Science Friday - Frozen Frogs, Yeast, Paleobotany. April 27, 2018, Part 2

Episode Date: April 27, 2018

When winter comes, animals have several options for survival. They can leave their habitats entirely for warmer environments, search for a cozy cave, or even find insulation under a toasty snowbank. And if you’re a wood frog in chilly Ohio or Alaska, or the larvae of a certain wingless midge in Antarctica, you might also just stay put, and freeze solid until the sun returns. But to survive such extreme low temperatures, the bodies of these animals have made some special adaptations: sugars that act like antifreeze, and processes for keeping ice outside their cells to protect their tissues. Yeast helps your bread to rise and beer to brew, but did you know that there’s yeast in the guts of insects? Or that your body is covered—and filled—with yeast cells? In this segment, recorded live in Miami University’s Hall Auditorium in Oxford, Ohio, mycologist Nicholas Money helps Ira uncover the hidden world of the humble fungus. His new book “The Rise Of Yeast” details some of the ways that the ubiquitous microorganism has helped shape civilization, from baking to biotechnology. Paleontologists and anthropologists might look to the fossilized bones of early hominins to help fill in the evolutionary story of our species. But paleoecologists like Denise Su, curator and head of paleobotany and paleoecology at the Cleveland Museum of Natural History, are more interested in what type of environments these early human ancestors were living in millions of years ago. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato coming to you from Miami University's Hall Auditorium in Oxford, Ohio. I think we can all agree that human civilization is pretty complicated. There are different elements that made us the complex creatures we are today. Some might say fire. It allowed early humans to set up camp or language helped us develop large groups. My next guest said there's another driver of civilization, yeast. You heard me right. yeast, the simple fungus that you bake with. He's here to unlock the mysteries of yeast and what it's done for us. Nicholas Money is the author of the new book, The Rise of Yeast.

How the sugar fungus-shaped civilization. He's also professor of botany at Miami University in Oxford. Welcome to Science Friday. Thank you for having me. You're a mycologist, right? That's somebody who studies mushrooms? Mushrooms and other fungi. That's right.

What is yeast? Is a plant, is an animal? What is it? So there are about 1,500 different species of yeast, and these are single-celled fungi that reproduce by forming buds. And so they're structurally simple examples of other fungi, things that produce mushrooms, much more complicated structurally. But yeast is a surprisingly complicated thing in its own right.

One thing that's, I find interesting, culturally, is that. Mycologists like me that study fungal biology don't tend to know much about yeast. And similarly, yeast biologists rarely refer to themselves as mycologists. They would say that they're cell biologists that happen to use yeast as a model system in their experiments. But they would rarely regard themselves as mycologist, people interested in going out into the woods and finding mushrooms. You guys are sort of separated. You study how mushrooms transport their spores, and we have some video clips. I want you to explain what's going on in this video clip here.

So this fungus here is a fungus called pylobulus that grows on the dung of herbivores, and it shoots this packet of spores, that black thing that you see at the tip of this filament contains tens of thousands of microscopic spores, and this beautiful organisms, gorgeous thing, fires its spores into the air, it's its mechanism of of dispersal and it's shooting that mass into the air about 30 miles an hour but the acceleration is astonishing. The acceleration is tens of thousands of G because this thing's going from a standing start to going kaching in literally in in millions of a second and so what we've done

here at Miami University is to use high-speed cameras to actually capture these these beautiful movements. I mean, they're fantastically interesting scientifically, but they have an artistic beauty also. Is the mushroom, the flowering part of the plant, of what we're talking about? So there are no flowers

that are produced by mushrooms and other fungi. I mean, they're not related to plants closely at all. They're much more closely related to animals, including us, than they are to plants. So there's no flower, but it's a reproductive structure. So let's talk about the yeast. We were talking about

yeast tonight. How does yeast get around? Is it in the air all around us? So that's a good question. So with hundreds of different species of yeast, some of them are in the air a lot of the time. And in fact, they're actually an important cause of asthma, particularly childhood asthma. They're throwing up tons of megatons of these spores into the atmosphere every year, and we're inhaling them. We're inhaling them right now in this room, undoubtedly. But the The particular yeast that we used for baking and brewing is, it's a bit paradoxical. We don't know how it gets around.

