Transcription
If there's no variation, if there's no mutation, there's no way for natural selection to happen. Herman, I heard tell our ability to form sounds was a genetic defect, if you will. We don't want to think of speech as a mutation. We want to think of it as an adaptation. All adaptations start off as mutations. So, you know, natural selection is the survival of the fittest, but mutation is the arrival of the fittest. Oh, Mitra. Yo, that is dope. Oh, another t-shirt. We're in the mode. Arrival of the fittest.
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This is Star Talk special edition. Today we're going to be talking about the human condition. That is centerline to what Star Talk special edition is all about. And of course, if it's special edition, it means we've got Gary O'Reilly. Hey, Neil. All right, Gary. Yep. Former soccer pro. Yes. And of course, Chuck Nice. Hey, Chucky, baby. Hey, what's happening? So, Gary, tell me about the human condition and what's going to happen today.
All right. Um I suppose in many ways this is the specialist edition because we are talking about the science behind the things that make us different that make us special and that's as a species makes us adaptable. So what makes us special mean which makes our species special. Yeah. Among all species of life on earth. Mhm. I mean humans have survived and thrived in just about every location, every climate on Earth. Well, so far that is that things are changing. This adaptability has seen the human form take many different body shapes, sizes, blood types, and skin colors. Yet, with all this uniqueness, we are 99.9% similar in our DNA. So, 999 n Yes. Yes. It's even even more than 99.9. Go ahead.
Okay. Now seems like a good time to understand a little more about the diversity and our diversity and adaptability through the lens of evolution and biology. So if you would introduce our guest. I will. This is an old friend of mine who left town some years ago before co. We hadn't heard back from him. Well, maybe he was as good a friend as you thought. I'm thinking it. You're saying it. Professor Herman Puner. Welcome back to Star Talk, dude. Hey, thanks for having me back. So, the last time you were here was like early co EC EC early co and all I remember is that you talked about zebra testicles. That's all I remember. It left a left an impression. That's good. That's good. We'll have to dig that one up out of the archives. So, right now you're a professor of evolutionary anthropology. I love that. That's great. Ooh. Ooh. and global health at the Duke University's Global Health Institute. You got your work cut out for you, too. I can tell you that right now. Yes. Yeah. It's a strange time to be in academia and public health. It's a funny intersection at the moment. Exactly. Okay. And you're uh recognized researcher in human energetics. I love it. Human energetics and of course evolution, which is fundamental to that. author of a 2022 book, Burn, and in 2025, Adaptable: How Your Unique Body Really Works and Why Biology Unites Us. Oo, cool. Penguin Random House. Yeah, interesting title. Oh, yeah.
So, let me just say you left town and you didn't tell me you left town because you used to be right here. Were you at NYU? Where were you? I was at Hunter College in the grad center and um here in New York City. That's right. That's right. And coming over across town to hang out at the AM&H occasionally with some of our mutual friends. Yeah. Yeah. We're here in my office now at at AM&H American Museum of Natural History for those who just tuned in.
So, can we think of our adaptability as some kind of superpower distinguishing us from all other animals on Earth? Cuz I've thought long and hard, what is special about we can't fly, we don't run fast, almost everything that would kill us in the wild is cuz the other creature is better at it than we are. So to think of our adaptability as a unique feature of being human, I got to hear more from you on that. And by the way, what are we what are we doing here? Seeing as though we're every other animal is better at something than we are, right? What how do we get here? They got sharper teeth. They got better eyes. They run faster. They can take to the skies. They can swim. They can breathe water. Like what the hell? Like breathe water. Yeah. in the pantheon of superheroes like we suck. Yeah. Yeah. You know, we're the we're the superhero that can we're the shifters, you know, that that that change the shape shifters, right? We uh we can be successful anywhere on the planet because we've got this crazy kind of dual inheritance that we talk about. We have all these cultural inherit from generation to generation about how to survive in different environments. We've got this body that's very we might be generalists in a lot of ways, right? We're good at a lot of different things. Maybe we're not as good at sprinting as some animals, as good at climbing, but we can kind of do it all fairly well, and we end up getting everywhere across the entire planet. Think of another species, I don't know if you could that's been as successful in as many climates. Wait, wait, wait, Herman. The bacteria in your gut are traveling with you. That's true. They are as per the mitochondria in our cells as well. Right. There you go. This was smart bacteria. They knew what what who who to bet on? Who would have bet? Well, you know, I wanted to call the book Protein Robot because I like to think of us as like these kind of damp RVs trundling along the Earth, right? With all of our microbiome on board like passengers with us. Damp RV. Damn, that sounds hard to clean. Yeah, I'm I'm not rating that Uber, right?
