WEBVTT - Crab Body Plans (Featuring Dr. Jo Wolfe) 0:00:06.360 --> 0:00:09.959 An idea has taken hold of the public imagination. The 0:00:10.080 --> 0:00:14.760 idea is that nature just keeps inventing crabs. Crabs are 0:00:14.800 --> 0:00:18.000 just the ideal body plan and are incredibly beneficial. This 0:00:18.239 --> 0:00:21.040 idea emerged from a review paper that was written during 0:00:21.079 --> 0:00:24.000 the pandemic by a group of scientists led by doctor 0:00:24.079 --> 0:00:26.560 Joe Wolf. But the thing is that the idea that 0:00:26.680 --> 0:00:31.120 sort of emerged into the memo sphere is really quite 0:00:31.160 --> 0:00:33.800 different than the idea that was initially presented in this 0:00:33.840 --> 0:00:36.640 review paper. So today we have doctor Joe Wolf on 0:00:36.680 --> 0:00:38.519 the show, and she's going to tell you about what 0:00:38.560 --> 0:00:42.479 we actually know about how often the crab body shape 0:00:42.640 --> 0:00:45.200 pops up in nature, and what we know about whether 0:00:45.280 --> 0:00:48.519 or not that crab body plan is beneficial. Welcome to 0:00:48.640 --> 0:00:51.800 Daniel and Kelly's extraordinarily crabby universe. 0:01:05.200 --> 0:01:08.320 Hi. I'm Daniel. I'm a particle physicist, and I'm crabby 0:01:08.440 --> 0:01:09.319 in the evenings. 0:01:09.640 --> 0:01:13.320 Oh. Hi, I'm Kelly wieder Smith. I'm a biologist, and 0:01:13.400 --> 0:01:17.200 I want to believe I'm not crabby in a like 0:01:17.280 --> 0:01:22.080 Circadian rhythm sort of way. Maybe never. What is crabby, Daniel? 0:01:22.160 --> 0:01:24.320 Like, I've just noticed that between me and my wife, 0:01:24.360 --> 0:01:26.440 I tend to have more energy in the mornings, and 0:01:26.480 --> 0:01:28.720 she tends to have more energy in the evenings, which 0:01:28.760 --> 0:01:31.319 actually has worked out well as parents, because I get 0:01:31.400 --> 0:01:33.360 up early and I'm ready to go, go, go and 0:01:33.400 --> 0:01:35.680 get stuff done and help the kids with X Y Z. 0:01:36.520 --> 0:01:39.119 And when it's like nine pm and the kids you're like, oh, 0:01:39.160 --> 0:01:41.840 by the way, I need forty five cupcakes for tomorrow, 0:01:42.360 --> 0:01:45.280 Katrina's like okay, I'll spin that up, or like, let's 0:01:45.319 --> 0:01:48.520 go buy these special shoes you need for tomorrow's activity 0:01:48.640 --> 0:01:51.320 or whatever. So you know, as a team, it worked well. 0:01:51.360 --> 0:01:53.280 But yeah, I tend to be more tired in the 0:01:53.320 --> 0:01:55.600 evenings and she tends to be more slow to move 0:01:55.680 --> 0:01:56.320 in the mornings. 0:01:56.640 --> 0:01:58.600 We also have that division. Zach is more of a 0:01:58.680 --> 0:02:01.480 night person and I'm more of a morning person, and 0:02:01.560 --> 0:02:03.160 so I'm the one who make sure everybody gets up 0:02:03.160 --> 0:02:05.360 in the morning and we don't miss school, and Zach 0:02:05.520 --> 0:02:07.080 is the one who when the kids are kind of 0:02:07.120 --> 0:02:09.200 dragging their feet, he makes sure they get into bed 0:02:09.520 --> 0:02:11.280 because I'm a zombie. 0:02:11.360 --> 0:02:13.480 Isn't it funny how to get together you have to 0:02:13.520 --> 0:02:15.359 have sort of those rhythms in common. But then to 0:02:15.480 --> 0:02:18.680 survive as a parent, it's better to actually have the 0:02:18.720 --> 0:02:19.920 opposite routines. 0:02:20.360 --> 0:02:22.120 I mean for us, Like when I was younger, I 0:02:22.120 --> 0:02:24.639 could roll with it, like I'd rather not stay up late, 0:02:24.680 --> 0:02:26.320 but okay, final I'll stay up late. And even if 0:02:26.360 --> 0:02:27.960 I have to get up early, I can do that too, 0:02:27.960 --> 0:02:29.959 because I'm young and I can do anything. But now 0:02:30.080 --> 0:02:33.800 like I can't deny my daily rhythm anymore. 