WEBVTT - From the Vault: TEETH 0:00:05.720 --> 0:00:08.039 Hey, welcome to Stuff to Blow Your Mind. My name 0:00:08.080 --> 0:00:11.200 is Robert Lamb and I'm Joe McCormick, and it's Saturday. 0:00:11.240 --> 0:00:13.560 Time to go into the vault for an older episode 0:00:13.560 --> 0:00:17.520 of the show. This one originally aired on July nineteen. 0:00:17.840 --> 0:00:21.560 It's about teeth. I'm ready to bite. Yeah, well, let's 0:00:21.600 --> 0:00:23.680 bite right in and figure out what we're biting with. 0:00:27.320 --> 0:00:29.159 Welcome to Stuff to Blow Your Mind, a production of 0:00:29.200 --> 0:00:38.040 I Heart Radios How to Work. Hey you, welcome to 0:00:38.080 --> 0:00:40.040 Stuff to Blow Your Mind. My name is Robert Lamb 0:00:40.120 --> 0:00:43.000 and I'm Joe McCormick. And if you've been listening to show, 0:00:43.120 --> 0:00:45.960 you know we just had our friend Katie Golden from 0:00:46.040 --> 0:00:48.839 Creature feature on. I think it was the episode right 0:00:48.840 --> 0:00:52.120 before this one where we talked about teeth with with 0:00:52.240 --> 0:00:54.480 Katie and that was a lot of fun. But Robert, 0:00:54.680 --> 0:00:57.720 I couldn't stop thinking about teeth. Oh yeah, I mean, 0:00:57.760 --> 0:01:02.320 teeth are weird. Teeth are wonderful and strange and grotesque. 0:01:02.960 --> 0:01:05.959 I was actually just at the dentist yesterday for a checkup, 0:01:06.240 --> 0:01:08.840 and I just kept thinking about just how weird it 0:01:09.040 --> 0:01:11.880 is that that I just regularly go to this place 0:01:12.319 --> 0:01:14.759 and pay another human being to reach into my mouth 0:01:14.840 --> 0:01:19.440 with special instruments and clean my weird bone like jaw protutions. 0:01:20.480 --> 0:01:23.880 The outside bones outside bones. Never forget your teeth are 0:01:23.880 --> 0:01:26.520 outside bones. Their bones that you wash. Oh this this 0:01:26.600 --> 0:01:29.920 is from Kimmy Schmidt. Right, Yeah, Titus Syndromedon sings that song. 0:01:29.959 --> 0:01:32.360 I think he's auditioning for like a chewing gum commercial, 0:01:33.200 --> 0:01:35.920 But he's actually wrong, I'm sorry to say, despite how 0:01:36.000 --> 0:01:38.400 much I love that moment from the show, teeth are 0:01:38.480 --> 0:01:41.399 not outside bones. They are not bones at all. They're 0:01:41.480 --> 0:01:43.759 totally different thing. We can explain that in a minute. 0:01:43.760 --> 0:01:46.560 But yeah, yeah, I mean, well, let's go ahead and 0:01:46.600 --> 0:01:48.920 get into it. So, yeah, our teeth are bone like 0:01:49.160 --> 0:01:52.160 in many respects. Uh yeah, but they are not bones. 0:01:52.200 --> 0:01:56.320 So just for an example, bones are composed of calcium, phosphorus, sodium, 0:01:56.320 --> 0:01:59.600 and other minerals. Uh and but mostly it's the protein 0:01:59.720 --> 0:02:04.040 call legend that forms the living growing collagen framework in bones. 0:02:04.760 --> 0:02:08.800 Bones have impressive regenerative powers. You break a bone, it 0:02:08.880 --> 0:02:11.720 can even like a really vicious break of a bone, 0:02:11.919 --> 0:02:16.240 and it can heal back. Also, bone marrow produces red 0:02:16.280 --> 0:02:19.720 and white blood cells. Teeth do not have bone marrow. Instead, 0:02:19.720 --> 0:02:23.080 they have dental pulp. So teeth, on the other hand, 0:02:23.160 --> 0:02:26.639 are you know, they're composed of calcium, phosphorus and other minerals. 0:02:26.880 --> 0:02:30.160 They're harder than any bone that we have in the body. Yeah, 0:02:30.280 --> 0:02:32.920 but they also lack the regenerative powers of bones. So 0:02:32.960 --> 0:02:35.720 if you crack or break a tooth, you're gonna need 0:02:35.800 --> 0:02:38.639 at least a root canal, if not a total extraction. 