Speaker 1: An idea has taken hold of the public imagination. The
Speaker 1: idea is that nature just keeps inventing crabs. Crabs are
Speaker 1: just the ideal body plan and are incredibly beneficial. This
Speaker 1: idea emerged from a review paper that was written during
Speaker 1: the pandemic by a group of scientists led by doctor
Speaker 1: Joe Wolf. But the thing is that the idea that
Speaker 1: sort of emerged into the memo sphere is really quite
Speaker 1: different than the idea that was initially presented in this
Speaker 1: review paper. So today we have doctor Joe Wolf on
Speaker 1: the show, and she's going to tell you about what
Speaker 1: we actually know about how often the crab body shape
Speaker 1: pops up in nature, and what we know about whether
Speaker 1: or not that crab body plan is beneficial. Welcome to
Speaker 1: Daniel and Kelly's extraordinarily crabby universe.
Speaker 2: Hi. I'm Daniel. I'm a particle physicist, and I'm crabby
Speaker 2: in the evenings.
Speaker 1: Oh. Hi, I'm Kelly wieder Smith. I'm a biologist, and
Speaker 1: I want to believe I'm not crabby in a like
Speaker 1: Circadian rhythm sort of way. Maybe never. What is crabby, Daniel?
Speaker 2: Like, I've just noticed that between me and my wife,
Speaker 2: I tend to have more energy in the mornings, and
Speaker 2: she tends to have more energy in the evenings, which
Speaker 2: actually has worked out well as parents, because I get
Speaker 2: up early and I'm ready to go, go, go and
Speaker 2: get stuff done and help the kids with X Y Z.
Speaker 2: And when it's like nine pm and the kids you're like, oh,
Speaker 2: by the way, I need forty five cupcakes for tomorrow,
Speaker 2: Katrina's like okay, I'll spin that up, or like, let's
Speaker 2: go buy these special shoes you need for tomorrow's activity
Speaker 2: or whatever. So you know, as a team, it worked well.
Speaker 2: But yeah, I tend to be more tired in the
Speaker 2: evenings and she tends to be more slow to move
Speaker 2: in the mornings.
Speaker 1: We also have that division. Zach is more of a
Speaker 1: night person and I'm more of a morning person, and
Speaker 1: so I'm the one who make sure everybody gets up
Speaker 1: in the morning and we don't miss school, and Zach
Speaker 1: is the one who when the kids are kind of
Speaker 1: dragging their feet, he makes sure they get into bed
Speaker 1: because I'm a zombie.
Speaker 2: Isn't it funny how to get together you have to
Speaker 2: have sort of those rhythms in common. But then to
Speaker 2: survive as a parent, it's better to actually have the
Speaker 2: opposite routines.
Speaker 1: I mean for us, Like when I was younger, I
Speaker 1: could roll with it, like I'd rather not stay up late,
Speaker 1: but okay, final I'll stay up late. And even if
Speaker 1: I have to get up early, I can do that too,
Speaker 1: because I'm young and I can do anything. But now
Speaker 1: like I can't deny my daily rhythm anymore.
Speaker 2: Well, I think that leads to the obvious and deep question,
Speaker 2: which is when are crabs crabby? Do they tend to
Speaker 2: be energetic in the mornings or what? Or crabs just
Speaker 2: crabby all the time.
Speaker 1: I don't know. Probably depends on if you're harassing them
Speaker 1: or not. They're probably crabby whenever you know, young kids
Speaker 1: are trying to pick them up.
Speaker 2: They just want to be crabs, man.
Speaker 1: Yeah, just let them be crabs. And speaking of crabs
Speaker 1: have been sort of all over social media since the pandemic,
Speaker 1: and there's this idea that the optimal form for organisms
Speaker 1: is the crabby shape. And so we had this great
Speaker 1: question from a listener, and let's go ahead and listen
Speaker 1: to that question.
Speaker 3: Now, Hi, Kelly and Daniel, listen, what's the deal with crabs?
Speaker 3: Why does nature keep reinventing them? Can we get a
Speaker 3: new blueprint, maybe something with wings, crab wings. Anyway, I'd
Speaker 3: love to know why some of Nature's designs get recycled. Thanks,
Speaker 3: guys love the show.
Speaker 1: So it turns out that I happen to know doctor Wolf,
Speaker 1: who is one of the people who wrote the review
Speaker 1: paper from which this Crabby Body Shapes meme emerged from,
Speaker 1: and she's a little bit frustrated with how it has
Speaker 1: sort of taken off in a sort of inaccurate way,
Speaker 1: and so I invited her onto the show to give
Speaker 1: us all the details of what we know about this
Speaker 1: question and to sort of talk about how this idea
Speaker 1: took off and went off in weird directions.
Speaker 2: It's amazing that you know so many influential, famous scientists, Kelly.
Speaker 1: I've just harassed a lot of people throughout my life,
Speaker 1: I think, for various projects, and they've all just been
Speaker 1: nice enough to keep talking to me.
Speaker 2: That's wonderful. Well, it's really great to see friends succeed.
Speaker 1: It is, yes, right, and Joe is at Harvard, which
Speaker 1: is incredible, and so let's go ahead and start that interview.
Speaker 1: Doctor Joe Wolf is a research associate in organismic and
Speaker 1: evolutionary biology at Harvard. Welcome to the show. Joe. Hi,
Speaker 1: I'm so excited to have you here. And my husband
Speaker 1: I've been talking to him. I was like, Oh, we're
Speaker 1: going to ruin the crab thing, and he's like, Oh,
Speaker 1: you're gonna do the what planket thing, which is like
Speaker 1: what he's sort of, you know, come to know me for.
Speaker 1: But anyway, so let's jump right in. So when you
Speaker 1: hear folks say stuff like nature keeps inventing crabs, what
Speaker 1: do they mean? And what are the crabby features that
Speaker 1: are being honed in on?
Speaker 4: Here, I'll answer the part about what the crabby features are.
Speaker 4: I suppose this is something that's been and observed several
Speaker 4: times within a group called decorpod crustaceans. So decor pods
Speaker 4: contain probably the most crustaceans that most people are familiar with,
Speaker 4: crabs as well as shrimps and lobsters. And what we
Speaker 4: think that we understand when we see a crab, like,
Speaker 4: everyone has an image of what they imagine, and that
Speaker 4: is something that has a flat and wide carapace. Usually
Speaker 4: it's kind of oval around shaped, right, and generally the
Speaker 4: only thing that you see sticking out are legs and
Speaker 4: cloths so unlike with a lobster, where it has like
Speaker 4: this long abdomen and a tail fan sticking out, crabs
Speaker 4: don't visibly have that. It turns out that they do
Speaker 4: have the abdomen, but it's actually folded underneath the body.
Speaker 4: So the folding that is kind of one of the
Speaker 4: other major crabby features, and it actually covers up the underbelly,
Speaker 4: if you will.
Speaker 2: So the thing that makes something crabby are a flat
Speaker 2: carapace and then eight legs. Basically no, no, all right.
Speaker 4: Technically they do all have eight legs, but some of
Speaker 4: them do not have eight visible legs, and some of
Speaker 4: them that back there is super tiny, and sometimes it's
Speaker 4: in a specified chamber where you couldn't see them.
Speaker 1: Wow, all right, what are they doing in there?
Speaker 4: They're like cleaning some of the more sensitive anatomy.
Speaker 1: Huh yeah, okay, I didn't know that. Cool.
Speaker 2: Well, I wish I had special invisible legs to clean
Speaker 2: my sensitive anatomy.
Speaker 4: Yeah. So this is actually one of the main differences.
Speaker 4: So the idea that a crab like form has evolved
Speaker 4: multiple times has been known for over one hundred and
Speaker 4: forty years. And if we think about the tree of life, right,
Speaker 4: so This is like how different species are related. It's
Speaker 4: a bigger, an older version of the same thing as
Speaker 4: us having a family tree. So in the crustacean family tree,
Speaker 4: there are two groups which are each other's closest relative.