0:02:34.120 --> 0:02:36.720 Well, I think that leads to the obvious and deep question, 0:02:36.800 --> 0:02:39.720 which is when are crabs crabby? Do they tend to 0:02:39.720 --> 0:02:42.480 be energetic in the mornings or what? Or crabs just 0:02:42.560 --> 0:02:43.440 crabby all the time. 0:02:44.080 --> 0:02:46.160 I don't know. Probably depends on if you're harassing them 0:02:46.240 --> 0:02:48.840 or not. They're probably crabby whenever you know, young kids 0:02:48.880 --> 0:02:49.840 are trying to pick them up. 0:02:51.080 --> 0:02:53.040 They just want to be crabs, man. 0:02:52.919 --> 0:02:55.679 Yeah, just let them be crabs. And speaking of crabs 0:02:55.760 --> 0:02:59.640 have been sort of all over social media since the pandemic, 0:03:00.080 --> 0:03:04.120 and there's this idea that the optimal form for organisms 0:03:04.280 --> 0:03:07.359 is the crabby shape. And so we had this great 0:03:07.480 --> 0:03:10.079 question from a listener, and let's go ahead and listen 0:03:10.120 --> 0:03:10.720 to that question. 0:03:10.760 --> 0:03:15.519 Now, Hi, Kelly and Daniel, listen, what's the deal with crabs? 0:03:16.040 --> 0:03:19.160 Why does nature keep reinventing them? Can we get a 0:03:19.200 --> 0:03:25.440 new blueprint, maybe something with wings, crab wings. Anyway, I'd 0:03:25.480 --> 0:03:28.560 love to know why some of Nature's designs get recycled. Thanks, 0:03:28.560 --> 0:03:29.520 guys love the show. 0:03:30.800 --> 0:03:35.080 So it turns out that I happen to know doctor Wolf, 0:03:35.160 --> 0:03:37.280 who is one of the people who wrote the review 0:03:37.320 --> 0:03:42.760 paper from which this Crabby Body Shapes meme emerged from, 0:03:43.120 --> 0:03:45.720 and she's a little bit frustrated with how it has 0:03:45.800 --> 0:03:48.160 sort of taken off in a sort of inaccurate way, 0:03:48.600 --> 0:03:51.040 and so I invited her onto the show to give 0:03:51.160 --> 0:03:53.400 us all the details of what we know about this 0:03:53.520 --> 0:03:55.760 question and to sort of talk about how this idea 0:03:56.360 --> 0:03:58.640 took off and went off in weird directions. 0:03:59.000 --> 0:04:02.440 It's amazing that you know so many influential, famous scientists, Kelly. 0:04:03.120 --> 0:04:05.280 I've just harassed a lot of people throughout my life, 0:04:05.320 --> 0:04:07.960 I think, for various projects, and they've all just been 0:04:08.040 --> 0:04:09.280 nice enough to keep talking to me. 0:04:09.640 --> 0:04:12.320 That's wonderful. Well, it's really great to see friends succeed. 0:04:12.840 --> 0:04:16.320 It is, yes, right, and Joe is at Harvard, which 0:04:16.360 --> 0:04:20.960 is incredible, and so let's go ahead and start that interview. 0:04:22.600 --> 0:04:25.719 Doctor Joe Wolf is a research associate in organismic and 0:04:25.760 --> 0:04:29.240 evolutionary biology at Harvard. Welcome to the show. Joe. Hi, 0:04:30.279 --> 0:04:32.440 I'm so excited to have you here. And my husband 0:04:32.480 --> 0:04:33.880 I've been talking to him. I was like, Oh, we're 0:04:33.880 --> 0:04:35.800 going to ruin the crab thing, and he's like, Oh, 0:04:36.640 --> 0:04:38.600 you're gonna do the what planket thing, which is like 0:04:38.720 --> 0:04:41.120 what he's sort of, you know, come to know me for. 0:04:41.400 --> 0:04:43.960 But anyway, so let's jump right in. So when you 0:04:44.000 --> 0:04:48.320 hear folks say stuff like nature keeps inventing crabs, what 0:04:48.560 --> 0:04:51.560 do they mean? And what are the crabby features that 0:04:51.600 --> 0:04:52.520 are being honed in on? 0:04:52.560 --> 0:04:57.320 Here, I'll answer the part about what the crabby features are. 0:04:57.440 --> 0:05:01.320 I suppose this is something that's been and observed several 0:05:01.360 --> 0:05:05.480 times within a group called decorpod crustaceans. So decor pods 0:05:05.480 --> 0:05:09.440 contain probably the most crustaceans that most people are familiar with, 0:05:09.520 --> 0:05:13.320 crabs as well as shrimps and lobsters. And