Science Friday - Answering Evolution Questions, Planetary Protection. Aug 4, 2023, Part 2

Episode Date: August 4, 2023

We have a new podcast! It’s called Universe Of Art, and it’s all about artists who use science to bring their creations to the next level. Listen on Apple Podcasts, Spotify, or wherever you get your podcasts.   Protecting Other Planets From Earth’s Germs For decades, people have been trying to figure out how to avoid contaminating other planets as they explore them—an idea called planetary protection. As missions venture forth to places such as Mars or Jupiter’s moon, Europa, the need to protect worlds that could support life becomes more critical. And at the same time, as space programs begin to bring samples back to Earth from places like Mars or asteroids, planetary protection becomes a concern in another way—the need to protect Earth from potential unknown life forms from the cosmos. Sending humans to another world raises the stakes even more. NASA has a limit of no more than 300,000 spores (single-celled organisms) allowed on board robotic Mars landers. But human bodies contain trillions of microorganisms, making it impossible for human missions to achieve the same level of microbial cleanliness as robotic landers. Dr. Nick Benardini is a NASA official responsible for ensuring that the proper precautions are made to prevent humans from contaminating outer space. Ira Flatow spoke to him about how to avoid spreading microbes between planets.   Ask An Expert: An Evolution Education Most people raised in the U.S. were taught about evolution in science class growing up. But how much do you actually remember? Charles Darwin’s On the Origin of Species or Gregor Mendel’s pea plant experiments may ring a bell, but it’s likely most of us could use a refresher. A good grasp on the science of evolution is extra important these days, argues Prosanta Chakrabarty, author of the new book, Explaining Life Through Evolution, and curator of fishes at Louisiana State University. In 2008, Louisiana’s governor signed the Louisiana Science Education Act, which allows schools to teach creationism as an alternative to evolution. Chakrabarty joins Ira to talk about the science behind evolution and take questions from listeners. Read an excerpt of the book here.   To stay updated on all-things-science, sign up for Science Friday's newsletters. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Listener supported, WNYC Studios. This is Science Friday. I'm Ira Flato. A little bit later, we'll be taking your calls about evolution. What would you like to know about evolution? Well, you can ask an expert. Yeah, our number 844-724-8255-844 side talk. But first, remember the Orson-Wells radio drama,

and then the movie War of the Worlds, where the Martians try to conquer the earth, they actually start winning, and then mysteriously, they die. It turns out they die from what? The common cold to which they have no immunity. Science fiction. Yeah? Well, what about reality? What's to prevent just the opposite from happening?

I mean, a space probe returning from space to Earth, bringing foreign microbes to our planet. I bring this up because next month, NASA's Osirius Rex probe will bring the first sample of an asteroid back to Earth. The capsule is projected to land in Utah's desert, and scientists hope the sample of asteroid dust on board will help them get a snapshot of our solar system maybe 4 billion years ago. But is there any risk to bringing back material from space to Earth when we don't entirely know what's in it? Well, let me give you the flip side. What about when we send missions to other planets or moons like Mars or Europa? Could we accidentally contaminate them with Earth microbes? Here with me now is someone who thinks a lot about this question and questions like this.

Dr. Nick Bernardini is NASA's planetary protection officer based at NASA's headquarters in Washington, D.C. Welcome to Science Friday. Thanks for having me, Ira. Thank you for coming. Let's talk about a serious RECs projected to return to Earth next month, as far as we know, there's no life there, but how do we ensure that anything from that asteroid does not contaminate us? Yeah, that's an excellent question. So for planetary protection, we have a whole series of international scientists and engineers that think about this on a regular basis called Committee of Space Research. And so they put forth international guidelines.

and current understandings together and frameworks for what exactly is the type of potential science that can be conducted on these target bodies, as well as the type of potential for life on these target bodies as we go explore the solar system. And so we know that Osiris Rex is what we refer to as an unrestricted Earth return sample. this is of lowest likelihood of life or harboring life. And so we actually don't have any restrictions for bringing that asteroid material back, much like, you know, comets or much like our comments and other asteroids that we would bring back. How do we know, Dr. Benardini, how do we know what to look for if it's something we're not used to?

