In Our Time - Lamarck and Natural Selection

Episode Date: December 24, 2003

Melvyn Bragg discusses Jean-Baptiste Lamarck, the 18th century French scientist.Charles Darwin defined Natural Selection in On the Origin of Species, “Variations, however slight and from whatever cause proceeding, if they be in any degree profitable to the individuals of a species… will tend to the preservation of such individuals, and will generally be inherited by the offspring”. It was a simple idea that had instant recognition, “How extremely stupid not to have thought of that!” said T H Huxley. However, Darwin did not invent the idea of evolution and not everyone saw his ideas as original. The great geologist Charles Lyell repeatedly referred to “Lamarck’s theory as modified by Darwin”, Darwin complained to him, “I believe this way of putting the case is very injurious to its acceptance”. He desperately wanted to escape the shadow of this genuine scientific precursor and what has become known as the ‘Lamarckian Heresy’ has maintained a ghostly presence on the fringes of biology to this day.Who was Lamarck? How did Natural Selection escape from his shadow and gain acceptance from the scientific establishment? And has any evidence emerged that might challenge the elegant simplicity of Darwin’s big idea?With Sandy Knapp, Senior Botanist at the Natural History Museum, Steve Jones, Professor of Genetics in the Galton Laboratory at University College London and author of Almost Like a Whale: The Origin of Species Updated; Simon Conway Morris, Professor of Evolutionary Paleobiology at Cambridge University.

This BBC podcast is supported by ads outside the UK. Thanks for downloading the In Our Time podcast. For more details about In Our Time and for our terms of use, please go to BBC.co.com.uk forward slash radio 4. I hope you enjoy the programme. Hello, Charles Darwin defined natural selection in On the Origin of Species. Variations, however, slight and from whatever course proceeding, if they be in any degree profitable to the individuals of a species,

will tend to the preservation of such individual. and will generally be inherited by the offspring. It was a simple idea that had instant recognition. How extremely stupid not to have thought of that, said T.H. Huxley. However, Darwin didn't invent the idea of evolution, and not everyone saw his ideas as original. The great geologist, Charles Lyle, repeatedly referred to Lamarck's theory as modified by Darwin.

Darwin complained to him, I believe this way of putting the case, is very injurious to its acceptance. He desperately wanted to escape the shadow of this genuine scientist, precursor, and what's become known as the Lamarck in heresy has maintained a ghostly presence on the fringes of biology to this day. Who was Lamarck? How did natural selection escape from his shadow and gain acceptance from the scientific

establishment? And has any evidence emerged that might challenge the elegant simplicity of Darwin's big idea? With me to discuss natural selection is Steve Jones, Professor of Genetics in the Golden at University College London, an author of many books including Almost Like a Whale, the origin of species updated. Sandy Knapp, senior botanist at the Natural History Museum, and Simon Conway Morris, Professor of Evolutionary Paleobiology at Cambridge University.

Sandy Nap, can you tell us about Lamarck, French botanist born in the middle of the 18th century, and then? And then? Lamarck is one of the really enigmatic and interesting characters in the history of science because he was born the 11th son of a minor aristocrat in France and started out a career in the army

and turned out to have been dropped on his head and then had to go in convales and turned himself into a botanist. He worked at what was to become the National Natural History Museum in Paris and managed to survive the revolution and become made the director of what became known as invertebrate zoology

after the French Revolution. Now this was not a very prestigious post because the really prestigious things went to people who studied vertebrates and all those really nice furry things and birds. but Lamarck became director of insects and worms. And he's the one who coined the term invertebrates, which we use now to describe animals without backbones.

And what was his theory of evolution, and how did he arrive at it? He had... Evolution was in the air around that time. The idea of evolutionist change was very important, and it wasn't necessarily a new idea. And Lamarck wasn't necessarily the first one to articulate it. About that time, we're talking about around 1800. Yeah, 1800.

Between 1770s and 1800, about the cusp of the 19th century, essentially. he had two basic principles. All of life could be arranged in a scale, in a big line, from the most simple to the most complex, and that what life was doing was increasingly becoming more complex, he called that perfect. So his idea of complexity equaled perfectability. And that was what he felt was the driving force behind organic change.

He also, and this is the thing that Lamarck's really known for, is he articulated a principle which he called the use and disqual, use of characters. And that's what Lamarck is known for rather than the rest of his great big zoological philosophy book. Can you give us some examples of use and disuse of characters and explain why it's important? Okay. One of the reasons that Lamarck was actually discounted during his own time was because he was

staunchly materialistic. He did not believe that there needed to be any outside power or driving force other than life itself, driving change in life. So he was branded as a materialist and was vilified to a certain extent after his death because of that. But what his use and disuse of characters meant was he articulated it using, interestingly, in his zoological philosophy, he uses lots of botanical examples. He said, imagine if a seed of a particular plant were to fall in a rocky place, and the ones that survived would be smaller and perhaps have different flowers and fruits.

And generation after generation, then there would be a different kind of plant which occurred in that area than there would be an other place. for use and disuse, if a mole is underground all the time, it doesn't need its eyes, so its eyes go. They atrophy to a certain extent. And I think the example that everyone uses for Lamarck, which actually isn't one of the examples he used, except in passing, is that if a giraffe is in the African savannah and the food is all up at the tops of the trees,

the giraffe stretches its neck, its neck, and then the caricature of Lamarckian use and disuse of characters goes, that in one generation, that slightly longer neck will be passed on to the offspring. So we have Lamarck going towards simple to complex towards the idea of perfect. And we have Lamarck talking about acquired characteristics which become inherited. These are the two things that are... Those are two of the important things. There's anything else that's very important before we move on.

The other really interesting thing about Lamarck is he didn't believe in extinction. So what he felt was that this scale of simple to complex was regenerated by spontaneous generation down at the bottom all the time, that there was spontaneous generation occurring the whole time and that new unicellular organisms kept arising independently over and over and over again. Okay, that'll do for the start. Thank you very much. Steve Jones, why was he so vilified at his death and after his death?