0:02:38.919 --> 0:02:43.080 That is kind of strange. That seems I wonder what 0:02:43.160 --> 0:02:46.880 the evolutionary reason for that is. I would expect, you know, 0:02:46.919 --> 0:02:49.280 there would be a strong pressure on the ability to 0:02:49.360 --> 0:02:52.919 regenerate teeth. Well, it depends on how this really gets 0:02:52.919 --> 0:02:57.000 into like the bigger questions of of biological mortality, right, 0:02:57.080 --> 0:02:59.720 like what do you need your teeth for? How long 0:03:00.440 --> 0:03:02.720 are you going to be a viable organism? How long 0:03:02.720 --> 0:03:04.720 do you need to live, you know, in order to 0:03:04.760 --> 0:03:08.760 accomplish your genetic mission of you know, reproduction, uh and 0:03:08.800 --> 0:03:10.799 so forth, and and you know, the evolution isn't really 0:03:10.840 --> 0:03:14.799 concerned with long term dental health beyond that point. Well maybe, yeah, 0:03:14.880 --> 0:03:19.079 maybe we don't need teeth because um, well, for one thing, 0:03:19.120 --> 0:03:22.520 we're not like sharks, right, We're not just like biting 0:03:22.560 --> 0:03:27.320 indiscriminately into whole organisms and you know, cross bones and 0:03:27.360 --> 0:03:29.840 stuff like that. We we tend to if we're eating 0:03:30.000 --> 0:03:33.200 an animal, we kill it before we start biting into it. 0:03:33.680 --> 0:03:35.880 Uh so you know, you you would be able to 0:03:35.920 --> 0:03:38.040 have the time to seek out the soft parts to 0:03:38.080 --> 0:03:42.040 bite into, and so you're not using your teeth in 0:03:42.040 --> 0:03:45.160 a kind of like violent, fast moving kind of way 0:03:45.200 --> 0:03:47.520 like a lot of other organisms would. Yeah, and and 0:03:47.520 --> 0:03:49.280 and it really drives home one of the one of 0:03:49.280 --> 0:03:50.960 the key and I guess kind of obvious things that 0:03:50.960 --> 0:03:52.640 we're gonna we're gonna touch on here and there is 0:03:52.680 --> 0:03:57.760 that as as organisms evolve, their teeth are going to 0:03:57.880 --> 0:04:01.400 change to meet the demands of their diet. And if 0:04:01.560 --> 0:04:04.720 if you're if you do not need your robust teeth 0:04:04.720 --> 0:04:07.760 of old anymore, well, those those teeth are going to change, 0:04:08.440 --> 0:04:11.000 and you're gonna end up with a dental model that 0:04:11.120 --> 0:04:13.320 is going to be more in keeping with what you're 0:04:13.360 --> 0:04:16.080 actually going to use your choppers for. It's funny, you 0:04:16.080 --> 0:04:19.560 could think of teeth in a way as a form 0:04:19.640 --> 0:04:22.840 of convergent evolution. So like the same way that you 0:04:22.920 --> 0:04:28.200 see uh, wings evolving independently in different lines of animals. 0:04:28.240 --> 0:04:32.600 It's not that everything on Earth that has wings evolved 0:04:32.600 --> 0:04:36.160 from a common winged ancestor. So wings arose in one 0:04:36.160 --> 0:04:41.760 case in insects, and then they separately arose in you know, mammals, 0:04:41.800 --> 0:04:44.279 They rose in bats and stuff, and then they separately 0:04:44.320 --> 0:04:47.240 arose in the dinosaurs that became birds, and then also 0:04:47.360 --> 0:04:51.520 in the other the flying reptiles, right, which are not dinosaurs, 0:04:51.560 --> 0:04:54.880 but also independently evolved wings. Uh. So, so you see 0:04:55.520 --> 0:04:58.800 winged flight evolving over and over despite the fact that 0:04:58.920 --> 0:05:02.080 all these organisms don't come from wings of a common 0:05:02.120 --> 0:05:04.520 ancestor organism that I mean, I guess if you go 0:05:04.600 --> 0:05:06.640 far back enough, they all do have a common ancestor, 0:05:06.680 --> 0:05:09.600 but it didn't have wings. Um. And you can see 0:05:09.600 --> 0:05:12.680 a kind of similar thing in different things we call 0:05:12.839 --> 0:05:16.200 teeth that you know, lots of organisms have an opening 0:05:16.360 --> 0:05:19.040 of the elementary tract. They've got a mouth of some 0:05:19.160 --> 0:05:22.640 kind or another, and it it just often happens to 0:05:22.680 --> 0:05:26.160 be the case that organisms evolve a need to mash 0:05:26.240 --> 0:05:29.480 and crush and cut things that are going into the 0:05:29.520 --> 0:05:32.039 front of the elementary tract. And that's how you get 0:05:32.040 --> 0:05:36.000 these different evolutions of things that are like teeth. Uh. 0:05:36.040 --> 0:05:37.479 And there there are a lot of different