It gets around on us, and then we carry it in our, the things that we use in breweries and in vineyards, but it never gets airborne. I shouldn't say that. It gets airborne within the guts of insects, things like wasps and hornets will carry it around. So that's what's happening in nature,

that insects are carrying brewer's yeast around. I know that this part of Ohio played a big part in how we use use today. Charles Fleischman, right? Absolutely. Is he the creator of the dried little yeast packet? It's named after him started in Cincinnati? That's right. So the first commercial yeast plant in the United States was established in a community called Riverside

that's now incorporated into the city of Cincinnati. And Charles Fleischman and his brother were Jewish immigrants from Austria. They arrived at the end of the Civil War here, and they imported processes were making compressed yeast cakes that were, at that point, this was some big business in Europe, but bread in America was really awful until the Fleischman's introduced this practice. It was lumpy and it didn't rise properly. And so the Fleischman's just revolutionized baking in this country. And if you drive along River Road in Cincinnati today, there's a place, and you'll see it as River. It's a ballpark. There needs to be a historical marker there. I mean, this is the birthplace of American biotechnology. And there's no marker there at all. I bet you can still find traces of yeast in the soil. But yeah. It's interesting how you put the word need in when we talk about yeast.

Cincinnati also a center for brewing in America, right? Is it the same yeast? Is it the same yeast in beer that's in the bread? It probably is, actually, in terms of the one that Fleischman used, they probably took yeast that was being used in the local breweries. So breweries like Christian Morline's brewery was established in the 1850s, and still brewing wonderful beer today. So, yes, it's what we regard as the same species anyway.

So the yeast has to be alive, then, for it to do its job. And how does it stay alive on the shelf like that in those little packets? Well, it's in a freeze-dried form. So it's life in very, very slow-mo. So most of the water contents being removed. So it's in suspended animation, if you like, sitting there on the grocery store shelves until we add water.

And then this seemingly miraculous thing. I mean, it is miraculous, isn't it? Comes to, well, it's not miraculous. You really love your yeast. I do. I've grown to love yeast. And we don't have a great deal of choice about that since right now every person in this room is teeming with yeast cells on our surface and inside us. Yes, right up there in the balcony. Welcome.

Hi. My husband has some sourdough starter from 1885 that we've been making bread with all these years. He got it from his father who got it from a guy whose grandfather started it. He started it at a Montana lumber camp, where he started it. he was a cook. And I was just wondering, is the yeast that's in the sourdough, would that still be the original yeast from 1885? That's a great question. So some of the sourdough bakeries in San Francisco, so Budan, for example, they've been baking bread since what, since the gold rush. And they actually claim that it's the same strains of yeast and bacteria that are in their sourdough starter that they were using back late 19th century. But unless you're actually keeping

some stock in a cooled state, you know, mutation is occurring, so it's changing genetically over time. But clearly the stuff still works. And I've heard lots of stories of people that do maintain these sourdough starters for years. It's a different yeast, though. The one that we use in general for baking and brewing is a thing called Saccharomyces, the sugar fungus. But we're But the sourdough yeast is different. It's a species of a thing called candida. But the important point about sourdough breads is that they have bacteria, species of lactobacillus that are actually responsible for acidifying

and giving that sour taste to the bread. You say that yeast is more complex than the sun? I mean, tell us what intrigues you about yeast. How does it work like the cell wall, for example? So this picture here, it's an electron micrographs, a very high-powered view. of the interior of yeast cells. And what you're seeing there is indeed, each of the cells has got a wall around it,

but otherwise, if you look inside the cell, there's all of the same components in that yeast cell that we find in our own cells. And that's really what makes Saccharomyces such a brilliantly interesting thing biologically, is we can use this as a model for actually studying the way that we work. And there have been some fascinating experiments

in which, so we've got 46, chromosomes, yeast has got 16, and scientists have been actually replacing some of, they've got six of yeast chromosomes right now have been replaced with synthetic versions of those chromosomes that seem to work very well. And this is seen as a fantastically useful tool in biomedical research. Do you have a favorite yeast that? My favorite yeast is one that probably, this is getting a little bit esoteric. We like that. It's a thing called Dyson. DiPadaskus, because when I was...

I could have guessed that one. There's many people. Maybe I should stop there. Anyway, I fell in love with this yeast at the age of 1819 when I went to university in Britain, and a professor said, you should work on this, and I did, and it was marvelous. It was like being Charles Darwin offered a birth on the Beagle. I was going to get to study this yeast as a teenager. And yeah, I've never heard of that before.

You know, somebody... I'm serious. I'm marveling at your interest how you could know at such a young age that you're fascinated. It shows the power of a good professor, doesn't it? That this guy, he sold this to me. You had an unlimited check. I have right here in my pocket a blank check. And I'm going to give it.