Well, he has, of course, being French, being greatly misunderstood and misquoted. Darwin clearly didn't like him, and he didn't like him because of the inheritance of acquired character. because if in fact if you read Darwin on inheritance, Darwin got it wrong too in a rather confusing way and believed or seemed to believe in the inheritance of acquired characters. Darwin didn't like him because he was an optimist. Lamarck was an optimist,

and Darwin was deeply pessimistic, as any good scientist ought to be, because he saw somehow this life force that things could only get better. Lamarck? Le mark, yeah. Things don't necessarily get better. If you look back through the 3.5,000 million years of life, you can see that it's wrong.

There have been plenty of occasions. where life has in large proportion gone extinct. Things have got simpler, things have got, if you can use the word, worse. So they're not only in your view, they've not only not got better, but they've not got more necessarily got more complicated. Biologist to argue about that. Darwin was pretty stringent about it. He said he used a phrase something like, never say higher nor lower.

The notion of evolution as an escalator. Things are bound to improve was alien to Darwin. Steve Gould was very insistent on the fact that that was literally true, when for most of life, life has been nearly all bacteria. Well, life still is nearly all bacteria. There is froth on the bacteria, which is what we are, but that's a detail. So I think you're probably going a bit too far to say that things have not got any more complicated since they began. But the notion that somehow there's this great chain of being with the French Academy at the top, I think that's what really annoyed Darwin, and I think Darwin was

right to be annoyed. So he was annoyed with Lamarck, and yet he used the use and disuse idea to explain the progression or the development, didn't he? He used the disuse idea rather than like a drowning man grasping a life belt because he didn't really have very much. Darwin had been written to by a flenty Scottish engineer called Fleming Jenkins who pointed out after 1859 a fatal error in Darwin's notion which is that on the notion of blending inheritance that the mixing of the bloods which Darwin had held for much of his life,

then evolution wouldn't work. It's famously like mixing red and yellow paint. You get purple. You can't get red or yellow back again. Things kind of average. So Darwin was really thrashing around, looking for a mechanism whereby natural selection could transmit its products to the next generation. And use and disuse, he mentions in passing as a possibility.

But he certainly didn't dislike Lamarck but because of use and disuse. disliked him because he was an optimist. Can you just say how natural selection opposed Lamarckian ideas, and in what way? Just outline briefly natural selection and why it challenges what's fundamentally Lamarckism. Well, I think fundamental difference is that natural selection is blind and Lamarckism has a vision. That's the big difference.

The mechanical difference is that natural selection is nothing more than a series of inherited and successful mistakes. inherited differences in the ability to copy genes. That's what selection is. And that's probably the best idea anybody has ever had in biology because it gives a unifying mechanism which joins together all kinds of apparently disparate observations in biology. But Darwin himself wasn't as sure of it as you are now, was he?

He didn't have enough information to firm it up. And he leaned out for Lamar once or twice, though, didn't it? Oh, yeah. I mean, the origin is a very odd book. it's one of those rather strange books, which is much better in its first edition than in its sixth, which was the last one. The first one, you can see being written with urgency and passion.

And now and again, he puts in brackets, I have tons more information on this. If only I could put it in, and you think, thank God you didn't. It's long enough already. But then in later editions, people wrote to him and pointed out what seemed to be flaws,

and he was constantly on the defensive. And the irony is that most of those flaws, including the inheritance floor, including the age of the earth floor, they weren't wrong at all. Science had not advanced far enough for those things to be incorporated into evolutionary theory. Simon Conway Morris,

the physical mechanism for narrating characteristics through natural selection is called pangenesis. Can you outline that for us? Well, in principle, pan genesis is simply the idea that there are corpuscles which somehow, and Darwin couldn't articulate us very clearly, could carry the information in the blood

from presumably the reproductive cells and then be carried on to the next generation. And as Steve has pointed out, the difficulty with this, of course, is it led to this inevitable blending. There was no way in which the particulate information, which, of course, we now call genes, could be taken from generation in any comprehensible way. And, I mean, I should say with regard to Lamarck,

I think the fascinating thing about him is that he was so very nearly right and so massively wrong. And, of course, this is something which intrigues, I think, many scientists, because we can see other examples, for instance, within relativity, where at that time people are sort of just on the point of finding what we think we like to call the truth. Though I've noticed in passing, I like Steve's notion of things like foam and mistake.

Of course, all of us have these particular vocabulary which we like to employ to describe our science, and of course you begin to analyse those a bit more. Now, I should say also with regards to Lamarck, I think he deserves enormous credit, partly because he took the environment seriously, and we're still really not quite sure to be an ice age, yes. a kilometre of ice on top of you is hardly a selective advantage,

but when it gets very cold, does that really make a difference? We're not quite sure. He sort of saw the environment as an active moulding, almost purposeful object. And second, I think, which is very important, is in the way that Darwin, I think it's fair to say dithered about the connection between us, humans, and the rest of biology, the rest of evolution.

He had no doubt at all that we know, they're the monkeys, patently like us, we must be related. And this is something which Darwin, for very, various reasons, sort of dodged, I think. And actually was, I wouldn't go so far as to say dishonest. That would be a very wrong term. But nevertheless, was perhaps a little evasive.

So there is. Reticent. When you stand on this notion of Lamarck's idea of moving towards a sort of perfection, certainly a greater complexity, but Sandy also used the word perfection, and that has a sort of theological resonance about it. Is it because Lamarck was brought up in

at that time, that was 18th century still, he himself come a theological background, or did he carry those Judaic Christian ideas around with him, or what? And what do you make of that? Well, it's a very complicated question, because, of course, Darwin himself was, for many years, a creationist. And only later did he dawn on him in a sense that this couldn't possibly hold. I think it's probably fair to say that all scientists carry ideologies with them,

and it's almost impossible not to superimpose on the way you see life evolving some sense of your own place within that system. And, of course, the trick of the scientist is, often with desperate difficulties, to actually stand back and decide what is, you know, objective, whatever that means, versus, you know, as you say, perhaps a Judeo-Christian tradition or other sorts of things. I think, you know, the general sense of the thing is, I think part of the problem is, imagine going back to 18th century France. You have a time apparently of stability.