what we 0:05:13.640 --> 0:05:17.760 think that we understand when we see a crab, like, 0:05:17.839 --> 0:05:22.080 everyone has an image of what they imagine, and that 0:05:22.320 --> 0:05:27.320 is something that has a flat and wide carapace. Usually 0:05:27.400 --> 0:05:32.240 it's kind of oval around shaped, right, and generally the 0:05:32.279 --> 0:05:35.039 only thing that you see sticking out are legs and 0:05:35.120 --> 0:05:39.279 cloths so unlike with a lobster, where it has like 0:05:39.400 --> 0:05:43.520 this long abdomen and a tail fan sticking out, crabs 0:05:43.560 --> 0:05:46.880 don't visibly have that. It turns out that they do 0:05:47.320 --> 0:05:51.080 have the abdomen, but it's actually folded underneath the body. 0:05:51.680 --> 0:05:55.279 So the folding that is kind of one of the 0:05:55.279 --> 0:05:59.840 other major crabby features, and it actually covers up the underbelly, 0:06:00.040 --> 0:06:00.520 if you will. 0:06:00.920 --> 0:06:04.040 So the thing that makes something crabby are a flat 0:06:04.040 --> 0:06:08.840 carapace and then eight legs. Basically no, no, all right. 0:06:09.040 --> 0:06:12.880 Technically they do all have eight legs, but some of 0:06:12.920 --> 0:06:16.279 them do not have eight visible legs, and some of 0:06:16.320 --> 0:06:20.360 them that back there is super tiny, and sometimes it's 0:06:20.440 --> 0:06:23.920 in a specified chamber where you couldn't see them. 0:06:24.240 --> 0:06:26.359 Wow, all right, what are they doing in there? 0:06:26.520 --> 0:06:30.479 They're like cleaning some of the more sensitive anatomy. 0:06:31.080 --> 0:06:34.080 Huh yeah, okay, I didn't know that. Cool. 0:06:34.240 --> 0:06:36.440 Well, I wish I had special invisible legs to clean 0:06:36.440 --> 0:06:37.359 my sensitive anatomy. 0:06:41.480 --> 0:06:44.640 Yeah. So this is actually one of the main differences. 0:06:44.800 --> 0:06:49.000 So the idea that a crab like form has evolved 0:06:49.040 --> 0:06:51.080 multiple times has been known for over one hundred and 0:06:51.160 --> 0:06:55.040 forty years. And if we think about the tree of life, right, 0:06:55.600 --> 0:06:58.400 so This is like how different species are related. It's 0:06:58.440 --> 0:07:01.880 a bigger, an older version of the same thing as 0:07:01.960 --> 0:07:07.680 us having a family tree. So in the crustacean family tree, 0:07:08.000 --> 0:07:11.440 there are two groups which are each other's closest relative. 0:07:11.840 --> 0:07:14.560 One group is called the true crabs and one group 0:07:14.640 --> 0:07:17.840 is called false crabs. And so, Daniel, what you actually 0:07:18.000 --> 0:07:21.760 mentioned is one of the main obvious ways to distinguish them. 0:07:22.000 --> 0:07:26.640 True crab eight legs, false crab technically eight, but you 0:07:26.640 --> 0:07:31.600 will only see six usually or less. Permit crabs are 0:07:31.640 --> 0:07:34.200 part of that, and they usually only look like they 0:07:34.240 --> 0:07:39.040 have four because actually the back two pairs are involved 0:07:39.040 --> 0:07:40.080 in holding onto the show. 0:07:40.440 --> 0:07:43.280 And is that an arbitrary labeled true crab and false crab? 0:07:43.640 --> 0:07:45.640 Is there something just truer about one of them or 0:07:45.680 --> 0:07:47.480 is there like a value judgment there or is it 0:07:47.560 --> 0:07:51.080 like the remnants of an ancient argument among friends or what. 0:07:51.320 --> 0:07:54.720 No, it's a colloquialism. They have Latin names, So true 0:07:54.720 --> 0:07:57.920 crabs with brack eura and false crab with animura, and 0:07:58.000 --> 0:08:02.200 that actually refers to basically the folded under ab. 0:08:02.880 --> 0:08:05.080 It's really weird when you see an animal that's described 0:08:05.120 --> 0:08:06.200 basically about what it's not. 0:08:07.000 --> 0:08:10.160 You know, well, I think it's because within the false 0:08:10.200 --> 0:08:13.120 crabs