But you say in the subtitle of your book, Why Our Biology Unites Us. So where where does that what are we to make of that subtitle? Yeah. Well, so I don't know of any other species that has the sort of adaptability range that we do, right? Um everything from the ways that we learn how to make a living growing up because we have these different cultures that help us adapt to different environments to our physical characteristics that are a little bit different across the globe in different ways often as a sort of local adaptation to different contexts. Um skin color is a great example of that. Uh body proportions are another example of that. And so we are all of us expressions of this sort of shared common superpower that our species has, right? That adaptability is actually the expression of this uh you know the diversity is the expression of the adaptability. And so you know rather than thinking about it as a as dividing us, it actually is showing our common origins in the way. Yeah. I'm just going to let you know you keep talking about diversity and uh some people are going to come after you buddy. Well, you know, I man, I wanted to write this book. When I was writing this book, okay, it was 2022, 2023, and I thought, well, maybe this whole discussion about, you know, maybe the sort of universewide discussion about diversity and all those debates are going to be Pay by the time the the book's out. And turns out, no, we're still very much talking about all this stuff. Uh, and so I'm glad we did. I'm glad it came out when it did. I think, you know, the goal is to have it be this sort of common ground. You know, I want people to understand how the bodies work, why we're all different, how diversity happens, and have it be a kind of common ground that we can talk about these kind of big often polarizing ideas and discussions with a common, you know, a common set of facts, common evidence base. You have your work cut out ahead of you because everything you're saying that unites us, our culture uses to divide us. So, you got some work cut out to you to change the definition of diversity in that way. Yeah, just letting you know.
So, Herman, is there such a thing as a textbook average human? And what are the dangers if we start to perpetuate such a thought process? Yeah. Uh, so no, there's not. Right. Wait, wait, wait, wait, wait, wait, wait. Arithmetically, there has to be an average. So, your question should have asked, is there a normal person? Well, what's normal? Right. Exactly. That's a different thing. You There's always an average. You can always take an average, but it's Oh, but here so here's what I would say about that, Neil. Yeah. To push back a little is uh and and to agree with Gary, which I'm not sure if that's a good idea yet or not. You don't have permission to agree with Gary and disagree with me. We'll see. We've still got a bike to go. Yeah. You know, my introduction to human diversity well began an undergraduate in my coursework, but my actual physical hands-on introduction to this was dissecting a human. Right. And you Yeah. We were in medical school. Uh I I didn't I I didn't go to medical school, but I took the medical school gross anatomy class at Harvard. And so it was me and 50 aspiring doctors, you know, disassembling a person uh on these big dissection tables and every day you show up and you get your tools out of little case and you start taking a person apart and you know, 3 months and 160 pounds of human later, you've seen everything. I know a couple guys in Staten Island who do that for different reasons. Staten Island. Yeah, but pay attention to the nuance differences. That's what I want to know. But what you finally, you know, what you learn very quickly. And the reason, you know, you might think like, why do we bother doing that? It's kind of a oldfashioned way to do science or to learn medicine. But the reason you do it is that you immediately learn that, you know, the the branching of arteries through your torso as it as it comes out from your aorta and starts to feed all your organs. That set of branch that pattern of branching is not the same for everybody. And in fact, you know, often you find uh a branching pattern in the person that you're dissecting that doesn't match any of the variants shown in your dissecting text, right? And that the nerves are the same way. And you know, and that's just the stuff you can see with your naked eyes, right? That our diversity is down to the core. And so I would say if you think about if you think about like a parts list for humans, right? Maybe it's I'd be curious to think about this. Maybe it's 30,000 different parts that all kind of come together into your to make you up. I would bet that just in the same way that there's like never been a perfect March Madness bracket, there is no human that all the pieces match a textbook dissector piece for piece because you might be right. You might be that, you know, similar to the dissector on 99% of them, but there's 1% where you differ and there'll be a different 1% that I differ, etc., etc. So the mathematical way to say what you just did is whatever average