ancestor. She lived 2 million years ago. To get back to her time, you would need, on the same scale of pacing, to go about 2 kilometers. Quite a long way. Now, we’ve got some more ancestral portraits, and I’m going to call them up in order. So, will the person who is standing, who’s sitting behind Australopithecus, the first one, please, stand up.

Thank you. That’s Australopithecus. He is probably a direct ancestor of this one. He lived about 3 million years ago. So we’d have to walk 3 kilometers to get to his time. Now the next person, please. Thank you. That’s Ramapithecus, that would be possibly an ancestor, not just of us, but also of all the great apes, and he is about 14 kilometers away on our scale. The next one, please. Thank you. That’s an early primate, and to get to that one, you would have to walk to about Hemel Hempstead to get to the age of that creature. The next one, please. An early mammal, about Luton, that distance. The next one. An insectivore, with a little millipede in its jaws. Maybe, Newport Pagnell. The next one, please. That's an early mammalianlike reptile, and its distance is about Manchester. The next one. An amphibian… Middlesborough. And the next. Right, that’s a fish, just coming out of the water; just leaving the water, and coming to the land. And, its distance is about Carlisle. And I’ve left… do sit down, now, thank you very much. Those are all your ancestors.

This one is the oldest of all we’ve got here, it's about the same age as the Trilobite that we started with; they might have met. This is Pikaia, and in order to find its age you would have to slog it out all the way from here to Glasgow.
And, remember that our perception of historical time, back to the mists of antiquity, is a couple of paces across this green table. And, even with Pikaia, we have not finished. Because there are lots and lots of ancestors before Pikaia. If we go back to the origin of life, to the first bacteria, we are going back three and a half thousand million years. And, in order to pace our way back to that age, we would have to march all the way from here to Moscow.
These are the sorts of ages that we have to understand, if we’re going to understand evolution, and our brains are not equipped to do so.

When we were looking at our ancestors around there, we could be misled, because it gives the idea that evolution is marching inexorably towards a climax; the climax being, of course, us.
And that’s not the way it was. Evolution was marching in thousands and millions of different directions, at once.
This, here, is not the Royal Institution's Christmas tree, it’s the tree of life and it’s a representation of a tiny, tiny fraction of the lines of evolution that there were. The origin of life is down here. This is the first 1000 million years of life here. Coming up here. Now, each of these branchpoints represent an ancestor of whatever lies up the branches from it. So, for example, these… there are the plants.

This, I should say, is definitely not to scale. I just noticed. So, nevermind that. Forget everything about scale on this tree. What is correct is the order of branching, but not the detailed distances of the branches.
So, this branch represents the plants. Those two are closer cousins of each other then they are of that one. This branch represents the primates, with a gorilla and a human, and their common ancestor is there. This branch here represents carnivores, and there’s a branch with a lion and a tiger, and their common ancestor there – which is more recent than the common ancestor of the bear and the dog – but, that’s is the common ancestor of all the carnivores.

Here, we have a zebra and a rhino, not to scale, and you can see that they are more closely related to one other, than either of them is to these cloven-hooved animals: the bison, the sheep, and the goat. The sheep and the goat have the very recent common ancestor, they’re cousins. The bison has a slightly older common ancestor.
Here, we have two insects, a fly and a grasshopper, and they have an ancestor there. And then, they share an ancestor with the spiders a little bit earlier on.
This is a tiny fraction of the number of animals and plants that there should be on this tree. This tree should have some 10 or 20 million twigs around there.

And, the ancestors of all these animals are in the middle of the tree, going inwards like that. So all the ancestral portraits that we have just seen around there, they would be laid out along there. What we’re looking at here are all modern animals.
All those animals are cousins of one another and they’re cousins of us. These hamsters here are also cousins of us. Everything that’s alive today is a cousin of us. These fish are our cousins, this elephant, these elephants - by the way extinct elephants - are our cousins, this swift is our cousin. We know that they are all our cousins because we know that they all have the same DNA code. The DNA code of all living things alive today is the same. And, that is too improbable to have come about unless we have an ancestor. We’re all descend from one remote ancestor which lived probably between 3-4 thousand million years ago, and we are all, herefore, cousins.

If we ever meet life from another planet, the creatures from there will not be our cousins. They would have evolved entirely independently. They won’t have DNA, it would be my guess. However, I would be prepared to say that they are likely to have quite a lot in common with us, simply because there’s a lot of similar problems to be solved in living. And those problems are likely to be the same all over the Universe. So, although they won’t have DNA, they’ll have something very similar in function. It’ll do something very like DNA,and it’ll work in a similar way to DNA. I’d also be prepared to put my shirt on the bet that they will have evolved by the way equivalent of Darwinian Natural Selection.

If we’re ever visited by life forms from another planet, they will certainly have evolved the power to think and do science. Otherwise, they couldn't have got here. And their science is bound to be essentially the same as our science. This is because the principles of physics and chemistry are the same all over the Universe. They’ll have the same values of the constants - of constant pi as we have, they will have Pythagorean theorem, they will have relativity, although they won't attribute it to Einstein.

They’ll probably find us pretty childish, but they will be quite kind about our science. They’ll pat us on the head and say, "Well, what you know about Universe is pretty much correct. You got at lot to learn yet, but you are doing fine. Keep it up." That's what they would say if they were talking to our scientists. What if they were talking to our best lawyers or literary critics or theologians? I doubt if they’d be so impressed. They might be… their anthropologists, the equivalent of their anthropologists might be interested in us, but they would be bound to notice that our cultural beliefs are very local and parochial; not just by their standards, their universal standards, where they certainly would be, but even by our own standards. Because what people believe on our planet depends so much on whereabouts on the planet they happen to be born, which is a fairly odd thing.
The Adam and Eve myth is believed by a lot of people in certain parts of the world, but if you go to the other parts of the world you will find them believing very different myths.