Yeah, so this is exactly one of the conversations we have all the time. What is life? What do we think about life in the unknown, unknown space? And so we have a lot of conversations in the science community and international community about, you know, sample safety assessment. Really, what would we look for with life? And that gets down to, you know, understanding what life looks like from a physical or molecular perspective. what it looks like from an organic perspective. And so we use all of these clues that we can about life as we know it to infer about potential of life on other planets.

And so on Mars, for example, we see those signs. But on other asteroids such as Osiris Rex and Benu, we don't really, we don't see that. And so we're able to make those guidelines more unrestricted versus having. them more restricted like we would for our Mars sample return mission. Yeah, we have been exploring space since what, the 1950s. Have we improved in our space exploration techniques so that our spacecraft do not unintentionally bring back alien microbes such as on Osiris Rex? Yes, so we've definitely improved both in our obviously engineering capabilities as well

as our science knowledge. And all of those directly feed into our policies. a lot of our approaches that we take. For example, our understanding of clean room technologies and how we make sure that we can leverage these clean rooms which control particulates and organic molecules. So when we go to life on other planets, we don't inadvertently detect our own life because we built the spacecraft dirtier in what we thought.

That's just one of the examples of the types of advancements that we're using nowadays. You know, I started off mentioning a science fiction movie and the sci-fi movies we see in them we see extreme examples of what could happen when an alien pathogen infects earth people think this is not real because it's just something they see in the movies but you think of this every day absolutely we don't think of it in terms of you know hollywood or kind of this sci-fi angle but really more of it a scientific and evidence-driven perspective and that you know on mars itself we we never

know that, you know, for example, the samples that we're collecting right now are going to be lower likelihood to harbor life than, you know, a deeper depth or cave type of sample. So we have these scientific inferences that allow us to help develop that risk posture for thinking about what we need to do to ensure that the public is safe and that our spacecraft are clean when we go to visit other planets. Let's talk about that visiting other planets because one planet we visited a lot. is Mars, and I remember going way back into the 70s, Viking. Were these planets, were these probes pristine when they landed on the planet?

So that's a common misnomer, is that, you know, is that we send sterile or clean spacecraft. Matter of fact, we can't, given, you know, the fact that we humans have life and the rooms that we assemble and test and launch operations all have. some bit of biological presence, although that's not saying that it's completely dirty. We highly control these. We're talking, our spacecraft are less than half a million organisms per spacecraft. That's compared to think about perhaps a probiotic that you might take on a regular basis. That probiotic is 40 times more organisms than what we allow on our spacecraft to go to Mars.

Yeah, but when we went to the moon, the Apollo astronauts left an enormous amount of human poop on the moon, didn't they? So, yeah, so that's certainly something that we have to mitigate in thinking about when we introduce humans is what we do with, you know, human waste streams and what the microbial transport could be just because of those humans being present. And let's imagine an astronaut gets sick in space. Just sky with me now. How does scientists determine, how do they determine if someone who gets sick in space, it's because of in-flight sickness, a pathogen from Earth or maybe a planet, some other pathogen that snuck in? How would you know that?

Yeah, so that's exactly the type of work that we're doing right now with our knowledge gaps and planning for moon to Mars. And so, you know, we have the luxury right now on the International Space Station. that if an astronaut gets sick, you know, we have several days we can get that astronaut back down to Earth for medical attention. You know, once we start talking about lunar surface missions on upcoming years, you know, some of that may be upwards of a week before we can get that astronaut back to Earth. And then even Mars is particularly more time-consuming from orbital dynamics perspective. We're talking upwards of 600-plus days depending on when that astronaut were to get sick. And so we have to think about that a little bit different than what we do currently with our International Space Station astronauts.

Do you have special testing kits that would quickly diagnose that? Yeah, so that's what we're looking at developing with the Office of Chief Health and Medical at NASA. And so we need to, you know, kind of work through from a planetary protection perspective and a built environment's perspective if it's, you know, a human-associated organism or if it's something from Mars. And so we're working to fill those knowledge gaps and to develop a framework for that kind of decision-making, you know, within this next decade. One question that I always get, and I've been talking about this for quite some time, is from people who do not think we should be exploring other planets.