you might obtain, it's not useful because the variance is so high on that average. H because think about it. I mean right you can say an average and you look for someone who matches the average and no one does because everyone is scattered around to the left and right of the average on the chart. So okay, I'm with you on that. How how should that inform us on a sociological level? Yeah. So, you know, once you start to appreciate how diversity what it looks like that it's sort of multi-dimensional, it's not just, you know, for example, skin color in this country is historically used to divide us, right? into into different categories. And if you're black or you're white, you're thought about you're in this category or that category. If you really understand human diversity, you realize that there are sort of subtle differences across all these different modalities. You know, in terms of the way our cardiovascular systems work, digestive systems, skin, of course, sure, nervous systems, all of it. There aren't sort of neat categories that we can box people into. And I think it forces us to kind of to see diversity the way that it is, which is again this sort of individualized expression of these common forces, right? So it's a it's a an expression of our humanness, right? Rather than, oh, you're in this box and I'm in this box and we can kind of caricature it and pretend that we know something about you just because we put you in this particular box. That's not actually how the body works or how diversity works. How diver So to that point, I read a pretty cool paper out of uh I forget which part of Harvard, but was the basis for the predicate there's no such thing as race. And that race is a completely manufactured construct and it was based on what you just said that which is there's no box in which you can put enough people to say this is what white is or this is what black is. Uh, but the thing that I didn't really understand was how the scientists from Korea had more in common with one of the scientists from the Netherlands than one of the other scientists from the Netherlands on a biological level. Like that was part of it. Yeah. Yeah. So, I mean it depends on what they're measuring genetic differences or that kind of thing. Take this. Here's a kind of toy example, but it's a real biological phenomena. Blood types. Okay, blood type, right? So, I don't know if you know if you're type A or type B or type O, whatever it is. All of us in this four, the four of us sitting here might have all the same blood type, right? Maybe we're all type A. And that would mean that we have the same genetic variant. And in that way, in that particular locus, that gene, we're all more similar to each other than other people who have type B blood. All right? So in that measure, we're all a group and we're all different from somebody else. If we go by skin color, the amount of melanin in our skin, right? Well, there's differences in that, right? Who has more melanin who doesn't have as much melanin? Um, and that might break us down differently. So there's an unlimited number of boxes that you could Exactly. And not only that, but the there aren't even hard edges on the boxes because if you look at something like skin color in this country, we often put people into sort of black or white. But of course, skin color is everything in between too, right? So, especially if you look globally, there's no, you know, you get everything from pretty dark because you have a lot of melanin in your skin to very light because you have very little. And there's everything in between. So, there's no hard edge where you say, "Okay, now I stopped this category and I'm into that category." And of course, President Obama could have legitimately been declared as a white president cuz he's exactly half white, but by his European mother, right? But instead, we call them a black president because of the social norm. Exactly half black. Right. Right. So, so I in in one of my books, I forgot which he imagined him running for president in an African country as the white guy. That's hilarious. Oh, no. That is so funny. Yeah. I mean, historically, it's even crazier. Like, there were people who, you know, groups who now we consider as sort of obviously white in the US, people from, you know, Ireland, people from Italy who in late 1800s would have been considered black. Yeah. Yes. You know, that they weren't white until the powers that be that are because it's a socially constructed power move to make these groups until the powers that be decided that they were in the in the white group that they became white until they felt outnumbered. Yeah. They're like, "We need some help." How'd you guys like to be white? Get ready to leave the world behind because on Paramount Plus, Star Trek Strange New Worlds is back for an all new season of genre bending adventures, romance, mystery, action, space zombies, special guests. This show is going where no show has gone before. One show, infinite adventures. Don't miss the new season of Star Trek Strange New Worlds premiering July 17th with new episodes on Thursdays only on Paramount Plus.
