Science Friday - Which Feathered Dinosaurs Could Fly? | Some French Cheeses At Risk Of Extinction

Episode Date: February 20, 2024

How Do You Know If A Feathered Dinosaur Could Fly?Not all birds can fly. Penguins, ostriches, and kiwis are some famous examples.It’s pretty easy to figure out if a living bird can fly. But it’s a bit tricker when it comes to extinct birds or bird ancestors, like dinosaurs. Remember, all birds are dinosaurs, but not all dinosaurs evolved into birds.Scientists at Chicago’s Field Museum wanted to figure out if there was a way to tell if a dinosaur could fly or not. They found that the number and symmetry of flight feathers are reliable indicators of whether a bird or dinosaur could lift off the ground.Ira talks with two of the study’s co-authors about their research and how it might help us understand how dinosaur flight evolved. Dr. Yosef Kiat is a postdoctoral researcher and Dr. Jingmai O’Connor is the associate curator of fossil reptiles at The Field Museum in Chicago.Sacre Bleu! Some French Cheeses At Risk Of ExtinctionThere’s bad news for the Camembert and brie lovers out there: According to the French National Center for Scientific Research, some beloved soft cheeses are at risk of extinction. The culprit? A lack of microbial diversity in the mold strains used to make Camemberts and bries.As with many foods, consumers expect the cheese they buy to be consistent over time. We want the brie we buy today to look and taste like the brie we bought three months ago. But there’s a downside to this uniformity—the strain of Penicillium microbes used to make these cheeses can’t reproduce sexually, meaning it must be cloned. That means these microbes are not resilient, and susceptible to errors in the genome. Over the years, P. camemberti has picked up mutations that make it much harder to clone, meaning it’s getting harder to create the bries we know and love.Joining Ira to talk about this is Benji Jones, senior environmental reporter at Vox based in New York City.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.

There's bad news for the Camembert and Bree lovers out there. According to the French National Center for Scientific Research, some of our beloved soft cheeses are at risk of extinction. They're concerned that the microbial diversity needed to make these cheeses is dwindling dramatically and therefore we may have trouble making them in the future. It's Tuesday, February 20th, but, mon dieu, today is Science Friday. I'm Cy Freight producer Kathleen Davis. As with many foods, consumers expect the cheese that they buy to be consistent over time.

We want the brie that we buy today to look and taste like the brie that we bought three months ago. But there's a downside to this uniformity, and it's making it harder to create the cheeses that we know and love. We'll get to that story in just a bit, but first, what feathers can teach us about the evolution of flying dinosaurs. Not all birds can fly. I'm looking at you, penguins, ostriches, and kiwis. Now, it's pretty easy to figure out if a living bird can fly, but what about extinct birds or, say, bird ancestors like dinosaurs? Remember, all birds are dinosaurs, but not all dinosaurs evolved into birds. So scientists wanted to figure out if there was a way to tell if a dinosaur could fly or not. They found out that the number and symmetry of flight feathers are reliable indicators of whether or not a bird or a dinosaur could lift off the ground. Pretty interesting, isn't it? Joining me now to talk more about their research and how it might help us better understand how dinosaur flight evolved are my guests from the famed field museum in Chicago, Illinois. Dr. Yosef Kiat, postdoctoral researcher, and Dr. Jingmei

O'Connor, Associate Curator of Fossil Reptiles at the Field. Museum. Welcome to Science Friday. So exciting to be here and tell you about this really awesome research that Yosef has led. Okay, Dr. Kea, let's get right to the bottom line. What are the characteristics of a bird or dinosaur that can fly versus one that cannot? So we found the asymmetry of the primary feathers, one of the most important feathers to flying in birds, differ between flying and flightless birds species with only little overlap between these two groups and then we apply this results to the extinct species, I mean dinosaurs, steambeards and non-aviant dinosaurs.

And then we can reconstruct the flightability in this species. And we found that asymmetry of the primary feathers also occurs in some. extinct species and this is mean that this species already have flight ability and the second important result we found

that among modern beards all flying species have 9 to 11 primary feathers when the beards have fewer or more feathers than 11

primaries it must be lightless species. And then we again go back to the extinct species, non-aviant dinosaurs or steambeard. And we found that in some species we can find more feathers than 11. Yosef, when you discovered this 9 to 11 feather feature in the birds that can fly the primary feathers. Were you surprised by this? I'm not surprised because I see it before I try to test it. But after I test it in a large number of species,

yes, it's become slightly surprised that this continue to be a strong rating all tested species. I mean, it's really astounding on my part because, see, Yosef has, you know, ringed, like, thousands of birds. You know, he's caught so many birds, so he's really familiar with modern birds, whereas I'm a paleontologist, right? So I don't really know that much about living birds. If you think about them, they have so many different ways of flying, right?

