WEBVTT 1 00:00:00.440 --> 00:00:03.240 When it comes to a great deal, Virgin Mobile doesn't 2 00:00:03.279 --> 00:00:07.599 play around, introducing a new symplan price locked at fifteen 3 00:00:07.639 --> 00:00:11.679 euro month for life with unlimited data, calls and text 4 00:00:11.880 --> 00:00:15.839 and ninety nine percent coverage. Switch today at Virgin Media 5 00:00:15.960 --> 00:00:19.519 dot ie Virgin Media It's playtime. 6 00:00:19.719 --> 00:00:22.160 TNZ supply fifteen europer month locked in while a Virgin 7 00:00:22.160 --> 00:00:25.199 Mobile customer twelve month contract including a limited data, standard 8 00:00:25.199 --> 00:00:27.760 calls and text to all ours networks offer ends Februar eighteenth, 9 00:00:27.800 --> 00:00:30.079 twenty twenty six. See Virgin Media dot ie. 10 00:00:30.320 --> 00:00:31.280 Hey Mark, how are you? 11 00:00:31.719 --> 00:00:32.759 Oh? Not great? 12 00:00:33.320 --> 00:00:36.640 A sore throat? I think I'm coming down with cold. 13 00:00:36.799 --> 00:00:39.920 Oh no, you should try a Vogel sore throat spray. 14 00:00:40.159 --> 00:00:42.840 It's a natural remedy with echination and sage and can 15 00:00:42.880 --> 00:00:45.640 treat symptoms of coals and flus, including sore throats. 16 00:00:45.840 --> 00:00:46.280 Perfect. 17 00:00:46.679 --> 00:00:47.640 I'd give that a try. 18 00:00:47.679 --> 00:00:50.520 So we leave sore throats symptoms with a Vogel A 19 00:00:50.600 --> 00:00:54.320 Quena four sore throat spray made from echinasia and sage 20 00:00:54.359 --> 00:00:57.520 herbs and designed to reach irritated parts of the throat, 21 00:00:57.759 --> 00:01:00.799 available from health stores and pharmacies nationwide. 22 00:01:01.079 --> 00:01:04.120 Always read the leafless Oh hey, it's your neighbor's Wi 23 00:01:04.120 --> 00:01:06.959 Fi network that shows up as New England clam Router 24 00:01:07.239 --> 00:01:09.519 Ali word and we are biting up just enough to 25 00:01:09.599 --> 00:01:13.840 chew about ancient animal anatomy, particularly little weird teeth. I 26 00:01:13.879 --> 00:01:15.640 know you never knew that you needed to know about this, 27 00:01:15.799 --> 00:01:19.560 and it's wild. It's fascinating, I promise you. It's like 28 00:01:19.599 --> 00:01:21.840 a little corner of the earth in time you'd never 29 00:01:22.040 --> 00:01:25.719 otherwise imagine unless you are this ologist or one of 30 00:01:25.719 --> 00:01:31.159 their colleagues, paleontologists who study fossilized prehistoric tissue samples. I 31 00:01:31.239 --> 00:01:33.959 love this This ologist, an old friend I met on 32 00:01:33.959 --> 00:01:37.799 the internet on Twitter, ye old Twitter, and someone who 33 00:01:38.159 --> 00:01:41.120 was always on hand to help identify a bone, who 34 00:01:41.159 --> 00:01:45.040 popularized the hashtag guess the skull and loves the history 35 00:01:45.040 --> 00:01:47.159 of bones. They were born in Morocco. They grew up 36 00:01:47.159 --> 00:01:50.159 in Egypt and moved to Canada as a preteen, then 37 00:01:50.200 --> 00:01:53.120 did undergrad in pre med at the University of Toronto 38 00:01:53.159 --> 00:01:56.920 before getting a master's in ecology and evolutionary biology there 39 00:01:56.959 --> 00:02:00.159 studying animal jawbones. Then they got their PhD at the 40 00:02:00.239 --> 00:02:03.719 Humboldt University of Berlin and as a postdoc at the 41 00:02:03.760 --> 00:02:07.879 University of Chicago. Has already published several papers, including the 42 00:02:07.920 --> 00:02:11.199 twenty twenty five Nature paper The Origin of Vertebrate Teeth 43 00:02:11.520 --> 00:02:15.439 An Evolution of Sensory exoskeletons. That's like shaking up the 44 00:02:15.479 --> 00:02:18.879 fossil world. And in addition to being a professional paleontologist 45 00:02:18.960 --> 00:02:22.319 and an evolutionary biologist, they are also a celebrated science 46 00:02:22.319 --> 00:02:25.360 communicator who says that they love finding creative ways to 47 00:02:25.360 --> 00:02:28.879 make science accessible, weird, and wonderful for everyone, which this 48 00:02:28.960 --> 00:02:32.000 episode does so much. So we're going to get into 49 00:02:32.000 --> 00:02:33.639 it in a minute, but first, thank you so much 50 00:02:33.639 --> 00:02:35.879 to patrons of the show who make it possible and 51 00:02:36.080 --> 00:02:38.960 they send in hilarious and thoughtful questions before we record. 