Welcome to STEMology – Show Notes

Season 1, Episode 20

Kelvin’s BALLS, robotically printed bridges, dino breathing, and thrice sexy algae

In today’s episode of STEMology…

David and Sophie are talking about Kelvin is famous for many things, and he proposed an item that can spin in fluids in any direction.. But he may have been wrong.  3D printing has gone big with a robotically printed bridge, a discovery that dinosaurs could have breathed in a completely different and new way and a species of algae has been discovered with three sexes

Kelvin’s BALLS

So what they did is they said they built this thing (Isotropic Helicoid) as per Kelvin’s recipe and then they dropped it into a viscous fluid…… and what they observed was…. nothing. They observed no rotation, so they dropped it in and it didn’t rotate.

Watch the bridge unveiling video here

And then they’ve also developed an advanced sensor network. That is going to monitor the bridge or the bridge, his behavior over its life. As people sort of walk across it … if you think of a bridge that was built 50 or a hundred years ago, the type of traffic on the quantity of traffic that be going over, it will be vastly different to what it was when it was built. And so from a safety perspective, that’s really cool and interesting, but presumably they’re interested in how it fares given that it’s 3D printed and the fact that it’s been manufactured in this way and no one’s ever done that.

Credit: AP Photo/Aleksandar Furtula

Dinosaur breathing

Understanding how this dinosaur could breathe would maybe help paleontologist figure out what biological features allow certain dinosaurs to survive or  cause them to go extinct.

Third Sex

 They reckon this particular algae species might be a bridging point between algae that have two sexes and algae that are hermaphroditic, they only have one sex. Which kind of raises an interesting point of like, why have sexes  at all, like, isn’t it just a bit weird and complicated to have two, why not just have one

This is a “kind of, sort of, vaguely close” copy of the words that David & Sophie speak in this episode.

IT IS NOT 100% accurate.  We are very sorry if we have spelt something completely incorrectly.  If it means a lot to you to have it corrected, email us at stemology@ramaley.media


STEMology s1e20


[00:00:00] [00:00:00] David: [00:00:00] to   episode 20 of STEMology

[00:00:01] Sophie: [00:00:01] A podcast sharing some of the interesting fun, and sometimes just patently bizarre news in science, technology, engineering, or maths.

[00:00:10]David: [00:00:10] Your hosts are Dr. Sophie Calabretto and Dr. David Farmer. In today’s episode of STEMology, Sophie and Dave that’s me. We’ll discuss Kelvin’s balls,

[00:00:19]Sophie: [00:00:19] Robotically printed bridges, Dyno breathing, and thrice sexy algae.

Kelvin’s balls

[00:00:26] David: [00:00:26] Kelvin’s balls.

[00:00:28]Sophie: [00:00:28] Yes, Kelvin’s balls. So Dave Kelvin was, he was a pretty famous dude. He had a lot of things named after him. I think probably the most famous he had an SI base unit of thermodynamic temperature named after him. I don’t think I could ever say that about myself.

[00:00:42] David: [00:00:42] No, I can’t say that about myself. So that said the absolute temperature scale that goes down to absolute zero, which is minus 273.15, something, something, something

[00:00:51] Sophie: [00:00:51] Yeah, exactly. So it’s the absence of all heat. Um, and, Kelvin is the equivalent in size to a degree Celsius, and he had a bunch of other, if you’re [00:01:00] into sort of like electricity and thermodynamics and fluid mechanics, like this was quite an impressive man.

[00:01:05] David: [00:01:05] Yeah. he formalized the first couple of laws of thermodynamics, which is for anyone listening, who doesn’t know that’s a huge deal. So that’s the first two laws are the first one is the conservation of energy. So energy cannot be created or destroyed, which is a really fundamental

[00:01:17]Sophie: [00:01:17] it’s pretty important in our universe a little bit.

[00:01:21] David: [00:01:21] And I think the second one is a bit entropy, right? So the second one is about how things in the universe always become more disordered and therefore time goes forward.

[00:01:31] Sophie: [00:01:31] Yeah. so my favorite Kelvin thing is as a fluid mechanist is a Kelvin Helmholtz instability. So obviously he shares this with  our friend Helmholtz and that’s like, if you’ve ever seen clouds that look like rolling waves, Dave, That’s a Kelvin-Helmholtz instability. So think about it like a breaking wave.