This is a Hindu myth which is also very beautiful and there are other Hindu myths as well. This is another Hindu myth of churning the milk of the ocean with a churn. Gods and demons churning an axle with a turtle on the bottom, and out of the ocean came - as butter comes out of milk - came all living creatures. These creation myths are very beautiful, but they’re all different from one another, and they can't all be true.
And it’s very odd if people believe simply what the other people in their country happen to believe, just because they are in that country.

Look how scientists handle their disagreements now. Take a particular disagreement: why did dinosaurs go extinct? There are various theories. This is a theory that a comet or meteorite hit the Earth, and caused a catastrophe that drove dinosaurs extinct. And a lot of scientists believe that. A lot of scientists, on the other hand, believe that a virus killed the dinosaurs. And another lot of scientists believe that the mammals arose and ate the dinosaurs eggs. I’ve no doubt that there is something going for all those theories. But, the point is that different scientists believe them, and the reason why they disagree is that there isn't enough evidence yet. Everybody knows, everybody agrees about what sort of evidence would be needed in order to make them change their mind.

But, suppose science worked like creation myths, or like languages. Here we have a map of world's languages. In this red area English is spoken. There Spanish is spoken, there Russian is spoken. And it’s quite natural that you should be able to plot a map like that; that people should speak the language of their country. But what if scientific theories were like that? What if we had the similar map of the distribution of scientific theories?
Suppose, in the red area, everyone believed the meteor theory of the dinosaurs’ extinction. in that area everybody believed the virus theory, and in that area everybody believed the mammals-eating-the-eggs theory. Wouldn't that be a pretty silly sort of science?

Imagine the scene: two scientists arguing, and one of them says, "I believe the dinosaurs went extinct because a comet hit the Earth. Why do I believe that? Because that is what my father and grandfather believed, and that's what people in my country have always believed." "But I believe that it was a virus that drove the dinosaurs extinct. Why do I believe that? Because my father and grandfather believed it, and that's what people in my country have always believed."
Or, suppose the conversation went like this: "nevermind the evidence, I just know that a comet struck the Earth because it was privately revealed to me that a comet struck the Earth." "And I just know that it was a virus because I just know it, because I just know it, because I have faith that it was a virus."
If you overheard conversation like that you would think they were pretty odd scientists, wouldn't you? You’d have seen no reason to believe any of them.

Growing up in the Universe partly means evolving from simple to complicated, inefficient to efficient, brainless to brainy. But it also means growing out from parochial and superstitious views of the Universe. Going up to a proper scientific understanding of the Universe, based upon evidence, public argument, rather than authority or tradition or private revelation. Growing up means trying to understand how the Universe works, not copping out with supernatural ideas that only seem to explain things but actually explain nothing. You might say: "can you really afford to be snooty about the supernatural? After all, many of us have probably had uncanny experience, like telepathy. We, perhaps, dreamt about somebody whom we hadn't thought of for years, and then, the very next day, we had a letter from them, and we think, what an amazing coincidence! There must be something supernatural. It seems so spooky."

That is the supernatural explanation. What would a natural explanation of an event like that be? Well, what we have got to do is to come to a proper assessment of how likely it would have been that this could have happened anyway by sheer luck?

And, there are ways of doing it. And we can run a very simple experiment here, on a very small scale. We are going to do it by tossing pennies. It may be that, somewhere in this audience, is somebody who is psychic and is capable of willing a penny to come down heads or tails. A what we have got to do is to identify that psychic individual. So, Bryson is going to toss a penny, and I want, I’m going to ask everybody on this side, let's forget about the gallery because I can't see them up there. Everybody on this side of me here, is to will it to come down heads. Really think of it coming down heads. Try to make it to come down heads: we’ll try to see whether the psychic individual is on that side. Or, on this side, everybody should will it to come down tails. Okay, so, off we go.

Tails, right. So if we’ve got a psychic individual, it must be on this side. Now, will everybody this side, please, stand up. We’re going to try to do this by elimination. Now, everybody on this side of the aisle, will it to come heads, everybody on this side of the aisle, will it to come down heads.

Heads. Sit down, please. Stay standing up. Now, we have got a bit of a problem here. Let's say, everyone from behind the row that was holding up the portraits of ancestors should will it to come down heads, and everyone from the ancestral portraits downwards - tails. Tails. Right. The back rows then, sit down, please. Right, now we’re narrowing it down. How many tosses have we done? Three? Right. Now, one, two, three, four… let's say the back two rows of those standing, will it to be heads, and the remainder, tails.

Tails. Back two rows, sit down, please. Right, now, 1, 2, 3, 4, 5, 6… okay, we we’ll make it simple. From that row heads and front two rows, tails.

Tails. Back row, sit down. Right. Back row heads, front row tails.
Tails. Right, let’s say, from Coca Cola to the left, heads, and the other one ,tails. Heads - down, please. No, Coca Cola, stand.

Right. Heads, tails? Heads. Heads. Right. Well done.
I do not know how many tosses that was, but congratulations. Let us suppose that it was eight. It was, was it? Right. Now, what’s your name?

Donny.
Johnny? Yes, well… Donny? Now the question is; is he psychic?

He managed to get it right eight times in a row, and that’s very impressive. But, of course, there is absolutely no evidence whatever that he’s psychic. He did, indeed, think about heads and tails and they did come down the right way. But if you think about how we set the experiment up, with successive divisions, he could have thought about ham and eggs, and it would have given the same result! It had to come out, because of the number of people here. It had to come out that somebody was, apparently, psychic. Now ,we have only got a few hundred people in this room. But, if you think about doing this with a million people or two million people, we could have gone on tossing pennies for a very long time, and in the end of that time, we’d have got a very impressive result.

Now, when people write into the papers with uncanny experiences, it’s just like that, because the circulation of a tabloid newspaper is up in the million, and if only one of them has to write in then you can see exactly what happens. There’s got to be somebody out there having an uncanny experience at this very moment, which means absolutely nothing.
So whenever you hear a story about uncanny, spooky, telepathic experiences think about this experiment and think about how likely it would be to come about anyway. Put your trust in the scientific method, put your faith in scientific method. There’s nothing wrong with having faith… I’m going to move Faraday out of the way. There’s nothing wrong with having a faith in a proper scientific prediction.