Then you have this extraordinary revolution, which Le Mark actually coasted through, in a sense. Of course, you compare him for the fate of Lavoisier, the discover of oxygen, it was guillotined. And then he rins into an area where British power is beginning to grow. He runs into another Frenchman called Cuvier, who was incredibly competent, and I think in many ways incredibly unpleasant person, but a genius in certain respects. And then this other young man is up in Cambridge briefly,

goes off for the Royal Navy, comes back five years later with an idea about some finches from islands off South America, and the rest is history. But Simon, I mean, I think it's very important to remember that LeMarc was almost 100 years before Darwin, They didn't overlap. They aren't the same generation.

They never co-occurred. And I think one of our problems with dealing with Lamarck and why Lamarck becomes almost heretical is because we think of him in the same breath as we think of Darwin. And he's not. He's a generation earlier. But I think it's quite important whether or not he had a religious or theological view on his... Did he have an influence on Darwin?

Did Darwin read Lamarck and say, I have learned something from that? I mean, Darwin says in the origin, Lamarck was the first man whose conclusions on the subject, that's evolution, excited much attention. He first did the eminent service of a rousing attention to the probability of all changes in the organic world being the result of law and not of miraculous interposition.

Well, that's pretty generous. I mean, I think he sort of admits that he had the idea. But of course, lots of people have the idea. There's a whole industry that sort of digs the lint out of Darwin's naval and says, oh, look, we find this idea of natural selection in a book about marine timber that was. written 30 or 40 years before. I think it was in the air. It was in the air. But he came up with a mechanism and that, you know, might have failed,

but that's the thing which drove before. Then went into a decline, came back again, was abused, came back again. And now with the genetic theories, seems to be broadly right, Sandy. Well, I think it's quite... Lamarck basically said that things were going towards the more complex, but there was a competing factor, which was that things were becoming more disorganized. So he saw the whole direction of things as a tension between complexity and destruction to a certain extent. And I think he didn't think of things having a direction in terms of sort of theology or from worse to better. He saw it purely materialistically as from very simple to very complex. And as I understand it, from then on, his ideas were derided, left behind, but they keep looping back.

And we'll try to keep them looping back through this conversation. But move on now to the natural selection notion. And the rocket hit, which was the blending idea, Steve, which you touch. done earlier. If you can push into that a bit more, we'll take it on from that. Well, Dom was a great believer in the notion that nature doesn't make leaps. And he was a gradualist of extreme view. Every piece of progress took place very slowly. And there's a certain element of truth, or strong elements of truth, in what he says. And the problem was, under those circumstances, as we discussed,

if you're blending your parental abilities each generation, a small improvement in your mother, let's say, is going to be halved in yourself because it's blended with your father who hasn't improved. And so these things will just dilute away. And the irony is that when genetics was finally re-established in about 1901, then people swung quite the other way. They saw these gene mutations,

which were large and changed the number of the eye-coloured of fruit flies, let's say. And they said, oh, well, Darwinism, all this slow change is quite wrong. It's evolution by jerks, not by creeps. It's huge changes we can see. And it took a long time to reconcile those two. And I'm not to be convinced. I'm not to be fair. I'm not convinced that actually genetics and evolution are yet completely reconciled.

What would you say to that, son? No, I don't think they're completely reconciled by any. any margin indeed, in fact, and because, of course, one can do spectacular experiments where a gene is put in an inappropriate place and either the organism dies or it sprouts, eyes, all over its body and things like that. But the really deep connections as to how it is

that these corpuscles of information, which we now call DNA, are then translated in, for instance, a group of biped sitting around a table chatting in a way which they can understand each other. As soon as you step back, I think, goodness, how on earth is all this happening? Yes, each one has a mechanism. You can understand the genes. If I knock out atonal, I can't hear.

If I knock out Pax 6, another gene I can't see. But on the other hand, there's many other lines of evidence suggest the way the embryology folds. Yeah. Can we go back to just take this idea of blending to the next stage, how it was uncoupled when William Bateson discovered the work of Mendel and what Mendel had done and what Bateson did with the discovery, Simon? Well, what Bateson did was effectively read a paper. on the way to London from Cambridge on the train.

And presumably the train took slightly longer than it does these days and he's able to understand that in this paper there was, through the work of Mendel, at last a description of the genetic information. And it's a fascinating story, partly because that discovery should have been found many, many years before. It was actually recognised widely. It was published about five years after the origin of species.

And it was such an elegant piece of work. It has fell into place beautifully. And of course, Bateson was a very interesting man in his own respect, extremely pugnacious, rather sort of difficult person to deal with. And he was fascinated in evolution, partly because at last they had the mechanism of Mendel, but he was also interested in what we call variation. And he was particularly interested in the gaps which apparently separate different sorts of organisation and how it is that sometimes seemingly nature jumps across these gaps, because that is a sort of saltation. And that was something which, as Steve says, is very, very difficult to accept.

But Mendel was a monk who did. is experiments with peas, green-potted peas and yellow-potted peas, smooth peas and wrinkled peas. On this simple basis, he erected the theory which complemented, and as it were, when it was reworked by Bateson and later mathematicised by, I'm rushing on a bit now, complemented and let Darwinism give it a new cylinder. So can we just go back to the peas? Those peas are very important, first of all, because it was a tractable system which worked. Mendel subsequently tried it with other plants

and it was a disaster for all sorts of good biological reasons. Can you just say how the... Just for those who have not picked up Mendel's peas in the course of their lives, can we just do it for them now, this boxing day morning, and all will be revealed. So we open that pot of peas, we're about to cook them, and we notice that some of the pods contain peas

which have got a smooth skin, some have got a wrinkled skin. That's just a simple observation. What Mendel did, and it's quite clear that, in a sense, he knew what he was going to find. He had an idea in his mind to test before he actually went through an exhaustive series of experiments, which went on for about eight years in total. And effectively what he did is he cross-pollinated the plants,

whereby the piece of pollen, which effectively is a male, went to the female, that is the thing which will provide the fertilised seed. And then the fertilised seed develops in one direction from another, and by doing very careful experiments, he found that there was a consistency, an absolute constancy, in the ratios which produced a wrinkled seed versus the smooth seed, and indeed many other characteristics. That's the basis of genetics that you can combine things,

and added to that is the fact that sometimes one version of a gene, a thing technically called an allele, is more powerful, it's dominant, and therefore, even though the other part of the genes there are ready to work, it's always overridden by the other one. So he did these experiments, and you can get what's effective, a recessive or a dominant, or you can get a mixture. Those ratios are mathematically precise, and he understood that, I think, in advance of actually doing the work,

He knew what to find. So you could have a lot of green peas, and out of those green peas, you could get yellow peas because the yellow gene had lingered on. What Mendel really did is he just took what people had been doing for centuries, which was basically breeding plants and breeding agricultural crops, and he turned it into, he mathematicized it. He showed that the ratios,

that if you did particular crosses of one yellow ones with green ones, you would get three green ones and one yellow one. And he showed that these ratios were consistent, and I think people had noticed that you could get differences in crosses, but it's the ratios which are important for now. So when Bateson brought that to light, as it were, even though, as you say, Steve Jones, in one of your books or articles that it had been around for 3040, it just hadn't been read by people.