[00:01:47]Yeah. So basically you’ve just got like, two different fluids with the velocity difference across the interface. So it’s kind of like if you’ve got air, but then you’ve got like denser clouds and cause like the clouds a bit dense, they’re moving slower, you get this kind of cool instability.

[00:01:59] Like it’s [00:02:00] a real thing. And then you can see in the sky, which I think is really pretty, but Kelvin, Dave was maybe wrong one time.

[00:02:06]David: [00:02:06] He was maybe wrong one time and it has to do with his balls, AKA his Isotropic Helicoid, which are two words that you’re going to have to explain. Yeah.

[00:02:16]Which is to say, I would love it if you’ve explained them to me.

[00:02:19] Sophie: [00:02:19] okay. Basically what happened in 1871. So a little while back, Kelvin proposed what they’ve called a hydrodynamics brain teaser. Is there an object that looks the same from any direction? And that will naturally rotate when it moves through a fluid.  All right. So then Kevin thought, yes. And he’s proposed this Isotropic Helicoid. So isotropic basically just means that it’s a physical property in which you have the same value when measured in different directions.

[00:02:46] So if you think, and so we’re talking about drag in this sense. So the idea behind an isotropic helicoid, is that it must experience the same amount of drag from the fluid, regardless of its orientation. So if you think of a sphere, if I drop a sphere in water or something, it doesn’t matter how the sphere is oriented.

[00:03:03] You’re just going to get the same drag. So we’re creating this thing, but we also want to

[00:03:07] David: [00:03:07] So That would be PO as opposed to something like a propeller, which would be deliberately yeahwould move in the fluid in such a way that it’s useful, but it has to be orientated in a particular way in order to move the fluid.

[00:03:18] Sophie: [00:03:18] Yeah. So it’s kind of like if you had a missile and you dropped it, point down, it’s going to go faster than if you dropped it like sideways and

[00:03:24] it sort of just like splats in the water. Now a circular helicoid is a minimal surface having a circular helix as its boundary.

[00:03:32] Basically, this just describes, I know, like this bit, I couldn’t even unpack. It describes what this thing looks like basically. So what we have, I want you to think you’re playing the game minesweeper, so you’ve got these like little mines, but rather than like pointy bits on our landmine or our mine think of you’ve got semicircle flat paddles, and these things are kind of arranged almost to make a double helix around this sphere.

[00:03:55] So what we want, but it doesn’t matter which way you look at this thing. It looks the same [00:04:00] in every direction. Right. It doesn’t matter what direction you look at it. And when we drop it into the fluid it’s gonna rotate is, what Kelvin has proposed. and no one’s done anything since 1871 about it. and then they decided, Hey, let’s see if we can build one of these and see if it works.

[00:04:14] Cause Kelvin got a bunch of things right maybe he has created this amazing sphere- like apparatus that will have the same drag every way, but also rotate. And then Dave, we went into this paper and there’s a mathematician and a fluid mechanist. I’ve never felt so thick in my life. it starts off with like a wee bit of tensor calculus, so Dave, you know, what number is,

[00:04:36] David: [00:04:36] Yeah,I know what number is yep.

[00:04:38] Sophie: [00:04:38] you know, an, a vector is.

[00:04:39] David: [00:04:39] Yeah, that’s a number with a magnitude associated with it.

[00:04:42] Sophie: [00:04:42] Yeah. So basically think about a row of numbers in a box. You’ve got matrix, which is like a square of numbers. Now it tends to think of a cube of numbers.

[00:04:52] David: [00:04:52] Okay. That’s really helpful. Thank you.

[00:04:54]Sophie: [00:04:54] I’ve just angered all the pure mathematicians because basically a tensor is matrix of matrices. But if you say that to [00:05:00] them, they get quite offended because there’s something about other properties.

[00:05:03] I’m not really concerned. It’s just complicated maths. And what they did is so they 3D printed one of these, isotropic helicoids they’d made it as 1.74 centimeters wide. They made it with a 3D printer. That was a form two dario lithography 3d printer, which is a process based on light curing of liquid materials into a solid shape, which is fun.

[00:05:27] And, you know, I like to look up, an apparatus every now and again. And if we wanted to buy a form two basic package, uh, we could get a refurbed one for $2,400. so what they did is they said they built this thing as per Kelvin’s recipe and then they dropped it into a viscous fluid. So a viscous fluid is just fluid with viscosity. So a bit of thickness and, uh, they use Silicon oil and what they observed was nothing. They observed no rotation, so they dropped it in and it didn’t rotate. And they went, well, this is weird cause mathematically due to the symmetries, this thing should turn. And that’s where that tensor [00:06:00] calculus came in in the beginning.