Speaker 4: One group is called the true crabs and one group
Speaker 4: is called false crabs. And so, Daniel, what you actually
Speaker 4: mentioned is one of the main obvious ways to distinguish them.
Speaker 4: True crab eight legs, false crab technically eight, but you
Speaker 4: will only see six usually or less. Permit crabs are
Speaker 4: part of that, and they usually only look like they
Speaker 4: have four because actually the back two pairs are involved
Speaker 4: in holding onto the show.
Speaker 2: And is that an arbitrary labeled true crab and false crab?
Speaker 2: Is there something just truer about one of them or
Speaker 2: is there like a value judgment there or is it
Speaker 2: like the remnants of an ancient argument among friends or what.
Speaker 4: No, it's a colloquialism. They have Latin names, So true
Speaker 4: crabs with brack eura and false crab with animura, and
Speaker 4: that actually refers to basically the folded under ab.
Speaker 2: It's really weird when you see an animal that's described
Speaker 2: basically about what it's not.
Speaker 4: You know, well, I think it's because within the false
Speaker 4: crabs you see something that looks like a crab, but
Speaker 4: they're not within the same group. So what that means
Speaker 4: intert of the family tree is that the ancestral form,
Speaker 4: or at least what we assume to be the ancestral form.
Speaker 4: And definitely many of the forms within the enemure or
Speaker 4: false crabs, many of those are elongate and they look
Speaker 4: more like a lobster. So some of them look like
Speaker 4: crabby and oval, and some of them look wrong and
Speaker 4: have like this abdominent tail and the tail fan like
Speaker 4: a lobster, which crabs don't have.
Speaker 2: Well, I'm feeling for the false crabs because I'm often
Speaker 2: described by my teenager's friends as like Hazel's dad or
Speaker 2: signs of the dad. I'm just like to find a
Speaker 2: relation to somebody.
Speaker 1: Else, something better.
Speaker 2: Yeah, exactly, something better. That's the implication right there, And
Speaker 2: so feeling for these false crabs. I'm on the false
Speaker 2: crabs team over here.
Speaker 4: They're actually my favorite, so.
Speaker 2: They're your favorite too. Yeah, there we go. The downtroden exactly,
Speaker 2: the crab crushed under the foot of evolution.
Speaker 4: They do have fewer species, so the true crops they
Speaker 4: have at least seventy five hundred described species, and the
Speaker 4: false crabs have like twenty five hundred. I'm saying described
Speaker 4: because we don't know their true.
Speaker 2: Diversity, and so you're talking about the various shapes of
Speaker 2: these critters today, and then you're also talking about the
Speaker 2: family tree. What is the relationship between these things? Is
Speaker 2: their common ancestor also krabby or did they evolve crabbiness independently?
Speaker 2: How many times has nature like invented crabs.
Speaker 4: So they did evolve it separately. It's challenging because we
Speaker 4: don't know what their exact ancestral look like. In order
Speaker 4: to be able to do that, we would ideally have
Speaker 4: many many fossils that came from the oldest point as
Speaker 4: close to the divergence of those groups possible. They do
Speaker 4: have a pretty good fossil record, but a lot of
Speaker 4: the fossils are just the care pace. And the reason
Speaker 4: for that is if you think about what happens to
Speaker 4: a quarks, Basically, if you throw it in the water,
Speaker 4: you know the parts that can fall apart will fall
Speaker 4: apart or be scavenged. So pretty much what happened to
Speaker 4: them is that. And so if you only have the
Speaker 4: care pace. Upon is that we already know that things
Speaker 4: that look similar in this group might not be both relatives.
Speaker 4: We know that from modern groups whose DNA that we have.
Speaker 4: So if we see something that looks similar and it's
Speaker 4: only the care pace, we can't always be certain in
Speaker 4: the fossil record, so that's kind of why we don't
Speaker 4: know what their exact ancestors are. However, we can look
Speaker 4: at least within the living groups at what their closest
Speaker 4: relatives are, and that can kind of help. And so
Speaker 4: within both the true and crabs we see krabby and
Speaker 4: not so krabby forms. So actually what we see is
Speaker 4: within the true crabs. Probably there's two instances where the
Speaker 4: Krabby form has evolved. One is in a pretty small group,
Speaker 4: which is kind of what we call the out group
Speaker 4: to the rest, So that means that basically the first
Speaker 4: branch that evolved from the true crabs. Within that group,
Speaker 4: we see one set of sort of rounded little guys
Speaker 4: that look like craps, and these are called the sponge crabs.
Speaker 4: They're called that because they usually make a hat out
Speaker 4: of a sponge and they wear it.
Speaker 1: Oh that's so cute. I have a new favorite crab.
Speaker 2: Now, why do they make a hat out of a sponge?
Speaker 4: Well, I guess it makes good camouflage if you look
Speaker 4: like an inanimate object a living thing, but nonetheless, hopefully
Speaker 4: no one's gonna come ool with you.
Speaker 1: Right, Do we have any tests to see if that
Speaker 1: actually works, like if you take their sponges off or
Speaker 1: you give them a better sponge. Has anyone actually shown.
Speaker 4: I don't know. I know I've seen some videos of
Speaker 4: people making like out of kitchen sponges and seeing how
Speaker 4: the crabs because they kind of like cut them up
Speaker 4: a little bit of their claws so they can do that,
Speaker 4: But I don't know if anyone's published a systematic test
Speaker 4: of that. There are other groups that hold things on
Speaker 4: top of themselves, like a hat. Hermit crabs technically are
Speaker 4: kind of doing that, so they shove their back end
Speaker 4: into it too.
Speaker 1: I love that they're like cutting their hats to fit
Speaker 1: the way that they want it. Anyway, this is very exciting.
Speaker 1: I could talk about this for five hours, but maybe
Speaker 1: we should keep going.
Speaker 4: Right, So that's the first group, and then the other
Speaker 4: group from the true crabs is there isn't a good
Speaker 4: common name for but it's the majority of true crab diversity,
Speaker 4: and I guess they can be called the higher true crabs,
Speaker 4: although that's a value judgment, and it's just referring to
Speaker 4: the fact that they share a common ancestor amongst themselves.
Speaker 4: So the vast majority of true crab species fit inside that.
Speaker 4: So that's like spider crabs, swimming crabs, decorator crabs, pretty
Speaker 4: much all land crabs, most of the ones that people eat,
Speaker 4: those are all within the higher true crabs or you
Speaker 4: breck eree, So those guys are almost all having the
Speaker 4: crapit for.
Speaker 2: And when we talk about this history, is this recent history,
Speaker 2: like this stuff has evolved in the last ten thousand years,
Speaker 2: one hundred thousand years. Are we talking hundreds of millions
Speaker 2: of years or what's the timescale?
Speaker 4: It's hundreds of millions, Yes, it's quite old. These guys
Speaker 4: were and off pretty much around the time of the dinosaurs.
Speaker 4: So if a dinosaur went for a swim, then they
Speaker 4: might have encountered some crabs. Even there were some crabs
Speaker 4: starting to go at least into brackish water environments also
Speaker 4: at that time, so they could have met up.
Speaker 2: I have the impression when I hear about a species
Speaker 2: that hasn't changed in hundreds of millions of years. That
Speaker 2: has sort of reached some plateau where like you can't
Speaker 2: really improve very much. Is that totally falls And it's
Speaker 2: just that the time scales so long, like in a
Speaker 2: billion years, crabs will look different, or have we somehow
Speaker 2: found some niche where it's really not going to change
Speaker 2: much more.
Speaker 4: That doesn't actually describe crabs, it's a term used to
Speaker 4: describe horseshoe crabs. So I guess we've got to address that.
Speaker 4: Elephant and horsy crabs are not a crustacean unfortunately.
Speaker 2: Oh wow, they're false false crabs.