It was even in the Encyclopedia Britannica, as I understand it, and Darwin, who read everything, just happened not to read this. Nevertheless, when it came on track, what did it do for Darwin's view? Oh, I think it rescued it, actually. I mean, Darwin, by the end of the 19th century, had really rather faded. He was seen as not a very important figure. And in fact, that continued for some years.

But what it did was to rescue Darwin from this dilution problem. I mean, what Mendel did in this context was, I suppose Mendel was the Plato of his day. He separated the soul from the body. He separated the gene from what the gene makes. So that you have an everlasting gene, which goes on from generation to generation.

But the feeble body, the fee plant, dies. and that is the gene therefore is our link with the past and we're all living fossils we're filled with the genes of our ancestors and that's such a familiar notion to us I don't think we can really plumb the depths of Darwin's confusion it was such a shocking idea

but Mendel had it unfortunately the 19th century didn't notice how important it was but once it was noticed really I mean it took over immediately Sandy can you viceman came in on that idea too of the separation didn't he and he created what's called the Weissman Barrier.

Yes, what a Weissman did is he basically first articulated the idea that the germ cells, the things that go on, that unite, say the pollen in the egg or the sperm and the egg, were different to the rest of the cells in your body. And so he got partway to this idea that there might be a place in the body where particulate inheritance happened, but he didn't get quite all the way there. He really articulated the difference between the germ line and what we call the somatic line or the body, the cells in your body.

Simon, doesn't this seem the opposite of Lamarckism what Weissman was doing? If creating this barrier, I mean, developing what Steve is, I thought, rather graphicly called the platonic idea of the soul and the body to temperate these two sorts of cells. Oh, it was, first of all, extremely important because it means that the only part of us

which has some sort of immortality is my sperm and my wife's eggs, for example, they're the things which carry the genetic information on to anything else. But I think the difficulty is that, as Sandy said, Lamarck was a century beforehand, and he came almost out of an 18th century fronds, and his whole world picture was so radically different

from where Darwin ended up, and Darwin, I think, ended his life more or less in a sense of confusion. And then, of course, over the small irony, there's this man apparently in an obscure monarchy, not that obscure, a trained scientist, which is perhaps less widely known, Gregor Mendel, and he's the one who then takes that story forward. And I think the point about it is, from the respect of science,

it's easy to tell these stories backwards but there are many things which we can't possibly know because we don't even know the right question to ask at the moment and that's equally true from the point of view of a vice-visman he had got to a magnificent stage the separation of the germline from the somer but that's only part of the story what right question don't we don't we know to ask at the moment

I think that sentence just about gets this shall we all shall we speak some things the irony is it's the same question it's the same question that they were asking in the 19th century which is why they ignored Mendel. I mean, what Mendel did was to give a general rule. But in the 19th century, he was just working on peas. Who cares about peas?

They didn't seem to be any general rules. The 19th century was much more interested in the question, how do you get from a formless blob of cytoplasm, which is a fertilised egg? And the fertilised egg of an eel looks rather like the fertilised egg of an elephant. How do you get from these apparently identical cells to an elephant or an eel?

And that was the interesting question, and that still is the interesting question. And I think we're somewhat nearer, but I still think we're an extraordinarily long way away from knowing the answer. It seems to me that the more we find out, the more we come back to that big question, and the less we seem to know. And Simon's quite right.

You can look at this backwards and think, oh, well, Darwin was mad because he thought gemmules went from here to there. Weissman was crazy because he didn't realize, or Lamarck was considered mad in his day because he felt that the union of sperm with egg was what started off development, which was way ahead of his time. But you sort of dismissed Weissman.

No, you didn't dismiss, Simon. Anyway, I thought that Le Maherstman had it in for LeMarg, didn't you? I'm quite interested in keeping Lamarck in this conversation because it's a new figure, I suspect, to most listeners. It's quite new to myself. And lots and lots about Darwin, lots and lots about DNA, which we might get to who knows. Anyway, but this, but Weissman was determined to,

to repudiate Lamarck, and he cut off the tails of rats in order to set in motion, as he thought, a tailless rat. That was shoddy thinking, I'm afraid. I know, but it was shoddy thinking and it didn't work and so on and so. Nevertheless, he still thought, an interesting thing, he still thought Lamarck was worth all that effort. Well, yes, because I think intuitively, and I think that's another danger with trying to be a scientist,

something seems so reasonably, it seemed to make sense, And something like Lamarckism is exactly the way we'd expect the world to be. After all, we're surrounded by the environment. It's always pushing us. We have an intentionality about us. We want to get our necks longer to get those tasty leaves at the top. Why can't we do it? Why can't we transmit it to our children?

I think partly it's because as humans, there is an element of a sort of Lamarckism in our culture. It's not really Lamarckism, but we can transmit information from generation to generation and make the future generation radically different, which is not possible biologically. But Simon, I think one of the really important things about Lamarck is that he's used as a straw man

by a lot of people. And what people object to about Lamarck is the caricature of Lamarckism, which is put up. So the caricature of in one generation I can transmit my longer arm because I've sat farther away from my computer to my children. Lamarck never, ever said that.