[00:06:01] And so they then manufactured an unisotopic helicoid, which is the, it was the same kind of thing. So it’s just a sphere and you had your paddles, but they were slightly different orientation. And depending on how, you know, where you looked at this feel like it looked different. and they dropped it in different ways and they also found that that didn’t rotate and they went, well, this is a problem. Now, Dave, I’ve got a few issues because they said mathematically, it should happen. And physically it didn’t. But so they dropped a very small sphere into a very viscous fluid. So what we’re talking about is a very small Reynolds number. So a Reynolds number is something that fluid person uses to talk about the ratio of viscous to inertial forces. So basically a very small Reynolds number means your object is moving slowly and your fluid is very thick and a very high Reynolds number means that your object is moving very fast and your fluid is very thin. And, so the Reynolds number is so small.

[00:06:52] We would refer to this as a Stokes flow, which is just, this is what happens when like you’re looking at like microfluidic channels, like tiny [00:07:00] things, moving through thick

[00:07:01] David: [00:07:01] So, so what you’re saying is that the experimental conditions were such that if they were going to detect a spin, it was going to be a very, very small spin and it would be very, very difficult to experimentally detect. Is that what you’re saying?

[00:07:12] Sophie: [00:07:12] Yeah, because the conclusion that they’ve come as they went, and then they did a, like a bunch of modeling and they found that like you do get these hydrodynamic interactions between these veins, which are the, you know, our little paddles, that allow  a net talk to develop, i.e you’ll get rotation, but this talk was too small to observe for the helicoid that they fabricated.

[00:07:29] And so they’ve suggested that like optimizing its design, you could get it to the point where that talk, that net talk  would be observable. So just the use of running a fluid and a biggest fear. Like, I’m not really sure what we’ve concluded here.

[00:07:41] David: [00:07:41] Okay. So Kelvin may have been wrong

[00:07:43]Sophie: [00:07:43] He may have been wrong.

[00:07:44]David: [00:07:44] Apparently it’s not the first thing he was wrong about. Apparently I read, this week that he was famously skeptical of,  Aviation. So he refused an invitation to join the aeronautical society writing. I have not the smallest molecule of faith in aerial navigation, other than ballooning or of [00:08:00] expectation of good results from any of the trials we hear of

[00:08:02]Sophie: [00:08:02] Oh dear. Okay.

[00:08:04] David: [00:08:04] no airplane will ever be practically successful

[00:08:07] Sophie: [00:08:07] All right. So everyone needs to drop their level of respect for Kelvin by like one to three notches at this stage, I think maybe, but look, you know,

[00:08:15]David: [00:08:15] laws of thermodynamics. Pretty good.

[00:08:17]Sophie: [00:08:17] Pretty good. other things not so good. So yeah, maybe Kelvin was wrong. Maybe not. We will be able to report back later if they’ve managed to create a larger, isotropic helicoid.

[00:08:25]David: [00:08:25] if you’ve created an isotropic helicoid the appropriate size or, have not refused to drop a tiny one into water, then send us a

[00:08:33] Sophie: [00:08:33] yeah. Right into STEMology,, and a report on your successful isotropic helicoid.

Robotics Print Bridge

[00:08:39]   From 3d printed balls to  3d printed bridges, opened by Queens with amazing names and small robots

[00:08:56] David: [00:08:56] Yes, mate,

[00:08:57] Sophie: [00:08:57] loved everything. Loved everything about [00:09:00] this. Everything, Dave.

[00:09:01] David: [00:09:01] This past week Dutch Queen Maxima teamed up with a small robot on Thursday to unveil a steel 3d printed pedestrian bridge over a canal in the heart of Amsterdam’s red light district. What a wonderful sentence.

[00:09:16] Sophie: [00:09:16] Dave and I quote, Maxima pushed a green button that set the robot’s arm in motion to cut a ribbon across the bridge with a pair of scissors. Did you watch the video?

[00:09:25]David: [00:09:25] I didn’t watch the video. There’s a video.

[00:09:27]Sophie: [00:09:27] took me a while to find it on the internet. so basically this particular robot is kind of like a torso robot without a head.

[00:09:32] And she presses the green button and this thing kind of goes down and it grabs the ribbon with one clampy hand and its other hand is a pair of scissors and it cuts it. and they all looked very impressed. And then a little while after like they all go into a bar and they just like, leave the robot there.