52 00:02:39.039 --> 00:02:41.479 Thank you to everyone out there supporting the show by 53 00:02:41.520 --> 00:02:44.759 wearing our merch from ologismerch dot com. As a reminder, also, 54 00:02:44.800 --> 00:02:47.199 we have a shorter kid friendly episode suitable for all 55 00:02:47.240 --> 00:02:52.439 ages and classroom safe and those are called somologies Smologies. 56 00:02:52.840 --> 00:02:55.560 They're available in their own feed wherever you get podcasts, 57 00:02:55.599 --> 00:02:58.319 you can subscribe. And thanks to everyone who leaves reviews 58 00:02:58.400 --> 00:03:01.639 of the show and to evidence that I do read 59 00:03:01.639 --> 00:03:04.280 them all. Thank you to recent reviewer Coco reads Books 60 00:03:04.319 --> 00:03:07.360 who said that ologies quote can make the most obscure, 61 00:03:07.439 --> 00:03:11.240 weird topic super interesting. Coco, you have no idea, We're 62 00:03:11.280 --> 00:03:14.639 about to do it again, Okay. Paleohstology it comes from 63 00:03:14.719 --> 00:03:18.360 the words for old tissues, and the histo in tissues 64 00:03:18.439 --> 00:03:21.120 comes from an older Greek word that means web. And 65 00:03:21.240 --> 00:03:22.840 I was in Chicago a few months ago for our 66 00:03:22.840 --> 00:03:25.919 friend's wedding, and the afternoon before the rehearsal dinner, I 67 00:03:26.000 --> 00:03:28.759 romped off to the Field Museum to lurk behind the 68 00:03:28.800 --> 00:03:31.479 scenes with this ologist I had been admiring from the 69 00:03:31.520 --> 00:03:35.039 Internet for years. I saw drawers of bones, millions of 70 00:03:35.159 --> 00:03:39.680 years old skulls, microscopes, and the evidence that changed how 71 00:03:39.680 --> 00:03:43.000 we think about what grows in our mouths. So prepare 72 00:03:43.039 --> 00:03:45.639 to drop your jaws as we discuss the origins of teeth, 73 00:03:45.719 --> 00:03:48.800 why yours hurt sometimes, how they got in your mouth, 74 00:03:48.919 --> 00:03:52.719 the long debated rumors of extinct species, how particle accelerators 75 00:03:52.719 --> 00:03:56.960 and paleontology worlds collide, what tools fossil pickers rely on, 76 00:03:57.039 --> 00:04:01.120 teeny tiny mysteries, busting age, old flame plan and why 77 00:04:01.159 --> 00:04:03.280 you should hug a chery before it kills you. Plus 78 00:04:03.319 --> 00:04:07.800 why a catfish might become your overlord. With science communicator, researcher, paleontologist, 79 00:04:07.919 --> 00:04:14.759 tooth enthusiast and researcher of ancient tissues paleohistologists. Doctor Yara Tardi. 80 00:04:33.240 --> 00:04:33.519 Fir Sing. 81 00:04:33.560 --> 00:04:35.839 I'll have you as we could say your first and 82 00:04:35.879 --> 00:04:37.120 last name in the pronounce you use. 83 00:04:38.040 --> 00:04:45.240 So I'miara Haredi, doctor Haredi, doctor Jara Haredi. She her pronouns. 84 00:04:45.600 --> 00:04:47.759 When did you defend your phg I. 85 00:04:48.000 --> 00:04:52.959 Was officially awarded to me in January twenty twenty two. Yeah. 86 00:04:53.000 --> 00:04:57.000 I followed you on Twitter for yearss. I know, in 87 00:04:57.040 --> 00:04:59.360 the beforetimes, in the before times, the rocking, it was Twitter. 88 00:05:00.319 --> 00:05:01.839 That's where all the scientists gathered. 89 00:05:01.959 --> 00:05:03.079 It was such a beautiful time. 90 00:05:03.120 --> 00:05:05.120 It was a beautiful time. I got to know your work, 91 00:05:05.160 --> 00:05:07.639 and I always loved that whenever someone found a like 92 00:05:07.680 --> 00:05:11.040 a raccoon skull under a shed, they would tag you like. 93 00:05:11.000 --> 00:05:13.079 Why is this? I did become like a go to 94 00:05:13.399 --> 00:05:16.319 bone and tooth person, which was my goal in the 95 00:05:16.399 --> 00:05:20.959 first place. And honestly that it's so sad because I 96 00:05:21.079 --> 00:05:23.319 used to suggest like social media as a go to 97 00:05:23.439 --> 00:05:25.360 thing all the time for even for like young people, 98 00:05:25.920 --> 00:05:27.879 like young people who are trying to get into science, 99 00:05:28.160 --> 00:05:30.279 because it was such a good resource. You know, I 100 00:05:30.319 --> 00:05:33.079 