you see something that looks like a crab, but 0:08:13.160 --> 0:08:16.080 they're not within the same group. So what that means 0:08:17.120 --> 0:08:21.239 intert of the family tree is that the ancestral form, 0:08:21.440 --> 0:08:23.880 or at least what we assume to be the ancestral form. 0:08:23.920 --> 0:08:27.240 And definitely many of the forms within the enemure or 0:08:27.240 --> 0:08:31.680 false crabs, many of those are elongate and they look 0:08:31.760 --> 0:08:35.720 more like a lobster. So some of them look like 0:08:36.120 --> 0:08:40.880 crabby and oval, and some of them look wrong and 0:08:41.000 --> 0:08:44.400 have like this abdominent tail and the tail fan like 0:08:44.400 --> 0:08:45.840 a lobster, which crabs don't have. 0:08:46.520 --> 0:08:49.400 Well, I'm feeling for the false crabs because I'm often 0:08:49.440 --> 0:08:52.800 described by my teenager's friends as like Hazel's dad or 0:08:52.840 --> 0:08:54.480 signs of the dad. I'm just like to find a 0:08:54.520 --> 0:08:56.160 relation to somebody. 0:08:55.720 --> 0:08:56.760 Else, something better. 0:08:56.960 --> 0:09:00.720 Yeah, exactly, something better. That's the implication right there, And 0:09:00.760 --> 0:09:02.840 so feeling for these false crabs. I'm on the false 0:09:02.840 --> 0:09:03.920 crabs team over here. 0:09:04.080 --> 0:09:05.880 They're actually my favorite, so. 0:09:05.840 --> 0:09:09.040 They're your favorite too. Yeah, there we go. The downtroden exactly, 0:09:09.440 --> 0:09:11.400 the crab crushed under the foot of evolution. 0:09:11.720 --> 0:09:15.480 They do have fewer species, so the true crops they 0:09:15.520 --> 0:09:18.800 have at least seventy five hundred described species, and the 0:09:18.840 --> 0:09:22.959 false crabs have like twenty five hundred. I'm saying described 0:09:22.960 --> 0:09:24.840 because we don't know their true. 0:09:24.600 --> 0:09:28.560 Diversity, and so you're talking about the various shapes of 0:09:28.600 --> 0:09:30.800 these critters today, and then you're also talking about the 0:09:30.800 --> 0:09:34.160 family tree. What is the relationship between these things? Is 0:09:34.200 --> 0:09:38.199 their common ancestor also krabby or did they evolve crabbiness independently? 0:09:38.480 --> 0:09:41.640 How many times has nature like invented crabs. 0:09:41.720 --> 0:09:47.040 So they did evolve it separately. It's challenging because we 0:09:47.080 --> 0:09:49.760 don't know what their exact ancestral look like. In order 0:09:49.800 --> 0:09:52.839 to be able to do that, we would ideally have 0:09:53.320 --> 0:09:57.880 many many fossils that came from the oldest point as 0:09:57.880 --> 0:10:01.600 close to the divergence of those groups possible. They do 0:10:01.679 --> 0:10:05.160 have a pretty good fossil record, but a lot of 0:10:05.200 --> 0:10:09.000 the fossils are just the care pace. And the reason 0:10:09.040 --> 0:10:11.640 for that is if you think about what happens to 0:10:11.880 --> 0:10:14.360 a quarks, Basically, if you throw it in the water, 0:10:15.040 --> 0:10:17.840 you know the parts that can fall apart will fall 0:10:17.880 --> 0:10:22.840 apart or be scavenged. So pretty much what happened to 0:10:22.920 --> 0:10:25.599 them is that. And so if you only have the 0:10:25.640 --> 0:10:28.600 care pace. Upon is that we already know that things 0:10:28.640 --> 0:10:31.720 that look similar in this group might not be both relatives. 