Speaker 4: Right, yeah, yeah, they are. They're pretty much like interactive
Speaker 4: like spiders and scorpions, and the way that we distinguish
Speaker 4: different groups among arthropods. So archipods first of all, are
Speaker 4: the animals that have jointed legs. So within the horseshoe
Speaker 4: crabs and iraqeids those guys versus crustaceans, it's basically the
Speaker 4: number of segments of their head that is the main
Speaker 4: morphological way that they were first identified. And DNA data
Speaker 4: also verifies that these are separate groups. So they are
Speaker 4: at least five hundred million years different so horseshoe crabs Also,
Speaker 4: although they are around it, they don't have the same
Speaker 4: body parts as a crustacean, So they don't have this
Speaker 4: abdomen that folds up underneath. When you imagine a crab,
Speaker 4: it's not like this little taper bit and then a
Speaker 4: long spine at the end. Right, there's like a middle
Speaker 4: piece that crustaceans have that they don't have. So they're
Speaker 4: a little similar, but I wouldn't personally describe them as
Speaker 4: having the Krabby forma. Some people have said that they
Speaker 4: do if they're trying to make a really really broad
Speaker 4: ecological argument. People have also said that rais, you know,
Speaker 4: like the sting rays, that they're like that too. Of
Speaker 4: course those are vertebrates, so that's really different. So yeah,
Speaker 4: if you want to get really broad, then there's a
Speaker 4: lot more examples, but none of them have the abdomen
Speaker 4: folding up, which is one of the features that I
Speaker 4: think is really important.
Speaker 2: But you brought up horseshoe crabs because they have sort
Speaker 2: of stabilized on long terms and you don't expect them
Speaker 2: to evolve.
Speaker 4: Or here's the thing, they have been evolving the whole time.
Speaker 4: Their morphologies are similar to fossils, But when we study
Speaker 4: the DNA, they have been changing the whole time. So
Speaker 4: the morphology what we see visually seems the same, but
Speaker 4: they've been change so evolution has proceeded. I guess morphologically
Speaker 4: maybe they are very suitable for life through a lot
Speaker 4: of changes in the world, which is great. But no,
Speaker 4: it's kind of a fallacy that they haven't changed.
Speaker 2: Well, it would make more sense for evolution to be constant, right,
Speaker 2: I mean the environment keeps shifting, right. Earth is not
Speaker 2: the same, the climate is not the same, the other
Speaker 2: critters crawling around the Earth are not the same, so
Speaker 2: it makes sense for things to continue. I always thought
Speaker 2: that was weird. So you're telling me the things are
Speaker 2: constantly evolving, And so the idea that like crabs have
Speaker 2: reached some final form is a misunderstanding.
Speaker 4: It is. Yeah, so even within like the crustacean crabs,
Speaker 4: the deck pods, so true in false crabs, to say
Speaker 4: that they haven't changed even since the fossils, that's completely untrue. Actually,
Speaker 4: they have huge rphological variety. Why there are so many species.
Speaker 4: The horses youp grabually have four living species. But I
Speaker 4: just told you that there's like eleven thousand living species
Speaker 4: of crabs, and then there's also thousands of fossil species
Speaker 4: as well that are no longer a lot, so they
Speaker 4: have actually changed a lot. But it's true that there
Speaker 4: are examples of organisms like the horship crowd that haven't
Speaker 4: changed that much morphologically. So yeah, the true crabs as
Speaker 4: well as the false crabs, they have been morphologically changing
Speaker 4: as well in response to changes in their environment and
Speaker 4: so on.
Speaker 1: And I'm going to pull us back a little bit.
Speaker 1: So Daniel had asked you how many times nature invented crabs?
Speaker 4: Right, I got to two of them, right, So the.
Speaker 1: Sponge crabs and the higher true crabs are two examples.
Speaker 4: So now we got to switch over to the false crabs,
Speaker 4: which are Maya Daniel's favor. So those guys, they have
Speaker 4: at least instances, and the probably the oldest instance is
Speaker 4: what's called porcelain crabs. Those guys are little filter feeders
Speaker 4: and they live mostly in core reefs or intertidle zones.
Speaker 4: So if anyone lives near a beach, which in Irvine
Speaker 4: you probably do, we definitely do, you could probably see them.
Speaker 4: I went in a tide poole there I have definitely
Speaker 4: seen them in southern California. So they'll look like a crab,
Speaker 4: but count the number of legs and then you'll see
Speaker 4: they're pretty small too.
Speaker 2: We go to the tide pools all the time, but
Speaker 2: we try not to disturb the little critters because I
Speaker 2: feel like if everybody comes and like picks up a critter,
Speaker 2: then we're just going to be like wiping out some population.
Speaker 4: I think that probably is a safe bet. I wouldn't
Speaker 4: recommend handling animals in the wild if you aren't going
Speaker 4: to be very gentle. Obviously I have to do so
Speaker 4: because I have to collect them for work. We can't
Speaker 4: get the DNA if we don't capture and I'm sorry
Speaker 4: kill them, I know. I mean, I'm a vegetarian, so
Speaker 4: like I won't even a crab. I've never eaten a
Speaker 4: crab in my life.
Speaker 2: Oh my gosh. Even the ones that you capture and
Speaker 2: kill for their DNA, well, you.
Speaker 4: Got to put them in preservatives. So actually a lot
Speaker 4: of them we do put in ethanol. So yeah, that
Speaker 4: would be like making an alcoholic beverage.
Speaker 2: But crab cocktail.
Speaker 4: That would be disgusting. Like if you actually open some
Speaker 4: of these vials, I know Kelly has done this, Like, uh,
Speaker 4: you know, a little one is fine, but like some
Speaker 4: are really big or like even giant squids are nothing.
Speaker 4: You open them up, you can pretty much get high
Speaker 4: off the fumes.
Speaker 2: Yeah, and you know that Kelly has done this.
Speaker 4: Is that what? Yeah?
Speaker 2: Oh yeah, Kelly has snorted squid fumes. Wow, that is
Speaker 2: something I've learned about Kelly today.
Speaker 4: Well I've done it too.
Speaker 1: It wasn't squid fumes, it was large quantities of preserved
Speaker 1: fish vomit. But yes, you do get a little bit
Speaker 1: sort of high sitting around these samples.
Speaker 2: What does that go for on the street, Kelly.
Speaker 1: Nobody wants it. Actually, it turns out.
Speaker 2: Price is zero.
Speaker 4: There were some samples that we did for one of
Speaker 4: my projects that we had to dissect and we got
Speaker 4: them from like the fish market. So actually my colleagues
Speaker 4: ate the parts that I didn't dissect. I had to
Speaker 4: dissect them, but I didn't look at it. So yeah,
Speaker 4: so you can't eat force and the crabs though they're
Speaker 4: really small. But the other main one within the false crabs,
Speaker 4: lots of people eat that's king crabs. So like Alaska
Speaker 4: king crab that's really famous. That's not truly a crab.
Speaker 4: It's false crap. Count the number of legs.
Speaker 2: Not truly a crab. Oh my gosh. Yeah, taste pretty crabby.
Speaker 4: Yeah yeah. So those guys, they live pretty much white
Speaker 4: bold waters. So the only way people are going to
Speaker 4: encounter them without going out in a boat is if
Speaker 4: you're in pretty much quite cold places, so like the
Speaker 4: Pacific Northwest. I would say southern California. There might be
Speaker 4: a few, but they're more common furthermore, so that's why,
Speaker 4: like Alaska is one of their hot spots.
Speaker 1: They've got their own TV show.
Speaker 2: I don't know if we're just whims, but the water's
Speaker 2: pretty cold hair in southern California.
Speaker 4: Oh well, I am from Canada, so.
Speaker 2: Do you call me a whim? That's why I live here?
Speaker 4: Yeah. Yeah. So then there's the third group within that
Speaker 4: false crabs, and I hesitate to quality group because there's
Speaker 4: actually only one species, which is the only species in
Speaker 4: his family, so it's just weird. And it's this one
Speaker 4: species called lomas Herca is the Latin name. The nickname
Speaker 4: of it is the harry Stone crab, and it's ecology
Speaker 4: is pretty similar to porcelain crabs. They're in the enter
Speaker 4: title zone, but it only lives in southern Australia and
Speaker 4: its claws look like giant mittens. I was supposed to
Speaker 4: go to a conference in Brazil in twenty twenty. Of
Speaker 4: course that happened to the pandemic. But one thing I
Speaker 4: was told is that at resilient conferences sometimes there's costume parties.