They think we should be focusing on the problems here on Earth. It's a good point, given all of our problems with climate. climate change, why do you think we should explore other planets? And why should we be so concerned about bringing our environment over there? Well, I think from a perspective of going and exploring, I think obviously it's human nature to go explore. And I think from having other planets and being able to have that curiosity, I think that's essentially inherent in our human DNA. There also is a lot of potential spin-offs that we've seen throughout the years with NASA products that we might need for space that put into our daily lives and impact Earth. I'm thinking Velcro also perhaps a lot of our environmental life support systems that we have for water cleaning coming up.

So I think there's a lot of cross-pollination and cross-potential for, you know, the technologies to be fed forward into improving our Earth life that we see on a regular basis. Do you think we need a better technology for sterilizing, to use a better word, the craft we send out, especially for going to Europa or some other place? So I don't think it's necessarily the sterilization. I think it's more along the lines of how do we keep it clean. That's really the hardest job that we have. So whether that's thinking about different types of bio-barriers or protective shields after we keep it clean, perhaps it's more stringent types of clean processing. And we're leveraging heavy right now on the medical sterilization industry with high heat, vapor hydrogen peroxide, you know, solvent types of cleaning methods.

very similar to, you know, med device, for example, or pharmaceuticals. Yeah, we look forward to talking more with you and learning more about this. Thank you, Dr. Bertadini, for being with us. Welcome. Thank you. Nick Benardini is the Planetary Protection Officer at NASA. We have to take a break, and let me come back. We're going to back to, yeah, let's go back to the biology class. For a crash course on the science of evolution, what would you like to know that you always

wanted to ask. We have an expert. It's ask an expert this hour on Science Friday. Our number 844-724-8255-844-Sight-Talk. Stay with us. We'll be right back after this break. This is Science Friday. I'm I, Myrop-Fledo. We're heading back into the classroom for the rest of the hour. A bit of Biology 101. I mean, most of us were taught about evolution in science class growing up, right, but how much do you actually remember and what questions do you have now that you were afraid to ask the teacher back then? Well, my next guest has written a whole book about the science of evolution, how it has changed everything from bacteria to humans. So it's time for you, our listeners, to ask an expert about evolution. There are no stupid questions, only questions

that don't get asked. A number 844-724-8255-8-4-Sy-Toc. Or you can tweet us at Cy Fry. Let me introduce my guest. Dr. Prasanta, Chakrabardi, author of Explaining Life Through Evolution, which will be out next week on August 8th. He's also the curator of fishes at Louisiana State University in Baton Rouge. I don't think we've ever had a curator of fishes on the program before. Welcome to Science Friday. Welcome back. Thanks. Thanks, Ira. It's great to be on the show with you. It's nice to have you. Let's start by talking about what inspired you to write this book. because I know you live in Louisiana, a state where anti-evolution science education is law. Was that partly?

What inspired you? Yeah, absolutely. That was probably the first thing that got me putting pen to paper was these anti-evolution laws that were passed by the legislature from Bobby Ginger era. And they're still there. Yeah. Is this an American phenomenon? I mean, the question of evolution and how to teach it? It's not just American, but it is.

sort of uniquely something special about some countries for sure. So India just stopped teaching evolution at the K-12 level. Turkey recently stopped, basically banned teaching evolution as well. But the way we teach it and the way we've dealt with it in the United States is sort of state-by-state has been pretty unique. You know, you have found that you mentioned this in the book because I can relate to this. You talk about that some people have a fixed mindset about something, let's say they don't believe in evolution. There's virtually nothing you can do about it, right? No amount of data will change their minds.

They have a belief system of what you call mistrust. And as I say, we have found that here talking with people on this program. Tell us about what you have found. Yeah, and that's always been my goal is not to convince somebody of one thing or the other just to explain that. evolution is how we understand and explain the origins and diversity of life. And this is how scientists understand it. This is how I understand it. And I can't make somebody's belief system collapse in a way that they need to see the science of evolution the same way I do.

So I don't go out to sort of change their mind just to get them to understand. And hopefully that might start a little crack in their understanding to get them to think about science. a little bit differently. So to gain trust first, I think, is the most important thing before they start to understand what you do and how you understand it. Getting trust is a hard thing. Yeah, sure. It's very hard. There is a famous mural, I think we've all seen it, called the March of Progress, depicting evolution as a progression from monkey to chimp, then to a hunched caveman, leading directly to modern man. You show it in your book, and you say this image has done more harm than good trying to better explain evolution to people. Why do you say that?