0:10:31.800 --> 0:10:34.880 We know that from modern groups whose DNA that we have. 0:10:36.160 --> 0:10:38.240 So if we see something that looks similar and it's 0:10:38.360 --> 0:10:41.240 only the care pace, we can't always be certain in 0:10:41.280 --> 0:10:45.480 the fossil record, so that's kind of why we don't 0:10:45.520 --> 0:10:50.160 know what their exact ancestors are. However, we can look 0:10:50.200 --> 0:10:54.600 at least within the living groups at what their closest 0:10:54.640 --> 0:10:57.920 relatives are, and that can kind of help. And so 0:10:58.200 --> 0:11:03.040 within both the true and crabs we see krabby and 0:11:03.200 --> 0:11:06.880 not so krabby forms. So actually what we see is 0:11:06.920 --> 0:11:10.920 within the true crabs. Probably there's two instances where the 0:11:10.960 --> 0:11:14.559 Krabby form has evolved. One is in a pretty small group, 0:11:14.600 --> 0:11:17.600 which is kind of what we call the out group 0:11:18.160 --> 0:11:21.559 to the rest, So that means that basically the first 0:11:21.800 --> 0:11:27.280 branch that evolved from the true crabs. Within that group, 0:11:27.800 --> 0:11:30.880 we see one set of sort of rounded little guys 0:11:30.880 --> 0:11:33.080 that look like craps, and these are called the sponge crabs. 0:11:33.480 --> 0:11:36.319 They're called that because they usually make a hat out 0:11:36.360 --> 0:11:37.520 of a sponge and they wear it. 0:11:37.920 --> 0:11:40.400 Oh that's so cute. I have a new favorite crab. 0:11:40.480 --> 0:11:44.480 Now, why do they make a hat out of a sponge? 0:11:44.559 --> 0:11:48.120 Well, I guess it makes good camouflage if you look 0:11:48.320 --> 0:11:53.400 like an inanimate object a living thing, but nonetheless, hopefully 0:11:53.520 --> 0:11:54.559 no one's gonna come ool with you. 0:11:54.679 --> 0:11:56.920 Right, Do we have any tests to see if that 0:11:56.960 --> 0:11:59.280 actually works, like if you take their sponges off or 0:11:59.320 --> 0:12:01.920 you give them a better sponge. Has anyone actually shown. 0:12:02.000 --> 0:12:05.640 I don't know. I know I've seen some videos of 0:12:05.720 --> 0:12:09.480 people making like out of kitchen sponges and seeing how 0:12:09.520 --> 0:12:11.240 the crabs because they kind of like cut them up 0:12:11.240 --> 0:12:14.000 a little bit of their claws so they can do that, 0:12:14.040 --> 0:12:17.000 But I don't know if anyone's published a systematic test 0:12:17.040 --> 0:12:20.760 of that. There are other groups that hold things on 0:12:20.840 --> 0:12:24.120 top of themselves, like a hat. Hermit crabs technically are 0:12:24.200 --> 0:12:25.960 kind of doing that, so they shove their back end 0:12:26.000 --> 0:12:26.600 into it too. 0:12:27.120 --> 0:12:29.440 I love that they're like cutting their hats to fit 0:12:29.920 --> 0:12:32.520 the way that they want it. Anyway, this is very exciting. 0:12:32.600 --> 0:12:34.760 I could talk about this for five hours, but maybe 0:12:34.760 --> 0:12:35.520 we should keep going. 0:12:35.600 --> 0:12:37.480 Right, So that's the first group, and then the other 0:12:37.559 --> 0:12:40.160 group from the true crabs is there isn't a good 0:12:40.200 --> 0:12:43.680 common name for but it's the majority of true crab diversity, 0:12:44.200 --> 0:12:47.240 and I guess they can be called the higher true crabs, 0:12:47.240 --> 0:12:51.040 although that's a value judgment, and it's just referring to 0:12:51.040 --> 0:12:54.200 the fact that they share a common ancestor amongst themselves. 0:12:54.200 --> 0:12:57.640 So the vast majority of true crab species fit inside that. 0:12:57.760 --> 0:13:03.160 So that's like spider crabs, swimming crabs, decorator crabs, pretty 0:13:03.200 --> 0:13:06.720 much all land crabs, most of the ones that people eat, 0:13:07.120 --> 0:13:11.320 those are all within the higher true crabs or you 0:13:11.480 --> 0:13:14.559 breck eree, So those guys are almost all having the 0:13:14.640 --> 0:13:15.160 crapit for. 0:13:15.800 --> 0:13:18.760 And when we talk about this history, is this recent history, 0:13:18.920 --> 0:13:21.000 like this stuff has evolved in the last ten thousand years, 0:13:21.000 --> 0:13:23.319 one hundred thousand years. Are we talking hundreds of millions 0:13:23.360 --> 0:13:24.920 of years or what's the timescale? 0:13:24.960 --> 0:13:28.400 It's hundreds of millions, Yes, it's quite old. These guys 0:13:28.480 --> 0:13:32.000 were and off pretty much around the time of the dinosaurs. 