Gresham College Lectures

A Small History of Big Evolutionary Ideas

October 20, 2023 Gresham College
Gresham College Lectures
A Small History of Big Evolutionary Ideas
Show Notes Transcript

The theory of evolution is often described as the biggest idea in the history of humanity. But evolutionary theory itself has evolved over time, often via landmark contributions from some very unusual characters.

This lecture investigates some of the biggest ideas about evolution, as well as some of the most ill-conceived.

We’ll meet aristocrats and criminals, clergymen and dictators and consider how evolution is as much a product of history as it is of biology.

A lecture by Robin May recorded on 16 October 2023 at Barnard's Inn Hall, London

The transcript and downloadable versions of the lecture are available from the Gresham College website:

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My name's Robin May. I'm Gresham, professor of Physics. Um, and this safely mentioned is my first lecture in this series about evolution. And I am fairly sure that many of you will be listening to this thinking, why do we need another series on evolution? Uh, we have been talking about this literally for 150 years and more. Um, what can possibly be new? And, and the first thing to, to say by way of apology is that there is very little new I can teach you about evolution. I think, uh, I'm not actually an evolutionary biologist, and I'm certainly not a historian. Um, but what I hope I'm gonna get across to you tonight and in the rest of this lecture is that evolution is not just about stuff from the past. It's about things that are very relevant to our everyday life and to our lives going forwards. And my, I guess my central theme is that actually I think there are solutions to modern human problems, uh, for which evolutionary thinking can be incredibly powerful. And that even if you are someone who's completely uninterested in biology or fossils or things going extinct, actually a little bit of evolutionary biology might still be useful. Um, but tonight what I want to do really is sort of set the scene and talk a little bit about how we got here. Where did evolutionary ideas come from? Who were a few of the major thinkers there? Uh, what were the ideas they had and why do we actually care? Why is it important here in, uh, 2023 to be thinking about these ideas still when they have been kicking around, literally since Victorian times and before? Um, and there are literally thousands of excellent books, reviews, um, TV programs, all sorts of things out there that will tell you an awful lot about the big thinkers in evolutionary biology and their big ideas. And I'm in no way gonna try and recapitulate that. So this is very much my personal take on some big thinkers and some big ideas. Um, so forgive me if you think, gosh, what he's telling me I already know, um, or I would've picked a completely different set of people. Uh, but to start us off, what I'd like you to do is exercise your brains a little bit. And I have three questions for you. Uh, there is no test, and I won't, uh, I won't, uh, give out a prize, the end, I'm afraid. Um, but I'd like you to think a little bit about what you would pick in answer to these. So, first of all, question one. Here we have, uh, four individuals, a bearded white male, another bearded white male, a unbearded white male, and, uh, thank goodness, a lady here on the end. Um, uh, which of these thinkers do you think is most influential in our moderny modern evolutionary thinking? So this is, uh, for those of you who don't know, Charles Darwin on the left, Alfred Russell Wallace, Richard Owen, and here on the end, Beatrice Potter. Have a think, hold that thought. Question two, which of these organisms or entities do you think has been so important in our thinking about evolutionary biology? Is it the Galapagos Finch? Is it this bacteria? Is it e coli? It could be any bacteria. Uh, is it a dictionary? This happens to be a Dutch one, but any language will do. Uh, or is it this thing that we call sweet corn over here? Or maize, if you are in the us, hold that thought too. And last question that I promise, I won't ask you any questions and I'll talk instead. Um, which of these topics do you think is most strongly influenced by our thinking about evolutionary biology? Is it a diversity of species, drug resistant infections, food intolerance, or resistance to viral infections? So with those thoughts in mind, I'd like you to put out your hand if you thought a was the answer to all three of those. Not bad, actually. I was expecting a bigger room for, I'm guessing most people actually secretly thought a and you're just not going to be a hand up for at least for some of those answers, because the story we are told about evolution, and it's a correct story, is there was this revolutionary idea from this young man, Charles Darwin, who sailed around, uh, the world as a part of the ship's crew, uh, on H m Ss Beagle. And this is the story that most of us learn at school. Um, so in the top corner here, you have h m s beagle. And, and those of you will be familiar with this story, the young Charles Darwin, who was essentially at a bit of a loose end, kind of slightly lost his way, tried medicine, decided he didn't like the sight of blood, quite reasonably, wasn't quite sure what to do, and was proposed as essentially captain's companion on h m s Beagle. Uh, but he seemed like a sort of decent chap to get stuck in the cabin with for a very long period of time. Um, and off he set, uh, on this voyage, which ended up being many years around the world. Uh, and of course, they're all familiar with this idea that one of their stops on this journey, uh, were the Galapagos Islands off the coast of South America. And whilst there he was pointed out by, uh, local people that they could identify, uh, the finches that he shot, no photography in those days, I'm afraid. Charles Darwin's approach to, uh, biodiversity was if you see it, shoot it, um, and then take it home again. And they, they correctly, uh, pointed out they could identify the dead finches he had, uh, down to the island they came from, based simply on what they looked like, the shape of their bill, uh, the structure of their wings, so on and so forth. And, and Darwin, uh, had this remarkable idea, um, based on that and many other ideas that what these birds were demonstrating was selection in response to the environment. So you had, uh, an evolutionary process going on, on a diversification. That is the story I think that most of us learn. Uh, but actually I think there are other dimensions here. And one of the things that's not celebrated enough, I think, is that Darwin's thinking on this was also influenced by many other species that are much closer to home. And in particular, he spent a lot of time thinking about pigeons. Uh, and in fact in his later book, uh, the Domestication of Livestock, uh, he talks a lot about, uh, finches, uh, finches, pigeons and doves and other livestock species, and how man has had this role in selecting, uh, those species. And what he was struck by when he looked in pigeon fanciers pigeon lofts, uh, was just how much change a pigeon fancier could create in his animals in a very short period of time, right? So you could breed pigeons that had particular coloration or flu faster or wear fatter, and within a human lifetime, actually you could get measurable change in those species. Um, and I think one of the things that we tend not to think about today is that impact of that observation of human-driven evolution on what turned out to be natural evolutionary thinking. And one of the ideas that I think historians often wrestle with a little bit is how this idea landed into essentially a Victorian society at the time. Uh, and one of the things that strikes me is that this was a, a pretty revolutionary idea, and it certainly was not without, uh, its opponents people who, uh, argued it, but actually it had a relatively smooth ride as far as kinda heretical science ideas have. And by the end of Darwin's life, as you may know, I mean, he was a celebrated national hero. Uh, most people had at least some, uh, sort of begrudging acceptance of evolutionary, uh, thinking. And I think there are two possibly, uh, reasons that contribute to that. Uh, and one of them that people very rarely comment on is that actually Charles Darwin was, by all accounts, even his enemies accounts a really decent chap, right? He is someone who was a family man who was very even tempered, who