Yeah, it's an interesting figure that's usually the shorthand people use when they say evolution. And it shows this progression from sort of what we expect to be lesser beings to us. And so it looks like evolution is goal oriented, which it is not. It looks like we're the top of, you know, the pinnacle of evolution, which we're not. You know, there is no pinnacle. There is There is no goal. It's much more of a fanning out from that origins of life and to the diversity of life we see today. So, you know, an amoeba or, you know, a cardinal that we see today is also the descendants of that first life. And it wasn't leading to us. Monkeys aren't evolving into us. We are apes. We have common ancestry. Common answer. Different. Different. Yeah. Yeah. How do we know that evolution is real? Let's get that right out of the world. way quickly. Sure. For me, the best evidence is we can look at what we call the tree of life, this connection of relationships between all life on Earth through the DNA that we can examine

and compare and study. And we can put fossils on that tree of life. So we can place where we're fossils that we find almost every day fit within that three and a half billion years of life on Earth. So for me, the evidence of evolution is all around us. It's in our body. You know, we don't have a perfect body. In fact, we have many what I'd call flaws or not perfect, perfectly fit elements, including our backs and knees. So for me, the evidence is everywhere. Well, we have some, I said that I'm going to give my listeners a chance to ask everything they wanted to know, and they have so many questions. So let's go right to the mat in Rome, Georgia. Hi, welcome to Science Friday. Hi, Matt, you're there. Hello. Hey, there.

Yes, Ira. Hi, how are you? Hey, how are you? Great. Go ahead. So I love reading about human evolution, and I find it interesting to read about Neanderthal populations that lived alongside homo sapien population. And then from my understanding, we're considered two different species.

But then I also read that we were mixing with the two populations, and we even carry neandesal genes with us today. So my question is, how do we know that they were two different populations, and if so, how can we have nandesol genes in us? Yeah, great question. Great question. What do you say about that, Prasanta? Yeah, it is indeed a great question, Matt. So in part, you know, our closest living relatives are chimpanzees,

but our closest relatives that we know about in the history of time were neanderthals. So we are Homo sapiens and they were homo Neanderthalists. And there are, in fact, many people in the U.S., your people of European descent that have about 2% of their genome, has Neanderthal in it. And how does that happen? Well, we have not one or two Neanderthal ancestors, but maybe many. That's how you can have those remnants of another species DNA in our own genome. So there was a bit of, let's say, hybridization going on between our species. There's also some controversy about whether Neanderthals were, in fact, a different species.

Perhaps we were so close that they don't deserve to be in their own distinct species, and there might be a subspecies of Homo sapiens. But for now, I think most people are going with them being separate, but that there was quite a bit of hybridization maybe 25,000 years ago or so in Europe. Matt, does that answer your question? That's great. Thank you so much. Thank you. You're welcome. All right, let's stay with the flow here. Let's go to Fred in Bellingham, Washington. Hi, Fred.

Welcome to, let me sure I got you on the air. Welcome to Science Friday. Oh, I may have, let me try Fred there. Fred, hi, welcome to Science Friday. Am I on? Yes, you're on. All right. I've been wondering for some time whether life has emerged more than once on Earth. Is there a unique evolutionary line? Hmm. Oh, deep thoughts today on the show. I wonder that same thing. So we know that we can connect all life on Earth living today to a single common ancestor. However, you know, life probably had many spurts and starts and maybe some missfalls before that.

So we can trace the earliest life on Earth from fossils to about three and a half billion years ago. but maybe in the time between the origin of the earth, about a billion years before that, and that three and a half billion years, there were multiple origins. And what we see today is the who survived from that one common ancestor. So maybe, I mean, it would be great to know. We just don't know. We know that life evolved at least once, but perhaps more than once even before that. Cool.

We have a comment, a question from Twitter. when does the line get crossed from a new species? Jake and Little Rock wants to know. Yeah, that's a case-by-case basis. So if we look at populations that are diverging, if they are close together, if they don't have a geographic barrier, sometimes that can take a very long time.