[00:09:47] David: [00:09:47] That’s brilliant, but if the robot wanted to drink, he’s got arms.

[00:09:49] Sophie: [00:09:49] Exactly. And I tried to find the name of the robot. Cause you know, we’ve, talked about pepper and we’ve talked about other robots and I could not find the name of the robot, but if you Google Queen Maxima robot, I have [00:10:00] found five separate incidences of Queen Maxima interacting with a different robot.

[00:10:07] There’s five separate pictures of her, just  like talking to a robot in Google images.

[00:10:12] David: [00:10:12] She’s called Maxima. It’s not surprising. She sounds like a Power Rangers villain.

[00:10:15] Sophie: [00:10:15] That’s true. She does. But anyway, day, shall we get back to this bridge because we’ve managed this way. You and I have managed to print a, so it’s a 12 meter bridge. It’s 5.4 metric tons. And so the whole idea of 3d printing this bridge was that it’s just going to be there for two years while the bridge that previously spanned the canal is renovated and it was 3d printed using a technique called wire and arc additive manufacturing or WAM that combines robotics with welding.

[00:10:44] David: [00:10:44] Yes. I read a little bit about this too. It’s robot controlled welding, which is already really, really, really cool. it’s a kind of metal and arc gas welding. So this sent me down, I dunno, about you Sophie, they sent me down a welding rabbit hole.

[00:10:58] Sophie: [00:10:58] I did. Yeah, I did learn a bit about [00:11:00] welding and different kinds of 3d metal printing.

[00:11:02] David: [00:11:02] Yeah, so metal and arc gas, welding, which is a kind of arc welding and listener arc welding is where you have an arc gas that comes out of the welder and you have a big metal electrode that gets really hot, so hot that it melts. But basically what’s happening is you’re generating an electric current that arcs between the electrode and the welder and what you’re welding so that the things get fused together.

[00:11:25]Sophie: [00:11:25] yeah, that’s basically it. So you’ve got like, and so in this case, we have our wire that it’s when melted by this arking process that you’ve just described is coded, is extruded and forms these kinds of little beads of metal. And then it just builds up the beads into like a big 3d shape. So he likes sort of layer by layer, but it looks, did you watch a video of this one, this one, that, that was really cool watching

[00:11:46] David: [00:11:46] I didn’t watch the video that I just watched the video of Maxima pushing the button and like the robot like holds the ribbon. It’s adorable, holds the

[00:11:52] Sophie: [00:11:52] it’s got a little, yeah, it’s got its own like ribbon clamp hand, and its scissor hand..

[00:11:57]David: [00:11:57] It’s so good.

[00:11:58] Sophie: [00:11:58] It was very cute, but yeah. [00:12:00] And so the whole idea with this is, yeah, they’ve built this. So it’s a Dutch company, called MX3D, but apparently these steel structures group at Imperial college in London conducted the underpinning research and validation of this bridge, including testing destructive forces on printed elements, advanced digital twin computer simulations, non-destructive real world testing on the footbridge.

[00:12:21] And then they’ve also developed an advanced sensor network. That is going to monitor the bridge or the bridge, his behavior over its life. As people sort of walk across it.

[00:12:31] David: [00:12:31] I like that. Well, that’s really interesting, isn’t it? And that’s something in bridges that’s becoming a thing because bridges are built. And then, so for example, if you think of a bridge that was built 50 or a hundred years ago, the type of traffic on the quantity of traffic that be going over, it will be vastly different to what it was when it was built.

[00:12:47] And so from a safety perspective, that’s really cool and interesting, but presumably they’re interested in how it fares given that it’s 3d printed and the fact that it’s been manufactured in this way and no one’s ever done that.

[00:12:57] Sophie: [00:12:57] Yeah. so it was quite funny. Cause as I said, they’ve got this digital [00:13:00] twin of the bridge. So the data from the sensors on the real bridge is going to input information into this digital bridge, which is just a computerized version. which will then imitate the physical bridge with growing accuracy in real time.