was very tolerant. And he sort of argued his case quite quietly. And I think there's an interesting message here about delivering difficult ideas with a very measured response. And I wonder how much that's kind of, uh, uh, making it difficult for people to say, this man here is the end of human civilization. Um, and he's a kind of enemy of humanity, uh, because when he's so patently not that, and the second point, I think, uh, was one of timing. So evolutionary ideas had been circulating for quite a long time, actually probably over a hundred years. And indeed, uh, Darwin's grandfather was one of the people who first sort of mooted this idea that maybe species change, uh, and some kind of process was shaping diversity, but it hadn't caught on, it hadn't kind of got the zeitgeist. And I think that one of the things that might have contributed to that was actually the enormous change happening in the world around people at this time. Uh, this is of course the moment when essentially Victorian innovation is striking, uh, and the industrial revolution is taking place. And so people were very struck by things like, uh, steam trains. This idea that we suddenly were able to transport over vast distances at great speeds. Um, there was all sorts of innovation in pretty much every area of life. Everything from printing books to, you know, public transport and this idea that humans could somehow conquer the world with innovation. And so I think if you're in that environment, it's maybe not such a big step to think, well, if we can create all these things that even 20 or 30 years ago were unthought of, what might the magnitude of time be able to, to do with kind of all species? And therefore, this idea that evolution was driving diversity, I think fitted this sort of innovative, forward-looking Victorian mindset. That's pretty wild speculation on my part. But, um, 'cause I'm given the lecture, I can speculate in the questions, you can all complain about it. Okay, so Darwin sort of set this scene and he, he, he launched this, uh, you know, famous book, origin of Species. Uh, I would point out that even when it was launched, this became a bestseller straight away. And heretical ideas very rarely do that. So that's another bit of evidence. I think that people were ready for this as an idea. And the idea as I hope you all know, but let's just recap, is one that is really quite simple, and it relies on two things. It relies on the fact that most organisms, overproduce offspring, we produce more offspring than can be sustained by the environment. And therefore, resource is limiting 0.1 and 0.2, that that process of reproduction is not an exact carbon copy. There is variation inherent in reproduction. And so what you're producing are diverse offspring. So here we have a little blue blob, the little blue blob, uh, reproduces and produces new blobs, which are largely kind of similar to that blob, but they're a little bit different. And what you see then, the environment that those offspring are born into will benefit some and be detrimental to others. And so not all of them will survive, but the ones that do survive will inherit that trait that they have maybe slightly less blueness or slightly more less blobbies or whatever it is. They will reproduce and they will produce their own offspring. The ones that died clearly didn't. And those offspring will then go through the same process of diversification and selection and so on and so forth. And over time, in multiple generations, what you end up with essentially is a tree that looks like this very nice early one, uh, from a German author here, in which origins, a single origin species has diversified and proliferated. And what you can see actually nicely illustrated in this tree, is that not all branches go all the way at the end. Things die out. And this of course explained one of the great big conundrum at the time, which was Richard Owens discovery, um, of dinosaur fossils of these, these animals that were clearly no longer present in the world. Where had they gone, what had happened to 'em? And so Darwin's idea, um, gave justification to this principle that not all species live forever. So that's the basic principle of evolution. So all of that, I suspect most of you listening to this think, God, I knew all this already, why I waste the last five minutes of my life. Um, and the reason I want to, to, to waste the five minutes of your life is 'cause I think this approach, this idea of natural selection and variation impacts lots of things about our lives, including things that are really quite different, uh, to how Darwin and others originally intended them. Um, and I'm gonna give you an example, which I suspect I, I'd wage. Every single person in this room has an example of this. In fact, I can see one at the back right now of evolutionary processes that have driven something central to most of our lives. And so to do that, I'm gonna introduce you, uh, into this new species, one that I suspect you're familiar with here. Uh, this is the species, telephones non-mobile. And for those of you of a certain age in the room, and I count myself in this, this is a device that used to be plugged into your wall via a wire. And it had a big disadvantage, which was that if someone phoned you and you picked it up, particularly if you're a teenager and it's your boyfriend or girlfriend phoning, um, you couldn't escape the family 'cause you were plugged in at the other end and you had to sit in the lounge or under the stairs, uh, stuck on a mo on a wire. In about the 1980s, a new species arose diversifying from this one. And here it's here. This is the telephone, it's mobile. I, um, uh, mobile in this, uh, particular instance was a bit kind of stretching it to be honest.'cause the first mobile phones, uh, were actually pretty immobile. They're the size of a suitcase, and you had to carry them around. Um, and I recall my, my father was a policeman. I recall him being issued with this amazing new piece of kit to the mobile telephone that occupied sort of half of our camper van when we went on holiday. Um, uh, it was not ideal. But here we have an example of essentially, uh, evolution happening. So you have a species and a new thing arises that has a different phenotype, a different outward, uh, appearance. In this case, it's lost the wire that connected it to the, to the war. And it turns out that the environment that that landed in was ready for that. This was an advantage to have no wire. And so this species was highly successful. Um, and what you see is very rapidly it started to diversify, um, and become more and more refined. And what you see over time, so this is now 20 or 30 years later, is lots of different species that have arisen from that. They all look a little bit different, but there are some trends, right? So for example, they have all become smaller over time because no one actually wants a mobile phone that weighs 25 kilos and you have to kind of carry around on a cart. But there are other features which have diversified. So some people like a phone that's got a big fat screen, some people like one that has buttons, not so many of those anymore. Um, some of the, I used to quite like these ones that you flip down and flip back up again. And so you get diversification in response to selection. The s pressure in this case is us, right? We are choosing things. And I suspect if I asked you all to reach into your pocket and wave your mobile phone, what I would see is a diversity of mobile phones based on the environment that you've applied to them. So for some of us, that might be how much it costs for others. Is it waterproof?'cause I keep dropping in the toilet. Uh, whatever it is, there is a selective pressure. And essentially the reason I think this is important to note is that this is precisely the same process that has driven the evolution of Galapagos finches or bacteria or whatever else it is, except that we are applying it. And so I think that are lessons we can learn from evolutionary biology. If you are, for example, running a company and you've got a brand new innovation, you might want to think a little bit about this process of diversification and selection and how it's going to impact on your particular market. And we're gonna come back to that later in the lecture. For those of you who legend in the series, for those of you who can stick it out to the end and talk a little bit about why this might be important. So let's wind the clock back again then. So we, we are not gonna talk about mobile