Other times, there are species like ferns that can duplicate the number of chromosomes they have, and in an instant, they're a new species, essentially. So it just depends. It depends on the group and how reproduction happens and how much hybridization, like we talked about Neanderthals and humans and homo sapiens. So it depends, and it's not always something

that everybody agrees on here. Right, right. Well, speaking of agreeing on, has our understanding of evolution evolved? I mean, let's say since Darwin's on the origin of species? Sure, absolutely. Yeah, Darwin, the great evolutionary mind, didn't know about genetics, and he didn't know about hormones,

and he didn't know about many of the things that we use to study evolution today. So a large part of what he explained was natural selection and adaptation, but he couldn't explain neutral evolution, which is genetic drift, and the other mechanisms that we know and understand today about how species change and evolve over time. How much do in common do we humans, we modern humans have with, let's say, algae, bacteria, single cell organisms? For me, that's one of the most amazing things about us in particular and the life on Earth that we see today is how much of our genes are shared. So I think there's something like 60% of our genes that we have, and we only have about 20,000, 25,000 genes, are found in things like banana.

You know, there's so much shared genes, genes that we got from viruses, you know, bacteria. There's so much crossover. And so, you know, onions and strawberries have more DNA than us. And how that makes us us and how it makes them that is just the marvel of life. And so there's a lot of cover. You know, I learned that this last week I was up in Maine at the Scudic Institute. and I had a great time with those folks up there. And I was watching what they call rockweed,

which is the seaweed that grows on all those rocks in Maine. And a scientist was telling me that people don't know that seaweed is not a plant. It's an algae. And in fact, because it is an algae, it's closer genetically to humans than it is to plants. And I thought that just blew my mind. And mushrooms. Mushrooms are closer.

You know, it's like fungi. The whole tree. you know, it's an unbelievable and it's amazing. It is because you say in your book that nothing in biology makes sense except in the light of evolution, and that's sort of what you're talking about.

Yeah, if you attribute that quote to me, every evolutionary biologist is going to roll their eyes, but I'll take it. It's from Theodosius Zibzanski. And yes, it's true, though. Every time I think about any part of biology, if we don't think about how we've changed and transformed over time

and how life has moved us to where we are, it's very difficult to explain without evolution. Let's go to the phone. Before we go to the break, let's go to Chris in Cleveland. Hi, Chris. Hey, Ira, how are you all doing? Hi, nice. Thanks to have you. You got a question for us. Yes, sir, I do. Believe in evolution. Actually came about Australia physicists from May. But yet none of them referred to anything in the Bible, especially in the beginning of Genesis, where it talks about where mankind came from. And I'm quite certain that God didn't create us to be swinging from treaties or

so do you have an actual answer for that? Good question. Why it seems to be so complicated that when we go to Revelation, I'm sorry, Genesis the answer is right there. Okay, good question. Let's see if we can get an answer. What do you have to say about that, Prasanta?

Sure, and people have their understanding of how our origins came from and some have a biblical view and I don't want to change anybody's minds about that. We could stop studying everything if we just believe in our religious texts and leave it at that. And so in Genesis, you know, if you follow the Genesis version, you can accept that,

but also have a scientific curiosity, which many scientists hold both religious beliefs and scientific ones. And so our origins can both be something that includes the three and a half billion years of our understanding of how life has changed over time, and includes us being mammals and being apes and being vertebrates. And also, if they want to believe an origin that includes a creator, I have no qualms with that, and many scientists don't. We don't need to pick or choose one or the other. I think it's best to let people believe how they want to believe, but also understand how the scientists understand their own work.

Chris, I hope that answers your question. Thank you, gentlemen, very much. You're welcome. Thank you. On number 844-724-8255, this is Science Friday from WNYC Studios. Talking about evolution, when did you, Dr. Chakrabati, get interested in this? Yeah, and I always loved animals. I'm a New York City kid, and I grew up and go to the Bronx Zoo and the American Museum

and Natural History and look up at the dinosaurs and wonder where they went and where they came from. and that led me down this slippery slope where I am now to studying evolution at Louisiana State University. And you're a little, as you said at the beginning, you're upset that the evolution can't be taught the way you think it should be in schools. Yeah, and I fear that it's going to be worse. There's some legislation that may come down throughout the United States that may change how we study the separation of church and state. is that definitely being challenged. And I think that's unfortunate. I think science should only be taught.