Speaker 4: So I was planning to make giant mittens and wear
Speaker 4: them on my hands to be this crab.
Speaker 1: See there are some biologists that are fun at parties.
Speaker 4: Yeah, yeah, I don't know if people would think that
Speaker 4: would fun, but you know my colleagues would ever. So
Speaker 4: it's got that, and then the rest of it's kind
Speaker 4: of camouflage to look like it's covered in algae and
Speaker 4: it's brown, and then randomly it's got like these bright
Speaker 4: blue antennae.
Speaker 1: It doesn't sound like it would help with camouflage.
Speaker 4: No, I don't know what's up with that. It's not
Speaker 4: super well known. So I actually did get a chance
Speaker 4: to see this species in Tasmania. I went there a
Speaker 4: little before the pandemic and I pretty much went with
Speaker 4: the express purpose of finding this crab. So I'm texting
Speaker 4: my collaborators, I'm like, oh, I'm going to find it.
Speaker 4: I'm going to find it. And it was like, you know,
Speaker 4: because of the intertitle, you can only look for a
Speaker 4: couple hours a day because the rest of the time
Speaker 4: it's covered in water. It was like the last day
Speaker 4: before I found them, I was kind of freaking out.
Speaker 4: I was like, oh no, I came all this way
Speaker 4: and I didn't and we got to them.
Speaker 2: And what does it look like on the Crab Researcher
Speaker 2: group chat when you finally find this elusive crab?
Speaker 4: Well, we actually named the crab Researcher group chat to
Speaker 4: I saw lo miss. I still call that years later.
Speaker 4: Our chat is actually still called that.
Speaker 2: I love these little revealing elements of nerd culture, you know. Yeah,
Speaker 2: there was a great moment when I made the scientific discovery,
Speaker 2: and then there was an even better moment when I
Speaker 2: gloated about it in the group chat.
Speaker 4: So true.
Speaker 1: Well, we're all happy for our friends when they find
Speaker 1: the thing that they've been looking for.
Speaker 2: Yes, absolutely absolutely shared joy.
Speaker 4: Anyway, it got meiled back to the US to my
Speaker 4: colleague in Miami, and eventually she extracted DNA from it.
Speaker 4: We got our data very nice.
Speaker 1: Yes, awesome. Yeah, Okay, so we have established that as
Speaker 1: far as we know right now, nature has quote invented
Speaker 1: crabs five times. And when we get back from the break,
Speaker 1: we're going to find out if five is a big
Speaker 1: number or a little number. And we're back. So Joe
Speaker 1: told us that nature has invented crabs five times. If
Speaker 1: you go on social media, you would think that nature
Speaker 1: is just like constantly inventing crabs. Whatever that means. Should
Speaker 1: we feel like five is a big number or is
Speaker 1: five a like little number? In terms of nature inventing things,
Speaker 1: I think.
Speaker 4: It's a bit of a Goldilocks situation. So basically convergent
Speaker 4: evolution where you see similar traits evolved multiple times in
Speaker 4: different unrelated groups. This is actually pervasive. So one quite
Speaker 4: famous example is echolocation, where both That's and Wales have
Speaker 4: both people, so that's two times, and a lot of
Speaker 4: the examples are two times. But there's also a lot
Speaker 4: of examples that have a ton of times, so like
Speaker 4: bioluminescence or having venom, those have evolved like one hundred times,
Speaker 4: so there can be some that are quite a lot.
Speaker 4: I think though, that there's something that makes crabs being
Speaker 4: five times particularly interesting, and it's kind of because it's
Speaker 4: not just the number of times, but you have to
Speaker 4: think how long is the period of time in which
Speaker 4: that's happened, Right, So crabs common ancestor between the true
Speaker 4: and false crabs is something like three hundred million years ago.
Speaker 4: So five times within.
Speaker 5: Three hundred million years is actually pretty good, whereas bar
Speaker 5: the un essence being one hundred times, and so that's
Speaker 5: including all of life, like even back to here to
Speaker 5: have violins, So that's billions of years.
Speaker 2: So we need to consider like the denominator like out
Speaker 2: of how many possibilities, and we need to consider the
Speaker 2: time span, like how many opportunities are there exactly, And
Speaker 2: so you're saying five is actually not that big a number, Well.
Speaker 4: It's not that big a number, but it's also not
Speaker 4: that small. So there are some other groups that are
Speaker 4: much more recently involved, that have more groups. But one
Speaker 4: thing that I think is interesting is that in many
Speaker 4: of those they're so recent that there's not that much
Speaker 4: variation in them to begin this. So, like one famous
Speaker 4: group that's a model for studying competant evolution is a
Speaker 4: group of lizards called annals or anolus, and they live
Speaker 4: in the neotropics and on different islands within the Caribbean,
Speaker 4: they have repeatedly basically colonized to the islands and evolved
Speaker 4: multiple what's called eco types. So there's animals that live
Speaker 4: on the ground, there's animals that live on tree and
Speaker 4: higher up in the tree. Something like that need happen
Speaker 4: multiple times every major island, so like four times at least,
Speaker 4: probably more. And the thing is, though they can't do
Speaker 4: much else other than that, they're always going to keep
Speaker 4: doing that every island that they go to. I'm simplifying it,
Speaker 4: but perhaps there is so much variation. So even though
Speaker 4: we see the same base form with the flattened carapace
Speaker 4: and the folded up happening multiple times, within that, there's
Speaker 4: a lot of variety. They have spikes or not spikes,
Speaker 4: the shape and length of their legs and claws, all
Speaker 4: of this is completely changed many many times. So it's
Speaker 4: kind of a good example in that regard too, because
Speaker 4: when we want to understand evolutionary process, at least to me,
Speaker 4: the reason to understand this is because we want to
Speaker 4: explain variation. You can do things with analysts like experiments.
Speaker 4: You can move them from one island to another and
Speaker 4: then see what are going to do much harder to crabs,
Speaker 4: but you know, we don't know what we're going to
Speaker 4: get either necessarily perhaps, so it's kind of fun.
Speaker 1: If this is an intermediate example of how often this
Speaker 1: kind of stuff happens. What are your thoughts on why
Speaker 1: everybody thinks nature invented crabs? Why is this the example
Speaker 1: that like just took off and took over the internet?
Speaker 4: So in the paper, and I think the oversimplified explanation
Speaker 4: is that we often talk about potential adaptations because the
Speaker 4: assumption is that convergent evolution is a case where an
Speaker 4: organism has faced with the same environmental challenge and so
Speaker 4: it's going to solve that challenge in the same way.
Speaker 4: So the two main ideas for this to adapt to
Speaker 4: are either being best able to escape from predators, either
Speaker 4: by running away, or also because when you're folded up,
Speaker 4: you're potentially a smaller target to be grabbed, I suppose.
Speaker 4: I guess, like just think about if you're trying to
Speaker 4: grab a crow versus if you're trying to grab a lobster.
Speaker 4: There's a back end on the lobster and there isn't
Speaker 4: on a crap, right, So that's one and then the
Speaker 4: other idea is that it improves their locomotion, so like
Speaker 4: crabs can walk sideways. I think it's more complicated than
Speaker 4: that because some of the groups within, even in the
Speaker 4: false crabs that don't have this folded up body, they
Speaker 4: can sort of jet backwards, sort of swimming like, and
Speaker 4: this is called like the tail flip escape reaction. It's
Speaker 4: got fancy name, but it's just jetting backwards. And crabs
Speaker 4: can't do that anymore when they fold up. They need
Speaker 4: the tail to do that so they can escape in
Speaker 4: a different way. I don't know which one is better.
Speaker 4: I think in science what we usually want to do
Speaker 4: is we want to know if something is affecting an outcome,
Speaker 4: we would have to do an experiment on it. And
Speaker 4: there are biomechanical studies on how crabs walk, but none
Speaker 4: of them are comparative, so there's no control you need
Speaker 4: to look at. Is it a better performance at locomotion
Speaker 4: or predator avoidance under the same conditions as a not
Speaker 4: said crappy body and nobody has done that yet.