You know, you have, like, bounding flight and soaring flight. And if you think about the shapes of birds' wings, they come in all different shapes and sizes, right? Some are very long and narrow, and some are big and broad. And despite that enormous diversity, only nine to 11 primary feathers. So yeah, for for Yosef, it was something he noticed while doing research and then tested it and proved it was right. But for me, you know, he's just sharing this data with me. And I have to say, I was quite surprised. And I think it's, it's really, really interesting. And I really hope that this opens up new avenues of research and that developmental biologists, you know, people who'd work on

biomechanics, et cetera. I really hope they jump in on this, this interesting observation and try to help us understand the why that's underneath it. When you say help you understand the why, exactly what why are you looking for? Why do all flying birds have only nine to 11 primaries? I mean, that is a very narrow range, considering this enormous diversity. And so there must be a reason why. And I would, I would love to know why. And then what we notice is that, you know, When a long period of time has passed since flight has been lost, then the wing develops a new function. And the number of feathers changes with those other functions. So, for example, with penguins and their forelim now being a flipper that's essentially used for underwater flight, the feathers are now very small,

but they're now functioning more similar to body feathers to just really insulate the surface of the flipper. that once long, long ago used to be a wing. Wait, wait, wait, I got to stop you there for a second. You're saying that a penguin used to fly? Penguins evolved from birds that were able to fly. Yes. So one of the prerequisites, one of the very first steps in evolving a penguin was the loss of flight.

Now, there probably was an early evolutionary stage where they could basically fly underwater. So if you look at birds that forage in the water, they either forage with their feet or with their wings. Yeah, I'm thinking of carmarants here. Exactly, yeah. And so this early stage would have been having a wing that can function for flying underwater and also flying. But eventually as the animals became more dependent on this underwater foraging ecosystem,

the wing and the whole body shapes ever more for life in water. You were talking about birds that developed feathers earlier in time were different than other birds. Explain that. They had different functionings for their feathers. Feathers are features that all living birds, which all have a common ancestor, they inherited from non-avian dinosaurs. And in fact, you can trace the earliest feathers back to being present in the ancestors of both pterosaurs and dinosaurs. So these primitive early ornithidirons had very simple feather structures that most likely evolved for insulation. And then only in dinosaurs closely related to birds do we see modern feather morphologies evolving. And we know that the arrangement of these

feathers forming a wing-like structure on their forelim also evolved for some other purpose that was not flight. And then evolution basically hijacked this existing structure for a new purpose for aerodynamics, for flight. One thing that we understand from the research led by Yossif is that actually the current fossil record is not capturing the early stages in the evolution of these feathers and the evolution of this proto-wing structure.

Right now in the fossil record is a taxon called caddipteryx. It's an oviraptorosaur. But Yossif's research suggests that this is a secondarily flightless dinosaur. We just think anyone who is investigating this area needs to take the soft tissues into account. They need to account for what the feathers are telling us. And this is something that people really haven't done previously.

People try to understand how flight evolved, but didn't actually look at the feathers that were sustaining flight themselves. You've mentioned secondary flightless a few times. Please explain to me what that means. Why is that a key issue here? So, you know, when we think about one of the most important characteristics of living birds is their ability to fly, but not all birds can fly. And the birds that cannot fly, like penguins and ostriches, but also things like flightless cormorants, they all have lost their ability to fly at some point during their evolution. So they evolved from birds that were able to fly. So this is what we mean by secondarily flightless. And actually something that I think is really interesting about Yossif's research, basically what it says is that

birds that lose their ability to fly are evolutionarily short-lived lineages. Like once they lose their ability to fly, they go extinct within several million years. But in terms of lineages that have lost their flight and have been around for a very long time, there's very few. It's essentially penguins and different lineages of paleochnathous birds like Kiwis and ostriches. If the feather data is correct and cut Codipteryx is a secondarily flightless dinosaur. Then it means that secondarily flightless dinosaurs did not have the same problem as secondarily flightless birds. This would mean that the loss of flight in the case of non-avian dinosaurs did not hinder them, the way it seems that the loss of flight hinders most modern avian lineages. Dr. O'Connor, can you paint this a picture of what does a codipterus look like? If you're going to imagine Codipteris, it would be, about the size of like a large turkey, and it would have very short arms, but with tiny little

wings, wings that are proportionately much shorter than you would see in a chicken or any bird that's able to fly, just like tiny little wings that were probably used for ornamentation, but maybe they were used for running, we're really not sure. The legs would have been really strong, robust legs, so an animal really adapted for running, and it would have had like kind of a big belly, because most specimens preserve a huge masses of gizzard stones or gastroless inside the stomach. The gastral mass in non-avian dinosaurs is bigger than it is in birds. And it's probably because once you evolve flight, you're kind of trying to constrain your body mass. You want to be as light as possible.