So her if we look at the latitudes here on Earth, how have humans adapted in terms of their biology to survive at these different latitudes? Yeah, there's a So that brings up an important point to start with, which is that a lot of the variation that we see in head shape, size, all the different physical characteristics we see. This is a all the rage in the late 1800s was how long versus how wide your phenology. Oh yeah. Yeah. Yeah. If you were dulosyphalic or brachioalic or all these things. Yeah, I remember that. So almost all of those kind of variations are just noise and slush and genetic mutation that's tolerated because there's no strong selection to to to get rid of it. Right? So a lot of the variation that we see the superficial variation a lot of that is just sort of tolerated noise. Now that said, there are cases where you have a strong enough selection pressure that's that's localized and strong enough and and longlasting for generations to generations that you get local adaptation to a particular circumstance or particular pressure. So latitude is a great one. So I have to clarify something here. Correct me if I'm wrong, Herman. When you say adaptation, you mean those who don't have their variation die so they don't propagate their genes. So no organism adapts. You're talking about the ensemble statistics of a generation where only some that happen to have the variation walk through the precinium into this next world where they can survive better. Yeah. I just add to that that you can one way to to sort of lose that game is to die. The other way to lose that game is to not have any kids or not have as many as your DNA into the future. Right. Gotcha. Okay. Pick it up. Sorry. So latitude is a great example of a pressure that's stable over time. Uh you know the Earth has been spinning on the same you know the equator has been the equator for a long long time and it's been hot at the equator for a long long time and colder towards the poles. And so that heat differential, for example, has shaped body shaped, size, and proportions. We see uh populations near the equator that are on average tend to be taller, thinner. People populations near the poles tend to be a bit stockier and heavier. And that's because you want to get rid of heat if you're in a hot environment at the equator all the time. You want to hold on to your heat if you are towards the poles. So the physics of that I think we have an explainer on it where if you are rounder you are better insulated against losing heat because how are you going to lose heat? Through your skin basically the more round you are. Yeah. And and if you ever see a pigeon in the winter they puff up. They're very round. Or cats when they that cats do the same thing. They make themselves round and round when they're cold. And we do that too. We'll we'll bring our arms in. Well, the fur and the feathers come up and they trap a layer of air. That helps too. Yeah. Yeah. But also try to round themselves. Whereas in the in the summer, the cat is all esplou on the pavement as that's so true. Like and it's so funny when you look at lions, they lay stretched. Yeah. But when your cat is cold, and they're very similar, they wrap up. So Okay. So, I just want to make sure that the listener got the physics of what you just implied there. Absolutely. Yeah. Yeah, I got a So, there's a a fun field story there, a piece of my research that kind of touched on this in a way I wasn't expecting. We do research in northern Kenya. There's a population there. They're called the Dosich. They live with their their goats and camels and cattle. It's a pastoralist group. They're like the Messiah. You might have be more they're more, you know, you might have heard of the Messiah. It's a similar kind of population. And we started work there in 2017. And we were talking to one of the uh NOS's charities that had set up shop in this little village called Ilarette. There's this German uh charity. We're talking to the the head of the charity and because you know we wanted to get a sort of health and nutrition research project started. We thought we should talk to people who have been doing health and nutrition sort of outreach and he said, "Oh, it's terrible. It's terrible here. Everybody, all the kids, you know, 70% of the kids are malnourished here." And we thought, "Oh my gosh, that is really that is terrible." And so we kind of thought about that and kept that in our our minds. And as we're kind of visiting that village and the surrounding villages, it doesn't square though with what we're seeing because these kids don't look malnourished. These kids are running around happy, laughing, you know, families are big. Um people look healthy. And so we thought if they say that they're malnourished, then that's important to know. But that seems, you know, counterintuitive based on just interacting with this population. Fast forward a couple years, we've got ourselves a big data set on thousands of children who've been measured from the day they're born every few months to the time they're five or six years old. And what you can see when you look at these kids heights and weights is that they're born around the same size as all the other kids on in the world. And then they start to their weight starts to fall off a little bit, but their height goes grows fast, right? So they're by the time they're three, four years old, kids in this population are taller than three or four year olds in most of the rest of the world because they have been adapted that population has been adapted to be tall and thin. And so this German charity was looking at the ratio of weight, which was the same as everywhere else, maybe a little bit low, to height, which was tall because they were adapted to be tall. That ratio looked bad. It made them look malnourished, too thin, too light. They're just skinny. But they're built they're they're actually they are built to be skinny. So once again, there's a European bias brought into Africa to pass judgment on who's there. Yeah. Well, that'll be the folks. So So had the Kenyon anthropologist gone to Germany, they would say, "Y'all some fat ass folk, right? Too much BRZ. Too many BRZs, guys. Got to cut back." Yeah. But uh I mean and it's you know it even goes further because the you know the Nairo folks from Nairobi who I was working with those folks from Nairobi aren't part of that ethnic group. They don't share that same you know to the same extent that same kind of tall thin bodybuild right? And so I'm actually more similar to my Nairobi colleagues even though our skin colors are different on that dimension than either of us are to this northern Kenyan population that's tall and thin. Right? So like the whole to to to even begin by using the kind of American racial categorization to try to make sense of what's going on there. You're sunk from the beginning. It's folly. Yeah. Yeah.