things you 0:05:37.560 --> 0:05:41.080 might call teeth, and not all are evolutionarily related to 0:05:41.080 --> 0:05:45.440 the calcified structures we see in animals like ourselves. In fact, 0:05:45.640 --> 0:05:48.480 one great example of a whole different kind of of 0:05:48.600 --> 0:05:52.520 twothworld that I was thinking about just recently is uh. 0:05:52.720 --> 0:05:56.159 It reminds me of this controversy over the mouth of 0:05:56.560 --> 0:06:01.560 a Cambrian predator that I have been calling Anomala carus 0:06:01.640 --> 0:06:05.000 or Anomala carress. I just found out that some people 0:06:05.040 --> 0:06:08.200 pronounce it anomalachrus. And now now I feel like my 0:06:08.240 --> 0:06:10.520 whole world has been turned on its head. I don't 0:06:10.520 --> 0:06:12.240 know which to say, but I think I'm gonna keep 0:06:12.240 --> 0:06:15.120 saying Anomala caress even if that's wrong, for the sake 0:06:15.160 --> 0:06:18.720 of consistency. This is this is basically, if you've ever 0:06:18.760 --> 0:06:20.960 been to a natural history museum, you've probably seen a 0:06:21.000 --> 0:06:25.720 representation of this. Uh, this this prehistoric fish. Yeah, I mean, 0:06:25.760 --> 0:06:28.600 well not a fish, well fish like organism and the 0:06:28.839 --> 0:06:33.080 this long predating fish. So the Cambrian period, of course, 0:06:33.120 --> 0:06:36.160 you know, it's roughly five hundred million years ago. It's 0:06:36.240 --> 0:06:39.080 the first time in the history and the fossil record 0:06:39.160 --> 0:06:42.800 of Earth where we suddenly see this explosion and diversity 0:06:42.839 --> 0:06:46.320 of animal body forms. You know, before this, there were animals, 0:06:46.400 --> 0:06:49.160 and most of them had soft bodies and leave very 0:06:49.200 --> 0:06:52.239 little records. But there were things like worms of various 0:06:52.320 --> 0:06:56.920 kinds um But but then suddenly around the Cambrian period 0:06:57.200 --> 0:06:59.320 you see all these different life forms emerging, and a 0:06:59.360 --> 0:07:02.200 lot of the life worms have hard shells. This is 0:07:02.200 --> 0:07:05.200 where you see the explosion of trilobytes. It sometimes thought 0:07:05.200 --> 0:07:08.680 of as the Age of trialobytes, which are these scuttling 0:07:08.760 --> 0:07:11.240 you know, almost like insect or crab like creatures that 0:07:11.280 --> 0:07:13.280 would move along the bottom of ocean floors and have 0:07:13.360 --> 0:07:16.440 these hard shells on their backs. But Anomala carrass or 0:07:16.480 --> 0:07:20.600 Anomalocros appears to have been the top predator or one 0:07:20.600 --> 0:07:24.560 of the top predators of the Cambrian period, which was 0:07:24.640 --> 0:07:27.960 and it was this lobed swimming predator that grew up 0:07:28.000 --> 0:07:31.680 to about six ft long. And when the fossils of 0:07:31.720 --> 0:07:36.640 Anomala carrass were first discovered, paleontologists thought that they were 0:07:36.680 --> 0:07:41.480 actually looking at two different species because it's a mostly 0:07:41.720 --> 0:07:45.480 soft bodied organism, so its entire body usually doesn't get 0:07:45.520 --> 0:07:49.200 preserved or doesn't get preserved very well. And since most 0:07:49.240 --> 0:07:52.200 of their bodies are these soft parts that don't get fossilized. 0:07:52.320 --> 0:07:55.520 Usually there were really only two parts of the body 0:07:55.960 --> 0:07:59.840 that paleontologists kept finding. These two parts were, first of all, 0:08:00.200 --> 0:08:04.120 these little pairs of shrimp looking things that they would 0:08:04.160 --> 0:08:05.880 come in pairs, and they would kind of have these 0:08:06.280 --> 0:08:09.240 curved shapes and they, I mean, they look like shrimp shells. 0:08:09.240 --> 0:08:11.840 That's the best way to put it. And that's actually 0:08:11.840 --> 0:08:15.840 where the name of Anomala carus comes from. H Anomala 0:08:15.840 --> 0:08:19.040 carus means, you know, anomaly in cars means weird shrimp 0:08:19.240 --> 0:08:22.600 or usual unusual shrimp. So you have these pairs of shrimps. 