phones anymore. Let's talk about post darma. So Darwin's had this great idea, it's sort of landed quite well. People are kind of interested. And what has happened immediately in this atmosphere of sort of Victorian innovation and particularly of exploring the world, and I use exploring slightly in in inverted commerce here, was exploring in, in Victorian times also of course meant quite often invading places. Um, but nonetheless, Victorian, uh, England essentially has opened its eyes to the world and they have seen diversity everywhere, including in humans. Um, and so people started to ask the reasonable question, does evolution also apply to humans? And actually, it's interesting to note that Darwin really shied away from this. And it famously, in his book, he says, almost nothing about the evolution of humans other than this slightly cryptic sentence saying, um, in time, uh, light will be shed on the problem of where humans came from and just leaves it there. Which is kinda the ultimate cliffhanger for a sort of box set series, isn't it? Um, but he left, he didn't wanna ask the answer the question, but, uh, the same was not true about others. And in particular, this chat, this is Francis Galton, this is Darwin's cousin, actually half cousin. Um, and Galton is someone who picked up this idea, particularly as it pertains to humans. And uh, the story is that he was struck by this when he was going to agricultural faires and looking around, um, and noting the diversity of animals, for example, on display and also the diversity of humans. And started to think these things are not that different actually. Um, and in particular, Galton was struck by this observation, which is, uh, to paraphrase his words, pedigree dogs. So if you have two pedigree dogs like these two here, and you were to cross breed them, which might be tricky in this particular case, but nonetheless, you're, if you cross breed two pedigree dogs, you do not end up with a litter of puppies that look half like this and half like this, right? What you end up with are a bunch of puppies that all look sort of a little bit generic, the so-called kind of mongrel state or whatever. Um, and what golden thought this was was the reemergence of what he called ancestral characteristics. So his thinking was through breeding. What we've done is we've got rid of all these kind of old characters, but they're still there somewhere. And then when you cross things, they bubble back up. And what you look like is more like your ancestral state. So in this case, more like a wolf and less like a chihuahua or a, or a great Dane. Um, so that in its own was quite interesting. But what Garin realized was, or maybe this may also apply to humans, so do we get this thing of what he called regression, this idea that we gained backwards, it's a slightly unfortunate term, but going backwards to some kind of common state. Um, and to ask, answer that question, he did, uh, which was actually a really revolutionary thing, the first human study in which he issued questionnaires to people. So he had a brilliant idea. He thought if we could just get data by asking people. So he went out and he asked people to fill in forms, um, in this case about their height. And he said, I want to know your height, your what husband or wife's height, and the height of your adult children if you have adult children. And what he showed in a slightly complicated way here is something quite interesting. So here, what we're looking at on, uh, the top axis here is the mean height, the average height of the two parents, okay? It's in inches.'cause uh, you know, bear with me. And on the, uh, going upwards on the vertical axis, you've got the mean height of the adult's children. And what he shows is something quite interesting that if you are two very tall people, um, so up here in the top corner, you don't have children who are very, very tall just like you. Um, and if you're very, very short, you don't typically have children who are very, very short. What you have on average are children who are average. Okay? There is a slight bias, and you might be able to see this line going through here. So if you are two very tall people, your kids might well be slightly taller than average, but they're not necessarily gonna be as tall as you. So if you are six foot six and married to someone who's also six foot six, it's very unlikely your children will be six foot six, although they might be say six foot. And so he realized that this was the same as those, uh, dog examples. What were happen, what's happening here is that there's not direct inheritance. There is some bias towards something, but there is this process that he called regression to the mean. In other words, on average stuff goes back to some kind of average place. And that had a very important, uh, uh, impact because he realized there were two things here. First of all, that it doesn't matter how extreme populations are, they tend to come back to some midpoint. And second of all, he realized the importance of a lot of sampling to do this. If you pick one person, imagine when you pick this person down here, you might come up with a model that's completely incorrect. What you need to do is to sample a lot of people to come up with a, a suitable answer. And this is a process, uh, that we understand as normalization. You can see it graphically mapped out here. So this is quantifying something doesn't really matter what it is by picking things and quantifying bit by bit. And what you see on this, uh, on this loop of a video is that when you start off, you end up with a pattern that's really not very accurate at all. But the more times you sample the better and better you get. Um, and when you do that, what you end up with ultimately, if you sample enough times, is something that looks like this. And this is what we now know of as a normal distribution. And a normal distribution is really important in biology because many, many biological characteristics follow this pattern. So if this was height, for example, what you see right, is that there are some very short people and very tall people, but most people are somewhere in the middle. Weight is the same, eye color is the same, all sorts of things the same where you have this graded variation. And so what Galton realized really was that this was true also of inheritance, but to see it, you needed to do a lot of sampling. And so he went out and did lots and lots of sampling of humans. And actually he made really, really profound and important advances in evolutionary thinking. Unfortunately, for go, I think if he'd stopped there, we would all be standing here saying, what a fantastic chap, just like Darwin, brilliant ideas. Uh, but unfortunately Galton was not like that. Uh, and he went, uh, further, much, much further. Um, and what he decided was that humans vary and there's some inheritance here. Um, and so let's put this to, to work. And in his ideas, it's worked for the improvement of the human race. And so, goin unfortunately is the person who came up with this term, uh, eugenics. And he proposed this idea that you could improve the human race essentially by breeding out stuff that he viewed as undesirable. And it's really important to note that in Golden's world, optimum, the best possible human race was surprisingly enough, white middle class, in fact, upper middle class, slightly aristocratic, preferably English, uh, all the things that he was, um, and he launched a society called the Eugenic Society. And in doing so, essentially, um, set the scene for really many of the major, you know, disasters and biological crimes of the next a hundred years. I think one of the things that really strikes me here is that the premise here is actually not bad. So this is a, a later poster from the, uh, from the Eugenic Society, uh, which has, you know, this slogan, live, love and marry wisely, all three of which I think most of us would agree with are not bad, bad ideas. Uh, this bottom bit is the bit, this is very bothersome, and I think it's particularly challenging on two points. So go, uh, is, is wrong and he's wrong, deeply wrong for two reasons. First of all, he is wrong as a concept, right? Culturally, this is a deeply unsettling and unpleasant idea, but he's also wrong scientifically. And I think the, the most interesting thing about Galton was for someone who was a great observer of the world, he failed dismally to observe in his own data that this is not true, okay? And that if you look at data, for example, around many of the