This is a heavy cannon ball. I'm going to stand here, and I’m going to release it, and it’s going to come… it’s going to go over there, and it is coming roaring back towards me. And all my instincts are going to tell me to ‘run for it’. But, I have enough faith in the scientific method to know that it is going to stop just about an inch short, or perhaps less, of my head. So here goes.

I felt the wind of it! The Nobel Prize winning scientist Sir Peter Medawar, in a joint book written jointly with his wife, wrote the following:
"Only human beings guide their behavior by a knowledge of what happened before they were born and a preconception of what may happen after they are dead. Thus, only humans find their way by light that illuminates more than the patch of ground they stand on."

Well, that’s all for today. In the next lecture, I shall be turning to the problem of design, and the difference between genuinely designed things, like that electron microscope, and apparently designed things, that are not really designed, like this elephant and like this swift. Thank you very much.


Episode 2: Designed and Designoid Objects

Today's lecture is about the problem of design. So, the obvious place to begin, isn't it, 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’s pure luck that’s just produced by Physics alone.

That’s 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 stuck up together, in the way that they – quote – "want to do".
It’s is a different kind of crystal, a desert rose. Almost looks as if it might be made by jeweller.

But, all these objects are fortuitous. None of them is designed. All the stones belong in a 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’re ready to look at some objects that really are designed. This microscope, nobody could possibly mistake that for an object that 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’s not much doubt that they’re designed. They are shaped in a way that you wouldn’t normally expect a stone on the beach to be shaped.

This one’s a bit more doubtful. Experts tell us, archeologists tell us, that that is a designed object, that some primitive people did indeed shape that for a purpose, and I'm prepared to believe them. But that’s a slightly more difficult case.
Nevermind 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 than the microscope, but it works very well in 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 the 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.

If 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’s not a designed object. It is a simple object, which just happened to be.

So, we’ve 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’ll 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.

Thank you. Now, this is Andrew, isn't it? And what's the snake called?
Squeeze.

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. And, 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…
All right.

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’s a great gaping maw, which is capable then of swallowing very much larger prey than you would 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 among 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, is. 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’ve seen a designed pot, and we’ve seen a simple, accidental pot. Now, here’s a designoid pot. This is a pitcher plant. Here you see the individual pitchers. There’s an enlargement. They’re filled with water, and they’re 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’re going to see… There’s the full pitcher. There’s a fly climbing up it. There’s 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’s 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 the amount of water that it holds over the weight of the plant material itself, we’d find that it is a very efficient pot, indeed. But, we’d also find that, if we look 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’s more interesting is that this internal structure is very well fitted to make a lot of oxygen and secret it into the water of the pitcher. And this has a very useful effect, because, in the water of the pitcher, are living a lot of motley crew of little maggots and other insects. Now, what are they doing? Well, it’s all very well eating insects, like a pitcher plant does, but a plant doesn't have any teeth, and it’s difficult to eat insects, if you haven't got teeth.

So, what the pitcher plant in effect does, in effect, is to borrow the teeth of these maggots in its pitcher. 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’s another sort of pot, a designoid pot. This is made by a trapdoor spider, you can 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 comb, more like this honey comb here. The potter wasp female builds a pot like that out of mud, and lays her egg 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 the potter wasp's pot, but it 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 the bee's predators, the predators who might come and eat larvae out of the pot, would never have… would never know, in a million years, that there were any pots under there.
Here’s another beautiful example of designoid architecture.

These gigantic megaliths, like Avebury or Stonehenge, are built by the compass termite of Australia. They’re huge structures, like blocks of flats – certainly, on termite 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, which means that they don't heat up too much, which is why all these termite nests, they’re called compass termites, you can always, when you are in the desert, tell which direction is north-south by looking for a compass termites nest.

Even larger is this other… another kind of termite 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 then the structures that we would built 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’re switching now from objects which are apparently designed by animals to the design of animals themselves; the apparent design of animals themselves. And I’m beginning with camouflage.

If you are walking through the desert, you would probably think, to a 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 then, the next example. This looks to me exactly like seaweed, it’s one of my favorite of all designoid objects. It is, in fact, a fish; it’s a seahorse. There’s its head, there’s its neck, there’s its body. And these objects sticking out here are part of the fish's body, but anybody would think that they were parts of a seaweed. They are looking exactly like parts of a seaweed, and the seahorse hides among seaweed of just the right type. It’s almost perfectly camouflaged.

And we have a few more examples. This is a film of… and you’ll see what it is in a moment, it’s, in fact, 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’s another… 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 splodges of dark-coloured mould on the leaves. But those are not leaves. Those are butterflies. Look, there 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 it looks 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 colouration.

Camouflaged animals resemble inedible objects. Designoid objects sometimes resemble other designoid objects, for other reasons. Because they’re 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 just 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’s why it has the same shape as a dog.
Okay, perhaps you could take it now, Bryson. Thank you.

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, of course, the size of a skull would depend on how big the dog is anyway, 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. A 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’re doing the same job.
Two aeroplanes closely resemble one another not because of industrial espionage, not because of imitation, but because the wind tunnel is a great leveller of differences. These planes have both been designed for the same purpose, and, when you design airplanes for the same purpose of flying very fast through the 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 retina; in the camera, it is a film.

There are detail resemblances, as well. Both of them have an iris diaphragm: 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 says ‘when it goes brighter, close down the hole; when it goes darker, open up the hole’. And, the human eye also has an automatic light meter.