[00:13:13] And then the idea is that the performance and behavior of the physical bridge will be tested against the twin and essentially help answer questions about long-term behavior of 3d printed steel and how we can use it in the future and these kinds of novel construction projects. But it’s interesting that you just bring up bridges, Dave, cause you know, you can watch a lot of Videos on the internet, like bridges collapsing. And it’s almost like we have just a memory of about 50 years in terms of building bridges. Like every so often, they’ll just be like some epic bridge collapse. It’s like, we already knew the physics and the engineering issues with like the thing that you’ve designed, Just look to history and build a better bridge, but this is cool. I have a lot of faith in this bridge. Um, also, cause you know, they’ve got some scientists involved in the beginning who knew what they were doing and they’ve designed it like that. So yeah, we’ll see what happens, but just everyone, go and [00:14:00] Google Dutch Queen Maxima, small robot, 3d printed bridge, and just watch that delightful robot without a head or legs just open that bridge for us.

[00:14:08] David: [00:14:08] Please do. And I’ll leave you with this quote, which is by Tim Geurtjens, whose name I may have just massacred  and who’s of the company MX3D, but he said it was really, really What He said it’s really, really nice. Cause he said. It’s not just about making things cheaper and more efficient for us. It’s about giving architects and designer a new tool, a new, very cool tool in which they can rethink the design of their architecture and their designs, which I think is lovely.

[00:14:29]Sophie: [00:14:29] Yeah. So everyone should head to our show notes right now and go and watch that video of that delightful little robot opening that bridge because it is just charming.

[00:14:38] Dino breathing [00:14:48] David: [00:14:48] So from 3d printed bridges and robots to dino breath.

[00:14:53]An international team of scientists has used high powered x-rays at the European synchrotron to show how an extinct south [00:15:00] African 200 million year old dinosaur, heterodontosaurus tucki breathed.

[00:15:05] Sophie: [00:15:05] Yes. So, uh, before we get into the paper, that was again, mind melting. That happened a little bit this week. Let’s talk about heterodontosaurus tucki, Dave,  So heterodontosaurus means a different tooth lizard. Tucki was named after GC tuck who supported the discoverers according to Wikipedia. And I couldn’t find any more information

[00:15:27] David: [00:15:27] There you go potential philanthropists listening, give some money to people, get a dinosaur named after you, even if it’s a Turkey -sized dinosaur with weird teeth.

[00:15:35] Sophie: [00:15:35] Right. Yeah, exactly. so apparently, uh, I’m going to call this dinosaur H tucki from now on. So I don’t have to say heterodontosaurus a lot of times. so H tucki is one of the oldest and first evolving of the ornithiscians. It includes some of our favorite dinosaurs, this particular group. So triceratops, stegosaurus, but two of my favorites, the Parasaurolophus and the Pachycephalosaurus,

[00:15:58] David: [00:15:58] really. See, I hadn’t heard of those two ones and you’re [00:16:00] telling me they are your favorite

[00:16:01] Sophie: [00:16:01] I love them. So the Pachycephalosaurus, like imagine like a bold man with a really hard head and wear like Homer Simpson hair is, it’s actually spikes. And it’s the one that just like runs into stuff with its head

[00:16:11]David: [00:16:11] I know what you’re talking about about. It featured in the documentary film, The Land Before Time. So I I am aware of what you’re talking about

[00:16:16] Sophie: [00:16:16] And, Parasaurolophus looks like it has a high ponytail.  Anyway, so they’re very cool dinosaurs, but yeah, this one is, you said is Turkey size and then that just sent me right back to Jurassic park.

[00:16:27] You know, there’s the bit when they’re in the dig site and snake quarter Montana at the very beginning. And there’s that like smart mouth little kid who’s like when they see the image like the velociraptor below the ground

[00:16:37] David: [00:16:37] That doesn’t look very scary.

[00:16:39] Sophie: [00:16:39] More like a six foot Turkey. And I was like, whoa.

[00:16:42] And also you apparently you wouldn’t find velociraptors in Montana. So that’s a huge problem too. But yeah, so, what they did is, yeah, this particular dinosaur is lived in the early Jurassic periods around 200 million years ago, but it survived an extinction at the end of the prior triassic period.

[00:16:59] So the [00:17:00] idea about understanding how this dinosaur could breathe would maybe help paleontologist figure out what biological features allow certain dinosaurs to survive or  cause them to go extinct. and they already know that the skeletons of these ornithiscians and dinosaurs were radically different from the others.

[00:17:15] So yeah, they took it to Europe and they x-rayed it.

[00:17:18]David: [00:17:18] Yeah. with a really high powered synchrotronic stream of x-rays. and they developed this beautiful 3d model of this thing. And with a resolution that’s never really been seen before, and they saw some really interesting things and I’m terrified of describing them cause it means I’m going to have to explain how the thing breathed.