Science should be taught in the science classroom and nothing else. And any other intrusions of non-scientific thought will muddy our understanding. And so it should just be science being taught. Quick question from Joe and Orlando. Hi, Joe. Joe, are you there? Yes. Hi there.

I had a real quick question for you. I say the extent of my education evolution went back. high school in Florida where it's watching inherit the wind and the scopes trial. So forgive the, that's all I got. Quickly. So if we see apes now out in the zoo, will they become humans at one point down the line? Okay. I take my call off there.

Okay. No, they won't. Like we talked about the depiction of primates turning into humans today, that's not how evolution works. We share common ancestry, but things. alive today are not turning into humans. Their evolution is progressive but everything is moving in its own direction and not necessarily

towards a goal. So there was one point in common ancestry that there was a branching off instead of a following after. Exactly. So different animals branched off and chimpanzees did not become humans.

They just branched off into it. They had a common ancestor. Yeah, indeed. million years ago. It's hard to overcome some of these biases that we were, you know, taught in school and grew up with. But we're trying to do it. Our number 844-8255. We have to take a break. And when we come back, we'll take more of your calls about evolution with Prasanta Chakabrardi. Author of Explanning Life Through Evolution. Stay with us. We'll be right back. This is Science Friday. I'm Ira Flato. We're continuing our Ask an Expert segment. and this time about the science of evolution with Dr. Prosanta Chakrabardi.

We're taking your questions. What do you want to know about evolution? Our number 844-8255, if you'd like to talk with us, and we certainly welcome you. Dr. Chakra-Bardi is author of Explaining Life Through Evolution, which is out next week on August 8th. Dr. Chakra-Bardi, do you find it difficult to explain evolution to people? I don't. I try to think about my own understanding and how I came to learn and appreciate how beautiful the ideas are of evolution. And so I like sharing it and I move me to write this book and I hope people like it and understand it in a way that I do now. And I hope that works.

Let's go to the phones. Elijah in Cleveland. Hi, Elijah. Hey, there. Can you hear me, Elijah? Yes. Yes, okay, cool. Thank you so much for having me. Okay, so my question is we're talking about, you know, chimpanzees or, you know, apes involving into humans. There's a very popular video out there that you may have seen where AI predicted what human evolution is going to be, in which it goes from, you know, ape to man really quickly,

and then it goes from man to machine, and then it goes from machine to just a symbiotic, all you see at the end of it are, you know, tubes and pipes and the wires, you know, there aren't even robots anymore to where it just seemed like it would be a symbiotic collective of what the human mind created. How did they eat? The whole world would be nothing but wires and tubes and is AI going to benefit the planet kind of thing. Yeah, okay.

I get you drift. I get the drift. Let me get a, thank you for calling, Elijah. Let me get a comment. Sure. I'll stick with organic evolution, you know, how we understand our own body is changing. And there's a great book by Scott Solomon about future humans. and he goes into that a little bit.

I'll say that, you know, the beginning of that question started with, you know, we turned from chimpanzees into humans, and again, that's not how it works. We share common ancestry. Yeah. Not only, excuse me, not only as we talk about anti-evolution crusaders

being in many states, but many states have been dealing with anti-LGBQ bills. And you argue in your book that variations in sex and you, gender and sexuality can all be explained by evolution. Tell us about that. Sure, and I'll just start by saying, you know, first, you don't need an evolutionary biologist to tell you that the spectrum and diversity of life includes the spectrum of genders and sexes and sexualities. We can be nice to people and accept people for who they are without an evolutionary biologist

telling us, but there is this, we know, across diversity. of life of the species we know that there are different genders there's different sexes and species you know not everything is male or female there's many intersex people there are lots of ways that we can explain gender that are dealing with hormones and not necessarily something that matches your chromosomes or what's in your pants right and so our understanding of human sexuality and and genders is different than our understanding of how we test and study life on earth. But it's something that I think people often are asking, you know, why do we have people who aren't part of the reproductive group of people, you know, when they think about evolution?