All right. Isn't there an example of adaptability with people in the Andes and then acrossing the Himalayas, they're living at a similar altitude, but one of them will suffer altitude sickness. One of them won't. Why? Yeah. What's up with that? Yeah. Yeah. So, people, humans have uh gone into the high altitude parts of the world. Three big examples of this. The Ethiopian plateau and those populations aren't well studied. So, we don't know a whole lot about that physiology. The Himalaya, right, Tibet, Nepal, and that's been well studied. We know a lot about that. And the Andes in South America. And these are all independent evolutionary forayas into high altitude. And the problem is you don't have any oxygen up there. The air is still 21% oxygen, but the air pressure is so low that there just aren't as many molecules of oxygen available for you to get into your bloodstream. And so everybody's oxygen starve at these uh high high altitudes. And so there have been independent evolutionary changes, adaptations to this same uh this this real challenge of getting enough oxygen in the Himalayas. There is an alil that helps determine how much red blood cells you make. So, okay, let me back up. Red blood cells are the cell that carries oxygen. You need that. And they have a tough job at altitude because there isn't enough oxygen to go around. And so, what most people do, uh, and most populations do at altitude, you make a lot more red blood cells. Your body responds to the oxygen debt by making more red blood cells. And that's good for a while, but it makes your blood thicker and can lead to altitude sickness. And we still see a lot of altitude sickness in the Andes for example. They haven't kind of their bodies haven't figured out how to to deal with that. In the Himalaya, they don't have this issue of altitude sickness. Why not? Because there's an alil that uh has been gone to fixation. It's completely the norm the norm genetic variant in the Himalaya that helps them deal with oxygen debt without overproducing red blood cells. They produce enough to get to keep the oxygen going but not overproduce it and get sick. They also have bigger lungs. They have a bigger spleen, which is this reserve blood uh red blood cell tank that we all carry around. So, there's a whole bunch of adaptations that go to to try to get enough oxygen in.
So, where do the Neanderols fit into that particular scenario in the Himalayas? Yeah, I wonder if you wanted to go there. So, let's do it. Let's do it. Call them out. So, the first thing you have to understand is that humans historically have slept with anything that they encounter. Don't look at me and say that. And so humans, right, homo sapiens, we evolve in Africa about 300,000 years ago. And as we sort of become so successful, so adaptable, our superpower at full display, we get into Europe, we interact with Neandertols there. What do we do? We admix with them to use the sterile scientific term. And we have children. And um and we can still see the genetic evidence of that today. Um, a quick question I have to slip in there. You said 300,000 years ago we come out of Africa, get into Europe and admix with the Neanderthal implies Neanderthalss either left Africa earlier or evolved as Neanderthal in Europe. Yes. Now we know from DNA testing that pure Africans have zero Neanderthal DNA. So there must have been some deep European origins of the Neanderthal. Is that correct? Yeah, that's right. Whether it's deeply in Europe or sort of into the near east is much debated, but yeah, it's outside of Africa. So you know, humans and Neanderls of course have a common ancestor about 600,000 years ago. Those two branches go their separate ways. Ours in Africa, theirs in the near east in Europe. And at some point they become what we would consider to be the the Neanderl gene pool. And when our branch comes back in and overse intersects them again, we have these uh maidings and this ad mixture. And so we are fertile with each other because we have the same common ancestor even though we're many years such a recent one down from from the line. And an interesting fact that I discovered in my own work for star messenger that book was we grew up with the archetype of this stupid backward Neanderthal. Yeah. There the the caveman that knows nothing, right? Like that never that never, you know, stopped dragging its knuckles. Then we find out that black Africans have no Neanderthal blood. Yet there's ad mixtures in current European white people. And only then did papers, research papers start saying how creative and inventive thoughts were. There's a complete shift in the early 1990s. Herman, am I right here? Hermit, talk to me, Herman. Yeah, I mean that that's one retelling. I think that's pretty that's fair to the history of what happened there. I think there was already a reimagining of what Neanderls were like before that. But not that I saw Gary even Gary Larson was full full in on the on the backward Neanderthal. Not to mention the uh the Geico guys. Yeah. I would say that populations outside of Africa all have a little bit of neandertol in them because as we kind of get out of Africa into the near east and those inter those mings happen those genes kind of get washed to every population that's kind of downstream of that right? So Asians native Americans will all have a little bit of neanderl in them left over from that kind of crossing event that happens uh in the near east and euro that makes sense because it's you know those were the crossroads all those areas outside of Africa were actually the crossroads for tra for human travel. So it kind of makes sense. Yeah.