0:08:22.640 --> 0:08:24.880 And then the other part that they would often find 0:08:25.160 --> 0:08:29.960 would be these circular rings of hard looking plates. Now, 0:08:30.080 --> 0:08:32.800 the shrimp looking things we actually feel we actually figured 0:08:32.840 --> 0:08:36.400 out that these two different things actually were different parts 0:08:36.440 --> 0:08:39.680 of the same organism, this Cambrian predator. And so the 0:08:39.720 --> 0:08:43.560 shrimp looking things, it turned out, were curly we think, 0:08:43.720 --> 0:08:46.959 feeding tentacles that were on the underside of the head. 0:08:47.120 --> 0:08:49.320 So you'd see this thing swimming along. It's got the 0:08:49.320 --> 0:08:51.480 eyes in the front and then sort of as a mouth, 0:08:51.600 --> 0:08:54.920 it's got this like, you know, two lobed mustache of 0:08:55.080 --> 0:08:58.200 shrimp tentacles that we think probably could kind of like 0:08:58.280 --> 0:09:01.200 grab things and push them towards mouth parts, and then 0:09:01.240 --> 0:09:04.200 the mouth parts would be the other part that gets fossilized, 0:09:04.240 --> 0:09:08.080 that ring of plates, that's the mouth, that's sort of 0:09:08.200 --> 0:09:12.520 halo of teeth like a tooth lined sphincter of death. 0:09:12.720 --> 0:09:14.760 I mean, really, that's all a mouth is, is that 0:09:14.840 --> 0:09:17.360 it is the it is the anti anus, it's the 0:09:17.400 --> 0:09:20.439 other the other side of the organism. Yeah, just imagine 0:09:20.480 --> 0:09:23.400 like like an anus that's just surrounded by a circle 0:09:23.440 --> 0:09:26.160 of teeth that move inward. Right, And as we've discussed, 0:09:26.360 --> 0:09:28.240 we had we did a whole at least one whole 0:09:28.240 --> 0:09:30.760 episode on the evolution of the anus, and of course 0:09:30.800 --> 0:09:33.320 you didn't always have two openings in organisms. You had 0:09:33.400 --> 0:09:36.679 organisms that had to depend on one um orifice for 0:09:36.840 --> 0:09:39.720 both functions, right, Which is amazing that that we're not 0:09:39.760 --> 0:09:41.440 saying that's the case with a no, no, not at all. 0:09:41.559 --> 0:09:43.959 We're just sort of demystifying the difference between the anus 0:09:43.960 --> 0:09:47.000 and the mouth. Actually, I don't know for sure whether 0:09:47.040 --> 0:09:49.160 an Almala cars had an anus or not, but I'm 0:09:49.160 --> 0:09:51.839 pretty sure it had an anus. I had to get 0:09:51.880 --> 0:09:54.880 had some form of venus, right, it had, I would 0:09:54.880 --> 0:09:57.160 have to guess it had a one way digestive system, right. 0:09:57.200 --> 0:09:59.200 I mean those we discussed in those episodes. There are 0:09:59.320 --> 0:10:02.319 organisms that not or come to not have an anus. 0:10:02.559 --> 0:10:06.560 You know, sometimes an organism in a certain phase of 0:10:06.559 --> 0:10:10.680 its life no longer has to worry with defecating, or 0:10:11.080 --> 0:10:14.320 has come to a situation where it cannot defecate anymore 0:10:14.400 --> 0:10:16.600 and we'll just have to live with it. Yeah, certain 0:10:16.679 --> 0:10:19.640 varieties of scorpion that have lost their anus because their 0:10:19.640 --> 0:10:22.240 anus was on what like a third or fourth segment 0:10:22.280 --> 0:10:25.240 of their tail, which they jettison to escape a predict. 0:10:25.360 --> 0:10:29.040 It's a very sad scorpion story. But to the Anomala 0:10:29.080 --> 0:10:32.080 carus mouth So from what I can tell, there's actually 0:10:32.120 --> 0:10:36.280 still scientific disagreement about those mouth parts, about that sphincter 0:10:36.360 --> 0:10:39.679 of death, about that ring of teeth pointing inward. So 0:10:39.840 --> 0:10:44.199 it has long been assumed that Anomala Carus preyed on 0:10:44.360 --> 0:10:47.360 trial bytes in one way or another. But how right? 