I mean, if you look at him with rather less cloudy spectacles, I mean, I was lecturing yesterday about genetics and IQ. The average IQ, the British population, it's not immediately, I have to say, has gone up by 20 points in the last 30 years. So since you and I were young, Melvin, people are, if you believe, the test,

20% smarter than they were. I find that with young people all the time. So do you want. 20%? Now, that is on the first site, a perfectly Lamarckian thing. You know, we've put a great effort into almost accidentally making their environments much more enriched with programs like yours, and they've got much smarter as a result. And if you didn't know about DNA, that would be a purpose.

perfect example of Lamarck in inheritance. But of course, what it tells you is that DNA is just a chemical that works within an environment. And if you change the environment, the DNA will actually alter the way which it manifests itself. So I think you're right, Lamarck is a straw man and we're kicking him while he's down up to a degree. I think Simon said it at the very beginning is that the thing that Lamarck did, which I think subsequent generations up to now have ignored, is to recognize the importance of the environment, which we now recognize is very, very important. is still though in the 1920s we've got this man

Kemmerer trying to go along with Lamarckis but he did and the story of the midwife Toad which is an entertaining story and believed in by a great number of people at the time and we're talking about 1920s When I was at school we had to see a film about the midwife Toad and the Midwife Toad and the Midwif Toad is one of the great frauds and science

We better go at the start with the Midwife Toad Camer felt that Most toads breed in water. That's that far back I want to go. Most toads, most amphibians breed in water. And the midwife toad is an amphibian which does all its breeding on dry land.

And toads that breed in water have a sort of enlarged, the males have an enlarged patch on their forearms, which allows them to grab onto the female during mating and not slide off in the water. And Kamarer thought that he could put midwife toads, which, because they've read on land, had lost these

pads, or didn't have these pads, that he could put midwife toads in the water and cause them to develop these thickened pads which would allow them to mate. So he just kind of poor toads, I mean, these poor toads were thrust into these aquaria full of water and forced to mate underwater. And he maintained that he caused this to happen, that in a couple of generations he had thickened pads. Well, it was later shown that they were in fact India Inc. And that he just kind of died the toad's arms and, you know, so it was a big scientific fraud. But actually, if you think about it, the ancestors of both the aquatic breeding toads and the midwife toads were aquatic. And so knowing what we know about genetics, there is possibly genes that code for

something like that in both the midwife toad and the aquatic toad. So getting them back might not be such a surprising thing in the end. Why is this notion that what an organism passes on to its descendants is affected by experiences of life. Why is this such a hotly contested area? Well, it is. I think partly because it strays away from science into theology to a degree. I think actually,

there are great swings and roundabouts in science. It's sort of coming back. I mean, again, if you look at modern research, it's clear there's a plague of obesity around today, which we blame on change in the environment. And to some degree, that's true. In Britain, it particularly affects individuals, children whose parents come from the Asian subcontinent.

Now it transpires that in fact, because their parents were malnourished while they were pregnant when they were relatively poor, the children are much less able to deal with a very heavy, oily, rich diet. So that in some senses, again, that's Lamarckian. The experiences of the parents, nothing directly to do with biology, are being pushed on, nothing to do with genetics, are being passed on to their children. And indeed it might well be that because the children will be unhealthy as a result,

they'll be passed on to another generation for purely shared environmental reasons. But again, these are details, you know, these are cracks in the great cupillar of genetics. I mean, it does work. It's like St. Paul. St. Paul's gets a bit dirty now and again, but it stands up. And I think that's true of mentalism. And mineralism holds up, although there are certainly problems at the margin. Simon. Well, very little to add that.

I think, you know, there's a whole aspect about the way we run our lives. the way we are human, the way we think we are a product of evolution, and yet in many respects we choose the most bizarre diets. And it's often argued our craving for shellfish represents a time maybe 100,000 years ago when we first discovered this resource, and very few primates enjoy shellfish. Now, is that actually an evolutionary history?

Is it something we developed? Is there, in fact, a particular fatty protein or something in there which makes our brains bigger, which is a beautiful idea? And you can see the way these things meld together, but one's got to stand back from all this and realize that, you know, the way in which evolution works is effectively not Lamarckian. And you can bring Lamarck back,

and I think it's recurrently interesting the fact that he is, in a manner of speaking, resurrected roughly every 15 years. An experiment is performed, which is pronounced as being Lamarckian. I think the last serious ones were probably a little bit more than 15 years, but it's an idea which oddly will not go away. And, you know, as a scientist, one's slightly puzzled about this. Astronomers don't have this sort of problem.

They don't sort of think that somehow Newtonian mechanics is the answer. It's an answer, but it's an incomplete answer. And that's not true of Lamarckism. I think we find it very difficult to not understand something about ourselves. And I think that's what happens is you get to a point at which you say, okay, yes, Mendelianism works, and we can see how genes are passed from one generation to another. But then you think, well, there's this thing about us.

And we don't really quite understand that. And I can't explain it by a very simple story, which is an easy narrative to tell. And the whole idea of use and disuse and Lamarckian heritage, it's a very seductive narrative. Yeah, but we are right about us, aren't we? I mean, we're the one species which has really stepped outside the Darwinian arena.

You know, you can see it in every way. I mean, the fact that we're here, the example I often give is the case of the AIDS virus. I mean, the other primates have got HIV. It doesn't do them any harm particularly. The reason is that they've been through the crucible of the epidemic and only those with genes that allow them to survive have lived on. We're in the middle of that crucible.

But we will escape from AIDS, I hope, for entirely human reasons, with medicine, with behaviour, with common sense, with telling people what's happening, with understanding what could happen in the future. And that has nothing to do with genetics. There's nothing to do with Darwinism. So the attempt to use Darwinism to explain ourselves is, you know, it's Marx taking lessons from nature.

It's the pathetic fallacy. I mean, we have stepped beyond it. And in some ways, we are homo-lemaquius. We are the Markian. But that is just because we're us, and we're more than just a bit of DNA. But that AIDS brings in the idea of this body of knowledge entering into the body politic.

And there's an interesting example where Lamarckism was, to some extent, adopted in the Soviet Union by Lysenko, who's Stalin's chief scientific agronoma and dictated how the agricultural economy of Soviets would go and how they would study biology disastrous to both, but he took on these ideas very strongly. So it went right into one of the big empires of the 20th century

as an idea, as one of the ideas we've been talking about. Now, can you take that on a little bit more fluently than I've been going? What fertilisation is, is that if you put... This is Lysenko's idea. This was like one of... Well, it wasn't really Lysenko's idea. The idea he took up, okay. He borrowed it from somebody else.