So when these dinosaurs that are not flying, they're able to have really big gastral masses with these kind of large stomach. And then it also had teeth. So are you saying that this dinosaur's ancestors was able to fly and that this this dinosaur lost that ability? So that is what Yossif's feather data indicates. But that doesn't mean that that is what happened. But the data from the feathers is strongly suggesting that. Do we know why some dinosaurs went on to be able to fly and why some some were not? It probably has to do with ecology, right? And that's also why many birds lose their ability to fly. It only happens in certain ecological environments. So basically, if you're able to get food and to hide from predators without flying, then evolution will select for that. And that is because flight, powered flight, is the most physically demanding form of vertebrate locomotion. It requires enormous energy to. to fly. So if you can survive without flying, then natural selection will favor that. But that's

only possible for birds living in certain environments. But it's most common in birds that are aquatic or semi-aquatic, birds that are able to, you know, dive underwater in order to escape predators or hide and reeds on the lake shore. Well, good luck in your research. I want to thank you for taking time to be with us today. Our pleasure. And thank you so much for your interest. Thank you. Dr. Yosef Kiat, post-doctoral researcher at the Field Museum in Chicago, and Dr. Jingmei O'Connor, associate curator of fossil reptiles at that same field museum. If you celebrated Valentine's Day, you may have shared a delicious dinner with your loved one, including perhaps a variety of cheeses, or maybe you went all out

and did fondue. I love fondue. Well, I've got some bad news for week, Camember and Bree lovers. A lack of microbial diversity may be putting some of our beloved cheeses at risk of extinction. Oh, no, joining me to talk about this cheese crisis on the horizon is Benji Jones, senior and environmental reporter at Vox based in Brooklyn. Welcome back to Science Friday. Hey, thanks for having me. And sorry, it's not under better terms. Well, sacre blue, Benji, I mean, must we be prepared to bid adieu to our beloved French cheeses? How dire is the situation. Yeah, I was, I was very sad while writing this because I'm a fan of Brie. But yeah, it's not looking good for some varieties of cheese. So really, those brees and camemberars, which are those fragrant, white, soft cheeses are kind of at risk of extinction, according to

a couple of French scientists that I spoke to at the French National Center for Scientific Research. They're concerned that the microbial diversity needed to make these cheeses is dwindling dramatically and therefore we may have trouble making them in the future. So remind us how these soft cheeses are made. It's not the most appetizing process, is it? Yeah. So, I mean, I love learning about cheese and breads and other foods that are made using microbes because it's this whole invisible world in the foods that we're eating. Right.

So for cheese, it's very similar. So you take fresh milk, it's cow's milk in the case of brie and camembert. And then the first step is to introduce usually like a starter. So some bacteria and also rennet. And what that bacteria and rennet will do, is curdle the milk. So go from this very smooth liquid to like a gelatinous mixture. And then that produces curds, hence curdling. And then to go from there to cheese, you take the curds, essentially like smush them together and then let them dry out. And different cheeses,

whether they're hard or soft, it often is just depending on how big those curds are that you start with, how much moisture there is, and how long you age it for. So in the case of many cheeses, once you have those curds, the next step is to introduce yet another kind of microbe, which would be yeast or mold, so different kinds of fungi. And in the case of camemberin-brein-brey, they rely on a mold called geotrichum-cand-cadum, and also penicillium-camemberti. And penicillium-camamberty is really the quintessential microbe, this mold that gives the camemberes and the breeze, that white, fluffy texture and also a lot of their flavor.

And that's really where the problem lies with this kind of penicillium mold. What's the challenge here? Why is it disappearing? Why can't we just keep it going? Yeah. So the short of it is that the genetic diversity of penicillium camemberty, this mold that is essential for Camembert and for Breeze is itself potentially going extinct. It's lost all of its genetic diversity.