got jobs off of it. I got talking head gigs, 101 00:05:33.519 --> 00:05:36.800 I got collaborations, like actual science collaborations where someone's like, 102 00:05:36.800 --> 00:05:38.720 well wait, I have the machine that can do this. 103 00:05:39.000 --> 00:05:39.240 Yeah. 104 00:05:39.399 --> 00:05:41.879 I got friends, I got you know, all that kind 105 00:05:41.879 --> 00:05:45.040 of stuff. And it was really really beautiful place. Hopefully 106 00:05:45.079 --> 00:05:47.040 science will come together again somewhere else. 107 00:05:48.680 --> 00:05:51.600 Guy, So I am excited to catch up with you 108 00:05:51.600 --> 00:05:55.600 because I wanted to have you on for so long. Now, okay, 109 00:05:55.680 --> 00:05:59.079 the ology itself. I saw that you have a paper 110 00:05:59.199 --> 00:06:06.079 histological skeleto chronology that a possibility, paleo dentology. What are 111 00:06:06.120 --> 00:06:08.000 we thinking? What would you say your ology is? 112 00:06:08.600 --> 00:06:10.759 I mean when people ask me, like what my main 113 00:06:11.240 --> 00:06:14.920 method is, it's paleohistology. So I feel like that would 114 00:06:14.920 --> 00:06:17.079 be a really good one. And paleo hostology is just 115 00:06:17.120 --> 00:06:21.399 the study of ancient tissues. So histology is just literally 116 00:06:21.439 --> 00:06:24.319 the study of tissues, and then paleohstology you just make 117 00:06:24.360 --> 00:06:26.519 that ancient old old, yeah, old old. 118 00:06:26.959 --> 00:06:30.319 We're talking tissues, but we're also talking teeth. Is a 119 00:06:30.360 --> 00:06:30.800 tooth a. 120 00:06:30.759 --> 00:06:33.680 Tissue, so what makes up a tooth? Are the different 121 00:06:33.680 --> 00:06:36.879 tissues we'll be talking about, So like dentine enamel. Those 122 00:06:36.879 --> 00:06:38.600 are like words that people have heard from you know, 123 00:06:38.639 --> 00:06:42.560 your tooth paste commercials. Yeah, so those will be the tissues, 124 00:06:42.600 --> 00:06:44.199 but the structure as a whole is the tooth. 125 00:06:44.720 --> 00:06:48.000 And take me back, when did you start getting interested 126 00:06:48.360 --> 00:06:50.600 in paleontology? Oh? 127 00:06:50.680 --> 00:06:53.720 Girl, this is this is like I feel like it's 128 00:06:53.720 --> 00:06:57.680 such an odd story because so many people, especially in paleo, 129 00:06:57.879 --> 00:07:00.879 they were dino kids and they knew they you know, 130 00:07:01.000 --> 00:07:03.000 my husband's that way where he's like, I just knew 131 00:07:03.000 --> 00:07:04.920 that this is at least a direction I wanted to go, 132 00:07:05.040 --> 00:07:07.680 not paleo particularly, but like art for example, Paleo tends 133 00:07:07.720 --> 00:07:10.319 to be like that where a lot of people have 134 00:07:10.399 --> 00:07:13.160 been into it since forever. But I took like a 135 00:07:13.199 --> 00:07:16.240 couple of wrong turns to even get here. So I 136 00:07:16.279 --> 00:07:18.360 grew up in the Middle East, and in the Middle 137 00:07:18.360 --> 00:07:20.480 East you don't really have like a dinosaur phase as 138 00:07:20.480 --> 00:07:22.839 a kid. It wasn't marketed that way. You know, I'm 139 00:07:23.040 --> 00:07:26.560 nineteen ninety four, so goodyear. But you know, Jurassic Park 140 00:07:26.639 --> 00:07:30.680 was just becoming like big, and so it just wasn't 141 00:07:30.680 --> 00:07:32.279 as big in the Middle East, and it wasn't a thing, 142 00:07:32.319 --> 00:07:35.120 and I didn't really understand that that could be a career. 143 00:07:35.759 --> 00:07:38.920 And so then we immigrated to Canada and I started 144 00:07:38.920 --> 00:07:42.399 going to university and really being interested in science. And 145 00:07:42.680 --> 00:07:46.600 you know, I am Egyptian, so in our culture you 146 00:07:46.639 --> 00:07:48.600 can be a few things. You can be a doctor, 147 00:07:49.040 --> 00:07:51.480 you can be a pharmacist, you can be an engineer, 148 00:07:51.600 --> 00:07:56.759 or you can be a disappointment. So what I decided 149 00:07:56.800 --> 00:07:58.680 to go into a science and try to at least 150 00:07:58.680 --> 00:08:01.319 go into being a doctor. So I studying for med school, 151 00:08:01.800 --> 00:08:04.480 and man, I just wasn't enjoying it. And the parts 152 00:08:04.480 --> 00:08:08.000 that I enjoyed were the anatomy, the physiology, how things worked. 