most controversial areas, uh, like intelligence, you only have to look at the, the quantitative data, the kind of data that Goul was gathering to realize that actually this will never work because the impact of things like schooling, diet, family, background homes, all of these things massively outweigh that very small genetic basis, uh, that might contribute to these things. And so he was, he was wrong on a kind of societal basis, and he was wrong, uh, on a scientific basis. But nonetheless, this is something that unfortunately led of course to some of the most dramatic crimes, uh, of the 20th century. Uh, not least, things like the Nazi Holocaust, um, and massive programs of genocide all around the world, and a very unsettling legacy, uh, for, for this what was early on, a very promising piece of evolutionary thinking. And one of the most interesting things before we leave Galton, I think, is that actually towards the end of his life, um, he even epitomized, uh, this because, um, he, he sort of realized that he'd gone a bit out on a limb here. Uh, and in fact, one of the things that, um, gold struck Goldberg early on was that he suffered throughout his life, but particularly as a young man with significant mental health problems, and in fact abandoned his degree, uh, when he had a very serious breakdown. And so there's this quote of his, which I rather like, in which he points out, um, that these men who are in his words gifted like himself, of course, are also rather close, uh, to insanity. Um, and I think this is a very interesting idea because it points out, first of all why he's fundamentally wrong in this idea that you could improve the human race by breeding. Because of course what he's suggesting here is that traits are coupled together and he's right on this, they're coupled together. And so it's not possible to gain only one thing and not another. It comes as a complex mixture. And this is something in genetics that we call ply atropy, i v d, the idea that one particular gene might control lots of different things. And it's a theme we're gonna return to, uh, later in the series. Okay, let's move on from Golden, who's a, frankly quite a disturbing, uh, person. And think about where we went from here. So Galton and Darwin and others had launched this idea of natural selection. But of course, the thing that we always forget is they had no idea about the mechanism here, what could be driving evolution. They were observing hereditary prop differences, uh, but they had no idea how those things might be inherited. Uh, and of course now we know it's all about your genes. It's all about the d n a you inherit. And we know that largely thanks to this chap here. This is Gregor Mendel, who you will probably recall from school, uh, was a monk, um, who actually became, I like this. If you read his early letters, he became a monk essentially.'cause he wasn't sure what kind of career he did. And he, he writes, I would rather like to spend my days doing research, reading books and being undisturbed, and therefore I will become a monk. Um, so the first three things I can very much vouch for, I don't, don't think I'd go for the whole step of becoming a monk to, to achieve it. Um, but in his monastic garden, what Mendel did, of course, um, as we all know now, was lots and lots of breeding programs on vegetables and in particular on peas. And I'm sure we'll all recall this from school where you were told that peas are really important because they, uh, were the plant that allowed Mendel to realize that inheritance is what he described as particulate. And so these examples you might recall of wrinkled peas or smooth peas, green peas or yellow peas. Um, and for those of you who did sort of a level biology, you might remember doing Punnett squares and working out, if I cross a green in the wrinkles, how many green wrinkled peas will I get? So on and so forth. What he basically pointed out was that for some traits, it's not all about this blend, it's about single decisions. You're either wrinkled or you're smooth. You're either green or you're yellow. And therefore there were, uh, particles in his words that were being inherited from one generation to the other. Uh, of course, it's really important to remember that this was all done quietly and published quietly long before this process. So, so Mendel published this, uh, this paper on hybridization, uh, what we now call the genetics of hybridization, but in his words, the heredity of hybridization, um, in his local scientific society. And it was met with sort of the equivalent of a bit of kind of slow applause, which I'm hoping I'm not gonna get at the end of this lecture. Um, you know, very nice, but really like important. And it lay undiscovered essentially 40 or 50 years, and it's only in about 1900, um, that a number of scientists simultaneously rediscovered his work long after he was dead, uh, and realized that this could explain, uh, Darwin's observation of natural selection. There's a problem here, there, right?'cause I've just told you that Galton and many others have pointed out this distribution, this normal distribution things are blended and smooth. We don't come in two shapes as humans. We're not tall or short. You are everything in between. And yet Menlo is saying everything is inherited in these kind of particles. Either you are wrinkled or you are smooth, or you are yellow or you're green. Um, so how can those two things, uh, be reconciled? And of course, the reason they can be reconciled is exactly the same as the reason. I can show you this picture on a screen here, because behind this screen, in this screen, there are also particular decisions, right? If it's an r g b, a red green, blue screen, every pixel, every dot on a screen is one of three colors. So you'd imagine how can you come up with a picture if you have any three colors at your disposal? But of course, when you blend those in huge numbers, you can create images, um, that are all the other colors in between because the eye blends those three choices into the picture you see in front of you. And this is exactly how genetics works. You might have a single gene that is either on or off X or y, black or white. But when you blend them in a whole genome, in a whole organism, you end up with a massive amount of diversity. And the person who really kind of first realized that was this chap here with the Natty glasses, this is Fisher, Ronald Fisher, um, uh, who is another interesting and very complicated evolutionary biological, uh, character. So he was a mathematician, actually. Um, loved maths, particularly statistics. Um, and for those of you doing either maths with stats or biology, you'll come across fisher again and again and again because he's come up with all sorts of things that we talk about a lot, including this one called the P value. You might hear people talking about P values, which is how we measure whether something is statistically significant or not. So fisher came up with all these mathematical concepts about how you measure statistics and, and probability and things. Um, and he had the good fortune perhaps to be employed at the time, um, at an agricultural breeding station where people were doing enormous experiments to improve crops. Okay? And so they were measuring everything, how big is my carrot? How fast does it grow, how much foliage does it have, how orange is it? All these kind of things. And he essentially had this enormous data set in front of him, which he raided, um, to test his statistical models. And in doing so, he answered some really deep and profound questions in biology in particular, one that had vexed Darwin and other, uh, people, which is this idea of sexual dimorphism. Why is it that most animal species have different appearances of males and females quite often dramatically different, right? So here we have pheasants, for example. Um, 'cause that doesn't fit right, I've just told you natural selection selects for an optimum. So how can it be that this is optimum? But this is also optimum because they're really quite different. Surely one of those should not be successful. And what Fisher realized was that the power of sexual selection, the idea that mates choose each other, can drive the evolution of this dimorphism. And it can even drive it to a great extent beyond what seems feasible. And so he coined this phrase, uh, which we now know of as the fisher's runaway, which is the idea that if we select for a particular trait, even if the trait itself is disadvantageous, eventually it