Well, I don't have it. But I'm going to say I did. I know you're disappointed. What would you do? What research should we be going? That's a really good question. I think that it would be very, very interesting to focus on researching and we're actually physically manipulating yeast. There's a lot of work that was done

some years ago and actually sort of hands-on experiments on yeast, manipulating yeast cells, seeing the way that they respond, making measurements of the activity of their, the chemistry of their membranes and so forth. And we do live in an age right now where the focus is on the genome of yeast. And I think getting back to some of that very basic cell biological work, And I think that that will be a very interesting way of spending a great deal of money. Thank you very much. Nicholas Money, author of the new book, The Rise of Yeast, How the Sugar, Fungus-shaped Civilization.

He's also a professor of botany right here in Miami University in Oxford, Ohio. Thank you for after the break. I feel like this winter dragged on forever. We meet some animals that have adapted to tolerate harsh temperatures, some even freeze-solid. This is Science Friday. I'm Ira Flato, coming to you from Miami. University's Hall Auditorium in Oxford, Ohio.

Yes. It doesn't feel like spring is ever going to get here. Does it? You know, nighttime temperatures going down near freezing. But just think about the animals that have to live outside, how they must feel, right, in all this cold weather. Well, some of them have found unique ways of coping with the cold. Their tissues fill with something like antifreeze

to prevent ice from forming inside their cells. Some can super cool or they even deliberately let themselves freeze. Hard as a rock. There's a kind of frog that does that. We're going to look at that all in the name of getting through the winter. We're going to take a nice long look at a couple of those animals tonight with an eye towards learning their tricks and maybe applying them to help out we humans in some way. Let me introduce my guess.

Rick Lee is University Distinguished Professor of Biology, director of the eco-physiological cryobiology lab at Miami University. Welcome to Science Friday. Thank you very much. Clara Du Amarol is a comparative physiologist and assistant professor of biology at Mount St. Joseph Joseph University in Cincinnati and Miami University alum also. Welcome to Science Friday. Dr. DeRameral, you brought us a specimen from your work of sitting right there in the terrarium.

Yes. So in the terrarium, there are actually two wood frogs, which, which are one of the species of frog that I study, which are freeze tolerant. When you say freeze tolerant, does it really actually freeze solid? Yes, freeze solid. So I could hit it on a table? You probably shouldn't, but you could. How does it do that?

So basically, frogs are what people in general call cold-blooded organisms. And so when winter comes and the environmental temperatures drop low enough, the body temperature of the frog kind of follows that temperature. So they become relatively cold. And so if the body temperature drops low enough, so close to zero degrees Celsius, their body fluids slowly start freezing. So we study how they can actually do that. So they have a series of physiological responses that allow them to survive being frozen. This is here.

We have a photo of a frozen, that's in its frozen state. Yeah. That's ice on the outside? Yes. So it's basically there's a little bit of ice on the surface. And then if you would to actually touch it, you can actually feel like these sheets of ice, like on the ventral side. and on the legs and on the arms. So what benefit does it have from freezing solid rather than hibernating or something like that?

Right. So it has to do with the ecology and the behavior of the frogs. So these frogs, they don't really overwinter in a sheltered environment. They basically hibernate in shallow depressions in the forest floor where they're actually exposed to these low temperatures. And so this is one of the strategies that allows them to basically overwinter in those particular locations. And your work, Richard Lee, is on the largest. animal, land animal that lives in Antarctica. Exactly. I mean, who wouldn't want to work on the largest land animal?

That's right. Right there. What is that? What is it? In fact, I brought some of these for you. You look like a pretty strong guy. Oh, oh, oh, that's heavy. That's heavy. These are tiny little flies and the larvae. Flies and larva? You have both there, yes. That's the largest living land animal. Look, if you're going to be the largest land animal, you've got to stay there 12 months of the year. You can't be the penguins and the seals that come in and breed in the summer and then they leave. You've got to stay there and take it. And so some of these lunkers, I'm not kidding, are six millimeters long.

Well, we have some of the pictures of them on the screen there. Those are the larvae right there. They look like wormy things. That's what every good maggot looks like. So what happens to the larvae? They then... There's four larval stages. It takes two years.

for them to work their way through these stages, this same group of flies around here would complete their life cycle in a single year. But because of the short growing season, it takes two years down there. So they go through their first, second, third, to their fourth end star. They overwinter twice,

and then they emerge as an adult that only lives for seven to ten days. They mate, they lay eggs, they don't feed, and that's their life. I've been to Antarctica. It gets pretty cold in the wintertime. in Antarctica, how are they able to survive in the winter? So when I first went to the Antarctic to study these,

I had done my doctoral work in Minnesota and worked on cold tolerance there, and I said, wow, we're going to get to go to Antarctica and really see some cold tolerant animals there. So we get down there and we do the test, and they're a bunch of wimps. Yes, they can survive freezing, but it turns out that the environmental conditions along the peninsula are pretty mild because the ocean buffers the temperature of the islands and the peninsulas where they live. And so, therefore, they're very rarely exposed to temperatures lower than, say, minus 5 degrees centigrade.