And so for me, it's better for people to have an understanding of this diversity of genders and sexualities and I'd be accepting of it and not use evolution as some way to discredit how people live their lives. You have an example that might be a little shocking to our listeners who are fans of the movie Finding Nemo about how some fish have evolved, clownfish in particular. Yeah, clownfishes are sequentially hermaphroditic. So they all start off as males. and then the biggest one becomes the big dominant female

and bears the next generation. So if you remember the opening scene of finding Nemo, when Nemo's mother gets eaten, what would happen was B. Marlin, the larger clownfish surviving, would become the large female. Perhaps then, you know, another individual male, maybe Nemo himself,

would start a new family that way. And that's so, there's some strange things happening in the animal kingdom for sure or we would consider it strange from our human perspective. And we don't have anything like that in humans, but there are plenty of examples of this sort of non-binary

roles of sex in the animal kingdom. Let's go to Rebecca in Pensacola, Florida. Hi, Rebecca. Welcome to the program. Oh, thank you. Go ahead. I am a teacher, and I was just wondering how

your expert whose name I do not know because I tuned in a little hearty to the program could explain how I could explain to children like for example one of our in our elementary curriculum we talk about giraffes and how you know they evolved to have the longer neck so that they could reach the you know the food at the taller branches and like that's explained to children but then they you know proceed to ask other questions and I'm trying to think out how we can dumb it down without having them go home and say, you know, Ms. So-and-so was teaching me that, you know, what I learned at church is not true. And I did hear the caller who called in about Genesis, and I completely understand that,

but I'm trying to kind of dumb it down for children without getting super, super de-defer technical, but without causing, you know, parents to call the front office and say that, you know, we're not doing the right thing. So how you can teach it without saying the word evolution in it? No, no. I don't. Well, and I hate to say that because, I mean, the curriculum has the word evolution and the standards do teach, you know, well, and it's more probably adaptations, like animal adaptations and how their adaptations have evolved over time in order to help them, you know, adapt to their environment and survive.

know, survival is a citizen and all of that. So, yeah, I guess I'm just trying to figure out a way so that when they, because they're, you know, kids are inquisitive and curious and they want to know more, especially if this is something they haven't been taught. So I'm trying to figure out a way to kind of dumb it down for children. Okay. Let me just tell you, you're talking to Prasanta Chakrabardi, who wrote the book explaining life through revolutions.

I know you tuned in late, and that's who you're talking to. Just wanted to be polite on that. Yes, Prasanta, do you have a suggestion? I do, and I think actually the caller did a great job at explaining evolution there. I like when I'm talking to children, I like to couch it in terms of competition, at least the adaptation, natural selection part. And so I like to think of there being many individuals being born, and you can talk to the kids about their siblings and how they compete for resources even within the house.

And so, you know, if they want to have the most cookies or if they want to gain access to something, being taller, may allow them to do that compared to their sibling. And so I get them thinking about the giraffe, if you will, the taller drafts being born of those offspring can survive by reaching the most leaves, the highest leaves. And those that don't don't make it and may perish. And so I like, it's a bit of a dark competition story, but not everything can survive. Not everything that is born can survive. And so those that are best fit, does have those adaptations to survive in that environment, do so. And those that don't, don't. And so those that live move on to make the next generation with those adaptations.

So I usually try to put it in terms of siblings and other classmates, if you will, in terms of competition. hope that helps Rebecca yes it does I can envision the children saying like picking the shortest kid in the room

and saying you're out but yeah and then make sure the shortest kid knows that he can reach some stuff maybe the tallest kid can't right so they might work both ways

gotcha okay well thank you for that you're welcome thank you for calling yeah a lot of people have especially teachers have challenges to face.

I think so, and I hope this book helps them a little bit. It's meant for a general reader, so hopefully some school teachers can clean some stuff out of there for their classroom. All right. Let's see how many more questions we can get in. Let's go to Nathan in Springfield, Missouri. Hi, Nathan. Nathan, are you there?

Yes. Hi, go ahead. Yeah, I'm actually going to switch my question up a little bit just because I think we've already answered the one that I had initially. with the science of epigenetics and all of the new research that's coming out, historically I've always been taught that evolution was kind of based on random genetic mutations. However, whenever you take into account epigenetics and how much the environment really does sway those mutations, has that affected your research when looking back, kind of rolling back the timeline and looking at some of these

major mutations that have led to very, very successful species. For me, epigenetics is especially important, not just for my work, but I have identical twins. So, like, whenever I see... Can I interrupt and just explain for our audience what epigenetics is? Yeah. So epigenetics is many of the non-heritable changes that happen. So if somebody is a smoker, they may pass down to their next generation changes environmentally induced differences. So it's how your environment and DNA are interplay.