might be, might be selected for more and more and more and become quite, uh, ridiculous, to be honest. And the example that's usually used is the peacock's tail. There is no advantage that we can tell to a peacock and having such an extravagant tail, it doesn't help them fly. In fact, the opposite doesn't keep them warm at night, doesn't, you know, help them find food. Uh, and yet it has been selected for essentially because p hens like big tails. Um, and, and so over time every generation gets a slightly bigger tail and you end up with these enormous tails. Um, and that is part of the reason for that is that it is signaling the, the fitness of that peacock. So the tail itself is rubbish, but what the tail says is, I am such a fit and fantastic peacock specimen, um, because I can cope with this tail. So you definitely have to mate with me because my jeans are amazing. Um, and so this idea of fish as a runaway has, has taken off really, and that's turned out to be very, very influential. And in the later lecture in the series, we're gonna think a little bit about what that might mean for us as humans. But Fisher unfortunately, is also a very dubious character. He had all these brilliant ideas and many of which have shaped statistical thinking in biology for a hundred years. Um, but like many other evolutionary biologists at the time, he subscribed this idea that we might be able to improve humans, um, through a similar process. Uh, but perhaps even more famously or infamously, I should say Fisher, um, is remember today not just as a genius statistician, but as an example of someone who can get it so dramatically wrong. Because in his later years, he was one of the most prominent people to argue, uh, that smoking was not the cause of lung cancer despite an overwhelming body of evidence. And in fact, uh, for years and years and years, we used to be rolled out kind of on the radio to say, oh, this is all, this is all rubbish being made up by other people and actually set back the cause I think of, of public health gains quite significantly by being someone both prominent and respected and deeply wrong. So there we go. Just goes to show you can be brilliant in 50 years and still get it horribly wrong at the end. Okay, so we're gonna move the clock on. So we've done all this early evolution biology. The question now really in the sort of 1950s in particular started to be, well, we've kind of worked at the basics. We've done some stuff around height and weight and other characteristics. Um, but what about behaviors? Is it possible that evolution might also shape behaviors of animals? Um, and of course the answer to that is yes, but it would prove quite tricky to demonstrate this. And particularly around some of the complex behaviors that animals exhibit. And many people contributed to this idea of evolutionary behavior. But the person I really want to flag, um, towards the end of this lecture is this person here. This is Bill Hamilton, William Hamilton and Bill Hamilton, um, was another mathematician. You'll notice there's a common theme here of mathematicians, uh, driving evolutionary biology. And Hamilton is best remembered today, um, for a very simple equation. And they, this this statistic, right? That every time you show an equation in a book book sales drop by 50%. So I'm out to test with the same applies for an audience.'cause if half of you leave now and I do this, then I'll know it's also true. Good. It's not true. Um, so Hamilton posited this equation, which has become known as Hamilton's rule. And he was asking the question of why is it if we look out in the world around us, lots of other animals, not just humans, animals do stuff that seems altruistic, seems non-beneficial. Okay? Um, you might have seen examples, for example, of, um, female birds trying to lure a predator away from their nest at risk to themselves. So why do we do things that might be costly for ourselves might even kill ourselves? So why is this c this cost, um, of a behavior apparent? And what Hamilton realized was that if a costly behavior has a benefit to another organism that's completely irrelevant unless you are related to that organism. In which case, if the overall benefit to your relatives is greater than the cost to yourself, then actually it's worth doing that behavior. It's worth evolution selecting for it. So what he said was, for a behavior to evolve the cost of that behavior, c has to be less than the benefit of that behavior times by the relatedness of the person who's benefiting. So if you are a bird on a nest and there's a predator coming your way, all of those eggs in that nest are yours. So it is worth you disappearing off and trying to lure the predator away even though you might die because the overall benefit to your nest is, is important. And that turns out to have been a really influential idea in lots of areas of biology, but in particular in this idea of altruism in groups. So, um, here we have for example, mutual grooming. That's a relatively easy one to explain, okay?'cause mutual grooming, generally speaking, uh, if you groom somebody else, they might come back and groom you. So there's a direct benefit here. Much harder to explain when you think about things like social insects like honeybees. So bees, as you might know, when they sting, uh, somebody, they will die. The sting rips out in the bee dies. So that is a lethal, there's a huge cost to that. The bee is dead. And yet bees, as we all know, still sting to defend their hive. So why would that, uh, uh, that behavior evolve? And it turns out, um, there's a very neat trick here that we can demonstrate because this is all about the relatedness, um, of organisms. So for all of us in this room, and indeed for most animals, we have a reproductive system that looks a little bit like this. So if you're a dad, mum, we are deployed organisms. We have two copies of every gene, essentially one that you've inherited from your mom and one from your dad. And if you have kids with somebody else, those kids on average will pick up half of your genes and half of your partner's genes. So imagine you have four children randomly in dispersed. Each of those children will have, if your dad like me, will either have your dark blue chromosome or your light blue chromosome and the same thing from your mum, which means that for all of us, um, who have kids assuming they're actually yours, uh, then you are essentially 50% related, um, to your children, okay? Your children themselves are an average 25% related to each other. Okay? Makes sense so far? Something nod? Yes. Good. Very good. Okay, so this is quite straightforward. So for a human, for example, doing a behavior that might lead you to die is worth doing. If you've got four children, not so worth doing. If you don't, or equally worth thinking about three children, if you have any one child, actually statistically speaking, not worth dying to save your one child. If you have two, it's just about, it breaks even. Okay? But what turns out, so that, that sort of makes sense for humans, but it's much more complicated to understand for honeybees, why would a honeybee die, uh, for the whole hive? And it turns out the reason for that is an interesting quirk of the genetic system of these social insects. It holds through for honeybees or also for ants, for example. So honeybees, as you know, I hope have a queen, have a colony of the queen, right? And so what happens is when a, a queen is born, when he hatches, she flies off and she mates with a drone, the drone dies, she stores his sperm, uh, for the rest of her life essentially, and will continue to have babies, um, from that drone for a very long period of time. And those are what become, uh, the worker bees. But it turns out that in honeybees, queens females are deployed like humans. They have two copies of genes, but males are haplo. Males emerge from unfertilized eggs. So if a queen lays unfertilized egg, it will turn into a drone. It has only half as many chromosomes. That means if you are a drone honeybee, all of your children have all of your genes 'cause you haven't got any spare cup to give them, okay? Just like this. Uh, whereas if you're a queen, then you have this 50 50 relationship. What that means though, if you are born as a worker bee in a hive, it means slightly bizarrely that you are 50% related to your mum, but 75% related to your sisters.'cause you've all got the same copy of your dad's d n a, which means it is in your interest to look after your sisters and not for example, to have