153 00:08:08.240 --> 00:08:10.319 As I was studying for med school, I volunteered in 154 00:08:10.319 --> 00:08:13.759 a paleo lab and I fell in love with paleontology. 155 00:08:14.199 --> 00:08:16.519 And yeah, couple of right turns turned left, or a 156 00:08:16.560 --> 00:08:19.199 couple left turns turned right, and I got into paleo. 157 00:08:19.240 --> 00:08:21.519 They offered me a master's and I continued from there. 158 00:08:21.839 --> 00:08:24.480 What was it about it? Was it just the age, 159 00:08:24.600 --> 00:08:27.439 like the unfathomable age? Was it the structures? 160 00:08:27.800 --> 00:08:30.680 That's a really good question, and I can actually mark 161 00:08:30.759 --> 00:08:33.960 the point where it happened. They had me picking fossils, 162 00:08:33.960 --> 00:08:35.639 and picking fossils is when you just sit on a 163 00:08:35.679 --> 00:08:38.960 microscope and you're like picking little microscopic like little bones 164 00:08:39.000 --> 00:08:42.519 from salamanders or teeth, and that was fun, and I 165 00:08:42.519 --> 00:08:44.519 think the shape of fossils is interesting. And I was 166 00:08:44.559 --> 00:08:46.759 just kind of mind blown that these were from the Permian, 167 00:08:47.320 --> 00:08:49.879 so they were two hundred and eighty plus million years old, 168 00:08:49.879 --> 00:08:52.519 which breaks your brain, yeah, if you are not used 169 00:08:52.559 --> 00:08:55.759 to those numbers and who is Yeah. But then there 170 00:08:55.799 --> 00:08:57.799 was a PhD student in the lab at the time 171 00:08:57.960 --> 00:09:01.799 and he taught me this method calledology and the study 172 00:09:01.799 --> 00:09:04.120 of tissues. And I didn't understand what that meant at 173 00:09:04.120 --> 00:09:07.720 the time, because what do you mean tissues survived in 174 00:09:07.799 --> 00:09:10.799 these two hundred and eighty million plus year old fossils, 175 00:09:10.799 --> 00:09:12.440 And so we cut them up and you can see 176 00:09:12.519 --> 00:09:15.679 under the microscope the bone tissue. You can start asking 177 00:09:16.039 --> 00:09:19.559 different questions like how old does this animal, how did 178 00:09:19.559 --> 00:09:21.320 it grow? How fast does it grow? What are the 179 00:09:21.320 --> 00:09:24.399 blood vessels? Like, same thing with teeth, Does it replace 180 00:09:24.440 --> 00:09:27.200 its teeth? How does it grow its teeth? All that 181 00:09:27.320 --> 00:09:29.600 was still preserved, and at that point it went from 182 00:09:29.600 --> 00:09:33.639 like mind blown to like shattered, like gone, because that 183 00:09:33.759 --> 00:09:36.240 was crazy. You can see cell spaces, you can see 184 00:09:36.320 --> 00:09:38.720 lines where like you know this animal had a hard winter. 185 00:09:39.240 --> 00:09:41.120 All that was recorded in the fossils, and at that 186 00:09:41.159 --> 00:09:43.000 point I was like, oh wait, this might be a 187 00:09:43.039 --> 00:09:49.120 real signal, actual thing. Well before that, everyone's just photographing 188 00:09:49.159 --> 00:09:52.080 externally like these fossils and it's not that that isn't science, 189 00:09:52.120 --> 00:09:54.200 of course it is, but it just wasn't as it 190 00:09:54.240 --> 00:09:56.080 didn't tickle that little part of my brain of like, 191 00:09:56.120 --> 00:09:59.000 we can go deeper, we can see how this animal ticked, 192 00:09:59.279 --> 00:10:02.360 What did its blood vessels do, what did it cells do? Yeah? 193 00:10:02.480 --> 00:10:05.000 I feel like if you were not a fossil person, 194 00:10:05.080 --> 00:10:08.080 not a palaeo person, you think the only things that 195 00:10:08.159 --> 00:10:11.120 maybe survived were the bones, and then you read an 196 00:10:11.200 --> 00:10:14.240 article where you're like, we know that there were feathers 197 00:10:14.279 --> 00:10:17.080 in here. Okay, we know there were scales, but I 198 00:10:17.519 --> 00:10:22.519 either imagined hard bones that survived and everything else rotted 199 00:10:22.559 --> 00:10:27.360 out or scales something something still hard, something's still hard, Yeah, 200 00:10:27.399 --> 00:10:28.960 something with a structure to it. 201 00:10:29.039 --> 00:10:31.720 And that's fair because that's the vast majority of fossils. 