[00:17:34] And I don’t really know if I understand it, but let’s go for it. So they find two things that seem to be of interest. One is that it had poorly formed gastrilia and basically gastrilia are, it says when you look them up that they’re like abdominal ribs, but don’t refer to them as abdominal ribs. Cause that’s a poor way of thinking about them, but they’re basically like these kind of rib light structures that provided an attachment point for abdominal muscles, the muscles in your abdomen.

[00:18:00] [00:18:00] So it’s been shown in  dinosaurs previous to that, I presume that these muscles were important in breathing, by expanding the abdominal cavity. And the other thing they found in H tucki, which seems to be of interest was a well-developed anterior pubic process. Now I also just want to take a little sidebar here and say that this was my, one of my favorite things about the paper is that so pubic means related to the pubis, which is your hip bone.

[00:18:28] Right. But because they were talking about more than one, they would talk about pubis. Cause that’s the correct plural of pubis, but it’s just spelled pubes. So there was a lot, it was a lot of dyno pubes in this paper, which I really, really, really enjoyed. but so basically it’s got a well-developed anterior pubic process, which in later dinosaurs is important and breathing and basically this thing pivots and moves the abdominal organs down so that, air moves in and that’s kind of vaguely analogous to how a crocodile breathe, which is [00:19:00] apparently not how we breathe.

[00:19:01] Sophie: [00:19:01] Yeah. That’s the bit I thought. it was really cool. I was like, oh, and they’ve actually said that. Yeah, the lungs are ventilated by this novel pelvic muscle attached to the APP or the anterior pubic process, as you said, and it’s functionally analogous to the dorsal component of the diaphragmaticus of extinct crocodilians

[00:19:19] David: [00:19:19] That’s right. And so, and, this kind of pelvic breathing is also something that happens in birds, albeit in a different way. And in fact, it says something really great. It says it’s an archosaurians ventilation models. And so just another sidebar within a sidebar, archosaurians is a term, a cat shell term, to refers to dinosaurs, reptiles, and birds, which

[00:19:34] Sophie: [00:19:34] Oh, I didn’t know that archosaurians going to use that in a  sentence at least once every day, for  the rest of the week.

[00:19:41] David: [00:19:41] Yeah. So in archosaurian ventilation models, the involvement of the pelvis is ubiquitous ranging from pelvic rocking and birds to the hepatic piston, and crocodilians. Pelvic rocking and birds, which sounds like a 1950s lewd rock and roll song.

[00:19:54] So basically they’re saying, this anterior pubic process that they’re very excited about [00:20:00] changed within the ornithiscians how do I, am I saying it correctly

[00:20:03]So in early ornithiscians the anterior pubic process developed and then was preserved even when they went from two legged dinosaurs to four legged dinosaurs, and that kind of, preservation of the structure they reckon provide some evidence that it’s involved in breathing.

[00:20:24] Because obviously if you have a structure that’s involved in breathing, it’s important that you change it very gently when you change it, because it’s pretty important to your survival. So they have gastralia that are poorly formed, but a well formed anterior pubic process law, which suggests that maybe there are bridging point between animals that predominantly use gastralia and  those that used the anterior pubic process to breathe.

[00:20:47] I think that was my takeaway from the paper. I think.

[00:20:50]Sophie: [00:20:50] my takeaway was similar, but not as well explained, but yeah. So there you go. And I just, I liked the fact that, you know, this is, they’ve used a terrified, like terrifying [00:21:00] synchrotron, like the x-ray I looked at which one they used, it was just like the biomedical part of it.

[00:21:05] and I tried to work out how, if we went and like stood in front of these, x-rays how quickly would die, but that was too difficult to find on the internet.

[00:21:14] David: [00:21:14] But you would die. I presume you would die.

[00:21:16] Sophie: [00:21:16] Yeah. I think, I mean, you know, like pretty, I mean, not like instantaneously, like it’s not going to like completely explode us like an, a laser, but I don’t think it would be a good life afterwards, but yeah, so this particular, um, dinosaur they used apparently is the most complete fossil ever discovered.

[00:21:32] And so this is why we’re sort of able to do this because they basically had most of this dinosaur and it was found in 2009 in South Africa. H Tucki

[00:21:42]David: [00:21:42] what a man,

[00:21:43] Sophie: [00:21:43] What a man or a woman. I don’t know. I mean, it’s science says statistically, man,

[00:21:47]David: [00:21:47] they don’t, mention it.