Oh, like Miami. Kind of like Miami. That's right. So this is the banana belt of the Antarctic Peninsula. Well, Clara, let's talk about what exactly does cold damage our bodies in the first place. How does the cold damage our bodies? What's going on there? Well, so there are a few things. So in a fully frozen organism, there's a few things. So first of all, ice in general. So ice in the tissue is pretty damaging. If you think about during winter how you're supposed to leave your pipes running, you know, so that your pipes, your water running so that your pipes don't freeze over. Now think about the blood vessels in these animals, right? So if you have ice forming in them, you can have, you know, damage to the tissue, you can have internal bleeding and things like that. One of the other issues that is happening is when these animals are frozen, they're not really breathing. So, you know, there's no oxygen coming in, carbon dioxide being removed. So there's a lot of accumulation of toxic compounds, so to speak.

And so those are a few of the examples of the things that are basically dangerous and damaging for freezing. You know, Rick, when I was in Antarctic, I was watching them study the Antarctic cod, which has antifreeze. It's the same they said antifreeze that you're put in your car radiator just about. Yes, some of them do. And is this how they have antifreeze? is a method that animals use to survive? So the antifreezes that most insects use are low molecular weight sugars and polyhydric alcohols,

things like glycerol, sorbitol. The blood sugar of insects is triolosa, diaccharide. And so they accumulate these in high concentrations, just like the ethylene glycol you put in your radiating. And so the accumulation, though, is really incredible. It's very much a syrupy consistency. Now this can work in two different ways. Most insects do not survive freezing, but when you have high concentrations of these cryoprotective compounds, that helps them to super cool, remain unfrozen to very low temperatures, minus 40, 50, 60 or below. But if you're freeze tolerant, which a small handful of insects are, they also protect the insect as ice forms in the body. And Clara in animals.

So the wood frog does similar thing. So they accumulate basically cryoprotectants is the name we give to these low molecular weight compounds. And so it's blood sugar. So glucose, it's the blood sugar of vertebrates is what the wood frog accumulates. Another thing is urea. So that's usually a somewhat toxic compound in mammals, but the wood frog is able to tolerate large concentrations of these. And it helps in multiple ways, but one of them is to reduce the amount of ice formed when the animal is frozen.

So it's not exactly like an antifreeze, but it helps to minimize the ice and the damage. So there is a little bit of damage that goes on. I would imagine nothing's 100%. Exactly. And so when the frog defrosts, I mean, it's not anybody's sink dripping anywhere. What's the process like?

How does that happen? So basically, it's actually really cool because they start thawing. Cool is a good word to use it. I couldn't help myself. I'm sorry. My staff will hate me, but that's okay.

It's okay. You're good. It actually starts from the inside. So the core organs, so the heart and the liver are the first to thaw. And so you basically have like the heartbeat is one of the first things that come back. And when you look from the outside, I mean, you don't notice. The frog is like very still. You know, the eyes are kind of like glazed over because everything is frozen. But then slowly circulation starts happening.

Eventually you have respiration coming back. And they're very sluggish in the beginning. And it's super slow. It takes like 12 hours or so. And then eventually the animal actually starts moving. And then, you know, a few days later, it's fully back to normal. Does that give it a jump, head start on other animals? I'm sorry, I forgot.

So many. Well, actually, yes. So right about maybe like a month ago when we had a little bit of the thawing, that's when they actually come out and mate. So the wood frogs are actually like the first frogs, one of the few first frogs that comes out early in the spring to mate. and so they're the first ones to reach the ponds. They hibernating these kind of like temporary ponds.

And so that actually being freeze-tolerant and allowed them to respond so early to the upcoming spring allows them to get to the ponds early, mate, and then, you know, they go on on their business. Well, that is an advantage. Let's go to a question from the audience, yes. So I was recently invited to a salamander migration in mid-February.

And my friend who invited me said that, these salamanders are being radically affected by climate change. And so I was wondering what other animals might also be experiencing while going through these climate change changes. Claire, you want to go first? Sure, great question. So in the case of the freeze-tolerant animals, there are a few issues with the fact that the winters may be coming milder.