Really, if you look across the world at Camembert's and Breeze, anyone that you find in the grocery store, the kind of mold used to make that cheese is, I guess. identical, literally genetically identical. So we're not talking about like different individuals of the same species, but literally it is the exact same individual that has just been cloned over and over again. And the problem with repeated cloning is that it introduces errors into the genome, or at least it can. And in the case of this specific kind of mold, scientists have found that all that cloning has damaged its genome to the point where it's more difficult to reproduce it, to clone it even at all. And so the fear here is that it's becoming really hard to clone this very specific kind of mold used for camemberes and brie,

and therefore the supply chain of these cheeses is threatened. So why do we just rely on this one particular strain? So what's happened over many decades, at least for a century or so, is that cheesemakers, cheese producers have selected a very specific kind of cheese that they think looks good, smells good, is exactly what we think of when we think of camembert, this fluffy white, flavorful cheese. And these cheesemakers discovered that that fluffy white mold that we love is produced by this albino strain of a penicillium mold, and that is the penicillium camemberti. It's an albino strain. And so over time, all these cheesemakers were like, this is the very specific strain that produces the cheese that looks good, that tastes good,

that smells good. So we're going to only use this particular strain to make cheese. And over decades, all the other types of mold that were originally used to make these different cheese, cheeses disappeared out of disuse because they wanted this white specific cheese. Wow. And so it's this really intense selection force, like this human-driven selection of traits that we like in our cheese that have really lost all this genetic diversity. And now we're learning that that comes with some important consequences. This is Science Friday from WNYC Studios.

If you're just joining us, I'm speaking with reporter Benji Jones about the cheese crisis on the horizon in France. And so the cheesemakers actually brought this on themselves. That's right. We see this with other foods as well. Consumers often like certain traits. They want them all the cheeses that they see in the grocery store to look similar. They have expectations.

And so farmers will select the specific, in this case, microbes that produce those phenotypes, those visible and physical traits in the cheeses. You know, I'm thinking you mentioned other foods. I'm thinking of like the Cavendish Banana, right? Exactly. I mean, that's to me, like, the clearest parallel over, over years. We selected a specific kind of banana that tastes good, that ripens well, et cetera. And now nearly all bananas that are exported are genetically similar or identical. They're all this Cavendish variety. And in the case of bananas, and this could be true for cheeses as well, when you have this lack of diversity,

it's not just a problem for reproduction in the case of mold, but it can also be a problem when it comes to pathogen. So diseases that could wipe out one banana plant, can also wipe out all the other banana plants if they're genetically identical. So diversity is so crucial for resilience when it comes to food and when it comes to really biodiversity at large. Yeah, that's wines too, right? Grapes, kinds of things we make for that? Yes, exactly. Grapes, weeds, coffee even. I mean, this is especially relevant when we think about the ways in which the planet is changing. It's getting hotter in some areas, drier. And what that means is that you need varieties of food that are more tolerant to things like drought. So making sure that

you have that diverse group of plants to pull from to adapt to some of these stressors that are getting worse is essential. And again, it's just this tension with over time. Producers just like, they're catering to consumers. And I think a big takeaway when I was doing this story and like as a cheese lover is, look, we have to just get more comfortable with diversity in our foods. It's okay if the cheese is not perfectly white. It could be a little bit blue, for example, and it's still okay. So yeah, this is a case of not form over function, but fashion. over function. Exactly, exactly. We need to be a little bit more concerned with the things that make cheese resilient versus exactly what it looks like. Well, is there no hope then for the future of French

cheese? Or maybe we just have to accept not such beautiful looking cheese. Like, well, that we've been told is the way we should be eating it, right? Because if I hear what you're saying decades ago, they were very happy eating the kind of cheese, right? Exactly. What I loved, I was, was talking to these researchers at that at that French research institute that came out with this, this finding. And they were saying they looked at historical photos, these old paintings, actually, of cheeses of like cheese platters. You can kind of imagine what you might see in like the Met or something, these really old paintings. And a lot of them had breeze or camemberars that had very different colors. So oranges and blues and grays and browns. And so what the, what the researchers think is that

that was when the diversity of the molds used to make camembert and brie were more diverse themselves, and that diversity produces different colors. And the good news for us is that there is still lots of different molds out there that are diverse. So the closely related mold penicillium bforma, which is closely related to penicillium camemberti, naturally occurs in raw milk. And that will likely give those cheeses the same kinds of textures and tastes. It might make their color a little little bit different, but that's exactly the kind of mold that we can use, and those are much, much more easy to produce. Well, just like the cheese, Benji, we've run out of time, and it's time to bid you a fondue farewell, so. Yeah, and to your listeners, please say a prayer for

Camden Bear, which is the best pun I could come up with. Benji Jones, senior environmental reporter at Vox based in Brooklyn, New York. Thank you so much. And that's all the time that we have for today. A lot of folks helped make the show happen, including Nehima Ahmed. Santiago Flores. Rasha Ridi. Phyllisomeres. Robin Kasmir.

And many more. Next time, we'll talk about the mind-blowing amount of energy that AI consumes. But for now, I'm SciFRI producer Kathleen Davis. We'll see you then.