your own kids.'cause if you have your own kids, you're only gonna be 50% related to them. Whereas if you can look after your sisters, you're 75%. And therefore it makes perfect sense for honeybee to sacrifice herself in defense of this colony of sisters because it is strategically much better than going off on your own and trying to have your own babies. And so the genetics has driven the evolution of what appears to be a completely bonkers piece of altruistic behavior. And this idea of course of Hamilton's, um, which has now become kind of widely accepted, uh, formed the basis of some of the most revolutionary thinking of our, of our modern times in terms of evolutionary biology, particularly the idea, um, that was of course launched famously by Richard Dawkins here, uh, in his book The Selfish Gene in 1976, in which he pointed out that the idea of evolution, we think about individual organisms, individual animals or plants as the entity that is being selected. But that's not true. The thing that evolution selects are the genes that make up that organism. Organism. So actually what is driving evolution is the gene itself. And so whether a single honeybee lives or dies is not relevant, whether the genes in that honeybee live or die onto the next generation is what is important. And that's why you get these kind of, uh, evolutionary behaviors. And so let me finish by saying, well, you might be thinking, well, this is all well and good. I don't actually keep honeybees. Do I really care about honeybee? But actually this idea, Hamilton's rule has a bigger impact on your life than I suspect you might expect. So for example, anyone, anyone moved house recently, if you've moved house recently, put your hand up. No, that's disappointing, isn't it? If you hadn't moved house recently, then you might have done what Sydney I used to do when I moved house, phoned a friend, phoned some people say, could you possibly come and help me if you'd have done that, particularly if you needed a bit of extra car space to move house with, for example, you would've found that you phoned people in direct correlation to their genetic relatedness to you. So you are more likely to phone, for example, a full sibling. So genetic sibling than you would be a half sibling if your parents spit up and are married again. Um, and more likely to phone a half sibling than, for example, a step sibling who you're not genetically related to. Even more interestingly, um, if you have recently thought about giving any money away, you will have done exactly the same thing. And there's a really fantastic piece of, uh, fairly recent data that I wanna touch on, um, about money and cash. And in this experiment, uh, what they did was they got a group of volunteers to come in, um, and they said, uh, right, I'm going to pick on a particular volunteer. I'm gonna say for example, madam here, um, I would like you to give me some money. I will match that money and I will give it to this third person. Um, and the interesting thing about this experiment was you had to give real money. So actually cost you money. And the question would be, how much of your money are you prepared to give me in order for me to match it and give it to somebody else? And it turns out when you do that experiment and then the the somebody else varies. When you do that experiment, the amount of money that people are prepared to give is beautifully linearly correlated with how well they are related to the person that's going to receive it. So for example, you are prepared to give quite a lot of your own money to me to match, to give to a sibling, um, or a non-identical twin, which is of course genetically the same as a sibling. Um, if you go down to for example, a cousin here, the amount of money is a bit less a second cousin, even less someone unrelated very little money. Um, and in fact full. So there's even interesting outlines. Not that many identical twins you can get in these kind of studies, but identical twins are even higher again. So we are prepared to sacrifice our money in a way that is directly related to the genetic, uh, relatedness of the person who's gonna benefit. The most interesting twist on this though is that this is real, right? This actually cost you money and when you left, uh, uh, the trial, you had less money than you went in with. So it has, there's a real cost. You can do the same experiment and you can say, okay, now, now we're gonna do not money. We're gonna do, um, something really quite important and maybe life threatening like a kidney. I'd like you to donate a kidney to somebody else. Uh, and you might die because surgery is not without risk. How prepared are you to risk death for this other person? And what you see is that the curve is exactly the same except for one thing. So here is the line and you can see beautifully we're more likely to donate a kidney to a sibling than we are a cousin, than we are a second cousin, than we are someone unrelated. So we follow the same trend. But what you notice here is that we basically have this massive overestimation. We all think we are much more generous than we are. We say, oh yeah, I definitely give my kid my kidney to my cousin 'cause this isn't real, right? And when you actually do it for real, unfortunately all these, all these uh, buttons drop back, back down much lower here. So we overestimate our altruism, our charitable status until you make someone really do it. And then you go right back down to the actual biological prediction of just how much risk they're prepared to take for a cousin or a sibling or whatever. So I'm gonna kind of finish there, but I, before I do, I wanna just reassure any of you in the audience thinking this is so depressing. Um, you know, if you are sitting there thinking, but I'm the person who does, well maybe not give you a kidney, but I'm the person who would definitely give, you know, 50 quid to someone I'd never met.'cause they look like a, you know, a good cause. I am the altruist out there, um, who genuinely would not favor the people I'm related to. And if you're thinking like that, the good news is all is not lost for you evolutionarily, uh, because genuine altruism and this for those historians amongst you, this is Walter Riley allegedly putting his cloak down. Uh, for Queen Elizabeth, the first very altruistic. Um, but just like Walter Riley knew the reason for genuine altruism is not actually altruistic. And the reason for genuine altruism is because genuine altruists do a lot better in scoring partners. Uh, and in fact you can measure that. So if you measure, um, high or low levels of altruism, and this is measuring here overall reproductive success. So in other words, how many kids have you had over your lifespan? And it turns out that genuine altruists have more kids than people who are not very altruistic because they have better stable long-term partnerships. And that all sounds lovely and rosy. Um, but just to depress you slightly on my final piece of data here, if you do this not for lifelong relationships, but for one night stands, it turns out slightly depressingly that women are just as well behaved. They choose altruists men in the red line just don't care at all. They'll have a one night time anyone, whether you're an altruist or not. Uh, so you need to bear this in mind depending on your plans for a Friday night. Um, let me finish there. Thank you very much. I'm very happy to get any questions. Well, we've got lots of questions. I'm not sure you'll be able to <laugh> go through all of them, but, um, uh, what about the quest, the three questions at, at the beginning? Oh yeah, three questions. Sorry, I'm just <laugh>. I know. So, so the first I can, so I can tell you. So the answer is all of them, right? So the, the, the people there, Charles Darwin, you know, Alfred Russell Wallace, you probably also know, he was this person who independently came up with the same idea whilst he was trekking around, um, Indonesia and Papua New Guinea wrote to Darwin saying, I've had this great idea and, and triggered Darwin to basically get a move on and get his book done. Richard Owen was the third one on the, on the slide. He was the person who kind coined the word dinosaur. Um, very another very dubious, infamous character because he did all this pioneering work around dinosaurs. But he was basically a really arrogant, unpleasant person. Um, and deeply disliked Darwin who kind of leapt onto the scene and got hero worship and did everything possible to discredit him. And basically he's not really