But the idea that Lysenko... Lysenko used as the way to improve Soviet agriculture. I mean, you have to realize Lysenko was, came onto the scene at the time of collectivization, which was a time of great starvation in the Soviet Union. Terrible things happened to Soviet agriculture. And he brought forth this idea of vernalization, which means that you keep the seeds very cold. It's like keeping seeds cold and then their development speeds up. So what you would do is you would vernalize winter wheat.

So instead of planting wheat out in the autumn and letting it sit in the fields, where it can get frozen to death or trampled on by cows or any, all kinds of things happen to winter wheat. You could keep it in the cold over the winter, planted out in the spring, and have the same harvest at the end of the summer. So that was an idea. Actually, plant breeders had been using that for quite a long time.

But Lysenko brought this forth as the salvation of Soviet agriculture and basically made all kinds of mad promises that he would create new varieties of wheat by vernalization. that he would create completely new varieties of wheat, which is why we think that he had Lamarckian ideas. But in fact, Lysenko himself was not really scientifically trained. He had never read Lamarck. He'd never even read Darwin.

And the person, interestingly, that Lysenko cited when he talked about his scientific antecedents and where his science was coming from was not Lamarck, but Darwin, which is very, very strange. But just as a slight digression to this, not such a slight digression for those people involved, involved in it was that Stalin liked this idea because the hardiness of the seed represented perfectly the hardiness that he saw in the Russian people and the more they suffered

the better they would get. And this was such a coincidence, such a happy coincidence for him that he embraced it very firmly and with a death struggle really. Absolutely. I mean, Stalin saw the terrible things were happening in the Soviet Union. That happened. But this generation was going through the fire, was being vernalized as it were. And the next generation, would live in a state of bliss and perfect communism. And in fact, which we know not to be true. Yeah, which we know not to be true,

for reasons which, in Salon's view, would be biological. There aren't many famous Joneses in history, and I'm certainly not one, but there was a plant breeder in the US called Jones, who at the same, at the town of Vavilov, had a different idea involving crossing different lines of maize, growing them up, and that turned out to be fantastically productive.

And actually, many people argue, that is the reason for the economic dominance of the US, even to today. It's the triumph of American agriculture and the failure of Soviet agriculture and turned entirely on science, good science, winning over band science. I think it's also important, sorry,

I think it's important to add further that. There's this degree of viciousness about Lysenko and a way in which, you know, effectively he killed the study of genetics for all intents and purposes. It was anti-science in all reasonable ways, which is very paradoxical, given the materialist nature of the Soviet Empire.

And the worst of it is, that this whole thing was taken on board for basically entirely ideological reasons. And, of course, we know, fortunately, this could not ever possibly happen again. That is our great reassuring credo that, you know, these things are not involved with politics, and biology is this innocent science, which goes forth. Is that true? It's not true. It's not true.

I got the irony. Well, I think Lysenko is a great lesson to everyone, because Lysenko is one of science's great baddies. I mean, and he's a real baddie. And I think the most frightening thing about Lysenko is the way in which he did his quote-unquote science is he did what he called collective farm experiments. So what he would do is he would send out, he did science by questionnaire. So he would send out all these questionnaires to all these collective farms. And he'd say, how much vernalized wheat did you plant? What was the increase in harvest?

And of course, he was Stalin's man. They'd write back and say, we planted 80 percent and our harvest is up by 150 percent. It is fascinating for me sitting here listening to you three to think that a man working in a monastery garden in the last half of the 19th century and a man spotting a great deal of a strange behaviour among finches and then sitting in his own country house in later... These two people, not much later on,

are having a directly influence on the future of the Soviet Union, the future of America, the future of who feeds the world, who star. It is an extraordinary from study to, I can't think of an alliteration. Anyway. Yes, I mean, it shows the power of science, really. And the irony is, I think, if you put yourself forward by 500 years, geneticists today sitting around some circular table

in whatever succeeds at BBC will say, how did those fools around that table in 2003 come up with these ridiculous arguments? We know that their notion of genetics was completely wrong. Would they say, do you think that, well, I'm going to move on? now to DNA. Do you think they'll say that about DNA in 1953? Well, we've got a lot to be embarrassed about with DNA. I mean the big embarrassment is the discovery that

there are far fewer genes than there seems that there ought to be. I mean, the last count I went to a talk the other day was down to 21,600 and something. Now, that isn't many. That's about the same number of bits as it takes to make top of the range Mercedes with air conditioning. You need the air conditioning. Now, hold on, hold on. What do you mean?

You can't just do that, Steve. You've been doing that all... What does that mean? What does that What do you mean? Well, I mean, this is a simplistic view of having it, but if you take the old view of genes, every gene makes one product. So every gene makes one bolt or one nut or one dial. There are something over 20,000 of them.

There are something over 20,000 separate elements in an expensive car. Now, I would like to believe that we're somewhat more complicated than an expensive car. Rice plants, which seem to me rather low on life's intellectual pecking order, seem to have more genes than we do. So what conclusion do you draw from that? Well, the conclusion is... The number doesn't equal complexity, I suppose.

I think we don't understand it, is the answer. Maybe price plants are more complicated than we are. Well, indeed. It could well be. We don't understand. Perhaps this is where Lamarck was wrong, as he didn't really understand what complexity meant. Even though he struggled to actually bring it into the arena, in a way, very few people, even today, to find a way of measuring complexity is almost impossible. But, I mean, really, Steve, I mean, should we be so worried that it is a very? 20,000? I mean, I think it's an essentialist view of what is particle again, and it's given

as almost totemic, if not magic principle, whereby it makes things. Well, everybody around this table knows that, again, is not true. That's the way in which the information is stored. But everybody knows, I think, that information can be recombined in an almost infinite, you know, infinitely large number of possibilities. So where's the surprise? Yeah, but I just want to lay on you, Simon, the sort of elementary task I asked Steve to do earlier and the programme. Can you just say what DNA did, how I took the argument forward, and I asked Steve about natural selection,

can you just briefly say it, and then we can move forward? Well, DNA is a, I would argue, as others have, in one sense, is the most peculiar molecule in the universe. It's got some very, very peculiar properties. This whole chemistry is absolutely weird. You'd never predict it would form that double helix from the building blocks, but there

it is. And of course, what it does, is it just provides strings of information which can replicate, that is make an identical copy with quite incredible but fidelity and that's essential because otherwise I might come in with five years on my head instead of two or whatever else could go badly wrong and it goes badly wrong we see straight away what has gone wrong and that's where the power of genetics is you can make very small changes sometimes and lead to a disaster on the other hand how DNA actually makes us as ourselves of course

is a complicated story because it happens within the cell the information is taken out into another part of the cell it then goes to build these things called the proteins and that's really where all the action is and again the proteins in my view are some of the most peculiar molecules in a universe in their own way. You have a rather simple string of building blocks. They're called amino acids. You put them in a watery medium, and suddenly they almost crystallize.