202 00:10:31.720 --> 00:10:34.559 That's like ninety nine point nine percent of fossils are 203 00:10:34.600 --> 00:10:37.759 actually teeth because enamel is the hardest vertebrate tissue and 204 00:10:37.799 --> 00:10:40.600 so it survives really well, it's already very crystallized, so 205 00:10:40.759 --> 00:10:42.559 like how much more crystallized can the Earth make? 206 00:10:42.600 --> 00:10:42.679 You? 207 00:10:42.840 --> 00:10:43.960 Yeah, so they. 208 00:10:43.879 --> 00:10:47.279 Survive really really well, a bone being secondary to that. 209 00:10:47.480 --> 00:10:52.240 But there are exceptional preservation moments in Earth where the 210 00:10:52.320 --> 00:10:54.639 right bacteria didn't get to it or the right bacteria 211 00:10:54.720 --> 00:10:58.159 did get to it, and they preserve feathers, they preferserve skin. 212 00:10:58.639 --> 00:11:01.960 We now have ichtheosaur lubber people like, have you know, 213 00:11:02.080 --> 00:11:05.840 actually done isotopic measurements and know that it's fat that 214 00:11:05.919 --> 00:11:08.519 was preserved in a really interesting chemical way. 215 00:11:08.799 --> 00:11:12.279 And it is rock. But it takes the impression of 216 00:11:12.320 --> 00:11:13.679 all those tissues not. 217 00:11:13.639 --> 00:11:17.240 Always oh yeah, okay, yeah yeah yeah, so fair right, 218 00:11:17.480 --> 00:11:21.200 that's kind of the old thinking of like, well it's 219 00:11:21.240 --> 00:11:23.360 just an impression, like the scales for example, like how 220 00:11:23.440 --> 00:11:25.200 do you know, like dinosaur mummies and stuff. 221 00:11:25.320 --> 00:11:28.000 Sometimes they are impressions. Sometimes the soft tissue left an 222 00:11:28.000 --> 00:11:32.200 impression and then disappear. Sometimes the tissue itself gets mineralized. 223 00:11:32.639 --> 00:11:35.840 So for example, let's think of your skin. There's multiple 224 00:11:35.879 --> 00:11:39.000 layers in your skin, and some parts of them basically 225 00:11:39.240 --> 00:11:43.120 get replaced one to one, or they get cross linked 226 00:11:43.360 --> 00:11:46.799 or get changed in some chemical way that makes them stable, 227 00:11:47.279 --> 00:11:51.240 so they actually preserve as that tissue that has been 228 00:11:51.360 --> 00:11:54.000 infused with new chemicals that are stable. 229 00:11:54.200 --> 00:11:57.240 I didn't realize that soft tissues were even something that 230 00:11:57.279 --> 00:12:00.639 you could look at. Now, between the soft tissue and 231 00:12:00.679 --> 00:12:06.120 the teeth, teeth obviously evolved over time. When did things 232 00:12:06.120 --> 00:12:08.000 start getting teeth? 233 00:12:08.480 --> 00:12:12.399 So that is basically the question of my life. When 234 00:12:12.399 --> 00:12:14.960 did things start getting teeth? Or if I can like 235 00:12:15.000 --> 00:12:17.080 extrapolate that even more, it's like when did things start 236 00:12:17.080 --> 00:12:20.879 getting mineralized tissues? Okay, so we have this process called 237 00:12:20.879 --> 00:12:26.399 biomineralization where we or organisms as a whole, will basically 238 00:12:26.440 --> 00:12:28.559 take minerals from the environment and make a skeleton out 239 00:12:28.600 --> 00:12:30.120 of them. And we're not the first to do that. 240 00:12:30.240 --> 00:12:33.279 You know, Sponges have skeletons, they have glass skeletons. Shelled 241 00:12:33.360 --> 00:12:36.559 organisms like mollusks they have skeletons too. Those shells count 242 00:12:36.799 --> 00:12:41.440 calcium carbonate skeletons. Arthropods have exoskeletons. So just taking stuff 243 00:12:41.440 --> 00:12:43.320 from the environment and making your own skeleton, we do 244 00:12:43.360 --> 00:12:45.919 that too, and so we make bone, we make teeth. 