Now, I wonder whether we could have a volunteer to…
Right. In the front row there. Yes. Right.
What’s your name?
Gillian.
Gillian. Now, would you like to take your glasses off, Gillian? Thank you. And, come and sit down here, please.
Now, what you do, please, is look into the camera there, and they’re 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. Do you see it? I think it's best perhaps to look into the eye that I'm actually shining the light into. Not, 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.
Okay, well 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 are designed. I call them designoid, and I ask you to accept this different title.

But it’s 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 the 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.

Quite 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 kinds of food purposes. There’s 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 is 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’d never think they were the members of the same species, but they all, in fact, come from the same species, a wolf.

Now, how do we get… 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 will tell you very, very briefly what it is. You start with your ancestor, the wolf. And I’m 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. And, those are the ones that you breed from, and, on this side, you breed from the larger ones.

Now, it’s 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 wolfs. 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 different puppies, cubs, eventually, you may end up with something like what I hope it 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 and Wilf are Chihuahuas. Jemima’s a smooth-haired Chihuahua. Wilf is a rough-haired Chihuahua and both of them, comparatively recently, are descended from a wild wolf.
What’s its name? Sequin; is it a girl or a boy? It’s a girl.

This is Sequin, who’s a German shepherd, and, I think we could say, that Sequin is the one who most resembles the ancestral wolf.
And this is? Archie.
Archie, that's a fine name. Archie, a great Dane, and here’s what you get from breeding for larger and larger size, but they’re 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’s 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.

Now, 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’s 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 shortfaced tumbler pigeon. You see the extraordinary short face and the tiny, small beak. And that, again, is a product of artificial selection, just like in the case of the dogs and the cabbages.

The beak is so short, in the case of English shortfaced tumbler, that 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. If you… you probably know that the bulldog breed of dog has a head that’s 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, bulldogs would go extinct.

Now, Artificial Selection, the process that produces these dogs, and 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. And, 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’s got legs up instead of down. And, the way you breed anthromorphs…

Could I have a volunteer to…?
My goodness. Right. Yes, thank you.
Have you ever used a computer with a mouse?
Yes.
Yes, okay. What you do, then, is you choose the one you want to breed from, and just click it once. So, he’s 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. Lawrence seems to be breeding for longer legs, so I wonder if he’s 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’re getting longer and longer. Okay. Now, 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’re not made of DNA, but, nevertheless, they are genes in the sense that they are what goes through from generation-to-generation.

There’s 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’re seeing now, what Lawrence is doing, is Artificial Selection, just like our ancestors did with dogs and pigeons. But, he’s 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 lots of zigzags in the legs, are you?
All right. Perhaps we’d better proceed now, so thank you very much indeed, Lawrence.
Well, I hope, 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’ve seen it happening before our eyes in the computer arthromorphs.

But this’s just Artificial Selection. We only begun talking about artificial selection because we are 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 individuals shall live, which individuals 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 is 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 that they’ve got to catch.

Perhaps we could 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.

Now, there is a spider in the middle of its web and that, I think, shows quite nicely. Good.

Now, we know what the spider web is for: it’s for catching flies and other prey. It’s a net, and the… it works in two dimensions. It's… we would have liked to actually shown you a spider building its web but this one seems to be pretty satisfied with the web it’s already got. So what I am going to do instead is to show you a computer reconstruction of a spider's movements while it builds a web.
Now, you have to 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 is doing the structural spiral. It is a kind of scaffolding. And now it’s doing the sticky spiral, which is the bit that actually does the business of catching the flies. Let's have it once more, slowly. Right.

Right, there are the radii, now it's doing the scaffolding, and now it’s doing the real sticky spiral.

What we have seen there is not actually a picture of a web itself. That is a picture of the movements of a spider that were recorded on a particular day. That is a particular spider on a particular day. Its movements 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.

Now, in order to do our trick of making an arthromorphlike 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, I’m glad to say, 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.

Now, 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 build by the daughter spiders. Now, to begin with we can treat this just as if it was an arthromorphs program. So we want another volunteer, let's have a girl this time. Right. 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.

Here now. That web has gone up to the top there. That now becomes a parent. And, here are the daughter webs that are being grown. 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 was 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’re 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 cost is the amount of silk used by the webs made of silk. So the cost of the web is the amount of silk used, and the benefit is the flies.

Now, if you’d 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, when Peter gets it started up again and…

Right, so now we’ve got a new generation of webs being built, and we’re 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 is that one that has gone dark. So that one will now become the parent of a next generation.
And now, once again, the webs being build, the child's webs are being build. 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. Now, 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 we started the beginning of the night's run and, 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 flies just wheezing straight through, and not getting caught. But then, Natural Selection in the computer led to a gradual improvement in the web, more and more spirals, 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. They’d 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 are choosing the webs for breeding. They don't particularly want to fly into the webs, but, nevertheles,s 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 creatures. 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’.
And, 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 got a designer. But, I have spent the other half of the lecture showing you that there is 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 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 a 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 the form of random genetic mutation, 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’ve 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.

Now, anybody who was going to design a flatfish wouldn't do it that way. You’d do it like a skate, which is another… a kind of shark, which is also a flatfish. And it flattened itself, its ancestor flattened itself, by going onto 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 crystal, 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 don’t have to start with a complicated thing, like a creator.
On this simple foundation are build 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 "design" 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.

Genes are selected which influence the bodies of the ovenbird and the wasps, and particularly the nervous systems, which influence the building behaviour.

The birds and the wasps have no idea of why 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 are 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 that, he claims, is better than the ones 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, and I want to illustrate this with another computer program called "Biomorphs".
So, can we have a volunteer to run the Biomorphs…

Oh, dear, dear, dear… Right. Yes, please.
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’s 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’re 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’re 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, 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 object comes 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.

Episode 3: Climbing Mount Improbable

This is a stick insect. It may look fairy conspicuous on my hand, although I have made an effort to make it feel at home on my shirt, but you have to see it in its natural surrounding in order to see it at its best. There, it would blend in almost totally. The attention to details is astonishing. You can even see little marks suggesting bark on its back.

You could almost say that it fits its environment like a key fits a lock. And I've got something else under my hat.