So there's this great example of another kind of discovery from ancient genome. But by the way, all this is mind-blowing stuff. It is it is from DNA that we've gotten out of fossils, right? Which is sort of that's that's mindblowing. Jurassic Park completely. And we've discovered a whole new species of human ancestor or human relative I should say that's Neanderl like um in Asia called the Dennisovvens. Oh about that. No I heard about that. I didn't know anything about that. But so the Dennisovvens were they contemporary with the Neanderthal. Yeah that's right. That's right. Kind of Dennisovvens go one way humans Neanderls the other way and then Neanderls and humans split a little bit later. So they're even a kind of more distant relative of us in a way. So just I'd like because I'd like it knowing what's the etmology of Neanderthal and the etmology of Denisian. So Neanderls are so named because those initial fossil was found in the Neander valley and in German valley is tall. So it's Neanderl. Oh and that's why it's Neanderl and not Neanderthal because t h a l is tall in German. That's if you want to get pedantic America. We pronounce it how we want. That's right. That's right. That's fair. And then uh don't encourage him. Don't encourage him. And then um and then Dennis Silvin are found that the site is the original site is Dennisova. It's a Dennisova cave in uh in Siberia somewhere, I believe. Okay. Yeah. And they had just a couple finger bones. And those aren't really diagnostic. You can't figure out what species it is just from the bone, from the morphology, the shape of the bones. But they drilled into it, got the DNA out, and go, "Holy, this is a whole other group. This isn't Neandertols, and it's not Homo sapiens. It's something else." And that was the discovery that there is this, you know, unappreciated species that we didn't even know about. So, they got the DNA from the bone marrow. Any of your bone uh material will have cells in it. So, yeah, that's not just the marrow, but any of it. I I Why does DNA last that long? It's a pretty delicate molecule, isn't it? It doesn't last kind of fully intact. So, your DNA, if you stretch it, if you took all the DNA of your body and you stretched it out, you'd be dead. That's the first thing you should know. But second of all, uh it would get to like the moon and back or something like that. All your DNA stretched out. Then we discovered that not only is there this other species of human relative, but there's evidence of mating with them as well. Oh, so it wasn't just Neandertos, it was also Dennisovvens. And then you find out that this this gene variant that has been so key to the success of Himalayan groups, where did it come from? It came from Dennisovvens. Wow. So, you know, so there were these mating events with Dennisovvens. That gene variant ends up in the human gene pool sloshed around. Doesn't give you any advantage at sea level. you know, only when those populations begin to go up at high altitude does it turn out, oh, by the way, that variant's actually really good at high altitude and then it becomes the the variant that everybody has because of the selective process of, you know, reproduction and survival.
So, let me ask you this just for the sake of people being able to visualize what we're talking about. Yeah. because it seems like you're talking about different species. But what I'd like is if you were to take pictures of our DNA and superimpose them, what would that look like and how alike or different would we be between us and the recent between us and the recent ancestors? So, Dennis Ovenans, Neanderl, Homo sapien, and then you take those pictures, you kind of superimpose them. What would it look like? Yeah. So this is exactly what we do when we get the genetics to begin with to try to make sense of it. The best way to picture it is like a tree, right? So imagine a tree where all the branches are very hard clustered very tightly around the crown. That is the entirety of the human species over here. And then there's a branch that comes off real low and ends up over here somewhere. That's the Neanderl branch. And then it's like you discovered, oh my gosh, I didn't look closely enough. There's a branch that's even lower and goes out even a bit further and that's the Dennisovven branch. Okay? Right? And so if you were to overlay the A's, T's, C's, and G's of the genome on top of each other, you'd find they're very very similar. Um, all of those individuals, you have to really compare them at thousands and thousands of base pairs to to sort of see that clustering just because all mammals are pretty similar. All primates are real similar, right? You know, and so all these ancestors and relatives are real similar, too.