245 00:12:46.240 --> 00:12:49.559 Our skeletons are made of calcium phosphate. But what's interesting, 246 00:12:49.600 --> 00:12:53.240 of course, is that at least mineralized specimens fossilize really well. 247 00:12:53.360 --> 00:12:55.279 And so we can go back in time and be like, Okay, 248 00:12:55.320 --> 00:12:58.440 what's the first animal to have tooth tissues on it? 249 00:12:58.879 --> 00:13:01.720 What are the first animal to have bone tissues on it? 250 00:13:02.039 --> 00:13:03.960 And as far as we know, we kind of trace 251 00:13:04.000 --> 00:13:06.159 it all the way back, deep, deep, deep in time 252 00:13:06.279 --> 00:13:09.519 into like the middle or division, So about four hundred 253 00:13:09.559 --> 00:13:15.919 and fifty five million years ago. Yeah, hard to can sceptualize, right, 254 00:13:16.360 --> 00:13:20.279 So dinosaurs one extinct twin six sixty five. Yeah, yeah, right, 255 00:13:20.559 --> 00:13:24.799 So and then these bones existed for a very long time. 256 00:13:24.879 --> 00:13:27.559 Tooth tissues have existed for a very long time. And 257 00:13:27.600 --> 00:13:32.399 I say tooth tissues because they weren't exactly teeth. 258 00:13:32.799 --> 00:13:36.000 Were they ever made of cartilage and get harder or 259 00:13:36.039 --> 00:13:39.320 they were always mineralized. Did animals ever have like kind 260 00:13:39.360 --> 00:13:41.799 of gummy like bit like kind. 261 00:13:41.639 --> 00:13:45.200 Of like teeth, I love? Did they just gum things 262 00:13:45.200 --> 00:13:49.799 to death in the ocean? Yeah? Probably, But also more 263 00:13:50.039 --> 00:13:52.120 likely is that they were just suction feeding. There was 264 00:13:52.159 --> 00:13:54.879 some kind of filter feeding that happened early on. So 265 00:13:55.320 --> 00:13:59.159 the very first tooth like structures to appear in the 266 00:13:59.159 --> 00:14:02.240 fossil record don't appear in the mouth. They appear on 267 00:14:02.279 --> 00:14:06.120 the outside of fish. No appear on the outside on 268 00:14:06.320 --> 00:14:10.000 these like scales and the normal bone, which is partially 269 00:14:10.120 --> 00:14:13.000 nightmarish until you see how ridiculous these fish look like 270 00:14:13.679 --> 00:14:17.200 because they're nonsense looking. They look like you don't get 271 00:14:17.240 --> 00:14:19.080 like a handheld vacuum that you're gonna like clean your 272 00:14:19.080 --> 00:14:21.159 car with, or they look like that but stick googly 273 00:14:21.200 --> 00:14:24.519 eyes on the end. No, their mouth is always open 274 00:14:24.559 --> 00:14:28.200 because they don't have jaws yet. So these little tooth 275 00:14:28.440 --> 00:14:30.919 like things that are on the outside of these fish, 276 00:14:31.240 --> 00:14:33.120 we call them adontod's, So that's a word I'm going 277 00:14:33.200 --> 00:14:37.360 to be using often. So adontoad's are little chunks that 278 00:14:37.759 --> 00:14:40.480 basically look like a tooth, but they're on the outside 279 00:14:40.480 --> 00:14:42.720 of the mouth. They're made of enamel and denteene and 280 00:14:42.720 --> 00:14:45.080 they have a pulp cavity, but they cover the outside 281 00:14:45.120 --> 00:14:47.759 of fish rather than being the inside of the mouth. 282 00:14:48.039 --> 00:14:52.720 It sounds like a terratoma, you know, yeah, totally a 283 00:14:52.799 --> 00:14:58.399 blob item with tease sticking out everywhere. But what did 284 00:14:58.399 --> 00:15:02.440 they use them for on the outside boom exactly? 285 00:15:02.720 --> 00:15:06.440 We don't like, So we don't know, or we didn't know. 286 00:15:06.639 --> 00:15:09.080 We had a couple of hypotheses. Why would you have 287 00:15:09.159 --> 00:15:11.559 these things on the outside of your body. The very 288 00:15:11.600 --> 00:15:14.879 first answer was always like protection, Like, oh, you're making 289 00:15:14.879 --> 00:15:16.639 your hardest to show on the outside of the body. 290 00:15:16.679 --> 00:15:19.360 You're to make armor. You know, a lot of modern 291 00:15:19.399 --> 00:15:23.080 fish do that, Things like gar have really hardened scales 292 00:15:23.080 --> 00:15:25.799 that cover their entire bodies. Makes it harder for things 293 00:15:25.799 --> 00:15:28.159 to bite you. Yeah, it makes it harder for parasite 294 00:15:28.200 --> 00:15:29.919 to get attached, et cetera, et cetera. 295 00:15:30.360 --> 00:15:34.200 Please please see our grology episode about long cute, ancient 296 00:15:34.519 --> 00:15:38.480 patient poopable nightmare fish with the iconic biologist and punster 297 00:15:38.639 --> 00:15:41.720 doctor Solomon David, as well as our Terrotology episode about 298 00:15:41.720 --> 00:15:45.080 the history and culture of monsters in fiction. Because a 299 00:15:45.200 --> 00:15:47.840 terotoma is a blob that can grow in your body, 300 00:15:47.840 --> 00:15:51.039 but with fully formed teeth and clots of hair. And 301 00:15:51.120 --> 00:15:52.720 if you listen to the end of the episode, I'll 302 00:15:52.759 --> 00:15:56.240 tell you my own personal secret about tarotomas. But yes, 303 00:15:56.360 --> 00:15:59.320 millions of years before actual teeth. 