That interplay is epigenetics. So it's not just reading the DNA. It's how the environment and your genes are working together to produce different proteins or to produce different behaviors, for instance. So it's sort of this cloud around your DNA, how it's being read, can be determined by the environment in part. And so epigenics is extremely important. It explains like why if I put one of my identicals growing up in middle-class American family

versus one growing up maybe in a poor family in India will look very different, right just how their environment is impacting how their DNA is being read but i would say you know the heritable changes are still largely genetic and so although mutations can happen everywhere um the ones that are passed down in the egg and sperm are the ones that matter for heredity but epigenetics is certainly something that we're learning more and more about and their power is incredible in transforming how we act and might explain a lot more than the need to be able to be able to be able to even we know right now. This is Science Friday from WNYC Studios.

Talking about evolution with the Prasanta Chakrabardi, author of Explaining Life Through Evolution. We've talked about natural selection. What about unnatural selection? And I'm talking about here humans breeding domesticated animals to have certain traits. Are we playing a hand in evolution here? Sure.

Darwin starts actually Origin of Species with two kind of boring chapters on pigeons and domestic breeding of them because he wants to show that artificial selection which people understand better and that's the breeding of different breeds of pigeons

or dogs is the same thing that's happening in nature but to your question of how how are we impacting the world well we're also not just using artificial selection from breeding, but we'll start using CRISPR, these gene editing tools, and how that will change how evolution works. That's a big open question that we're still learning how we're doing that now. Interesting question. A tweet coming in from Flavio. He says, how music became so important. Is it

involved in evolution? I mean, every community has it. Yeah, for human evolution and questions like that, it seems like, you know, if we backtrack into, you know, what makes us successful, maybe what makes us successful versus species that lived with us, like the Neanderthals and Homoinaletti and other species, maybe it is we survived because we had these communities and maybe those communities had music and had religious inclinations or some beliefs that they were shared that allowed us to survive when other human groups. didn't. You know, other human species didn't. And so, yeah, that's an interesting question. You know, it's true. Everybody makes music and everybody seems to enjoy music. Maybe that's part of

our evolution, but it's a little bit beyond my scope of expertise there, too. Well, let's talk about the limits of your scope of expertise and not questioning, you know, how good you're at it, but what do you want to know that you don't know now? And what would it take to find that out. The biggest question in evolutionary biology is about the origins of life. And, you know, we know life evolved, and

life has a common ancestor. But what happened in those steps where we go from maybe that was something that was very, very simple, a few protein-building amino acids to something that could self-replicate.

Was it RNA? Was it something like a virus with rival? was it something extraterrestrial? You know, those early origins of life on Earth, that's the mystery of mysteries, as Darwin put it. You know, that's the real part that we're trying to better understand that we can reconstruct some things, but it happened a long time ago,

and most of that memory is erased from the fossil record. So that's still the biggest question, and the one I'd love to know the answer to it. The primordial soup that you're talking about. I guess if you understand the primordial soup here, you might be able to understand it on some other planet or moon or something like that. Yeah, I'm glad you said moon because that's my bet too. It's like something like one of some of Jupiter's moons that have more water than we do.

Yeah, yep. You and Arthur C. Clarks. Thanks for taking time to be with us today. Great. Thanks for having me. Prasanta Chakrabardi, author of Explaining Life Through Evolution on Sale next week. He's curator of fishes at Louisiana State Eighty. University in Baton Rouge. And if you want to read an excerpt from the book, head to our website, Science Friday.com slash evolution. One more thing before we go, we want to say goodbye to Gretchen

Smell, our Newmark J-Corps audience intern for the summer. She was such a pleasure to work with these last few months, and we wish for the best of her luck in her journalism career. If you missed any part of the program, you'd like to hear it again, subscribe to a podcast, or asking a smart speaker to play Science Friday, and of course, we're active all week on social media, Facebook, Twitter, Instagram. You can email us, yes, the old classic way. Remember email? SciFri at ScienceFriday.com.

Send us feedback. Tell us what you'd like us to cover. Have a great weekend. We'll see you next week. I'm Ira Flato.