0:13:32.400 --> 0:13:35.840 So if a dinosaur went for a swim, then they 0:13:35.920 --> 0:13:40.240 might have encountered some crabs. Even there were some crabs 0:13:40.240 --> 0:13:44.720 starting to go at least into brackish water environments also 0:13:44.840 --> 0:13:47.160 at that time, so they could have met up. 0:13:47.520 --> 0:13:49.480 I have the impression when I hear about a species 0:13:49.520 --> 0:13:52.280 that hasn't changed in hundreds of millions of years. That 0:13:52.360 --> 0:13:56.240 has sort of reached some plateau where like you can't 0:13:56.240 --> 0:13:58.880 really improve very much. Is that totally falls And it's 0:13:58.920 --> 0:14:01.640 just that the time scales so long, like in a 0:14:01.679 --> 0:14:04.840 billion years, crabs will look different, or have we somehow 0:14:04.920 --> 0:14:07.200 found some niche where it's really not going to change 0:14:07.280 --> 0:14:07.760 much more. 0:14:08.240 --> 0:14:11.240 That doesn't actually describe crabs, it's a term used to 0:14:11.240 --> 0:14:13.959 describe horseshoe crabs. So I guess we've got to address that. 0:14:14.000 --> 0:14:17.840 Elephant and horsy crabs are not a crustacean unfortunately. 0:14:17.960 --> 0:14:20.600 Oh wow, they're false false crabs. 0:14:20.320 --> 0:14:23.479 Right, yeah, yeah, they are. They're pretty much like interactive 0:14:23.760 --> 0:14:26.880 like spiders and scorpions, and the way that we distinguish 0:14:27.440 --> 0:14:30.640 different groups among arthropods. So archipods first of all, are 0:14:31.240 --> 0:14:36.680 the animals that have jointed legs. So within the horseshoe 0:14:36.720 --> 0:14:40.760 crabs and iraqeids those guys versus crustaceans, it's basically the 0:14:40.920 --> 0:14:44.360 number of segments of their head that is the main 0:14:44.480 --> 0:14:49.800 morphological way that they were first identified. And DNA data 0:14:50.200 --> 0:14:54.000 also verifies that these are separate groups. So they are 0:14:54.720 --> 0:14:58.760 at least five hundred million years different so horseshoe crabs Also, 0:14:59.360 --> 0:15:03.120 although they are around it, they don't have the same 0:15:03.120 --> 0:15:07.120 body parts as a crustacean, So they don't have this 0:15:07.200 --> 0:15:10.000 abdomen that folds up underneath. When you imagine a crab, 0:15:10.040 --> 0:15:12.280 it's not like this little taper bit and then a 0:15:12.320 --> 0:15:16.000 long spine at the end. Right, there's like a middle 0:15:16.040 --> 0:15:21.000 piece that crustaceans have that they don't have. So they're 0:15:21.040 --> 0:15:24.640 a little similar, but I wouldn't personally describe them as 0:15:24.720 --> 0:15:27.200 having the Krabby forma. Some people have said that they 0:15:27.240 --> 0:15:30.320 do if they're trying to make a really really broad 0:15:30.360 --> 0:15:33.800 ecological argument. People have also said that rais, you know, 0:15:33.920 --> 0:15:36.800 like the sting rays, that they're like that too. Of 0:15:36.800 --> 0:15:41.400 course those are vertebrates, so that's really different. So yeah, 0:15:41.440 --> 0:15:43.480 if you want to get really broad, then there's a 0:15:43.560 --> 0:15:45.880 lot more examples, but none of them have the abdomen 0:15:45.920 --> 0:15:47.960 folding up, which is one of the features that I 0:15:47.960 --> 0:15:49.080 think is really important. 0:15:49.360 --> 0:15:52.200 But you brought up horseshoe crabs because they have sort 0:15:52.240 --> 0:15:54.720 of stabilized on long terms and you don't expect them 0:15:54.800 --> 0:15:55.240 to evolve. 