0:10:47.400 --> 0:10:52.199 Trial bytes have these really hard protective shells on their backs, 0:10:52.320 --> 0:10:57.280 and some paleontologists thought, well, maybe the Anomala Carus would 0:10:57.800 --> 0:11:00.440 eat them by attacking them right after mole thing when 0:11:00.480 --> 0:11:03.320 their shells would have been soft, or maybe it would 0:11:03.360 --> 0:11:05.720 attack them by like scooping them up with its little 0:11:05.760 --> 0:11:09.680 feeding shrimps, the feeding tentacles, and then cracking or prying 0:11:09.720 --> 0:11:12.280 off the shell somehow with those rings of plate like 0:11:12.440 --> 0:11:15.480 teeth in the mouth. But I've read criticisms of this 0:11:15.559 --> 0:11:18.360 model coming from the last decade or so, basically saying 0:11:18.400 --> 0:11:22.760 that some current models of the Anomala carus mouth show 0:11:22.840 --> 0:11:24.960 that it just would not have been strong enough to 0:11:25.120 --> 0:11:28.680 crack through trialobyte shells, and maybe maybe it had to 0:11:28.760 --> 0:11:32.520 feed on soft bodied organisms like jellyfish or worms instead. 0:11:32.559 --> 0:11:34.840 I don't know if the idea of eating trio bytes 0:11:34.960 --> 0:11:37.240 right after molting would get around this problem. It might 0:11:37.360 --> 0:11:41.040 or it might not. Um So, did the Anomala cars 0:11:41.080 --> 0:11:44.800 actually have this this crushing sphincter of deadly teeth or not? 0:11:45.000 --> 0:11:46.480 I don't. I don't know if we know the answer 0:11:46.520 --> 0:11:49.320 to this right now. This seems like a still open question. 0:11:49.640 --> 0:11:51.800 I mean, obviously it did have these plates, it did 0:11:51.800 --> 0:11:54.040 have these mouth parts, but we don't know how strong 0:11:54.120 --> 0:11:57.319 its mouth was. Yeah, it is just so weird to 0:11:57.360 --> 0:11:59.360 look at a representation of these because it's like it's 0:11:59.520 --> 0:12:02.080 it's it's the sphincter of death. Like you said, but 0:12:02.120 --> 0:12:04.680 it's also this feeling. It's that it's like a teeth. 0:12:04.760 --> 0:12:07.960 It's like teeth made of broken glass, you know. Uh, 0:12:08.080 --> 0:12:11.440 it's it's very strange to to look at. Yeah, it 0:12:11.480 --> 0:12:15.040 was originally thought when people found the mouthparts in isolation, 0:12:15.120 --> 0:12:16.960 so you just be this ring of plates, and they 0:12:17.000 --> 0:12:19.480 didn't know it was the same organism as the pair 0:12:19.520 --> 0:12:22.839 of weird shrimps. They I think originally thought this might 0:12:22.880 --> 0:12:26.160 have been some part of of like weird old jellyfish. 0:12:26.679 --> 0:12:28.480 All right, on that note, we're gonna take a quick break, 0:12:28.480 --> 0:12:30.680 but when we come back, we will continue to explore, 0:12:30.760 --> 0:12:40.280 to explore the weird wide world of teeth. So another thing, uh, 0:12:40.480 --> 0:12:42.640 you know, we were saying, of course again that teeth 0:12:42.640 --> 0:12:45.320 are not outside bones. As great as the song is, 0:12:45.320 --> 0:12:48.480 they're not bones at all. They're these hardened structures. And 0:12:48.920 --> 0:12:53.080 one question is where do teeth come from? Like what 0:12:53.240 --> 0:12:57.280 is their evolutionary history as we know them? And the 0:12:57.360 --> 0:13:02.160 current evidence indicates that the earliest known teeth evolved and 0:13:02.200 --> 0:13:04.160 I guess this would be different than like the Cambrian 0:13:04.240 --> 0:13:07.160 sort of mouth plates. This would be like teeth in 0:13:07.320 --> 0:13:12.040 jawed animals, you know. Uh, the earliest known teeth evolved 0:13:12.320 --> 0:13:15.960 not as adapted bones, because that's where you sort of think, right, 0:13:16.000 --> 0:13:18.600 You think, well, you know you had some bone structures 0:13:18.600 --> 0:13:21.880 and overtime those evolved into tooth like shapes. Sos of 0:13:21.880 --> 0:13:23.640 the bones would be coming out of the jaw and 0:13:23.720 --> 0:13:26.839 doing that. But actually it looks like the earliest teeth 0:13:26.840 --> 0:13:31.040 evolved and not as adapted bones, but as adapted fish scales. 