Higher temperatures mean that these organisms are basically spending their energy reserves faster. The cryprotectants that they have come from energy stores, and organs like the liver mainly. And so if the environmental temperature is higher, maybe they won't freeze as much, but that also means that they're going through their energy reserves faster,

which means that they may not actually be able to survive the entirety of winter. And then a cold spell comes, and they need to make those crap protectants relatively quickly, they may not have enough to do them. And so they may actually not be able to survive. Right. Similarly, we've seen some insects.

You may be familiar with the Golden Rod Golf Fly, the Golden Rod, the weed, there's a ball gall on it, and there's a larvae within the gall that's freeze-tolerant. And it turns out that if you put those galls in the winter in a warmer microhabitat, they don't survive as well because they burn up their energy reserves too quickly. So that means that for them, colder is better for their winter survival. Wow. Let's go over here.

Yeah. The tardigrade is another creature, very microscopic, that can survive in some really extreme environments. and I was wondering how some of its survival mechanisms compared to the frogs or the flies that you have studied. Very interesting question and right on target because when we're studying the Antarctic Midge, we're particularly interested in relationship between freezing tolerance and dehydration tolerance.

And some of the same cryoprotective compounds are produced by tardigrades. Now, tardigrades can go down to less than 1% of their body mass as far as water goes. I mean very, very low. However, these fly larvae from the Antarctic, they can tolerate dehydration to about 30% of their initial weight. So we dry them out.

They look like little raisins. They look terrible. And then we add water, and they plump up, and they wiggle away, and I think I can hear them laughing at us. Because they are used to, experiencing different types of dehydration, both from just environmental dehydration, from exposure to salt water. But it also turns out that to survive freezing is all about surviving cellular dehydration, because as ice forms outside the cells, only water molecules join the ice

lattice. That concentrates the remaining solute, and therefore water is drawn osmotically out of cells and that's what probably regulates the lower lethal temperature for these. And so we're looking at cross-tolerance between freezing, dehydration, salinity tolerance, they go hand in hand and not surprising we see some of the same physiological mechanisms for protection. I'm Margaret Flato, this is Science Friday from WNYC Studios. Claire, you're shaking your head a lot. Yeah, so in for verbits it's the same thing.

So there are like these common themes that you see a lot of all of these like extremophiles. So they're, you know, they're usually resistant to tolerant to low temperatures, tolerant to low oxygen conditions, and then tolerant to dehydration. It's like the three major tenets of all of these organisms that can survive freezing, yeah. Now I understand that one of the cool things about this work is that you have to collect your samples in Antarctica year after year after year, and it looks like it to meet some wildlife along the way, some other wildlife.

some other wildlife. That's a lot of wildlife. That's exactly right. Tell us about these photos. What are we looking at? So this is us going out collecting insects. There's no butterfly nets down here. It's a very highly technical process.

It involves crawling around on sharp rocks with a spoon that we've stolen from the kitchen and scooping up these larvae. And then we take them back in the laboratory to study them. You also have some residents that seem interested. We do have some... friends there. These are Adeli Penguins here. And so it's just incredible. When I first

went down there in 1980, I kept saying, I just can't believe it. And I finally can only say, it looks to me like I've walked onto the pages of National Geographic. That's the only way I could relate to it. And that's a very rapidly changing climate now, isn't it? Yes.

And Clara, what about your work in Alaska? That sounds like it could be ripe with adventure, right? Yes, yes. It's pretty exciting. So for one of the projects that I did during my PhD, I had to go to Alaska three different times. And basically we were hunting from frogs. And so we had never actually been there. So we had to kind of scalop multiple locations.

There was a lot of adventure, like canoeing to like these deserted islands, getting lost in the middle of the woods multiple times. And yes, we store our frogs in the fridge. So this is like our hotel fridge. They like to eat hummus and drink Coke? Exactly. So you can see our diet. And then, obviously, you know, our prized collection,

each little cup has an individual frog with a little sponge with water to keep them moist. So, yes, it was like a 10-day trip. You know, every day you're working like 16 hours. You're just gorgeous location. But you're like, I need to get frogs. I need to get frogs. That's like the only thing you're thinking about.