Speaker 1: People keep saying nature invents crabs because that's great, but
Speaker 1: we don't even really have great evidence that the crab
Speaker 1: body shape is superior to other body shapes.
Speaker 4: We don't know that. I mean, I wouldn't be surprised
Speaker 4: if some of this was contributing to them, but it
Speaker 4: may not be. We just don't have what I would
Speaker 4: say is really strong evidence, and I wrote that in
Speaker 4: this paper, but well, we'll get to that later.
Speaker 2: I found it fascinating how different branches of science have
Speaker 2: different abilities to sort of control the experiments. You know,
Speaker 2: like in particle physics we can manipulate our experiments completely.
Speaker 2: Astrophysics they just sort of watch what the universe does
Speaker 2: and hope that it does something interesting that reveals some
Speaker 2: thing here. You have some opportunities to like influence, but
Speaker 2: you're not completely in control. But say you were somehow
Speaker 2: you know God or could control the universe, how would
Speaker 2: you set up the experiment to answer this question? How
Speaker 2: would you definitively prove whether crabs are a good outcome
Speaker 2: or not.
Speaker 4: You have to have the hypothesis of what their outcome
Speaker 4: is improving. So say you have the hypothesis that it's
Speaker 4: going to make them that are at escaping from a predator. Right,
Speaker 4: So you set up sets of tanks and you put
Speaker 4: a bunch of crabby bodies in one set of tanks,
Speaker 4: and you put a bunch of long boys in the
Speaker 4: other set of tanks, and then you put like a
Speaker 4: big scary fish in every single one.
Speaker 2: Long boy is not a sandwich, right, a sandwich.
Speaker 4: To me, sorry, I mean like squat lobsters or something.
Speaker 2: Then I'm thinking, like, you know, I'll have a long boy.
Speaker 2: Hold the olive oil, please.
Speaker 4: But all right, I think people do eat some of
Speaker 4: the squat lobsters actually, like in the Mediterranean.
Speaker 2: Yeah, everything's in delicacy somewhere, right, fish vomit is like
Speaker 2: very prized in the streets of some city around the world.
Speaker 4: Exactly.
Speaker 1: I'm not sure about that one.
Speaker 2: But all right, to get back to your crabby versus
Speaker 2: long boy experience, I.
Speaker 4: Yes, So then you put like a fish in there
Speaker 4: or I don't know, something that you know will predate
Speaker 4: upon them big scrap. You have a big tank because
Speaker 4: you're gone, right, So you have a really big tank
Speaker 4: and the only thing in it is the crab, and
Speaker 4: you maybe give them some rocks to hide in or not.
Speaker 4: Some will have rocks, some will have not maybe, and
Speaker 4: you basically see what happens and how many times the
Speaker 4: fish is going to catch the crab versus the elongated
Speaker 4: body form. And so this could be one example of
Speaker 4: doing an experiment like that. If they survive, then I
Speaker 4: guess natural selection has turned out in their favor. If
Speaker 4: they die, if they don't get to reproduce, so they've
Speaker 4: been lifings.
Speaker 2: Do we need to think even bigger though? I mean
Speaker 2: somebody could say, well, that's survival in your lab in
Speaker 2: an aquarium. Really the metric is like, have you survived
Speaker 2: on the planet. So when you need to like create
Speaker 2: one hundred or one thousand, duplicate Earth's branch evolution from
Speaker 2: the same point or something, and like see whether you
Speaker 2: get more fewer crabs on these planets? Like what is
Speaker 2: the real test? Like infinite resources here?
Speaker 4: This isn't specific to crabs, but there is something called
Speaker 4: the game of life, and it's a simulation to evolve.
Speaker 4: It's not like specific forms, but it's basically like little
Speaker 4: ask you guys or something.
Speaker 2: It's a little cellular automata.
Speaker 4: Yeah yeah, okay, so you know, yeah.
Speaker 2: Yeah, it's famous in programming circles.
Speaker 4: I would say that's actually the infinite resources explanation. It's
Speaker 4: not going to tell you isn't crabs specifically, but maybe
Speaker 4: you could add like a new package this programming thing
Speaker 4: it was invented like twenty or thirty years ago. Maybe
Speaker 4: make it a little more sophisticated now specifically crabby. Maybe
Speaker 4: there's a way to do this as a simulation.
Speaker 2: Well, that's fascinating you bring that up, because in the
Speaker 2: game of life, they've observed these self sustaining little systems.
Speaker 2: And for those of you who aren't familiar, there's like
Speaker 2: very simple rules about whether a cell has something in
Speaker 2: it or not, whether it eats something or moves or whatever.
Speaker 2: And there are these emergent structures that people have discovered,
Speaker 2: and some of them they call a crab. In this case,
Speaker 2: it's called the diagonal spaceship sort of looks a little crabby,
Speaker 2: And I don't know if it really would qualify as
Speaker 2: a crab or a false crab, or as a digital
Speaker 2: crab or whatever, or if it's just sort of inspired
Speaker 2: by this, you know, sort of concept out there that
Speaker 2: everything turns into a crab. So I don't know if
Speaker 2: it's evidence or if it just shows us the pervasive
Speaker 2: nature of the idea.
Speaker 4: I'm sure they didn't know about it, because until my
Speaker 4: paper and the associated work became famous recently, This wasn't
Speaker 4: known outside of like plustation systematic circles, so they probably
Speaker 4: saw it and thought it looked like a crab. I
Speaker 4: didn't actually know that part about it, so I'm going
Speaker 4: to have to check that out. Very cool.
Speaker 1: Yeah, So to pull ourselves back to the real world
Speaker 1: and out of the virtual world, we've talked about instances
Speaker 1: where you know you're working through the tree of life
Speaker 1: and the Krabby body form shows up. Do we see
Speaker 1: instances where the Krabby body form has shown up and
Speaker 1: then you lose it? Do we go in the other direction?
Speaker 4: Yes? Indeed we've seen this at least seven times, probably
Speaker 4: more than that, because there's a lot of shape variation.
Speaker 4: And the reason why this is possible is because of
Speaker 4: something called trade offs. So one trade can increase in
Speaker 4: Orban's fitness, and potentially the Krabby body can do this,
Speaker 4: but it might be decreasing the fitness of other traits.
Speaker 4: So depending on what happens in their environment, what's the balance, right,
Speaker 4: So there might be something else that's overcoming an adaptive
Speaker 4: advantage of being crabby, and I don't think there's something
Speaker 4: that's universally the case for these what we call decarsonizations.
Speaker 4: It's a pretty stupid name, but that's what we call it.
Speaker 1: Sounds like you're getting rid of cancer.
Speaker 4: Oh my god. So the actual name of crabs was
Speaker 4: originally called cancer, and the term cancer for the human
Speaker 4: disease actually came from crabs because the Latin name of
Speaker 4: craps is cancer, and the original medical doctors who saw
Speaker 4: tumors thought, oh, this like thing is branching inside of you.
Speaker 4: It's psycho crab. So yeah, huh, it's actually the same.
Speaker 2: Oh interesting. Well, I think the anomology is really fascinating
Speaker 2: also because we've been using the phrase getting crabby, which
Speaker 2: to me, you know, has all these implications like I'm
Speaker 2: krabby in the morning without my coffee, or you know,
Speaker 2: my husband gets crabby and I cook too much eggplant
Speaker 2: or something. Do you know where that comes from? I mean,
Speaker 2: I know that's totally not your field.
Speaker 4: Well, I mean anyone's field. So actually, funny story. I
Speaker 4: spent I would say a lot of years of my
Speaker 4: childhood kind of being a little afraid of crabs because
Speaker 4: I want to be very virild. Just when I was
Speaker 4: a kid and I went to the Vancouver Aquarium and
Speaker 4: my parents were filming me with like this ancient video
Speaker 4: camera VHS all of that O young and yeah, and
Speaker 4: I'm standing in front of the tidepool tank talking about it,
Speaker 4: and I pick up the dungeons crab and I'm talking
Speaker 4: and it's biting me and boom, what is hurting everywhere?