This is a different kind of stick insect, a leaf insect. It mainly resembles leaves, dead leaves. You see how it rocks like that. I suspect that it's got a second line of defense which is that when it's startled and when a bird might almost have got it, it then, I suspect, mimics a scorpion. You see how the tail has looped over the back there. If I saw that I might be momentarily startled, thinking that it was a scorpion.

Let's put these away. I will get that one… And I would call for a volunteer who is not frightened of stick insects. There we are.

Thank you very much.

Bryson and I are always doing double act like this.

Here is a couple of more…

There is a branch of a tree. Seems to be moving. There goes its head.

It's a bird. It flies off. A [missing word].

Those are rose thorns. That is not a rose thorn. It's a bug. It gains protection by looking like a rose thorn. You could almost say that it is like a key that fits into the brain of a bird and the bird mistakes it for a thorn. So bird has a rose thorn shape lock. If that sounds a little bit mysterious I hope I will explain it in a moment. Because I'm going to use the analogy of a lock and key. Wherever we see an apparently well designed animal or plant, it's as if Nature has the lock and the creature has the key.

The thing about a lock and key is that the key has an intricate structure which is very hard to imitate and that structure exactly fits the lock. This key fits precisely into the lock and the holes in the key fit the teeth in the lock. And the lock therefore opens. Just any old bit of bent wire won't do. It has to be the right key.

The principle of a lock and key is that there is something intrinsically improbable in the shape of the key. You need that key to open the lock. In the case of an ordinary lock you open with a key it is not easy to measure how improbable the key is. But here is a combination lock, an ordinary bicycle lock. Here we know exactly how improbable it is because there are three dials and each one has six positions. That means that there are six times six time six possibilities, which is 216. There is a 1 in 216 chance of opening it by luck.

And here is a model of the same combination lock so we can see how it works.

You have to get all three of the dials into position. This one’s combination is 6, 5, 1 and the lock opens. All three of the teeth have to be lined up. It isn't enough just to have one of them.

But the lock is just a parable. Let's get back to real life. If the thorn bug is a key, what this means is that just any old shape won't do. It must be the exact shape of a rose thorn. A stick insect must be exact the shape of a stick. An upper tooth must fit, bite snuggly against lower teeth in your jaw.

Yet the theory of evolution says that all these things evolved gradually, stage by stage. This means that they must have gone through intermediates, when they were not a perfect key fitting a lock.

The thorn bug must have been half like a thorn, the stick insect must have been half like a stick. But whoever heard of a key that only half fitted a lock? A key either fits a lock or it doesn't.

So how do real living creatures managed to evolve their perfection? How do they manage to survive the intermediate stages? How do they work when they are only half a key?

Well, let's approach the problem by going back to the combination lock. While I have been talking Bryson has been discretely doctoring his lock so it would behave in a different way.

If you could imagine a lock where instead of having to get all the dials in place at once… Supposing I was trying to crack a safe and there was money in there. As it is I can't do it because I have got to get all the dials in place at once and I have only got a 1 in 216 chance of doing that. In a real bank safe it would be one in billions. I can't do it. But suppose that I were able to try the first one at random and eventually find out how to open that. And then the safe door peeps open a little bit, a little bit of money drops out. I've done that one, now I can go on to the next one. And I find out how to open that one, I have only got 1 in 6 chance, that's fine. And a little bit more money spills out. And now the final wheel, I have only got 1 in 6 chance, that's easy and I open the entire safe.

It's now become a gradualistic combination lock, where before it was an all or nothing combination lock.

With this lock the maximum number of tries that you need in order to open it by luck is not 216 but a mere 18. So it is easy to open a gradualistic combination lock and I call this "smearing out the luck". Because we do not have to get our luck all in one ridiculously large dollop. Instead we can get our luck in drips and drops.

Each drip being allowed to come before the next drop and we go on to wait for the next bit of luck. It cumulates.

So, what have we seen so far? Although an animal may look like a key fitting a lock it's not a totally good analogy because in this case half a key is better than no key. If nature is a combination lock, it's a gradualistic combination lock, not an all or nothing one.

Now let's look at the same thing from another direction. It's been said that a monkey typing at random on a typewriter could eventually write the complete works of Shakespeare. I once did this experiment with my then 11-month-old daughter, Juliet, and this is what she typed. I let her go for a bit… And so on and so on. I realized after a bit that I would have to let her go on for at least a billion years before she got even a single phrase of Shakespeare.

The eminent astronomer, Sir Fred Hoyle, has pointed out that it is just about as unlikely that any complex living structure could spring into existence suddenly, by luck alone. He said: “It is rather like taking a junkyard and letting a hurricane blow through it and the hurricane has the luck to spontaneously assemble a Boeing 747”.

So here is our the junkyard, and the hurricane comes along, it's blowing like this. Hoyle's point is that the luck that would be necessary to spontaneously assemble a Boeing 747 like that is equivalent to the luck that you need in order to get something like an eye or a stick insect or hemoglobin molecule by sheer luck.

My reason for mentioning Hoyle's 747 is that I'm going to take his name in vain in the next demonstration.

We are going to have a computer monkey or rather we are going to have two computer monkeys, one called Hoyle and the other called Darwin. Both monkeys have the same task. Both have to type, not the complete works of Shakespeare, but one phrase from As You Like It: "More giddy in my desires than a monkey".

Hoyle types entirely at random. After every line that he types the computer checks to see if he has managed to hit the target line. If he does, the computer will stop, bells will ring, it will be the most improbable coincidence in the history of the world and I solemnly promise to eat my hat.

I would go further than that. I bet you everything I possess that it won't reach the phrase, shall we say, in the next 10 billion years.

I won't bet you. I will undertake to give everything I possess to the Royal Institution and here is the legal document signed by me which undertakes to make over everything I own to the Royal Institution in the event that the monkey Hoyle reaches the target phrase. But, of course, this is just to illustrate my confidence that chance on its own could never make an eye or a 747.