And then, of course, avoiding being eaten by bears or getting kicked by moose and things like this. I hate when that happens. I know, right. What kinds of things can you learn about freezing, not freezing, from these animals? Claire, let me ask you first, that might help benefit our health. Sure, sure, absolutely. So we're looking at these organisms that basically can survive being completely frozen

while we can't take a human heart and freeze it right now. So, you know, most organs have a shelf life of four to 12 hours after they're removed from a body. And if they're not used, then, you know, they're gone. You can't use them. So that would be a great application for the type of work we do. So if we can understand how these organisms can, yeah, tolerate the different compounds, these different stresses, are there things that we can extract from that to apply to, you know,

cryopreservation of organs would be one of the things. And, yeah, one of the issues is many of these cryoprotectants for mammalian tissues are toxic. But if you can figure out how these insects, how these frogs can tolerate such like high concentrations, so maybe you can then translate that to, you know, an actual application for Oregon crypreservation. Wow, that sounds fascinating. I want to thank you both for taking time to be with us today. Richard Lee, Professor of Biology, Director of the Eco-Physiological Cryobiology Lab.

That's Cold Stuff. Cold stuff. At Miami University. And Clara Do Amaral, a comparative physiologist, assistant to professor of biology at Mount St. Joseph University in Cincinnati. Thank you both for that for time to be with us today. After the break, we'll talk about how. fossilized pollens and plants can reveal clues about how our ancient ancestors evolve. This is Science Friday.

I'm Ira Flato, coming to you from Miami University's Hall Auditorium in Oxford, Ohio. Every few weeks it seems like we hear of a new fossilized skull or bone of one of our ancient ancestors, and each of these finds adds a little piece to the sprawling, complicated puzzle of where we came from or where our ancestors came from. And the other important question is how did they live? What was their environment like? Reconstructing ancient environments is called paleoecology, and my next guest is an expert in digging up the clues to our origin.

Denise Sue is the curator and head of paleobotany and paleoecology at the Cleveland Museum of Natural History. Welcome to Science Friday. Thank you, sir. Thanks for having me. You know, when you dig up a fossil of a hominin, one of our early ancestors, you're not really interested in the animal. You want to know what was the environment like around where it was living, but aren't you

missing out on the good stuff when you don't want to know that? I don't think so. Because an environment is really crucial to our understanding of how we evolved. We are part of an ecosystem. What happens around us affects us, and particularly at that time when really, you know, we don't new these cultural interventions that we have today. So it's really important to understand what the habitats were that our early hominy ancestors were living in.

So it's like trying to reconstruct a house and you just have a few of the beams lying around. Kind of, and you have to go and find the rest of yourself. You know, we try to do it from everything because the data is so scarce. And since I'm really interested in the whole ecosystem, that means I'm looking at the animals, the plants if they're there,

the, if there's ancient soil that's preserved and that's great because soil tells us a lot about what was actually going on. It can tell us about the vegetation and then also just, you know, what kind of depositional environment it was like. Let's show everybody what kind of stuff that you get to pick up at a site like this. Now what is this that we're looking at? So this is actually a psyched but this is from a Pennsylvanian. This is from about 300 million years ago. No hominins then. I can assure you. This is a specific. that's from my collection at the Cleveland Museum of Natural History. Now, sometimes we see scientists trying to look at the pollen.

Why is pollen so important to decide? Well, pollen allows us, it's actually vegetation, right? It tells us directly what the vegetation was like. Pollen preserves more easily than the big plant parts, like leaves, because they're preserved in the ancient soil. And does the pollen give you an idea of how old maybe the site is also? Sometimes. It depends.

Usually not, but it does give us a sense of what plants were there. And also pollen can travel very far, so it can tell us about generally what the region's environment was like. Not taking phone calls this hour, but as I say, there are microphones in the audience up there in the balcony and on the sides if you'd like to step up to the mic and ask a question. Now, I know you've worked at a site in Tanzania, right? Tell us what site that was on what you found, because Lucy was nearby, right? Lucy was nearby.

This is Lytoli, Tanzania. This is just in the Ungrown, Grame Reserve. And this is where the famous fossilized set of footprints of Osterpithecus Aphrens was found, and that's a species that Lucy belongs to. And this is a really interesting site because we don't have a large body of water there. I mean, right now there isn't any means. It's pretty barren. It looks like that. But in the past, it was much more wooded. There was more bushland and shrubland. But unlike other sites, unlike where Lucy was found, there was not a large pernip river or a lake, and that really changes the vegetation structure a lot. Why would anybody live in a site? It's a bad neighborhood, is what you're saying. Well, yeah, actually, it was a really marginal neighborhood for afferences. And so you can see the different. in terms of the relative abundance, the population density of afferance is at Lytoli versus