[00:21:48]Sophie: [00:21:48] they don’t mention it, but maybe, you know, we all breathe the same day for all.

[00:21:52] Just the same kind of dinosaur inside, you know,

[00:21:55] except we don’t breathe the same. Cause these breathe very differently.

[00:21:59] [00:22:00]


So Dave, from, dinosaurs that we don’t know the sex of to three sex algae discovered at the University of Tokyo.

[00:22:17] David: [00:22:17] sexy algae.

[00:22:19] Sophie: [00:22:19] Sexy algae. So yeah, apparently algae could actually help us understand how different sex systems like male and female evolved in the first place. Now, before we get into this, Dave, did you look at this paper

[00:22:31] David: [00:22:31] I had to look at this paper. I wonder if you’re going to say, well, I’m going to say, which is that it had the best opening sentence of a paper ever?

[00:22:38]Sophie: [00:22:38] I have never ever,

[00:22:42] David: [00:22:42] So do you want to read it?

[00:22:43] Sophie: [00:22:43] no. You’ve read it in your Scottish accent. Cause it be more. beautiful

[00:22:46] David: [00:22:46] Okay, best opening sentence of a paper ever. “Androgyny is found in certain gods in mythologies worldwide, and is one of the three sex phenotypes of ancient humans according to Aristophane’s speech from Plato’s [00:23:00] symposium.  So that’s amazing. this is researchers from the University of Tokyo and a number of other Japanese universities, have discovered that type of green algae, which is maybe not where you thought we were going to go with this. From what I just said called Pleo Doreena starry-eyed and it has three distinct sexes, male, female, and a third sex that they’ve called bisexual.

[00:23:20] Sophie: [00:23:20] Yeah. So this is the first time any species of algae has been discovered with three sexes and they do say they algae is a pretty broad scientific classification, Dave. So we should say that it’s just an informal term for a huge collection of these different creatures that use photosynthesis for energy, but they’re not plants because they lack many plants features.

[00:23:39] They’re not bacteria, despite cyanobacteria, sometimes being called blue-green algae, which is fun. Cause I grew up in Adelaide and the Torrens river full of blue-green algae turns out actually bacteria and yeah, don’t go swimming in there and they’re also not funky and so basically everything from many-celled  giant kelp species, all the way down to cute single-celled [00:24:00] dinoflagellates  can be classed as algae and so because it’s such a diverse group, such a large group. There’s a lot of variation in the way that, and I quote from the press release, “they get it on”, but generally algae I know I didn’t write it. Algae is able to reproduce asexually  by cloning themselves. And then they can also produce sexually with a partner.

[00:24:21] And that just depends on the life cycle stage they’re in and the algae and all that kind of stuff. And there’s also hermaphroditic algae and they can change depending on gene expression of the organism, what I didn’t realize Dave, so having three sexes and as in male, female and hermaphrodite called  Triosi estimated to occur in about 3.6% of flowering plants.

[00:24:43]and then now that there’s like random creatures, like certain sea animals and the Pacific mussels.

[00:24:48]David: [00:24:48] I was not aware of any of that.

[00:24:49]Sophie: [00:24:49] No  so what they’ve done now. So they’ve said, okay, this particular algae is different because the bisexual form of this haploid has both male and female reproductive [00:25:00] cells. So it’s not like a hermaphrodite where it can change. It actually yeah. has both.

[00:25:04] David: [00:25:04] To clarify, it’s weird because we’ve seen lots of algae that have male and female and lots of algae that have only one sex, which is like the bisexual sex, but it’s the only one that occurs. And this one is weird because it’s got male, female, and both. Yeah. Which is weird

[00:25:18]Sophie: [00:25:18] Exactly it is very weird. So the idea is that this P Starii form either 32 or 64, same sex celled vegetative colonies, and they have small mobile and large immobile sex cell, similar to humans. So obviously the small mobile or the male ones and the large immobile are the female sex cells. and then the idea is you just send these like male sex cells out into the world as sperm packets, and they find a female colony to attach to. But it, because they carry both forms, it means that they can create either male or female colonies. And therefore can mate with either a unisexual male or a unisexual female or another bisexual.

[00:25:58]David: [00:25:58] Yes. That was my [00:26:00] understanding too. And so what they were interested in is because, so what I’ve understood from the paper was that it’s been discovered that there’s a male gene in these sorts of organisms that you can point to. And if you express this gene, you’re a male So they went looking for a similar inheritable, bisexual factor.