nice. He has of course left the lasting legacy 'cause it's his museum in South Kensington, which is now natural, his museum. And the fourth one, Beatrice Potter. Anyone know why Beatrice Potter might have influenced evolutionary thinking? Oh, sorry, creativity. Creativity. Well, she was very creative and she was also, um, a really observant naturalist and she is one of the first people to look at lichen, you know, these crunchy things that live on gravestones and trees and stuff. Um, and, and she, although she was actually incorrect in her direct thinking, but she realized, um, that these structures were actually symbiosis between two organisms between, uh, bacteria and argi and a fungus. Um, and wrote a number of letters on this and many other subjects that sort of really brought, um, this kind of complexity of biology, the evolutionary thinking to the common, the common person. So, so yeah, an unknown as well as writing Peter Rabbitt, which is just brilliant. She also had a big impact on evolutionary biology. And for the rest you'll have to come back to the rest of the series or find out. Uh, do we know actually if there was any differences between Wallace's, uh, Wallace and Darwin's, uh, theory, evolutionary theory? That's quite interesting if they were working at the same time and one was pushing the other to publish his work. So we might assume they were they were pretty close or, Yeah, they were. So the, the ideas of of Wallis and Arm were very similar. I mean, obviously the species they're talking about quite different.'cause one was in, you know, Galapagos in South America and the other one over in, um, in the Pacific. Uh, but the, the, I mean, what, I guess what was very interesting about that correspondence was that both of them were kind of corresponding or coming up with these ideas that were not fully formed. And so then you kind of got this synthesis and you know, really to his credit, I think Darwin, I mean he could have basically buried Wallace, right? Wallace was over in the kind of malaria induced haze, um, you know, thousands of miles away. Uh, he could have said, alright, this idea we're in that letter, I'm gonna publish it. But he didn't, he fully credited, uh, Wallace and the, the two of them kind of went hand in hand for that. Um, I think that's a really nice example of, you know, how science should be sort of proper teamwork. Good. Um, we've got actually a question about, um, someone who wrote, actually I actually, I think before Darwin, Charles Darwin, sorry, let me find, um, that question. Uh, yeah. Could you please explain the difference between Lamar, Lamar and Darwinism? Sorry. And where does La Marxism stand today in modern evolutionary theory? That is a very good question. So La Marxism, for people who don't know, is this idea that promoted by Lamar, hence the name. The idea is that change diversification happens be within a lifetime rather than because of selection. So the idea and the example that's usually used is the giraffe's neck. So the idea is if I'm a giraffe and there's a, there's a tree that's a bit of outreach, I can stretch my neck just about reach the leaf. And then in my offspring, they're gonna be born with a slightly longer neck 'cause I stretched. And then when they have to get a leaf, they're gonna stretch as well. Over time you get this, um, this kind of almost promoted kind of change in phenotype. Now for many, many years theism was essentially completely discredited. And so this is absolute rubbish. And and largely speaking, it was rubbish.'cause we know of course, that that's not true. You know, for example, if you are a, if you're a carpenter, it doesn't mean that your kids are gonna spontaneously, you know, really have bigger muscles for cutting wood or something. But there is an interesting twist because in the last sort of 20 years, we've come to learn about epigenetics. This idea that you inherit your d n a, your genes, for example. Um, but there are things that modify the behaviors, genes and in some cases they can be inherited. And the best piece of data on that is during the Second World War. Um, when you had in the Netherlands, this, this thing called the vinta. So this, this starvation period in which the population under, under control by the, by the German army essentially were very, very calorie depleted. Um, many of those, uh, women were pregnant at the time. They had smaller babies. Um, you might expect that 'cause they were malnourished, but the babies of their babies, their grandchildren are also smaller than average. Um, so there is some kind of inherited impact of that external environment on, on those people. And we now believe that to be due to epigenetics, this idea that your d n a is modified by things and that is a kind of a source of Lamar. So, so there is a kind of resurgence to that idea, not in terms of all of evolution, but for some specific examples where he wasn't entirely wrong. Okay. Some trace acquired during your lifetime, essentially. Exactly. And there's a lot of interest, of course, in whether if that's true, can you modify things like diet or behavior or whatever and have some kind of lasting impact. It's a, it's a very hot and very interesting area. Okay. We'll take some, perhaps a question from, from the audience. Uh, yes. The lady here. Sorry. Can we have a, There's a microphone running in, running in from the back So we can hear you from people online. Thank You. Yes. Um, thank you. Um, more or less where you finished. Um, I've been looking after my granddaughter today and she's a lovely little baby. She's not as related to me as my brother or my sister, but I sort of feel because she's a lovely little baby with these eyes that look at you and she's so, you know, that I would be more inclined to, I, I hope my brother and sister not listen to this, uh, give her a kidney even though she's not related. So is it, is it is altruism influenced my things like that as well as how related you are to people. I I love the idea at this moment. There's a brother and sister, they go, what<laugh>? Um, so, so you're absolutely right. So there's a couple of things going on there. So, so, so I think in terms of grandchildren, so there is a genetic relatedness as you say about brothers and sisters, but there is also a long term genetic inheritance question. So, uh, you know, a grand, a grandchild with their whole life in front of 'em might go on to have 25 great grandchildren. And so there is a potential genetic there. Someone who may be no longer reproductive, for example, uh, is essentially yet they've done their genetic composition. So there's not much more you can influence there. That's part of it. There's also a second interesting issue, which is that it looks like evolution has shaped babies in particular to plug into, uh, behavioral things. So for instance, you mentioned like the eyes, for example. So babies have quite big eyes, right? And so we are programmed to want to kinda look after stuff with big eyes like babies. Uh, and actually this has been very interestingly exploited by Disney. So if you've ever seen a Disney ca you know, cartoon, the, the cute lovely characters, Mickey , they're really big eyes.'cause we go, oh, they're really cute. The baddies always have little tiny squinty eyes. Uh, and the thinking is that that is triggering this very deep behavioral response that we want to kind of look after these, you know, big eyed babies. Uh, so yes, there's some, there is definitely something there. And you know, of course we are humans for a good reason. We do all sorts of things which are not very genetically related. Um, and I think that's a good example of one. Good. Um, well that's a question is also well has to do with, um, climate change. And it's also a moral question ethics. Um, if extinction is a natural and normal process, is it right that we as scientists are interfering and trying to prevent species from becoming instinct? Oh, that's a, that's a nice laden question, isn't it? Um, okay, so what's my view on that? So, so I mean, I think the key point there is that we are overwhelmingly the cause of extinction of almost all of those species. Um, so on the one hand, you could argue we are part of the natural world. We're a natural selective process. Um, you know, if you don't fit with humanity's goals, then you go extinct, bad luck. That's natural selection, which is sort of true. Uh, I don't think, certainly I would not subscribe to that view. And I think most people probably don't think it's a good idea that, you know, cute panda bears