0:13:32.080 --> 0:13:34.600 I was looking at a paper from Biology Letters in 0:13:35.559 --> 0:13:39.840 by Martin Rooklin and Philip C. J. Donohue uh called 0:13:40.120 --> 0:13:44.400 roman Dina and the Evolutionary Origin of Teeth basically finds 0:13:44.480 --> 0:13:47.880 evidence from a species called roman Dina stalina, which is 0:13:47.960 --> 0:13:51.880 an extinct plaqueoderm, and a plaque aderm is a type 0:13:51.880 --> 0:13:55.720 of armor plated ancestral fish from more than four hundred 0:13:55.760 --> 0:13:58.880 million years ago. One plaque aderm you've probably seen fossils 0:13:58.920 --> 0:14:03.800 of before, is the awesome, the terrifying dunk Leosteus. This 0:14:03.880 --> 0:14:07.680 is another superstar of a sort of a prehistoric creature 0:14:08.160 --> 0:14:11.480 exhibits and museums. Yeah, you look up a dunkle osteous 0:14:12.200 --> 0:14:15.280 cast or a dunkle Osteus skull. I mean, it's chomp city, 0:14:15.440 --> 0:14:20.680 just unbelievable, and they got huge. Imagine this gigantic fish 0:14:20.680 --> 0:14:23.920 with this chomp city head. It is definitely something out 0:14:23.960 --> 0:14:25.880 of a movie. Oh yeah, well, like why we keep 0:14:25.880 --> 0:14:27.880 making all these shark tech movies. They need to make 0:14:28.640 --> 0:14:31.360 a movie about this. You can caught Dunkles like a monster. 0:14:31.360 --> 0:14:33.880 It would be just named Dunkles, I like it, or 0:14:33.920 --> 0:14:40.280 just dunks dunks dunks dunk dunks, dunk dunk dunk dunks. 0:14:41.120 --> 0:14:45.440 I'm sorry, okay, but anyway. In the study X ray 0:14:45.480 --> 0:14:49.400 analysis of fossil remains of this fish, again, this is 0:14:49.440 --> 0:14:52.600 not dunkle Osteus. This is a different plaque. DRM Roman 0:14:52.640 --> 0:14:57.160 Dina Stalina showed that scales evolved first the fish. Scales 0:14:57.200 --> 0:15:00.400 evolved first, and then teeth evolved in the s line 0:15:00.400 --> 0:15:04.400 of fish as an adapted type of scale cell along 0:15:04.440 --> 0:15:08.600 a structure called the toothplate. And isn't it weird how 0:15:08.760 --> 0:15:14.240 scales became so many different things like bird feathers evolutionarily 0:15:14.360 --> 0:15:19.400 are adapted from ancestral reptile scales. Scales over time grew 0:15:19.480 --> 0:15:23.280 into these these filaments and things that eventually became feathers. 0:15:23.920 --> 0:15:26.600 But it's also thought that mammal fur and mammal hair 0:15:26.680 --> 0:15:30.440 are adapted from scales of a common ancestor. Well, I 0:15:30.440 --> 0:15:32.800 mean they've they've had time, right, That's that's one way 0:15:32.800 --> 0:15:34.720 to look at it. And it seems like teeth or 0:15:34.720 --> 0:15:37.480 another example here and these fish from four hundred million 0:15:37.520 --> 0:15:39.720 years ago, it looks like teeth are coming out of 0:15:39.760 --> 0:15:43.080 the adaptation of scale cells. Now as we uh, you know, 0:15:43.320 --> 0:15:45.440 we're gonna go ahead and jump the time machine and go, 0:15:45.880 --> 0:15:49.320 you know, go go go forward in time here, and 0:15:49.360 --> 0:15:51.360 you know, it's easy to sort of fall into the 0:15:51.400 --> 0:15:54.200 trap of thinking, okay, certainly, especially when we get into 0:15:54.200 --> 0:15:57.680 mammal teeth, we're basically talking about the same scenario in 0:15:57.720 --> 0:16:01.040 any given organism, right, I mean, yeah, you're your dog's 0:16:01.080 --> 0:16:03.520 teeth don't look quite like human teeth, but there are 0:16:03.520 --> 0:16:07.000 a lot of parallels. A cow's teeth don't look exactly 0:16:07.080 --> 0:16:09.440 like a dog's teeth, but there are a lot of parallels. 0:16:09.880 --> 0:16:11.560 You know. But then again, as we know from our 0:16:11.560 --> 0:16:14.280 conversation with Katie, I mean, beaver teeth just chuck the 0:16:14.280 --> 0:16:17.360 boat over, right, And another one that really chucks the 0:16:17.360 --> 0:16:22.360 boat over are the are the teeth of elephants. And 0:16:22.400 --> 0:16:25.880 they're extinct ken Because when when you look at an 0:16:25.920 --> 0:16:28.760 elephant or a mastodon or a mammoth. First of all, 0:16:28.800 --> 0:16:33.840 they are polyphiodonts rather than uh, diffidants, meaning that they're 0:16:33.920 --> 0:16:37.400 psych They cycle through teeth their entire life rather than 0:16:37.440 --> 