And then they, for instance, accelerate a chemical reaction by maybe 10,000 times on the basis of a single substitution at one point in that protein. So these things are in one way precisely engineered. They're absolutely astonishing. But on the other respect, they are a product of natural selection as Darwin showed.

Yeah, I think that's right. I mean, we face huge problems, understanding what's going on. I mean, if you take the very hot topic nowadays, which is this question of how these proteins, these things are folded, the analogy which people use is exactly like taking a roll of sticky tape, unrolling it, scrunching it up, and every time you do that, you get the same scrunch pattern.

We simply do not understand how that happens. So there's a whole universe of ignorance on our part out there. It may be that genetics was the easy bit. I mean, what genetics has done, really, with the completion of the human genome project, is to complete the job that Vesalius, the Italian anatomists did when he started in the 15th century to dissect the human body.

Anatomy is now finished with a help of a few million dollars. Well, we know it took a long time from anatomy to heart transplants. 400 years. Yes, 400 years. And it might take just as long to go from genetics to gene transplants. So we're a long, long way away from understanding how the machine works

rather than just how it's made when it's at rest. And that's assuming, of course, we want to not only understand how the machine works, but want to tinker with it. So instead of having a Mercedes, I'll go back to the Morris Minor, for example. And there's a really important question, because potentially that technology is on our doorstep. And again, as Steve quite rightly said, in my opinion,

we are no longer Darwinian creatures. We've stood outside the arena. We're the people who can make the rules if we so choose. Andy. I think one of the interesting things about thinking about DNA is that when Watson and Crick first discovered or came upon or articulated, the structure of DNA is a double helix, which had a linear sequence of A's, T, Cs, and G,

the building block molecules of DNA and articulated also the one gene, one amino acid, sort of, you know, very linear and seductive narrative. It looked as though it was all going to be quite easy that what we could do is we could read the sequence of A's, T, Cs and G's,

and then we could just find the answer. The secret of life. The secret of life, exactly. And I think, again, it's, if we look back on it, we think, well, how mad were they to think that you could just read A's, T, C, and G's because we know all this about proteins.

How naive? How like Larmok? Well, exactly. And I think that at the time, the great excitement about the discovery of DNA and how it worked was that there was a mechanism for things to happen in a Darwinian way. I've been told that we use only 5% of DNA. That seemed, given how marvellous it is

and so on it said, what happens to the other night? It's called junk. Can it really be junk? It's called junk, and it might well be junk. I mean, that is really, it's hard to know what it is if it isn't junk. But you don't understand, call it junk. But there are embarrassing facts, which you're probably aware, there are certain species, a famous fish called the Fugu, which, like all fish, is effectively human under the skin.

I mean, apart from a few details, it's vertebrate just like us. That's got no junk, or almost no junk. So that fish manages without the junk, and we seem to have a whole pile of it. Other fish have a whole pile of it. So it may just be a sort of molecular tapeworm, this stuff. we've been infected by it and we have to live with it. Now that's a very unsatisfying conclusion to come to.

But it's a statement, certainly, that life hasn't been perfected. The notion that we're all full of molecular detritus is not one that Lamar could have right. We're not necessarily finely honed machines. Well, yes, again, you use the word perfection, and that's perfectly reasonable from a human context. I'm not so sure it really is junk DNA. Well, no, my. But only because I think at least the three of us are pretty well Darwinian in that thing.

and we're pretty well selectionist, and DNA is quite expensive to make, so why go to all that trouble? It should something be easily weeded out. And I think it's a fascinating possibility that actually the genome has a deeper structure to it, which, and who knows why this so-called junk DNA is doing what it's doing. And again, it's a sort of foam, a froth on the top,

all this sort of the genes, those 20,000 to make the equivalent to the Mercedes. And there may be another set of questions which we can't articulate. It's there. Everybody knows it's a problem. Somebody is going to go to Sweden and meet the king and say, well done. You've worked out junk DNA. Here is your prize. Well, in a way, you know, by saying we have this many genes and we've done the human genome and this is how many there are, implies that we won't discover anything else. And in fact, we may discover in 20 years

time that in fact there are 75,000 genes along that human genome and we just didn't recognize more than half of them. There's a curious parallel with dark space, isn't that? We suppose to know about 5% of what's really going. All the rest is supposedly black with nothing in it. And now people are saying, hold on, there's lots in it. We just haven't got around to finding out what the lots is. Perhaps 5% is... In many ways, it's the beauty of being a scientist. You know, I'm an obsessive reader of newspapers,

and every day the paper I read, and you can guess what it is, comes through the letterbox. Every day, it's effectively identical to the previous day, and yet I spend an hour reading it. And it's just the same doing science, because it never changes. Every morning, you think we didn't know that yesterday,

but we do know it today, trivial though it is. So it's a... I think, Darwin probably felt that. He was a great, you know, conglomerator of odd facts and putting them together. And I think we're just at the moment of doing that again. And going back to Bateson, he has his very famous quote, to treasure the exception. It's those things which worry us. Can I bring Lamarck back into this conversation again

with any of the raising in vibraries? Reasonally two American sciences, Rutherford and Lindquist, found that mutations in fruit flies, I'm reading this, greatly increased in certain atmospheric conditions. So if you can make evolution speed up, inherited conditions will speed up. Does this say something about natural selection? Does it challenge it in anyway, Steve? Well, it doesn't it challenges it.

It asks an interesting question. It basically asks the question is why is the mutation rate, the rate of error, what it is. Now, if you look at the chemistry of DNA, as Simon said, it's extraordinarily complicated. In fact, to a chemist, you ought to be dead. Arguably, if you're a chemist, you might as well be dead anyway. You know, the chemistry of DNA is really complicated, and it makes hundreds and thousands of mistakes, and these mistakes are fixed by enzymes, repair enzymes.