The real point of the demonstration is that the other monkey, Darwin, will get the target phrase. So what does Darwin do?

The same, but with a crucial difference. The Darwin monkey begins by typing a random phrase. So far the same as the Hoyle monkey. But now the computer breeds from that phrase. It breeds 50 offspring which are identical to the first phrase but with a tiny mutation, a tiny random difference in each of the 50 cases. The computer then looks at those 50 offspring and chooses the one which most resembles the target phrase, however slightly it resembles the target phrase.

So the generations go by and, generation after generation, it gradually becomes more and more like the target phrase.

Now, when I agreed to give these lectures I was told that I should always call members of the audience out to assist. But I was also told that it was silly to do this if all I was going to ask them to do was to come out and hit the return button on a computer. However, on this particular occasion, since so much is at stake, I thought it would be better if I did ask somebody who knows a lot about computers and is very good at pressing buttons, to come out and perform this onerous task. So, if anybody would like to volunteer…

Yes, right. Now, what's your name?

Andrew.

Well, you understand what's at stake, Andrew, do you? OK. Here is the target phrase, "More giddy in my desires than a monkey". There is the box where the Hoyle monkey is going to type. And there is the box where the Darwin monkey is going to type. Unless Bryson has been messing about with the program in order to deprive me of my worldly goods that is the way it is going to be. So, are you ready? Go!

Now you see the Hoyle monkey typing away entirely at random. The Darwin monkey is down here and I think we can begin to see something appearing in the Darwin's row.

"More giddy in my desires then the…

Bang. And he has got there. How long did that take? Anybody timed it? Not very long, I think. Andrew, thank you very much.

So I don't have to eat my hat and my worldly goods, such as they are, are safe. But the point really is not that Hoyle failed to reach the target. The point is that Darwin did reach the target and astonishingly quickly.

Well, there is a lot wrong with that as a demonstration of Darwinian natural selection. For one thing, it has a distant target in mind, which natural selection does not have. But it does, once again, show the key to the way out of the problem of mammoth improbability. Things like eyes and 747s that couldn't possibly spring into existence in a single, lucky shake of a dice, can come into existence if the luck is smeared out in many tiny steps and it is accumulated.

That is what this lecture is about: smearing out the luck, accumulating it, turned out to be an immensely important process. It is the process that makes it possible for us to be here, and by "us" I mean all stick insects, lions, elephants and bacteria, everything that is here.

And now let's look at a physical parable for this gradualistic solution to difficult problem.

This is a mountain. It's called Mount Improbable. Sitting on the top of the mountain is equivalent to being very well designed, to being an eye that works well, for example. Being at the bottom of the mountain is equivalent to being a distant ancestor that is not yet very well designed, that haven't yet acquired its good fitness to the environment.

Looking… facing you now is a precipice, a cliff which is called Sheer Luck. It is a sheer cliff. Jumping from the bottom of the cliff to the top corresponds to assembling a 747 by means of a hurricane or it corresponds to getting a complete eye in a single lucky mutation. It can't be done, you could no more do that than a mountaineer could leap from the bottom of a cliff to the top. But this isn't the only route up Mount Improbable. We have to go round the other side.

And you notice that round here is a gradual, sloping path, steadily inching its way up the mountain. If you follow it round you will find that even though some bits of it are a little steep, you can get from the bottom to the top without ever having to jump up a step. It's a gradual, inch by inch, path up.

Anybody who didn't know about the Ramp Evolution, which is what that is called, would, if they saw an animal perched on the top, a beautifully designed animal, and only saw the cliff, they would assume that it had to be the result of a miracle. But in fact the only way up Mount Improbable is the slow, gradual climb up the Ramp Evolution. You have to add all the little steps up together and after a very large number of steps you can climb very, very high indeed.

But we are still talking in parables. How in practice do living things climb Mount Improbable?

Well, of course, individuals don't climb it. It's lineages, groups of animals, species, that climb it, and they do it in evolutionary time. They and their descendants, and their descendants' descendants, they do it by going through an extremely large number of generations and we do have the time for an extremely large number of generations, because we have geological time at our disposal.

This generation by generation accumulation works only if there is reproduction with true heredity to carry the message through. And I must explain what that means, because just plain reproduction without heredity won't do, it's not enough.

It's possible to imagine reproduction without heredity. Fires, for example, have a form of reproduction without heredity.

If you imagine that this is a savanna, a dry savanna, the dry grass all over it. And a fire suddenly starts in one place. Sparks fly up and are carried in the wind and suddenly a spark lands there and a new fire starts. Both these fires are now flaming up and sparks again off, and another fire starts up which may be the daughter of this one. One starts up here which may be the daughter of that one. These fires are propagating, these fires are having children. The sparks are causing this fire to be the parent of that one, and in the next one we can see that you can have both, not mother and daughter, but grandmother, grandchildren fires.

Now, the fires might differ a bit. In this picture we've represented them by red, green and blue. Fires may, indeed, differ. But they get their qualities not from their parents and grandparents. A fire gets its qualities from its surroundings, from its environment. A fire gets its qualities from the direction of the wind, where it happens to be, or from the chemistry of the soil or from the dampness of the vegetation. Fires do not get their qualities from the spark that comes from their parent fire.

Now we are going to do the same thing with a Bryson special. And I'm going to stand well back. Where am I going to stand? Here? Right. We always have to have fireworks at the Royal Institution, so go ahead, Bryson, please.

Right. There is the first fire, there is the parent, but the sparks are flying up. It started another one there. That's the daughter fire. And a granddaughter, and a second daughter of this one.

But the point is that to the extent that there are any differences between these fires, they do not get their qualities from their parents. There are sparks that flow from fire to fire but all the sparks do though is to start a new fire. Nothing is carried in the spark. There is no information carried in the spark.