Hadar, which is where Lucy was found. It's much higher over there. Okay, let's go right here to the audience. Question, yes, sir. Obviously, big-ticket items are the full leaf, like the full leaves or teeth or bones, or those are like big-ticket items. Pollan is much more fine, much smaller. What about stuff like insects, like fungus, like the decomposers of our ecosystems? Do those provide more information? Yeah, so insects I don't preserve very well. Actually, the fossil record of insects are, it's very, very poor to begin with. I like Tolli, actually, we do have insect remains, which is pretty incredible. We have pockets where there was basically a seasonal pond, and so there's not very much, it's shallow, it's very calm, and insects and actually different

berries and stuff fell in, and so it was covered and preserved really quickly. So we actually have some insects from Lytoli. When I heard this, I just knew I had to ask you, and you know what I'm going to ask you, right? Do I? I don't know. You've found fossils of bunnies. Yes. Lots and lots of bunnies.

Yes, lots and lots of bunnies. What were they bunnies? Why so many bunnies? Who were they doing? Yeah, so we have lots, that bunnies are actually the most common animal in Lytoli. It is very odd. Everywhere else you go, had our, anywhere else. else it's basically you might get four or five specimens.

And we think it's directly related to the environment, that the environment was just really ideal for them. We have tens of thousands of specimens of bunnies. So there's a graduate student out there who wants to study the evolution of bunnies. Please let me know. Wow. Bummies. It just happened to be the right place, the right time.

I think it was just the right place. The habitat was perfect for them. And plus, you know, bunnies reproduced like bunnies. So if you have a few good seasons, and you know, we're talking about, you know, over time period of this is a 300,000 packet of time. So if you have some good seasons for the bunnies and over 300,000 years, and it's a great environment for them. Right. I'm trying to picture what bunnies eat. If there are so many of them, you know what was the vegetative, what was it like in that area when the bunnies were all? It was probably relatively open. There would have been patches. of lots of patches of grassland, actually.

And then sort of shrubland and bushland and probably riverine woodland along ephemeral river systems. So we didn't have any premonoeuvres there. Wow. Well, this is funny heaven. Let me go. Did we have somebody in the audience? Somebody was, yeah, step up to the mic if you have a question.

How does knowing about the environment that you like to study, how does that help fill in our knowledge about us, our ancient ancestors. I mean, what connection do we have to the bunnies? Well, it really helps us understand how it is that we evolved. There are some really key biological, morphological features that we have today that we don't really know why we evolved them. We walk on two legs, right? I mean, that is our defining characteristics. No other primate does that, at least habitually. And we have no choice but to walk on two legs. And I would argue that us standing up on two legs is the first step towards what we are today.

Our cell phones, can you imagine using that if you were actually running around four limbs? Right. And so understanding this, the morphological adaptations or the origins of this type of really crucial traits for our evolution, it really depends on, I think, understand the context. Now, I know you've also done paleontology work in the Yunnan province in China. Yes. In a site that, what, it's about 6 million years old and an old coal mine? Yep, that's right.

Why is that such a good place? Why are you interested in that? Well, so that was actually a bit of sort of a side trip for me, I guess. Six million-year-old sites are very rare. And so when a colleague said, there are some elephant teeth down there, it looks like it might be that time period interested, and I thought, why not? We'll just go take a look. And it is this coal mine. I mean, it is, as you can see there, it is a big hole in the ground. And it wasn't active coal mine until we started working there.

And it's just an incredible site. And it's a time period that's just not sampled well. And it's a really important time period for understanding human origins, because this is around a time that we appeared. But we appeared in Africa. But there are a lot more apes outside of Africa, in Eurasia. And so it was really interesting to go outside Africa to see what was going on elsewhere in the world during that time period. You found a complete fossilized skull of an ape in the same spot? Yeah, in the same spot. Wow.

It's pretty cute, right? How old is that, would that skull be? About six million years. Six million years. That's old for it. Yeah, it is. And it's actually the latest surviving ape of its lineage. It's, and it's Lufon Pithicus.

And it's this juvenile cranium. It's hard to really estimate how old it was because we don't know what the growth. developmental timing of this apis, but it had its first permanent molar that's already out. Wow, but it's a rare fine. It's very rare fine. There are other Lufonpithecus crania that's been found in China, but they're all pretty crushed and distorted. So this one was minimally distorted, and it's pretty complete.

As you can see, the bones are incredibly fragile. I mean, when we found it, we couldn't believe it. My colleague who was actually the specialist, he's the expert in studying myosal. seen apes looked at and he was like, that can't really be what I think it is, right? Is it a bird? Is it a bird? Is it a bird? Because he was looking at it upside down and the bone is so fragile.