Speaker 4: So I decided that crabs were my enemy. So I
Speaker 4: think it's all about how you approached them. That crab
Speaker 4: was crabby. It did not like being grabbed by a child.
Speaker 2: Fair enough, But why does krabby even have a negative connotation?
Speaker 2: I mean, it's the same with fishy, like something's getting fishy,
Speaker 2: but you know other things are neutral, like there's no
Speaker 2: meaning to I'm getting sharky or you know, I'm getting squiddy.
Speaker 4: There is sharky like shark tank right, like, oh yeah, untrustworthy?
Speaker 4: Are sharks right?
Speaker 2: All right? Interesting?
Speaker 4: I don't know why we use marine organisms as metaphors
Speaker 4: for negative emotions. That's kind of weird. Maybe we should
Speaker 4: all be compared to seals, where we're just like laying
Speaker 4: there chilling. That'd be nice.
Speaker 1: That's a vibe I can get behind.
Speaker 4: Yeah, yeah, I.
Speaker 2: Think it's amazing that you decided to study crabs after
Speaker 2: having that experience rather than running away from them, and
Speaker 2: that you advertise the existence of this video, which now
Speaker 2: we have to see.
Speaker 4: Oh, I don't think it's digitized. My parents might have
Speaker 4: a copy somewhere, but I don't know if it's in
Speaker 4: a format that can be viewed anymore.
Speaker 2: That should be on your website. I mean, if you're
Speaker 2: a crab researcher and you have this formative moment.
Speaker 4: Man, yeah, I should find out if I can. But
Speaker 4: you know, I think it's because I actually didn't really
Speaker 4: understand the difference between true and false crafts. But maybe
Speaker 4: I did somehow understand it because I never stopped loving
Speaker 4: hermit crafts. I thought they were wonderful, And when I've
Speaker 4: got older and started studying arthropod evolution, I kind of
Speaker 4: figured out that they were related. But yeah, hermit crabs
Speaker 4: never fell out of my heart. I love them.
Speaker 1: They also have a special place in my heart because
Speaker 1: I grew up near Atlantic City, and so every time
Speaker 1: we'd go to Atlantic City, you had to come home
Speaker 1: with some hermit crab pets and take the best care.
Speaker 1: And probably that was not good for the hermit crabs.
Speaker 4: I did some really bad things too, So I grew
Speaker 4: up in Toronto, which is as far away from the
Speaker 4: ocean as you can possibly be, so I had very
Speaker 4: limited chances to see any of these things. But when
Speaker 4: I was a kid, I guess pre aquarian incident. We
Speaker 4: did used to go to get caught a few times
Speaker 4: and I was colecting. You know, the typical kid gets
Speaker 4: bucket grabs whatever organisms, which I guess maybe Daniel, you
Speaker 4: don't do that with I did that. I was always
Speaker 4: grabbing them and putting them in a bucket. And there
Speaker 4: was one case where I had like a blue crab,
Speaker 4: like a swimming crab, and I put fishes in the
Speaker 4: bucket with it and brought it back to like the
Speaker 4: cottage that we stared at, and then it was just
Speaker 4: like the crab ate all the fish heads and left
Speaker 4: their bodies.
Speaker 1: I think every biologist has a story about how they
Speaker 1: learned about the cruelty of nature in an embarrassing or
Speaker 1: you know, not ideal way when they brought some animals
Speaker 1: into their homes.
Speaker 4: Exactly at least there wasn't our home.
Speaker 1: Yeah, yeah, I've got some stories too, but I brought
Speaker 1: it into my home. But let's take another break, and
Speaker 1: when we get back we'll talk about if nature ever
Speaker 1: invents crabs for reasons that are like random and not
Speaker 1: so good, and we're back. Okay, So we've talked about how,
Speaker 1: as far as we know right now, the crab shape
Speaker 1: has popped up five times in the tree of life
Speaker 1: and has been lost seven times in the tree of life.
Speaker 1: For those five instances where the crab body shape popped up,
Speaker 1: are those all because it was been official or do
Speaker 1: you sometimes get like a big morphological change for reasons
Speaker 1: that aren't beneficial.
Speaker 4: Yeah, this is something that isn't that commonly discussed in
Speaker 4: the public. But indeed, all traits don't necessarily evolve for
Speaker 4: a reason, or at least not for a direct reason.
Speaker 4: I would say, they're not all necessarily representing an adaptation.
Speaker 4: So an adaptation is going to be the case where
Speaker 4: individuals that have the trait where it improves this organism's
Speaker 4: function within its environment or whatever, so like making better
Speaker 4: at avoiding creditors and so on, then you will survive
Speaker 4: because natural selection is going to let things die that
Speaker 4: don't have this trait that benefits you. But parsonization, you know,
Speaker 4: first of all, we don't know if it evolved in
Speaker 4: the same kinds of environments every time, so it's tricky
Speaker 4: to guess whether this was always the case. So there's
Speaker 4: one term from biological literature called exceptation, and this is
Speaker 4: a case where a trait improves the organism's function and
Speaker 4: the environment where they live now, but the conditions where
Speaker 4: evolved were different. I think king crabs and hermit crabs
Speaker 4: are an example of this, So king crabs actually evolved
Speaker 4: from within hermit crabs. There's still hermit crabs too, but
Speaker 4: king crabs are parting them. So at some point in
Speaker 4: their history they had to get rid of the shell.
Speaker 4: The shell for the hermit crab is really important, right
Speaker 4: because they have like this long soft abdomen that could
Speaker 4: easily and immediately be eaten, and so the shell makes
Speaker 4: them safe. But somewhere they had to lose them. So
Speaker 4: what happened there They didn't like immediately get a mutation
Speaker 4: that made them totally hard and fold it up. There
Speaker 4: was some intermediate situation. So one thing that we suggested
Speaker 4: the paper, and actually that has also been suggested prior
Speaker 4: to us, is that maybe there was an environmental situation
Speaker 4: where there just weren't shelves available and they were there already,
Speaker 4: so they had to do something or die and probably
Speaker 4: a lot of the gut. Maybe that's what happened, and
Speaker 4: that would be a case of an exactation didn't evolve for
Speaker 4: the reason that we know now, But there was a
Speaker 4: reason then, and we don't know, because the fossil record,
Speaker 4: particularly for hermit craps is pretty bad. Them being soft
Speaker 4: or does not help.
Speaker 1: Yeah, now that always makes fossil stuff.
Speaker 4: It does, So that's one possibility. There's another possibility that
Speaker 4: I'm pretty interested in and curious about. Sometimes we have
Speaker 4: selection on a trait that isn't the one that you're
Speaker 4: interested in, and maybe that trait is correlated in the
Speaker 4: genome or in the process of development to the trait
Speaker 4: that you're interested in. It maybe being crabby is actually
Speaker 4: related to something else that selection is acting on that
Speaker 4: we can't see, especially if it's in the genome. We
Speaker 4: don't know very much about their genomes. Only a few
Speaker 4: species have been sequenced, maybe like ten or something, and
Speaker 4: that's only in the past couple of years. But two
Speaker 4: years ago there was.
Speaker 2: Like one why is it is it hard to sequence
Speaker 2: crab DNA?
Speaker 6: Well, we have lots of pieces of DNA, but sequencing
Speaker 6: the whole genome the technology to assemble genomes for which
Speaker 6: you don't have like a detailed reference has only become possible.
Speaker 4: Really in the past couple of years. It was expensive
Speaker 4: and technically difficult, and to spend that kind of money
Speaker 4: to do it, not a lot of people were going
Speaker 4: to pay for that. So yeah, it's recently become less expensive,
Speaker 4: and the software to do it has become easier, as
Speaker 4: well as the actual sequencing technology, because one of the
Speaker 4: things when you're sequencing a genome is you're actually sequencing
Speaker 4: arts like little pieces of DNA, and you have to
Speaker 4: using software. And that's why I said assembly. You kind
Speaker 4: of making the puzzle at the moment, and so if
Speaker 4: you don't have enough overlap of those pieces, you don't
Speaker 4: know what you've done. So the technology to do that
Speaker 4: has advanced a lot recently, So it's possible now that
Speaker 4: it wasn't before.