Take me back to when we went from grunts to articulate speech. Oh, that's an amazing What's up with that? That's very hard to know for sure. You got Morgan Freeman on me. What happened for us to have grunt versus speech? Oh yeah. Well, the so the anatomy of that is pretty well known. The the anatomy of the vocal tract for example has changed which allows us to have uh this sort of two compartment vocal tract, right? So your your larynx is down here real low and that gives you a vertical component to sort of shape the frequencies that come out of out of your your lungs as you you make noise and then you have this horizontal component from your the mouth and and those get shaped differently and give you all the aeu sounds. So we know the anatomy of speech very well when that evolved. Yes. Right. That is really hard to know for sure. And in fact, I don't think anybody knows for sure. We know it had to be at least when uh homo sapiens made it with Neandertols cuz somebody had to say, "Hey girl, what's happening?" Bring your fine ass on over to this cave right here. Let me holler at you. Thank you, Chuck, for reenacting. It's like we were there. Yeah, it's almost like we were there. Yeah. They say time travel is not possible, but I don't know. There you go. Okay. So, okay. Wait. So, but I heard that our ability to form sounds as you articulately described the two-dimensionality, the frequency and volume and texture of the of of our vocalizations that this was a genetic defect, if you will. from whatever was going on in the grunting community. There was some genetic alteration that changed it. So wait, this is we all share this mutation. Yeah, it's a mutation. It's a mutation. So everybody else was like, and then somebody was just like, oh dear, you're so ghost. My god. Exactly. What is it? I mean, seriously, is this how we're going to communicate? So, we don't want to think of speech as a as a mutation. We want to think of it as a as an adaptation. And maybe maybe there's no difference, but yeah, we want it to be we want it to be a feature, not a bug. A feature. Exactly. So, all adaptations start off as mutations. Oh. Ah, there's another t-shirt. So, you know, natural selection is the survival of the fittest, but mutation is the arrival of the fittest. Oh, nitra. Yo, that is dope. Oh, another t-shirt. We're in the motion. The arrival of the fittest. You need variation. You need mutations for natural selection to go. Oh, yep. That's the one that's going to work here and that one's not right. If there's no variation, if there's no mutation, there's no way for natural selection to happen.
Let's look at this situation of adaption of our environment. Yeah, the adaptation. You said adaption. I did. I know. I'm making them up as I go along. You're embarrassing your fellow Brit. It's our bloody language. We'll use it as we wish. Okay. Okay. You're sitting next to me. You are not uttering adaption. Oh man. I'll see you after class, sir. Okay. Go. So our adaption [Laughter] is being forced to speed up because of the environments we're being pushed into out of rural farming into town city and cities in particular at a rapid rate. That is as a rapid rate. But are we now being mismatched? Are we being confronted with circumstances that you know what this body has evolved for this environment, not that environment? I think the proof is already evident that we are mismatched and and I think it's more not the I'm sorry Herman I'm answer no Herman's got an answer for this I do this sometimes but I think it's more not the circumstance but technology and the circumstance together so for instance in disease we have diseases now which are chronic and major but how long ago were they not Herman oh that's yeah so the populations I live with hunter gather groups and even farming groups that I work with today, they are heart disease free, diabetes free. So the things that we're going to die from, they're protected against. And of course, the flip side is the things that we're protected against because of antibiotics and vaccines, that kind of stuff really gets them. Um, but you know, these lifestyle diseases were only an issue in the last couple hundred years. Hermit, if they're an isolated community, Yeah. That means there are no outside influences uh viruses, bacteria, other ailments that could influence them until they meet someone from the outside such as yourself. So, how many indigenous people have you killed with your That's a lovely question, Neil. I really appreciate you bringing that up. Uh, see, at least he's blamed you and not the British, cuz normally I am go-to for that. blaming you guys. It's time to blame somebody else here. Yeah. But you know, so that but that question raises the point that I think people get wrong all the time, which is people think that there that any human population is ever isolated. That's never the case, right? I mean, there always interactions. There's always gene flow and people flow and migration and movement. So there are no isolated groups anymore. Even these groups that we work with who are hunting and gathering or farming, it isn't that they don't interact with people who aren't. It's just that they like to keep their their their old ways. They're basically the Pennsylvania Dutch of Africa. Okay. No, that's exactly it. Actually, that's exactly what it's like. They they live in a world that they interact with people all the time and but they prefer to keep their own culture. So, you raised this issue about, you know, accelerated adaptation. Yeah. It's the brain, man. Because we have our brains are born unfinished, right? We learn. We we've created this entire cultural inheritance that we each inherit and learn. you know, it takes you 15, 20 years to learn it all so you can be a proper adult, a functioning adult. And so we have all this, you know, and and that cultural evolution can happen much faster than our biological evolution can. So we have these sort of this these two parallel tracks happening all the time. It's really