0:15:55.400 --> 0:15:59.640 Or here's the thing, they have been evolving the whole time. 0:16:00.160 --> 0:16:05.880 Their morphologies are similar to fossils, But when we study 0:16:05.960 --> 0:16:10.120 the DNA, they have been changing the whole time. So 0:16:10.400 --> 0:16:15.920 the morphology what we see visually seems the same, but 0:16:15.960 --> 0:16:21.360 they've been change so evolution has proceeded. I guess morphologically 0:16:21.600 --> 0:16:24.960 maybe they are very suitable for life through a lot 0:16:25.000 --> 0:16:28.840 of changes in the world, which is great. But no, 0:16:29.120 --> 0:16:32.280 it's kind of a fallacy that they haven't changed. 0:16:32.640 --> 0:16:35.760 Well, it would make more sense for evolution to be constant, right, 0:16:35.800 --> 0:16:38.360 I mean the environment keeps shifting, right. Earth is not 0:16:38.400 --> 0:16:40.360 the same, the climate is not the same, the other 0:16:41.000 --> 0:16:43.320 critters crawling around the Earth are not the same, so 0:16:43.360 --> 0:16:45.480 it makes sense for things to continue. I always thought 0:16:45.480 --> 0:16:47.360 that was weird. So you're telling me the things are 0:16:47.520 --> 0:16:50.360 constantly evolving, And so the idea that like crabs have 0:16:50.440 --> 0:16:52.840 reached some final form is a misunderstanding. 0:16:52.840 --> 0:16:56.920 It is. Yeah, so even within like the crustacean crabs, 0:16:56.920 --> 0:16:59.920 the deck pods, so true in false crabs, to say 0:17:00.120 --> 0:17:04.320 that they haven't changed even since the fossils, that's completely untrue. Actually, 0:17:04.440 --> 0:17:08.080 they have huge rphological variety. Why there are so many species. 0:17:08.200 --> 0:17:11.480 The horses youp grabually have four living species. But I 0:17:11.640 --> 0:17:14.640 just told you that there's like eleven thousand living species 0:17:14.680 --> 0:17:17.960 of crabs, and then there's also thousands of fossil species 0:17:17.960 --> 0:17:20.960 as well that are no longer a lot, so they 0:17:21.000 --> 0:17:24.440 have actually changed a lot. But it's true that there 0:17:24.440 --> 0:17:28.240 are examples of organisms like the horship crowd that haven't 0:17:28.320 --> 0:17:32.080 changed that much morphologically. So yeah, the true crabs as 0:17:32.080 --> 0:17:35.159 well as the false crabs, they have been morphologically changing 0:17:35.320 --> 0:17:38.399 as well in response to changes in their environment and 0:17:38.440 --> 0:17:38.760 so on. 0:17:39.600 --> 0:17:41.440 And I'm going to pull us back a little bit. 0:17:41.720 --> 0:17:45.800 So Daniel had asked you how many times nature invented crabs? 0:17:46.000 --> 0:17:48.960 Right, I got to two of them, right, So the. 0:17:48.920 --> 0:17:52.320 Sponge crabs and the higher true crabs are two examples. 0:17:52.359 --> 0:17:54.479 So now we got to switch over to the false crabs, 0:17:54.520 --> 0:17:58.919 which are Maya Daniel's favor. So those guys, they have 0:17:59.440 --> 0:18:04.040 at least instances, and the probably the oldest instance is 0:18:04.040 --> 0:18:08.520 what's called porcelain crabs. Those guys are little filter feeders 0:18:08.880 --> 0:18:13.520 and they live mostly in core reefs or intertidle zones. 0:18:13.920 --> 0:18:18.840 So if anyone lives near a beach, which in Irvine 0:18:18.840 --> 0:18:22.480 you probably do, we definitely do, you could probably see them. 0:18:22.560 --> 0:18:25.320 I went in a tide poole there I have definitely 0:18:25.359 --> 0:18:29.120 seen them in southern California. So they'll look like a crab, 0:18:29.160 --> 0:18:32.880 but count the number of legs and then you'll see 0:18:33.119 --> 0:18:34.080 they're pretty small too. 0:18:34.480 --> 0:18:35.879 We go to the tide pools all the time, but 0:18:35.920 --> 0:18:38.159 we try not to disturb the little critters because I 0:18:38.160 --> 0:18:40.439 feel like if everybody comes and like picks up a critter, 0:18:40.920 --> 0:18:43.120 then we're just going to be like wiping out some population. 