Speaker 1: So given that we're just at this point now where
Speaker 1: we're starting to acquire genomes and you know, maybe we
Speaker 1: could discover some more fossils. Like if we were to
Speaker 1: have you back on the show in twenty years, how
Speaker 1: likely do you think it is that the number for
Speaker 1: you know, carsonization would be five and decarcinization would be seven. Like,
Speaker 1: how likely do you think these numbers are to change
Speaker 1: over time?
Speaker 4: Well, I definitely think that sampling more species will change
Speaker 4: those numbers, and it will increase both of them, because
Speaker 4: we are largely making generalizations. And for me, because I
Speaker 4: didn't start out as a crab scientist, I mean, I
Speaker 4: guess I've been doing it for a few years now.
Speaker 4: My background was in other crustaceans before, so as I
Speaker 4: keep learning more, I start seeing more variation in their shapes.
Speaker 4: And one of the things here that we're also kind
Speaker 4: of obscuring is we're talking about it like you're a
Speaker 4: crab or you're not a crab, and I don't think
Speaker 4: it's very discreet. There's a continuum, like you can have
Speaker 4: some of the features but not all of it, especially
Speaker 4: since you're talking about something like a shape. A shape
Speaker 4: is like, you know, think about it like a vector graphic.
Speaker 4: A vector graphic for a really detailed polygon with a
Speaker 4: ton of little sides. If you zoom out far enough,
Speaker 4: it looks like a circle. So something like that is
Speaker 4: going on with these shapes too. They at different levels
Speaker 4: of study could look more and less similar. So I
Speaker 4: think we just need to have more species sampled and
Speaker 4: to study them in very sophisticated.
Speaker 1: So we've established that five is like a pretty big
Speaker 1: number given the amount of time we've been talking about,
Speaker 1: But evolving the crab shape five times is not a
Speaker 1: huge number, and it's been lost more times than it
Speaker 1: has been you know, found by nature. And there's tons
Speaker 1: of stuff that we don't know. And so what are
Speaker 1: your thoughts on how this idea became just like the
Speaker 1: go to idea for like what nature wants to make
Speaker 1: out of organisms.
Speaker 4: I think people were surprised because everyone thinks that they
Speaker 4: know what a crab is. Like some of these examples
Speaker 4: you probably haven't encountered in your life, like echo location,
Speaker 4: How many people have actually seen a bat in person?
Speaker 7: What people would run away from it? And a whale
Speaker 7: you have to be in the ocean to see it.
Speaker 7: So it's true that a lot of people haven't, but
Speaker 7: probably everyone has seen a crab in some way or another,
Speaker 7: even if it's just dead, even if it's on SpongeBob, right,
Speaker 7: they think they know what a crab is, and so
Speaker 7: I think some of it was that people were surprised
Speaker 7: to find out that not everything I think is a
Speaker 7: crab is a crap.
Speaker 4: The other thing is it went viral during the depths
Speaker 4: of COVID and people had nothing better to do than
Speaker 4: be on the internet. So some of it was probably that.
Speaker 1: And were you surprised, Oh my god, yes, or like frustrated.
Speaker 4: Well, I was surprised because we had recently gotten funded
Speaker 4: to do research on the evolutionary relationships and morphology of this.
Speaker 4: But our funding also actually started right before COVID, so
Speaker 4: it was supposed to be this amazing like tons of
Speaker 4: international travel blah blah blah. Yeah, we didn't get to
Speaker 4: do much of that, so you know, we were basically
Speaker 4: doing like phylogenetic systematics, like obscure stuff that most people
Speaker 4: don't care about. So I was shocked that it went
Speaker 4: like millions of people level viral. But I was kind
Speaker 4: of annoyed because I think it accidentally set off a
Speaker 4: few misconceptions. So one of them was that we discovered
Speaker 4: parsonization and that it was new. I don't want to
Speaker 4: imply that I just got this, because that's not true.
Speaker 4: We've known about it since before we knew what DNA
Speaker 4: even was, like over a century. We've known it's just
Speaker 4: it hasn't been studied in a really systematic way, so
Speaker 4: we're trying to put quantitative tools to the topic. And
Speaker 4: you know, myself and my collaborators we were like crustacean
Speaker 4: evolutionary biologists. We were just like, hey, this is cool.
Speaker 4: But it has taken on a bigger life now. So
Speaker 4: that's kind of one of the things that I just
Speaker 4: wanted to set straight. But the other I think more
Speaker 4: disturbing is the memes kind of set off some misconceptions
Speaker 4: of that evolution.
Speaker 2: And how do you think these misconceptions took root. Do
Speaker 2: you think it's journalists in good faith misunderstanding or do
Speaker 2: you think there's an aspect of like, hey, this story
Speaker 2: would be more exciting if it were a little bit different,
Speaker 2: so let me make it clickbaity and distort it a
Speaker 2: little bit. What do you think is going wrong there?
Speaker 4: I think a lot of the journalists have been in
Speaker 4: good faith. A lot of the journalists I talk to
Speaker 4: have science backgrounds. Yeah, but the headlines are often clicked
Speaker 4: baby the editors. Yeah, it's more the memes. So the memes,
Speaker 4: it's like multiple levels of translation. So someone's going to
Speaker 4: read it and then the next person is going to
Speaker 4: make a meme of it, and the next person can
Speaker 4: make a meme with the meal. So I mean that's
Speaker 4: like literally what memes are. Right, So when it starts
Speaker 4: getting to crab the ultimate form, how can that be
Speaker 4: if it's been lost seven times? Right, it can't. And
Speaker 4: to say things like any form is firstly invented by nature.
Speaker 4: Nature doesn't invent anything. Nature doesn't have a brain. That
Speaker 4: skate's a little too close to intelligence design for me.
Speaker 4: And then saying that one life form is superior to
Speaker 4: another also doesn't really sit well with me. I don't
Speaker 4: actually think that crabs are better than any other organism
Speaker 4: except in my heart, which I love them. You know,
Speaker 4: I got over the incident, so I love them alat
Speaker 4: now and I got gloves to hold them with, so.
Speaker 1: Good move.
Speaker 4: So, you know, instead of seeing it as crabs are
Speaker 4: better than everything else and that's why they evolved, you know,
Speaker 4: they're part of an ecosystem, part of many eco citizens.
Speaker 4: We see them all over the world, Like the amount
Speaker 4: of places that they live is actually quite astonishing. It's
Speaker 4: you know, from the deepest depths of the ocean and
Speaker 4: hydrothermal vents where they're like in a chemosynthetic ecosystem and
Speaker 4: all the way. There's a crab genus called Himalaya potomon
Speaker 4: and they're called that because they actually live in the
Speaker 4: Himalaya Mountains far far away from the ocean. What oh yeah,
Speaker 4: those guys. They do live near streams, so they get
Speaker 4: wet at least. But there are some crabs that are
Speaker 4: so terrestrial that they will drown if you subverse them
Speaker 4: in the ocean, like, they will live die. Yeah.
Speaker 2: Land crabs love it.
Speaker 4: Yeah, yeah, So they do have to mate like the
Speaker 4: larvae go into the water, but that's it other than
Speaker 4: that land.
Speaker 2: So given the crabs are everywhere on Earth a very
Speaker 2: adaptable to whatever environment, that sets me up perfectly for
Speaker 2: the question I've been dying to ask you, which is
Speaker 2: about Zeno krabologists. You know, imagine you're the biologist on
Speaker 2: some landing party. You're about to, you know, land on
Speaker 2: some alien planet for the first time. Do you expect
Speaker 2: to see crabs in some other evolutionary independent environment.
Speaker 4: Well, spoiler, but they did make crabs and star Wars recently,
Speaker 4: so technically I have to say yes.
Speaker 2: Right, I'm not a documentary.