And this, of course, this is where rabbits and humans and stick insects differ from fires. Don't be misled by the way, by the fact that rabbits and humans have a mother and a father. Stick insects only have a mother, like fires. In this particular respect stick insects are like fires. But in the important respect that I'm talking about, stick insects do not resemble fires. Because, unlike fires, stick insects have true heredity. At least some of their qualities: color, shape, eye, [missing word] and so on, they actually get from their mother, not only from their surroundings. Something travels from mother to daughter, something in the spark that travels from mother to daughter - there is information.

So what is this mysterious information that eggs contain and sparks don't?

Well, it is DNA. This astounding molecule which contains in the sequence of its bases all the information, or almost all the information that you need to build a stick insect or a rabbit.

DNA comes like an ever-flowing river down the generations. The river of DNA that flows through us into the future is a pure river that leaves us exactly as it finds us. With one exception.

There are occasional, very occasional, random changes called mutations. Because of these there is variation, genetic variation in a population. And that opens the way for natural selection. Those varieties of DNA that just happen to be good at building ancestors, at building bodies that have good eyes, good legs, good anything else, survive. So the world automatically becomes filled with good DNA. This mean good at making bodies that are themselves good at surviving.

This is the Darwinian explanation for why living things are so good at doing what they do. They are good because of the accumulated wisdom of their ancestors. But it is not wisdom that they have learned. It's wisdom that they chanced upon by luck, lucky random mutations, which were subsequently selected.

And in each generation the amount of luck was very small. But because the luck has been accumulated over so many generations we are impressed by the end product.

I want to apply this lesson to three particular cases, three particular problems that have given difficulty: the eye, the wing and camouflage. And I choose them because they are famously regarded as difficult.

First the eye. Charles Darwin himself said: "To this day the eye makes me shudder". Creationists are particularly fond of the eye because they like saying, "What is the use of half an eye?” An eye only works, they say, if every little detail is in place. Until you got that, the eye won't see anything at all. So how could it possibly have evolved?

And even serious scientists have sometimes queried whether there has been enough time for the evolution of the eye.

Suppose we start with an ancestor who didn't really have an eye at all but just a single, simple sheet of light-sensitive cells. That is represented by this screen here and there is a television camera behind, looking at the screen, and that we on the screen, on the television screen, shall see what this primitive animal would see.

So this animal with hardly any eye at all would at least be able to tell the difference between light and dark. Light and dark.

Now, the next stage in evolution would be to have a shallow cup. This animal would be able to tell the direction that light is coming from, because there a shadow would appear. A shadow would appear there. And if you can tell the direction a light is coming from, then you can tell the direction a predator is coming from.

Now, although we represented this as a cup coming out from the wall it would, in fact, probably be an indentation and it would be a gradual indentation. It's inconvenient to make a gradual indentation. It has to be made as a rather abrupt cup that comes out six inches at a time. But it is easy to see that that shadow effect that we have just been witnessing would work progressively and gradually as the cup gets bigger. Let's make it bigger still now, Bryson.

And this cup is even more effective and if we go on to the next stage when we make the cup gradually bigger again, so big that it becomes just a little hole in the end.

Like now. This animal has a very good idea of exactly where the light is and by the same token exactly where, for example, a predator is. And I think with this eye we might even get a little image. See if we can get an image of Bryson's hand. That smudge there is Bryson's hand and you can just about see a very dim image of his fingers.

So an animal with an eye like this would be able to see perhaps just little bit what kind of predator it was.

Let's go to the logical conclusion which will be a pinhole. Remember, it's all gradual, gradual change in evolution.

Now, let's see if we can see your hand again, Bryson. Now I can see a rather precise picture of Bryson's hand. It's not a very bright one but I can see every finger clearly delimited. So I could see, if I were this animal, I could see my predator in some detail.

There is an animal that has a pinhole camera for an eye. It's a mollusk called Nautilus. It's a relative of the octopus but it lives in a shell and there is its eye. It just has a simple hole and sea water can flow in and out of that hole. Here is the shell of Nautilus.

This bit of rock here shows ammonites which are, an now extinct, relative of Nautilus. They were once immensely common, as this rock suggests.

I like to think of all those hundred million-years-old dramas that must have been witnessed through the pinhole camera eyes of ammonites. We can't be sure they had pinhole camera eyes but it seems quite likely.

Now, pinhole camera is not a very good way of seeing. It does produce a sharp image but because it's so narrow you hardly get any light in. The answer to this problem is that ingenious device: the lens.

Nautilus has a pretty poor eye compared to its relatives, the squids and octopuses, because they do have a lens. And so we can't help wondering why doesn't Nautilus have a lens? Why didn't it evolve a lens?

Well, I suspect that Nautilus may have got itself stuck on a little peak, some way up Mount Improbable. You see, that although we have got one big peak there, there are various other peaks on the way. There are quite a lot of them. And since the rule in evolution is just to keep going uphill, when the ancestors of Nautilus came up the track here, up the path here and got to this point, that way uphill looked just as inviting, so to speak, evolutionary, as that way. Both of them were uphill. Evolution has no foresight, evolution has no way of knowing that if you travel up that way you are going to end up with a lens. For the moment this appears to be a perfectly good way to travel because the pinhole camera at this level of illumination is an effective eye.

So I wonder whether perhaps Nautilus has got itself trapped on top of this little hillock and is now unable to escape. Because escaping would mean going downhill into the valley and the one thing you cannot do on Mount Improbable is ever go downhill.

But let's imagine what the ancestors of the squid and octopus did when they got to this junction point here. They just happen to go on up this way. And they started evolving a lens and [missing word] at a different time in history.

How might the lens have evolved? Let's imagine that it started with just a single, transparent sheet of some transparent material. And all this was doing, it's not a lens yet, all that it's doing is protecting the eye. In Nautilus sea water flows right inside the eye. This animal now has some protection. And the eye is really just the same as though there wasn't any transparent material there.