But why do they fix it at that rate? Why don't they do it perfectly, or not at all? We don't know. And what this work on Drosophila has done is to find that if you give Drosophila big heat shock, what actually happens is that it sort of destabilizes the development of the thing. Heat certainly increases the mutation rate, and it also causes various proteins not to work properly.

so all kinds of strange variants appear in the population, which might be advantageous after a heat shock. Now, that's an interesting observation. I'm not convinced it really kicks Darwin particularly hard. I'm not sure that's any different than natural selection. No, I mean, they've made rather a song and dance about it. In fact, their great mistake in that paper which you quoted was to put in at the last line,

it has not escaped our attention that, which is the famous last line of the Watson and Crick DNA paper of 1953. It has not escaped our attention that herewith we have a mechanism of replication. So really everybody jumped on that and thought, oh my goodness, another breakthrough. I'm not convinced that it is. I mean, in a broader way, I think it's fair to say that evolution won't lie down in its own way. And every generation, and Stephen Jay Gould in his own way, I think sort of pursued that with some energy, somehow feels that it's incomplete.

And yet when you go back to it, it's very difficult to see where this incompleteness is from the perspective of Darwinism. How do genes, there's a new area of research called epigenetics, and trying to show how genes lead to the development of an organism. How do they know how to develop an organism? When you say how do they know, how do we as embryologists know, well we don't in a sense. What we can do is, again, study genes which turn on, turn off. The difficulty is, as I see it,

is that now we're beginning to understand the way all the genes metaphorically talk to each other, the so-called networks. They're not complicated. They are dazzlingly complicated. And the worst of it is that sometimes a network works for one stage of the embryology in one way and then it promptly turns to another thing and then goes back to another system.

and I strongly suspect as a scientist there must be rules of engagement here and again somebody else will be going to Sweden to meet the king for another prize because once those rules of engagement are decided how it is the genes go through the embryology then there will be I think a higher order of structure of what we call and again epigenetics what on earth does that mean is a word it's stuff we don't understand well it was actually invented by one of the people who taught me the little genetics I know C. C.H. Waddington who set up this institute of epigenetics in Edinburgh

I remember the thing being built, and we all stood around saying, do you know what epigenetics is? And we all assumed that somebody knew, and I'm not sure that anybody really does. Can I go... We've redefined several times, though, epigenetics. Simon just said the effect that natural selection is always being tested and will always be tested.

What about this notion of horizontal transfer of characteristics, Sandy? That would seem to challenge natural selection. With the GM crops, for instance, can you say what horizontal transfer means and why it seems to challenge natural selection? Well, what horizontal transfer essentially means is that genes go from one organism into another. And this has happened, apparently, there's a lot of debate about whether this has happened quite a lot at the very base of the tree of life down amongst the sort of bacteria. Bacteria exchanged genes through conjugation and through coming together and then coming apart again seemingly all the time.

And whether or not lateral transfer, which is essentially genes exchanging without reproduct. And this also happens in plants. Viral DNA gets inserted into plants completely naturally, particularly in things that are polyploid. So we have a lot of crop plants, like tobacco, for example, is a polyploid, which means it's a species that is two species which have normal numbers of chromosomes come together. The chromosomes double, and you get a free-living, freely reproducing species, which just has double the number of chromosomes. And it's always been thought that viral DNA, there is viral DNA in certain. into the tobacco genome in various places. And it was always thought that that viral DNA

had become inserted in there at the time when the genome was very unstable. Because when things do polyplodization, the genome is thought to be a bit unstable. Well, it turns out, and this is work of Conrad Lichtenstein at Queen Mary, is that one of these viral inserts is in one of the parents of tobacco. And so it's not necessarily this genomic instability. So how these viral inserts... So what does that mean?

It means that in tobacco's genome, and perhaps in our own. There are bits of DNA which we haven't got from our parents necessarily. At some point in the history of the organism, DNA has come in from somewhere else. Now that doesn't mean that I haven't got,

the tobacco plant which is growing down there didn't get it from its parents, but at some point DNA came in not through inheritance. Very briefly, does this, again, does this challenge natural selection because there's one question I want to bring it before we finish with Simon. No, I think it just makes the beautiful symmetrical

oak tree of evolution, slightly more complicated, a bit more like a banyan with several trunks. So I think it's a detail which is unexpected, but again, I don't think it's a killer fact. I don't think it is either. Simon, your most recent book is called inevitable humans, and can you explain why you, going back to Lamarck at the end, really, why you think there is a direction

in human selection? I don't think there's a direction in human selection. Well, I think there's a direction in human selection and human evolution in the sense that I'm trying to argue that the various properties which make us human are things which have evolved repeatedly in different groups and therefore it would be unsurprising if something like a human evolves on most planets.

But it's equally true that many species go in exactly the opposite direction. They become extremely simple. For instance, an extraordinary animal lives in the kidneys of the octopus, and we know it came from a much more advanced animal. So evolution, in a sense, can go in all directions. But I think what does matter is that if, as I argue in my book, that such things as advanced social systems, tool, technology, warm-bloodedness, vocalisation, intelligence have evolved multiple times which they have.

Those are the species which will take over the planet and decide its future. Yes, I mean, the problem really is, I mean, evolution is a comparative science, and we haven't got any other planets to look at. And equals one. So if we had another planet to look at, then we could discuss this scientifically, and these are good ideas, but at the moment they're untestable. Sand did you, how are you on that? I think Steve is absolutely right, but it is.

and that it is n equals one. We have one earth on which to look. But I think we ought to stay away from that Lamarckian idea of advanced and perfect and complex, that more complex means more advanced, because that's not necessarily true. But the world still changes forever. Oh, yeah. Well, thank you all very much. Thanks, Steve Jones, Simon Coyne Morris, and Sandy Knapp.

And thank you very much for listening. This is the last of the present series. We'll be back at the end of January. And in our time, archives available for listening on our website. side. Thank you. We hope you've enjoyed this Radio 4 podcast. You can find hundreds of other programmes about history, science and philosophy at BBC.com.com.uk forward slash radio 4.