304 00:15:59.360 --> 00:16:01.159 And of course the image of like teeth outside the 305 00:16:01.159 --> 00:16:05.080 mouth is so grotesque. Yeah, but if you think about 306 00:16:05.080 --> 00:16:07.480 like modern sharks, modern sharks have teeth outside the mouth, 307 00:16:07.559 --> 00:16:09.720 or they have these odontos they're covered in them. So 308 00:16:09.720 --> 00:16:11.879 if you put sharks one way, it's smooth, but if 309 00:16:11.919 --> 00:16:13.639 you put them the other way, it's super rough. That 310 00:16:13.759 --> 00:16:16.039 sandpaper feeling you get from sharks because they have little, 311 00:16:16.039 --> 00:16:17.559 tiny teeth all in their skin. 312 00:16:17.879 --> 00:16:24.440 Those are adontos. Yeah, exactly, hovered in tiny teeth. Mm hmm, yeah, 313 00:16:24.519 --> 00:16:27.240 I love that. The big teeth in a shark are 314 00:16:27.240 --> 00:16:30.159 what freak people out, but little do they know they 315 00:16:30.159 --> 00:16:33.759 have an army of tiny teeth also backing them up. 316 00:16:33.960 --> 00:16:34.200 Yep. 317 00:16:34.440 --> 00:16:37.879 So the first ones though we're outside the body, when 318 00:16:37.879 --> 00:16:40.919 did they start merging into the hole? 319 00:16:43.159 --> 00:16:46.360 Into the hole? Should we go back to the what 320 00:16:46.480 --> 00:16:49.360 are they four on the outside. So there's a couple 321 00:16:49.360 --> 00:16:52.279 of floating hypotheses. There's one that's like, okay, they're for 322 00:16:52.480 --> 00:16:54.360 protection because they're hard on their own and they're on 323 00:16:54.399 --> 00:16:57.080 the outside, and at that time period middle order of vision, 324 00:16:57.080 --> 00:16:59.960 there's like big scary things in the ocean, big cephalopo 325 00:17:00.080 --> 00:17:03.279 that's so big, squid not alloid looking things that would 326 00:17:03.279 --> 00:17:06.119 eat our little fishy ancestors. There's big sea scorpions that 327 00:17:06.160 --> 00:17:07.960 are bigger than you or I, that are up to 328 00:17:08.039 --> 00:17:10.880 like six feet or more. Again, things that would eat 329 00:17:10.880 --> 00:17:12.920 our little fishy ancestors, So it makes sense that the 330 00:17:12.960 --> 00:17:16.440 first hypothesis was protection. Another one that's based more on 331 00:17:16.559 --> 00:17:19.640 sharks is that maybe it helps them with low commotion. 332 00:17:20.200 --> 00:17:22.720 So when I said these fish are really weird looking, 333 00:17:23.039 --> 00:17:25.720 they don't have fins yet. So the first ones didn't 334 00:17:25.759 --> 00:17:27.839 have pectoral fins. They just had a tail. It's like 335 00:17:27.839 --> 00:17:30.559 a tube, like I said, it's an handheld vacuum with 336 00:17:30.640 --> 00:17:32.640 eyes on the end and an open mouth. So how 337 00:17:32.680 --> 00:17:35.440 do they move around in these like turbulent seas? How 338 00:17:35.440 --> 00:17:39.079 do you make your low emotion more efficient? Sharks they 339 00:17:39.200 --> 00:17:42.279 use the little spikes in their skin, these little teeth 340 00:17:42.319 --> 00:17:44.400 on the outside there are down to toads to help 341 00:17:44.440 --> 00:17:48.079 basically with hydrodynamics, the way that the water flows over 342 00:17:48.119 --> 00:17:51.039 their body is more efficient because of the little bumps 343 00:17:51.079 --> 00:17:53.960 all over them. So maybe the early fish did that too, 344 00:17:54.279 --> 00:17:56.799 So that's one other theory. And then the last theories 345 00:17:56.839 --> 00:17:59.119 that maybe it has something to do with sensation, that 346 00:17:59.160 --> 00:18:02.680 maybe because our modern teeth are soundsitive, maybe the outside 347 00:18:02.720 --> 00:18:03.519 ones are as well. 348 00:18:04.200 --> 00:18:06.400 How big were these outside ones? Were they teeny or 349 00:18:06.480 --> 00:18:07.119 were they like I. 350 00:18:07.079 --> 00:18:09.480 Should just show you. They're in the cabinets behind us. 351 00:18:09.799 --> 00:18:12.720 Yeah, grab one yeah, yeah, give me one second, okay. 352 00:18:12.920 --> 00:18:15.000 I just love that. You're like, well, we've got something 353 00:18:15.039 --> 00:18:18.200 that's millions and millions of years old over here, like 354 00:18:18.240 --> 00:18:20.480 how I would pull a coffee milk out of a cabinet. 