0:16:40.480 depending on a mere two sets of teeth, So more 0:16:40.520 --> 0:16:44.960 kind of like sharks to an extent. Basically like with 0:16:45.000 --> 0:16:47.320 a human, you have you have two sets. You got 0:16:47.320 --> 0:16:49.000 that first set, those baby teeth, and you get those 0:16:49.040 --> 0:16:52.040 adults set, uh, the adult teeth, and you've got to 0:16:52.080 --> 0:16:54.640 make that adult set last because those are the ones 0:16:54.680 --> 0:16:57.800 that are supposed to take you to the grave. Uh. 0:16:57.840 --> 0:17:00.800 With the elephant is a different scenario. Uh, there's still 0:17:00.840 --> 0:17:03.560 a limited number of teeth. It's not just teeth forever, 0:17:04.760 --> 0:17:07.080 but it's it's but it's also just a totally different 0:17:07.280 --> 0:17:10.160 um like way that they grow. So you have long 0:17:10.359 --> 0:17:14.200 ridges of teeth that move not from bottom to top. 0:17:14.280 --> 0:17:17.160 You know, like when when you think of like a child, 0:17:17.200 --> 0:17:19.560 a young child about their their their they lose their 0:17:19.560 --> 0:17:22.480 baby teeth and then those adult teeth grow up out 0:17:22.480 --> 0:17:24.760 of the jaw, like down down in the jaw and 0:17:24.800 --> 0:17:27.280 then they load up to the yeah or or down 0:17:27.359 --> 0:17:28.919 or you know, they come down and they come up 0:17:28.920 --> 0:17:31.400 out of the jaw. Right. Well, it's great to see 0:17:31.440 --> 0:17:33.879 those like cross sections of the jawbone at the baby 0:17:33.880 --> 0:17:36.640 teeth still in there is just disgusting. It's like, how 0:17:36.680 --> 0:17:38.680 could you ever look at a child the same way again? 0:17:39.240 --> 0:17:42.600 But with elephants, you have long ridges of teeth that 0:17:42.760 --> 0:17:48.440 move from back to front along upper and lower jaws lowly, 0:17:48.840 --> 0:17:51.960 slowly wearing into a shelf at the front as the 0:17:52.040 --> 0:17:56.280 roots are absorbed. So segments of the warranteeth in these 0:17:56.280 --> 0:18:00.359 teeth are are oblong looking things too, so bay Basically, 0:18:00.440 --> 0:18:02.920 they just move out of the back of the jaw 0:18:03.200 --> 0:18:05.160 along to the front of the jaw and then they 0:18:05.240 --> 0:18:08.760 break off in sections, sort of like a pez dispenser 0:18:09.080 --> 0:18:10.399 or one way I like to think of it. It's 0:18:10.400 --> 0:18:13.679 it's kind of like a toblarown bar. Each elephant tooth 0:18:13.800 --> 0:18:16.760 or masted on tooth is a toblaroom bar that gets 0:18:16.760 --> 0:18:19.800 worn down and as it reaches the front, segments of 0:18:19.840 --> 0:18:22.800 that tobler room bar just fall out, and then in 0:18:22.800 --> 0:18:26.919 the back of the jaw, new fresh teeth are growing out. Uh, 0:18:27.280 --> 0:18:29.280 you know, growing out of roughly the same place you know, 0:18:29.359 --> 0:18:32.399 where your wisdom teeth would be located. So this alone 0:18:32.440 --> 0:18:35.760 is crazy. You know, most animals have vertically grown choppers. 0:18:36.520 --> 0:18:40.160 But elephants and the kin of elephants essentially have six 0:18:40.240 --> 0:18:45.399 sets of molars that that replace over time. So basically 0:18:45.480 --> 0:18:48.520 the way the cycle goes is that, uh, they have 0:18:48.840 --> 0:18:51.680 you know, one set of molars at birth, um, and 0:18:51.720 --> 0:18:54.840 they keep those for about they lose those after two years. 0:18:55.080 --> 0:18:58.320 Then they get a second set, lose those at six years, 0:18:58.600 --> 0:19:00.200 and they get a third set, of fourth at a 0:19:00.240 --> 0:19:02.280 fifth set in a sixth set, and then the and 0:19:02.320 --> 0:19:05.199 in rare circumstances they will get a seventh set of 0:19:05.280 --> 0:19:08.080 molars that come out of the back. But then that's 0:19:08.080 --> 0:19:10.040 how you know you're dealing with like a real silver back. 0:19:10.119 --> 0:19:13.520 Like well, it's actually one way that the scientists are 0:19:13.560 --> 0:19:16.560 able to age the remains of elephants, Like you find 0:19:17.080 --> 0:19:19.679 