Oh, he's going to kill me that I'm telling the story. It's all right. No one's listening to it. We're among friends. And so it's very fragile and he was looking at it from upside down. And I'm looking at thinking, oh my gosh. I mean, this is, for a lot of people, this is the find of a lifetime. Wow.

Wow, that's great to have. Let's go up to the balcony. Yes, question from you up there. Step up to the mic. Yes, thank you. There's a lot that's been written recently in the last couple of decades from Lorraine Cordane on about nutrition in Paleolithic time. I was just curious. I've always wanted to ask an actual expert what their thoughts are on what we ate and kind of what our activity was maybe two and a half million years to

to pre-agricultural times? Well, probably a lot of just what could be gathered, really. We don't really know the exact kinds of vegetation that was in. We do know that early hominins ate a mixed of sort of C3 and C4 plants, so anything with fruits and leaves. And then C4 plants are usually in Africa, are grasses. They probably weren't eating the grass blades themselves, but they could have been eating the grass seeds or the sedges.

And by the time you get to two million years, they were also eating meat. Now, whether or not they were hunting or scavenging, that's a perennial question. But meat would have been part of the diet as well. We're talking with Denise Sue, in case you just joined us, she is curator and head of paleobotany and paleoecology, the Cleveland Museum of Natural History.

We are here in Miami University Hall Auditorial, in Oxford, Ohio on Science Friday. Thank you. Science Friday from WNYC Studios. How does what you're finding in China inform what you find in Africa? Are they linked or how does this all connect in your mind? Yeah, so six million years, this is really that transition period, sort of the end of the Miocene fauna, basically.

This is the group of animals. animals that came before really sort of we came along. And so at this site in China, actually, can see this transition of the apes, which is a relict, part of the relict fauna from before six million years. And then this new intrusion, these new migrants, we also have a monkey there at the same level.

And this is the first time that an ape and a monkey has been recorded from the same place and the same time. And so this, and we have this mix of fauna that's really more, one that's older, that is from older time period that's adapted for a more moist and wooded type environments, and then ones that are adapted for drier and more open environments. And these are the newer lineages that are coming in from the outside.

You look very excited about your work. I love my work. I think it's, I mean, I'm amazing who'll pay me to do this. Oh yeah, that's right. Don't tell my boss. Don't tell your boss. So, okay, let's talk about then, the history of your work.

Do you remember your first fossil find? Do you remember? Yes, actually. I was 20. I went to a kubi fora, which is in Kenya, and I found a primate radius. I was incredibly proud of myself. A primate what? Primate radius, so sorry.

The arm bone, one of the arm bones, the one on the thumb side. Where did you find it? At kubifora, it's next to Lake Turkana in Kenya. That's a very rich place. It's a very rich place. Fossala thing, yes. And so you were, all excited about that? I was incredibly

thrilled. I was the only person to find a fossil that day, so that made me even more proud. Wow, it's good. You thought of yourself as being Mary Leaky at that moment? You know, I don't know what I thought myself was Mary Leaky,

but I thought this is the most incredible feeling I have ever felt, and I was hooked. And that was it. I went back, changed my major, and here I am. That's hard to get that feeling back again, I would imagine. And another fine, have something as... Maybe not quite that rush, but I have to admit every single time I go out to the field and I find a fossil, it's still such a thrill because no one else has seen that in 3.6 million

years. I'm the first person to pick it up. And it's an incredible feeling. There must be, if I were to do that, I would have some self-thous. doubt. Yeah. Right? Well, I'm not a scientist, but I would say, I can't be that lucky that I'm the only

person who's ever seen that. And that's what I mean by the self-doubt. Can this really be what I think it is? My first year on the field, yeah, I felt like that all the time. And you have to get your eye in, your search image in. Although some people never quite pick it out. We have graduate students who, you know, who they're out there for five weeks. And by the time they, at the end of it, they're still picking up rocks for the most part.

Wow. Yeah. Well, we're very happy to have you here. Well, thank you. Thank you for taking time to be with us today. Thank you. Denise So is the curator and head of paleobotany and paleoecology at the Cleveland Museum of Natural History.

That's about all the time we have. Our heartfelt thanks to Gregory Crawford, Patty Libertor, and Pate Rudolph, Kevin Reynolds, and all folks at WBXU and Cincinnati Public Radio. And everyone here at the Hall of Aquarian for making this wonderful evening possible and to our production partners at the City University of New York.

Thank you all for coming.