355 00:18:21.240 --> 00:18:23.000 This is the first time I've ever heard the word 356 00:18:23.039 --> 00:18:26.400 odonto also, which is exciting. I didn't know that there 357 00:18:26.440 --> 00:18:30.799 was even a generalized name for them. This hall of 358 00:18:30.880 --> 00:18:33.759 cabinets is so bonkers. 359 00:18:34.319 --> 00:18:37.559 So I have a part of a headshield from adults fish. 360 00:18:38.240 --> 00:18:42.480 And what you can see here all these little bumps, 361 00:18:43.160 --> 00:18:44.440 each one of them's a little tooth. 362 00:18:44.920 --> 00:18:49.720 No, it looks adant to It looks kind of like 363 00:18:49.880 --> 00:18:52.799 a tiny cottage cheese ceiling, you know. 364 00:18:53.160 --> 00:18:55.000 Yeah, yeah, the popcorniness of it. 365 00:18:55.640 --> 00:19:00.160 The textures, they're like little tiny beads almost. And now 366 00:19:00.559 --> 00:19:04.920 you clarified that you have gotten flack here and there 367 00:19:05.119 --> 00:19:08.839 for calling it a tooth, because a tooth is in 368 00:19:08.960 --> 00:19:13.920 a jaw. But we're talking broadly to communicate what it's 369 00:19:13.960 --> 00:19:15.839 an analogous structure, right. 370 00:19:16.119 --> 00:19:19.920 Or homologous right, okay, because they have the same origin. 371 00:19:20.279 --> 00:19:22.920 So the reason that we know that these danto's on 372 00:19:22.960 --> 00:19:25.119 the outside of the mouth are even related to teeth, 373 00:19:25.160 --> 00:19:27.359 it's because they're made of the same thing. They're made 374 00:19:27.359 --> 00:19:29.599 of enamel, they're made of dente, and they have pulp cavities. 375 00:19:29.640 --> 00:19:31.920 They have the same blood supply, So they act very 376 00:19:31.920 --> 00:19:35.559 similar to our own teeth in the mouth, except that 377 00:19:35.640 --> 00:19:37.960 they don't replace the same way, and they don't have 378 00:19:38.039 --> 00:19:39.160 a job in that they. 379 00:19:39.079 --> 00:19:44.279 Don't And then they started coming merging. They started saying, 380 00:19:44.480 --> 00:19:45.400 let's get in the hole. 381 00:19:46.160 --> 00:19:49.279 So how did we get teeth in the mouth, or 382 00:19:49.319 --> 00:19:51.920 how did you go from Adonto's things that are bumpy 383 00:19:51.920 --> 00:19:55.319 outside the head to things that I can bite other 384 00:19:55.440 --> 00:20:00.559 fish with. So that happened along, we assume sometime probably 385 00:20:00.599 --> 00:20:01.240 the Devonian. 386 00:20:01.440 --> 00:20:05.119 So the Devonian was a cute little sixty million year 387 00:20:05.240 --> 00:20:07.559 era from about four hundred and twenty million years ago 388 00:20:07.640 --> 00:20:10.359 to three hundred and sixty or so million years ago, 389 00:20:10.440 --> 00:20:14.039 and it was a party. It involved plants growing on land, 390 00:20:14.559 --> 00:20:19.160 the formation of leaves and seeds, critters slithering out of 391 00:20:19.200 --> 00:20:23.920 the water into their terrestrial destinies. We had shelled bugs, 392 00:20:24.240 --> 00:20:26.759 We had fishes with jaws. In fact, it was called 393 00:20:26.799 --> 00:20:30.160 the Age of fishes. There were even now extinct things 394 00:20:30.200 --> 00:20:34.160 called placoderms, meaning flat plate fish that looked like they 395 00:20:34.200 --> 00:20:38.839 were wearing bulletproof vests and helmets. Four hundred million years ago, 396 00:20:39.000 --> 00:20:42.480 primitive sharks were like, hey, about a million years before 397 00:20:42.519 --> 00:20:46.559 trees existed, Sharks older than trees also be nice to sharks. 398 00:20:46.599 --> 00:20:49.480 Trees killed seventy one people in the US in twenty 399 00:20:49.519 --> 00:20:54.720 twenty three, but unprovoked sharks killed ten globally. Only two 400 00:20:54.759 --> 00:20:57.680 of those were in the US. Sharks are the eldest 401 00:20:57.720 --> 00:20:58.799