[00:26:15] So they did some pretty old school genetics and in old school genetics what you do is you breed animals together and basically if, so, if you imagine, a white rat and a black rat and you breed them together, then you can learn something about the inheritability from the offspring. So if you get three black rats and one white rat offspring. Then you’ve learned that white gene is recessive and the black gene is dominant.

[00:26:39] Sophie: [00:26:39] Would you ever get a gray rat? Dave? Just out of curiosity.

[00:26:42] David: [00:26:42] uh, I don’t know. Maybe if it was homozygous, it depends. I can’t remember. I’m struggling. I’m

[00:26:47] Sophie: [00:26:47] okay. I was just a kid. I was just like, well, to me, if I average black and white, I get gray. That’s not the point.

[00:26:53] David: [00:26:53] this is a very hypothetical scenario based on first-year biology, genetic knowledge, which is all I have, but [00:27:00] basically, they did some breeding experiments to look at the offspring.

[00:27:03] And I think what they found was that yes, there was from the proportions, there was some enough bisexuals produced that they can say yes, there probably is a bisexual factor that is inheritable.

[00:27:13]Sophie: [00:27:13] and then I, tried to, I’ve tried to, you know, get involved in this paper as much as I could even, I didn’t know anything that was happening. the bit that I was interested in is when they suggest that they separated these colonies and induce them to reproduce sexually by depriving them of nutrients.

[00:27:28] Right. And so I was like, well, what does that mean? How can I, induce someone to reproduce sexually by depriving them of nutrients? So I went, yeah. Someone someone, my friend, algae, not someone, but that’s a different episode of STEMology, I think. and so what they did is, I, you know, got into the nitty gritty.

[00:27:44] They grew these things on an AF 6 medium and then they grew them for a bit then transfer them to a soil medium, grew them some more. And after three or four days, the 10 mill culture grown on the VTAC plus soil mediums. That’s one that they’re hanging out on was mixed with 20 [00:28:00] mils of mating medium. 25 degrees on a 12 hour, light, 12 over dark shed, your under cool white fluorescent lamps. And so I went, okay, what does a mating medium? And they refer to

[00:28:12] David: [00:28:12] It’s

[00:28:13] Sophie: [00:28:13] as a

[00:28:13] nice right. And like, they describe, they say, you know, as per this other paper, and I went looking for this paper and no university that I have an affiliation with has access to this paper.

[00:28:26] So I still don’t know what a mating medium is. So like maybe Pinot noir. That’s probably, yeah.

[00:28:31] David: [00:28:31] That’s what I got for you, Pinot Noir and oysters.

[00:28:33] Sophie: [00:28:33] And oysters. And so they said that the sexual colonies and developed within, one day for the male strains and within two days for the female strains and bisexual strains. But yeah, no, none the wiser as to what a mating medium is and how I can induce people and, or algae to reproduce sexually by depriving them of.

[00:28:51] David: [00:28:51] Well, it’s kind of a cool experiment. So what they reckon because they reckon this is important because they reckon this particular algae species might be a bridging point between algae [00:29:00] that have two sexes and algae  that are hermaphroditic. They only have one sex.

[00:29:04] Which kind of raises an interesting point of like, why have sexes  at all, like, isn’t it just a bit weird and complicated to have two, why not just have one

[00:29:13]that everyone can just do everything and then you, well, not necessarily clone you could still have sexual reproduction, but just everyone could do either bit.

[00:29:22] Sophie: [00:29:22] Oh, I see what you mean. Okay. Yeah. No, that makes more sense.

[00:29:25] David: [00:29:25] Yeah, So I wonder what the advantage to the algae, of being sexy or non-sexy is,

[00:29:32]Sophie: [00:29:32] I don’t know. And why can’t we like, why can’t I have both Dave?

[00:29:36]David: [00:29:36] well, I think hypothetically anyone

[00:29:39] Sophie: [00:29:39] So, I guess, why have we evolved again? So why have we evolved to have two distinct sexual organs? This is there. Very interesting. All of a sudden I’m getting, I’m getting almost a bit philosophical

[00:29:48] David: [00:29:48] It is I’m sorry. I tend to do that sometimes.

[00:29:51] Sophie: [00:29:51] No, I love it. , but there, yeah, there you go. So we have a third sex in algae of both sexes and it could be that bridge that helps us understand things about [00:30:00] sex.