0:18:43.359 --> 0:18:48.440 I think that probably is a safe bet. I wouldn't 0:18:48.480 --> 0:18:52.359 recommend handling animals in the wild if you aren't going 0:18:52.440 --> 0:18:55.800 to be very gentle. Obviously I have to do so 0:18:55.960 --> 0:18:59.160 because I have to collect them for work. We can't 0:18:59.160 --> 0:19:02.760 get the DNA if we don't capture and I'm sorry 0:19:02.960 --> 0:19:06.480 kill them, I know. I mean, I'm a vegetarian, so 0:19:06.600 --> 0:19:09.280 like I won't even a crab. I've never eaten a 0:19:09.280 --> 0:19:09.960 crab in my life. 0:19:09.960 --> 0:19:11.960 Oh my gosh. Even the ones that you capture and 0:19:12.040 --> 0:19:13.919 kill for their DNA, well, you. 0:19:13.960 --> 0:19:17.479 Got to put them in preservatives. So actually a lot 0:19:17.520 --> 0:19:20.399 of them we do put in ethanol. So yeah, that 0:19:20.440 --> 0:19:22.919 would be like making an alcoholic beverage. 0:19:22.520 --> 0:19:25.320 But crab cocktail. 0:19:25.359 --> 0:19:27.879 That would be disgusting. Like if you actually open some 0:19:27.960 --> 0:19:30.919 of these vials, I know Kelly has done this, Like, uh, 0:19:31.080 --> 0:19:33.240 you know, a little one is fine, but like some 0:19:33.520 --> 0:19:36.000 are really big or like even giant squids are nothing. 0:19:36.119 --> 0:19:37.920 You open them up, you can pretty much get high 0:19:37.960 --> 0:19:38.800 off the fumes. 0:19:40.160 --> 0:19:42.160 Yeah, and you know that Kelly has done this. 0:19:42.320 --> 0:19:43.080 Is that what? Yeah? 0:19:44.280 --> 0:19:48.840 Oh yeah, Kelly has snorted squid fumes. Wow, that is 0:19:48.840 --> 0:19:50.600 something I've learned about Kelly today. 0:19:51.040 --> 0:19:51.920 Well I've done it too. 0:19:52.760 --> 0:19:55.880 It wasn't squid fumes, it was large quantities of preserved 0:19:55.880 --> 0:19:58.600 fish vomit. But yes, you do get a little bit 0:19:58.720 --> 0:20:00.720 sort of high sitting around these samples. 0:20:01.000 --> 0:20:03.280 What does that go for on the street, Kelly. 0:20:03.480 --> 0:20:05.760 Nobody wants it. Actually, it turns out. 0:20:07.080 --> 0:20:07.840 Price is zero. 0:20:08.440 --> 0:20:11.360 There were some samples that we did for one of 0:20:11.359 --> 0:20:14.320 my projects that we had to dissect and we got 0:20:14.359 --> 0:20:17.879 them from like the fish market. So actually my colleagues 0:20:18.280 --> 0:20:22.399 ate the parts that I didn't dissect. I had to 0:20:22.440 --> 0:20:25.520 dissect them, but I didn't look at it. So yeah, 0:20:25.680 --> 0:20:27.560 so you can't eat force and the crabs though they're 0:20:27.600 --> 0:20:32.200 really small. But the other main one within the false crabs, 0:20:32.720 --> 0:20:36.240 lots of people eat that's king crabs. So like Alaska 0:20:36.320 --> 0:20:39.840 king crab that's really famous. That's not truly a crab. 0:20:40.000 --> 0:20:43.239 It's false crap. Count the number of legs. 0:20:42.680 --> 0:20:45.840 Not truly a crab. Oh my gosh. Yeah, taste pretty crabby. 0:20:46.000 --> 0:20:50.760 Yeah yeah. So those guys, they live pretty much white 0:20:50.800 --> 0:20:55.280 bold waters. So the only way people are going to 0:20:55.359 --> 0:20:58.920 encounter them without going out in a boat is if 0:20:58.960 --> 0:21:02.320 you're in pretty much quite cold places, so like the 0:21:02.359 --> 0:21:07.040 Pacific Northwest. I would say southern California. There might be 0:21:07.080 --> 0:21:10.000 a few, but they're more common furthermore, so that's why, 0:21:10.080 --> 0:21:12.000 like Alaska is one of their hot spots. 0:21:12.280 --> 0:21:13.520 They've got their own TV show. 0:21:14.840 --> 0:21:16.440 I don't know if we're just whims, but the water's 0:21:16.480 --> 0:21:18.119 pretty cold hair in southern California. 0:21:18.280 --> 0:21:23.600 Oh well, I am from Canada, so. 0:21:22.600 --> 0:21:24.800 Do you call me a whim? That's why I live here? 0:21:24.880 --> 0:21:28.159 Yeah. Yeah. So then there's the third group within that 0:21:28.280 --> 0:21:30.960 false crabs, and I hesitate to quality group because there's 0:21:30.960 --> 0:21:34.159