Now we are going to use an optician set of lenses here. It would be nice to be able to have just one bit of transparent material which we would then squeeze and make thicker, but we can't do that. So we are going to replicate that effect by a whole series of little lenses.

So this is the next stage in evolution. This animal here… let's get an image of that. That's a rather better and, above all, brighter image of the hand.

Let's have the next lens in.

Right, now. If an animal had an eye like that it would have a really very, very clear view of its world. It could tell exactly what its predator was. Would anybody like to come out and have their face looked at?

Right, yes.

What is your name?

Say again?

Deleena [?].

Deleena [?]. Do you remember where Bryson put his hand? Can you put your face just down there? We need the lights down for this, I think, for this, don't we?

There we are. Very nice. This animal can even see what's its predator's face looks like. Upside down. But we all see upside down. Thank you very much, Deleena [?].

So we have a gradual pathway all the way up Mount Improbable, from no eye to an eye.

But has there been enough time for the evolution of the eye? Recently a Swedish scientist called Dan Nilsson has tried to answer that question. He did pretty much the same as we have just been doing here, but he did it with a computer. So, instead of going up big steps as we had to do with our wooden model, he was able to do it in very small steps on his computer, in fact, very small steps indeed. Deliberately he assumed that each step, which means each mutation, caused only a 1% change in the size of something, like, say, the steepness of a cup. He also devised a way of measuring the efficiency of an eye. He did this by telling the computer to measure various things about the eye that it just had [missing word] itself. And then the computer worked out, using the rules of physics, how good an image that eye would be capable of producing. And the question was, with those rules built into it, would there be a small gradient of improvement, starting out with a flat retina and ending with the proper eye, like ours. And you have guessed it, the answer is yes. This was Nilsson's staring point, with just a flat retina under a flat, transparent layer.

And now let's just run the simulation of… these are successive stages that Nilsson got and they are pretty similar to the successive stages that Bryson got with his model.

So, so far we haven't learnt anything that we didn't already know. There is a smooth progression up Mount Improbable for the eye. But Nilsson went on to estimate how many generations it would take to accomplish this evolution.

In order to do this he had to make some more detailed assumptions. I won't bother you with exactly what they were. All you need to know is that they were quantities which geneticists out in the field can measure and have measured.

And Nilsson put into his computer model values of these quantities that were conservative. Conservative means that he was erring on the side of deliberately biasing his calculation to make it slow. To give it an estimate on the slow side of evolution. Make evolution come out slower than it might otherwise have done.

But in spite of this, in spite of his being conservative and in spite of assuming that each mutation could only cause a 1% change, which is another conservative assumption, Nilsson found that the evolution of the eye, which we have just seen, would take a surprisingly short time. It would take about 250,000 thousand generations.

Well, that might sound like quite a lot of generations but we have a rather warped perspective. Because, after all, each one of us is only good for one generation. But our human perspective is not the one that matters. One that matters is the geological time scale. And on the geological time scale 250,000 generations is next to nothing. Probably only about a quarter of a million years since the animals we were talking about would probably have a generation time of about a year. And a quarter of a million years is really too short for geologists to even measure. It's like trying to count seconds using the hour hand of your watch.

So there really was no need for Darwin to shudder. Half an eye is better than no eye. Half an eye is better than 49% of an eye, 1% of an eye is better than no eye at all.

And far from there not being enough time for the evolution of the eye, the evolution of the eye is so quick and easy that it must have happened many, many times over. Eyes can evolve at a drop of a hat. And in fact, if we look around the animal kingdom, there are lots of different kinds of eyes dotted around. Each of them is different, many of them work on completely different principles and they have evolved quite independently of each other, many times over.

This is the shell of a scallop, a kind of shellfish. These things are not pearls, they are eyes. And they are very different kind of eye from anything we have seen and anything that we normally think about. Those eyes are reflector eyes. They have mirrors instead of lenses. Each one of these is a little curved mirror which works like the Jodrell Bank telescope. It forms an image in a way that a reflecting telescope does, not in the way our eyes do.

This is a compound eye of an insect. Each one of these little facets is one little eye and the whole assembly together is interpreted by the brain to make one big image.

Next eye. Next one.

These headlights belong to a spider. Once again, this is entirely independent evolution of the eye. It has nothing to do with the other eyes we have seen.

And next. And finally, an eye of a squid. This is the skin of a squid, there is its eye. The squid has a very excellent eye. They are like ours, with the proper lens, proper camera principle. But you can tell by looking at the details of it, especially how it develops, that it evolved entirely independently of ours. The same principle was hit upon entirely independently of ours.

Once again, remember, that each step is a small piece of random luck. As such, each step is not particularly impressive, in fact, it better not be impressive, because if it was, it would be a miracle and we no longer have a true explanation. The whole point of evolution is that it gets us up Mount Improbable without miracles.

Now I want to welcome two magnificent pinnacles of evolution on different peaks of Mount Improbable.

This is an imperial eagle and this is an eagle owl.

Look at the eagle first. It's a superb machine for catching prey. Its eyes are more acute than anything that we can offer. We have no idea of acuity of vision like the eagle has. Its claws are capable of gripping in such a way that it's almost impossible, once they've gripped you, to get them off. They have a ratchet mechanism inside so that the bone just catches and the eagle can hardly be prised off your hand.

Look at the beak. Superb instrument for tearing up its prey.

The owl is sitting upon a different pinnacle of Mount Improbable. It has good eyes but they are used in a very dim light and it relies more upon its ears. It has asymmetrical ears which enable it to localize its prey with pinpoint accuracy in total and complete darkness.

Its wings are very different from the eagle's wings and they are shaped so that they make it fly very quietly at night. It is a stern fighter.

Both these birds, in addition to having beautiful eyes and ears, have superb wings which brings us to our next topic.

Could we see some wings, do you think? Is it possible to … look at those wings.

Does the owl, did it itself [?]? Lovely. Beautiful. Thank you very, very much indeed.

Let's see some film of wings in action. This is a hawk. And watch the way it controls the sh