the remains of the jaw and you can look and 0:19:19.720 --> 0:19:21.520 you can see you can learn a lot from it. 0:19:21.560 --> 0:19:23.960 If it's a different type of elephant, can you know, 0:19:23.960 --> 0:19:26.280 if it's mammoth or mastered on you can you can 0:19:26.320 --> 0:19:28.800 study exactly what kind of foods it was eating based 0:19:28.840 --> 0:19:31.399 on what those teeth look like. But then if it's 0:19:31.400 --> 0:19:34.840 a particularly old elephant, um, well, look I'll say first 0:19:34.880 --> 0:19:37.960 let's say it was a you know, an adult elephant 0:19:38.040 --> 0:19:40.919 that wasn't too old, then you would see like the 0:19:40.960 --> 0:19:43.000 warren teeth, and then you would see in the back 0:19:43.080 --> 0:19:46.159 where fresh teeth were growing out. But then in the 0:19:46.280 --> 0:19:50.600 an older adult elephant, it's on its last set the 0:19:50.640 --> 0:19:54.120 hole in the back of the jaw, back on each 0:19:54.119 --> 0:19:55.960 side of the jaw would be closed. It has just 0:19:56.000 --> 0:19:58.920 become solid bone again because it is on its last 0:19:58.920 --> 0:20:01.919 set of teeth, and those are the teeth that are 0:20:01.920 --> 0:20:03.600 going to take it to the grave. I can't remember 0:20:03.600 --> 0:20:05.800 if you already said this or the teeth. Is it 0:20:06.000 --> 0:20:08.959 born with all these teeth already there or do the 0:20:09.000 --> 0:20:12.440 teeth like generate over time they generate? Okay, yeah, they're 0:20:12.480 --> 0:20:15.680 not already loaded back there. Um, so these are also 0:20:16.080 --> 0:20:18.760 these are known as high it's known as hind molar progression, 0:20:19.040 --> 0:20:21.879 also known as marching molars, which I particularly like that 0:20:21.880 --> 0:20:24.240 one because there's this idea that they're marching from the 0:20:24.280 --> 0:20:28.480 back of the jaw towards the front. And the main 0:20:28.640 --> 0:20:32.800 other extent creatures that have these are the manatees, which 0:20:32.840 --> 0:20:35.120 I'll get back to in a bit. And interestingly enough, 0:20:35.160 --> 0:20:38.159 the manatees have them, but the doo gong, the relative 0:20:38.160 --> 0:20:42.480 of the manatee does not. Kangaroo molars also apparently work 0:20:42.520 --> 0:20:46.760 in this fashion. Um. But but then other creatures like you. 0:20:46.760 --> 0:20:49.119 You might look to the rock higher ax, which is 0:20:49.720 --> 0:20:53.280 the elephants rodent like relative. But even though it has 0:20:53.359 --> 0:20:56.960 some elephant like qualities to its uh to, its teeth, 0:20:57.000 --> 0:20:59.960 including two rodent like front teeth, are actually tiny tusts. 0:21:00.400 --> 0:21:05.000 It doesn't have marching molars. Um. But I mentioned already 0:21:05.000 --> 0:21:08.840 how the elephant molars are also elongated. Uh. They they 0:21:08.920 --> 0:21:11.199 They're really crazy to look at because it looks like 0:21:11.320 --> 0:21:14.919 fused teeth in a sense. It's it's like a big 0:21:15.040 --> 0:21:19.320 long chunk of teeth and it's essentially it has enamel 0:21:19.440 --> 0:21:23.320 loops for grinding plant matter. So that's what the elephants 0:21:23.400 --> 0:21:26.320 using these for. It's just grinding top to molars against 0:21:26.320 --> 0:21:29.359 bottom molars and uh and that is of course wearing 0:21:29.400 --> 0:21:32.560 the teeth down as well, thus the need to continually 0:21:32.600 --> 0:21:35.520 replace them. Right, the elephant is herbivore. It's gonna be 0:21:35.560 --> 0:21:37.320 eating rough plant matters, so it needs sort of a 0:21:37.359 --> 0:21:40.000 mortal mortar and pestle in the mouth to to mash 0:21:40.040 --> 0:21:42.840 it up real good. Yeah. But again, when the when 0:21:42.840 --> 0:21:44.919 the teeth are done that's it. And this is going 0:21:44.960 --> 0:21:46.879 to lead in the wild especially, is going to lead 0:21:46.920 --> 0:21:50.359 to malnutrition and or starvation. So I encourage everyone to 0:21:50.359 --> 0:21:54.000 think about elephant teeth the next time you see an elephant. 0:21:54.280 --> 0:21:55.920