Speaker 4: No, so I would actually say no realistically, because to
Speaker 4: be a crab. You have to have the parts of
Speaker 4: an archipod. To start. You can't have a care pace
Speaker 4: changing to this shape. If you don't have a care pace,
Speaker 4: you can't fold up your open if you don't have
Speaker 4: a segmented body in the first place, the legs and claws,
Speaker 4: you have to have those. So for me, what I
Speaker 4: imagine aliens to be, and this, of course now is
Speaker 4: just complete speculation based in almost nothing. But you know,
Speaker 4: I would say, why don't we assume that aliens could
Speaker 4: be radio organisms? We have those on Earth like starfish.
Speaker 4: Why wouldn't they be colonial organisms? We have those corals? Right?
Speaker 4: I think crabs are awesome. And if Disney or any
Speaker 4: other out you would like to hire me as a
Speaker 4: consultant to help them make their monsters, I'd be happy.
Speaker 4: But yeah, I don't actually think that's what you'd see
Speaker 4: in space.
Speaker 2: Well, fascinating space crabs unlikely, that's the new meme.
Speaker 4: Yeah, so sad. But you know, if you do somehow
Speaker 4: get like an arthropod like organism, something that's segmented, then yes,
Speaker 4: I think it is possible you could. We don't know
Speaker 4: what the conditions would be like. You know, it's also
Speaker 4: not star wars where every planet is like one ecosystem. Right,
Speaker 4: you know, hard to say, right what kind of gravity
Speaker 4: they have? Do things live in the water at all? Right?
Speaker 4: Who knows?
Speaker 1: Let's end on more exciting notes. So we've poured a
Speaker 1: little bit of cold water on the you know, nature
Speaker 1: turns everything into crabs thing. But so let's talk about
Speaker 1: what is exciting. So you study convergent evolution and crustaceans,
Speaker 1: what are the interesting scientific questions you're excited about and
Speaker 1: what are the societal benefits for studying this kind of stuff.
Speaker 4: So from the biologist's perspective, we want to know if
Speaker 4: we can basically predict evolutionary patterns. And I don't necessarily
Speaker 4: mean predict the future. Although I don't necessarily not mean that,
Speaker 4: I also mean predict as in, like, do you get
Speaker 4: why given X, right? And convergent evolution is a really
Speaker 4: wonderful system for this because we already saw it multiple times.
Speaker 4: So it's kind of like having experimental rapplicits that have
Speaker 4: already happened in nature. So when we do this. I
Speaker 4: kind of alluded to this when I was talking about
Speaker 4: animal lizards. They have very similar forms. They're not totally
Speaker 4: predictable what's going to happen because they have been experimented on.
Speaker 4: But there is a higher degree of predictability because they
Speaker 4: are all basically starting from already a very similar point.
Speaker 4: So if you look further back to something that evolved
Speaker 4: a really long time ago convergently, like say eyes vertebrates
Speaker 4: and several podsic squids, we all have similar eyes, and
Speaker 4: there are genetic similarities, so like there's a gene called
Speaker 4: past six that is basically like make eye here when
Speaker 4: the gene gets expressed, but everything else about the eyes
Speaker 4: can be different because they're so distantly related. So I
Speaker 4: think the fact that within true and false crafts we
Speaker 4: see this, I mean, it is a distant common ancestor,
Speaker 4: but it's not so distant. Million years. Yeah, it seems
Speaker 4: a long time, but like in the scheme of animal diversity,
Speaker 4: it's not that distant. So seeing also the amount of
Speaker 4: variation that they have with all the options that their
Speaker 4: bodies can take, why are we seeing some of the
Speaker 4: same basic forms. Are we seeing the same thing being
Speaker 4: innovated and then just elaborated on, or are we seeing
Speaker 4: different things happening entirely? Is it adaptive? Is it not
Speaker 4: adaptive is it a combination? And I think being able
Speaker 4: to study different scales of convergence is really important because
Speaker 4: if we just study the same thing, then we're not
Speaker 4: going to have a fuller picture of whether we can
Speaker 4: really predict evolutionary outcomes.
Speaker 1: And how about we all have to write our NSF
Speaker 1: grants and other than you know, creating incorrect memes, what
Speaker 1: are some society reasons to study this?
Speaker 4: Well, certainly studying conversion evolution is also important for if
Speaker 4: I'll use my NSF speak, the bioeconomy. We live in
Speaker 4: a world where conditions are changing, and we want to
Speaker 4: have crops that can adapt to changes. We want to
Speaker 4: develop drugs that are going to be effective against new pathogens,
Speaker 4: and many of those things, you're going to see that
Speaker 4: conditions change in the same way multiple times around the world.
Speaker 4: We've seen this, of course with variants of COVID having
Speaker 4: the same mutations, so like when we're trying to make
Speaker 4: vaccines against them, we're looking at trying to fight convergent evolution,
Speaker 4: so that can certainly be quite important. Or like you know,
Speaker 4: we want to see how plants are going to respond
Speaker 4: to different toxins in the ground. Stuff like this but
Speaker 4: I think even studying crustaceans is important because, I mean,
Speaker 4: we've kind of alluded to this, but there's a big
Speaker 4: economy in people eating crabs. Like two fisheries in Alaska
Speaker 4: collapsed about four years ago, both the snow crab, which
Speaker 4: is a crue crab, and the lasting king crab, which
Speaker 4: is a false crab, and this is attributed to either
Speaker 4: climate change and or over fishing. Both are pretty bad,
Speaker 4: and the reality is it's three hundred and twenty million
Speaker 4: dollars in the economy, plus people who are not going
Speaker 4: to be able to eat, plus people's jobs. So that's
Speaker 4: really serious. And for us to be able to understand
Speaker 4: the resilience of these species two changes environmentally. I mean,
Speaker 4: obviously this's on a smaller scale within a species, but
Speaker 4: maintaining genetic diversity and stuff like this is really important
Speaker 4: to know about. Another interesting thing I would say is
Speaker 4: that there can be some possible knowledge about diseases that
Speaker 4: we can actually get from crustaceans. For example, crabs can
Speaker 4: regenerate their legs if you put them off. Arthur pods
Speaker 4: have a lot of superpowers because the way that they
Speaker 4: grow is by molting their entire episoskeleton, and they make
Speaker 4: what will become a bigger one, but it's like stuck
Speaker 4: inside and it sucks, and then when the old one
Speaker 4: fops off, then it kind of inflicts, and so they
Speaker 4: stick a new leg in there. So you know, obviously,
Speaker 4: people who have injuries might want to know about ways
Speaker 4: that this could be improved. So there's actually quite a
Speaker 4: lot even in these really obscure animals and seemingly obscure topics.
Speaker 4: It's true that I'm studying biodiversity. I want to know
Speaker 4: about why we see the forms that we do, and
Speaker 4: that may be very high level, but these organisms are
Speaker 4: important to us.
Speaker 2: So you can solve a lot of interesting science mysteries
Speaker 2: and learn about broader implications. But maybe you can't crack
Speaker 2: one of the deepest mysteries, which is why husbands are
Speaker 2: sometimes crabby in the morning.
Speaker 4: No, I can't crack that one.
Speaker 1: That's more of an NIH question than an NFF question.
Speaker 2: That's true, a set is more like our aliens krabby,
Speaker 2: and that we actually might have some hints about.
Speaker 4: Yeah, yeah, NASA does have an extra biology director, or
Speaker 4: at least we'll see what happens. But they have had
Speaker 4: but they don't usually do stuff like this. It's more
Speaker 4: realistic questions that they asked, like how would you detect
Speaker 4: if there's water on another planet and stuff like that.
Speaker 4: So yeah, not like literally our organs is going to
Speaker 4: be crabs on another planet. I think that it's cute,
Speaker 4: but they're not going to actually give you a million
Speaker 4: always could.
Speaker 1: Do that well. I see lots of great reasons to
Speaker 1: fund crab research, and Joe, we look forward to seeing
Speaker 1: what you do in the crabby space in the future.
Speaker 4: Thank you so much, thanks for.
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