fun thing about humans. There was a study done in comparison on back in the day when there were bus drivers and conductors on board and the health of the driver as opposed to the conductor even though they go to the same place. They travel together all the time. They breathe the same air. They breathe the same air. They see the same people. One is sedentary. The other is obviously mobile stamping tickets and checking up and down on the on the levels of the bus. These are situations now that we have not really been evolved to have a sedentary lifestyle. You talk about the hunter gatherers in Africa. So what are the overall health implications for modern health now that we're finding ourselves mismatched with? Yeah. No, that's it was that was a seminal study uh in the 1950s showing that the drivers who sat all day ended up getting heart attacks at a kind of scary rate. the their buddies who were walking up and down the aisles didn't didn't had healthy hearts. And so that was one of the early clues that physical activity, daily physical activity is absolutely essential for keeping your heart healthy. Um well, why is that? Well, because we've evolved for hundreds of thousands of years in an active lifestyle. That's the way our bodies are built to that's sort of the lifestyle our bodies expect. So you've got paleo diets. There's no way we're going back to a paleolithic lifestyle. No. So, what's what's our answer here? Well, the bus the London bused is a great example, right? Because you have the benefits of activity without having to, you know, cosplay as a as a Neanderthal or something like that. You can It's an example of how you can have physical activity in your daily life. You know, you guys are New Yorkers. You guys walk around the city and and get lots of physical activity. We meet our step minimum every day, right? And it's and it's not just the steps. uh the the last study that came out about New Yorkers who tend to be thinner than most other places in the country. It's the pace at which New Yorkers walk as well. New Yorkers tend to walk a much faster than any other place. So the two together, the fact that they walk everywhere and they walk briskly is what makes we're in a hurry even when we don't need when we don't need to be. There's this lovely study from the 70s by this husband and wife team. They looked at the average walking pace of people down sidewalks and how big the city was. They went all over the world to do this. And the bigger, more dense your city is, the faster you walk. Oh, cool. Okay, that makes sense.
So, Herman, the history of anthropology as applied properly or improperly on our species or on our populations. In almost every case led to some legislation, some laws related to those conclusions. be it to justify slavery to be it to limit immigration. So is there a policy implication that your work would bring to the front that is either progressive or regressive in the history of this exercise? I I think it does have big societal sort of implications, right? When we think about how the body works and we have a fluency in how our different systems work, we use that fluency with how our bodies work to understand diversity. I think that absolutely it's going to and what it's going to do is it's it's going to inform how we move ahead from you know the really old school ways of thinking about the body were very genetic determinist right we move into the 1900s and and and even recent times and it's very environmental you know it's all nurture into the nurture nature debate and I think we're moving to a third period here where we're in a personalized era, right? Whether it's personalized genetics or it's personalized ways of thinking about my health, right? And if we personalized diet, even perhaps personalized diet and if we leave that discussion just purely to the influencers or purely to, you know, the political class that doesn't have any fluency in how the body works or these sort of old school ideas about these sort of caricatures about our diversity, we're going to be in real trouble. So, I think that the book does kind of help inform those big discussions we're having right now. whether it's IQ, whether it's sex and gender, whether it's health and vaccines, whether it's, you know, all of these issues that are right, you know, in front of us today, they all fundamentally rest on how we understand how our bodies work and how our bodies work differently. And so, you know, the book isn't trying to get anybody to, you know, I'm not trying to make anybody think like I think, but what I do want to have is people a common evidence base for us to have those discussions. A fluency that we can have these discussions usefully and meaningfully. So, I think there are silent implications. I think the way that they shake out are going to be hopefully make make things better for everybody. And because of that, I'm cutting your funding. That's it. You no longer have a dime. Yeah. I I would laugh harder if it was uh so I say if it wasn't so true. If it weren't so tragic and true.
So Herman, thank you for returning to Star Talk. Yes. Oh my gosh. We miss a fun conversation, guys. Thanks. We miss you. You have a a unique combination of expertise that deeply informs what we care about here on Star Talk special edition. So that means we want to sort of have access to you further going forward. Hey, I'm always happy to be your uh your evolutionary anthropologist on call. I'm here. Everybody should have ahead. Yeah, now you say it. I want one, dude. Delight to speak to you. Thanks for enlightening us yet again. Thank you. All right. And of course, we're all going to look for your book, Adaptable: How Your Unique Body Really Works and Why Biology Unites Us. All right, the word unite is something we need today. So, thank you for being a part of that conversation. This has been Star Talk special edition. Neil deGrasse Tyson here, your personal astrophysicist. As always, keep looking up.
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