go extinct because they're not very compatible with humans. Whereas, you know, rats for example, they're pretty successful. Um, uh, so, uh, so I, I think there's an element about what is human. There is a second questionnaire I guess, which is if something is completely unrelated to human behavior, should you intervene a lot? And I think that is a much more tricky question. Um, and you know, one example there for example might be in terms of island ecology, you know, you might have an island which has a unique species on it. What about if some predator washes up not from a human boat, but you know, spontaneously should you intervene to protect that species? And that becomes a very deep and challenging ethical question. Um, and, and you know, and you can apply that right through indeed up until you know, things like, um, uh, you know, domestic livestock or pets, you know, other, so there's a big debate, for example, at the moment about, um, livestock breeds, right? Mm-hmm. So people don't like livestock breeds to go extinct, but there are some livestock breeds which are uneconomical. There are many that have significant welfare problems. So actually, is it reasonable to retain a livestock breed that has a welfare problem just because we think it's nice to have diversity? So yeah, no easy answers to that one I'm afraid. Uh, great. Hi. Yeah, thanks so much. Um, so question, going back to your slides with the mobile phones, it was started off as immo list and then, then went over. It seems to me that there's the tech, I mean, going to a biological, um, with the species, um, is quite a big jump, um, going from something which is wired to completely unwired. And it seems to me that when I learned it at school, the argument was that each intermediate step, each generation had a small selective advantage over the previous, and then it was selected for. But there are certain things which would require a huge amount of evolution before they're actually gonna be useful. So for example, like the, the wing of a bird, it's gonna be a, a huge disadvantage until it can actually fly or, or an or an eggshell would have to be sufficiently hard before it's, you know, so, so, so I guess my question is, um, yeah, so how, how does that, how do you square that circle? That's a, that's a great question. Thank you very much. Yes. I think there are two parts to that. So the first part is that really we know that on average, most evolutionary change is very incremental and very slow, but not always you can have these dramatic changes. And perhaps one of the best examples is multicellularity. So being a single celled organism to becoming a multi-celled organism feels like it should be incredibly complicated. And yet you can select single cell yeast, for example, within a very small number of generations. You will find you, if you make the conditions right, you will find yeast that grow as multicellular colonies. And so you can get that quite big change if the conditions are right. So I don't think we should rule out that big change is possible in, in some circumstances. Um, the second point about how these complex things, uh, evolve is a really good one. And actually Darwin himself, you know, wrote about this challenge of the eye. How can an eye be of, uh, you know, how can you possibly have got to this really complex organism called the eye from having those eyes at all? Because everything in between seems, seems rubbish. But actually of course, now we know that's not true. So for example, there are, um, you know, microscopic plankton that have photo sensitive cells. They respond to light or no light, they can't form an image, they can't do any of those kind of things. But it's a first step on a way towards forming an eye. And I think actually you mentioned bird wings. I mean, there's a very, there's a quite active debate about, um, the evolution of bird wings. But one of the suggestions, for example, is that bird wings might have been helpful either in Therma regulation, so to keep warm, possibly, um, or in breaking falls. So if you are, if you were a climbing lizard for example, and you kept falling outta trees, having something that just buffered the falls, like even if you can't fly, might still have been selected. And so I think for most of these apparently highly unlikely changes, you can actually work back and, and see where it might have come from. I mean, the caveat of course is we will never probably know, uh, 'cause we can't run the clock backwards and work that out, but I, I, I think I have yet to come across an example of something so profound that I can't imagine a way that it might have evolved in incremental steps. Going back to the gentleman mentioned the text. So that's a, I have a good tech question actually from someone <laugh> asking, are there any possible use of evolutionary theory in developing AI algorithms? Well, that's a very nice one, yes, because AI, of course, in principle runs exactly like that. Mm-hmm.<affirmative>. So you know, this idea that, you know, it's iterating on an enormous scale idea. So if you, for those of you who's, you know, chat G p t, this idea that you ask a question, what it's doing is it's testing out. So if I ask it, you know, are Gresham audience members a lovely bunch of people, um, it will test all these ideas in massive time and come up with a piece of text that is based on the most plausible, uh, process. So yeah, I think there's absolutely huge opportunities there for using that evolutionary theory to kind of come up with optimal ideas and actually maybe avoiding disasters in advance. So, you know, let's say for ai, but maybe for hardware, you might be able to do a lot of evolutionary testing and failing before you put it onto the market and then realize that everyone wanted a phone that does something you didn't design in, for example. Hi, so thank you for the question. Um, I was wondering if Darwin's idea, um, still play a role in modern day racism and going further also in human supremacy that is, uh, the way that humans, uh, seen on human animals and how they treat them, uh, to, to, to please themselves. Because even though Darwin, uh, sort of brought the human back toity and said, oh, we're also animals, if we look today, it, it didn't help our relationship with animals, for the animals. Yeah, That's, yeah. So that is, that's something that people wrestle with a lot. Um, and I think in terms of supremacy, uh, this idea of human supremacy, I mean, certainly early evolutionary thinkers, and Darwin actually didn't really himself comment on this, but many other people at the time essentially had this pyramidical idea of evolution that, you know, there were all these diverse lower organisms and the pinnacle of evolution was humans. Uh, you know, actually the science is precisely reverse, right? If you're, if you're looking at a pyramid, it's the other way around. Early, early species, were pretty undiverse and over millennia we've become more and more diverse. So we are just one branch of all these other branches. Um, you know, you can, you can argue that, you know, we are very optimal for our lifestyle, but we, you know, if you put us at the bottom of the ocean, we're pretty rubbish. I take my chances on an octopus over a human any day. Uh, so it's all about the kind of environment you see yourself in. So this idea of being perfect for the world you're in is clearly completely wrong. I think the legacy in terms of ofci so-called scientific racism is deeply disturbing. Um, Darwin himself, you know, there's no evidence they had in his ideas supported in any way, but you are right. The idea seeds, you know, a kind of environment into which people can have these, you know, deeply disturbing and ultimately enormously disastrous for the world. Uh, kind of ideas. I, I mean, I guess the argument against that is that this is true for almost all scientific ideas. I think, you know, splitting the atom was a terrific piece of physics. It's led to lots and lots of power. It's also led to atom bombs. Um, and, and so I think there is this problem that any, almost any new idea, AI you mentioned, you know, there's lots and lots of stuff out there right there. AI can do fantastic things. Diagnose your illness, help drive our cars. It can probably also do some pretty disastrous things. And so I think these ideas, it's about what we do with them and how we manage them as a population rather than somehow not having the idea in the first place. Well, thank you very much, professor May for this wonderful lecture. Thank.