Evolutionary Hangover


Full Transcript

Announcer: Welcome to Stuff to Blow Your Mind from howstuffworks.com.

Robert Lamb: Hey everybody. Welcome to Stuff to Blow Your Mind. I'm Robert Lamb.

Julie Douglas: And I'm Julie Douglas.

Robert Lamb: And tell me Julie, do you have a lot of stuff in your house? Would you say you are a hoarder?

Julie Douglas: I don't know that I would say that I'm a hoarder, but I do surprise myself when I open the closets and I think, "Oh my God. What is all that stuff?"

Robert Lamb: Yeah, because it's like - I don't feel like I'm that bad either. My wife is a very good influence on me because she'll throw things away at the drop of a hat.

Julie Douglas: She's a purger.

Robert Lamb: Yeah, definitely.

Julie Douglas: That's good.

Robert Lamb: And so that cuts down on the clutter, but still it's easy to be like, "Oh, I got a new phone. I should keep this old phone because who knows? The new one could break. I might need to fall back on this one." Or they'll be like, "Oh, I don't have time for this hobby anymore, but maybe I will someday, so I should just - I shouldn't throw it away or sell it or give it away. I should just put it in the attic for a little while."

Julie Douglas: Yeah, that's how I feel about my thigh master. I might use that one day.

Robert Lamb: As a weapon or -

Julie Douglas: Yes, definitely as a weapon. You never know.

Robert Lamb: Yeah, I think it could be retrofitted into a small caliber catapult.

Julie Douglas: Yeah, that's what I was thinking; some sort of sling device.

Robert Lamb: Yeah, but again, it's a slippery slope. Before you know it, it's like the house that we're in now that my wife and I bought that when we first got, it was just loaded with stuff like three Christmas trees in the attic; that kind of thing because the whole mindset can just go crazy. But what's interesting is that when you look to nature, when you look to evolution, you see a similar kind of hoarding going on. Or maybe not outright hoarding, but definitely hanging onto things that there's not really a use for anymore.

Julie Douglas: Like a genetic hoarding?

Robert Lamb: Yeah, genetic and even just physiological hoarding. We're of course talking about vestigiality, the occurrence of vestigial organs, vestigial limbs, vestigial body parts in all animals, but particularly in humans.

Julie Douglas: Okay. And so I'm thinking right off the bat I've heard about whales with hip bones or leg bones.

Robert Lamb: Yeah, you look at a skeleton of a whale and the head is very pronounced. All the skeletal system is clearly really important except for this little pelvic area and these little remnants of hind legs that just haven't been used in forever, but it's as if the whale's body on some - like on a very basic level is like, "Well, who knows? We might need to grow those legs out someday. We might go back to land. We've done it before. So we'll just keep this much around."

Julie Douglas: Huh. So it's sort of a law of probability thing going on in nature.

Robert Lamb: Yeah, this is the thing that keeps coming back to me as we are looking at it: on the one hand, these are souvenirs of an evolutionary past. They're pieces that no longer serve - either they don't serve a purpose anymore or they don't serve the purpose they were intended for, but there's - and then there's also a sense that evolution is kinda lazy; that it's not going to fix anything that's not broken, but it also doesn't just throw something out in the same way that an animal doesn't say just suddenly grow an entirely new limb for some new purpose.

If say a small badger animal at some point in the primeval past needed to get inside a log to eat a grub, it wouldn't grow a fifth grub grabbing instrument. It would develop a tongue that could reach in or nails that could dig into the trunk. It works with what it has. And so it's like a similar vestigialarity is like a similar thing in reverse, it seems, where you don't - if you don't need hind legs anymore, you don't just completely get rid of all the bones. You just sort of retract; you downsize that portion, but not to the point where you can't come back.

Julie Douglas: Okay. And so atavisms which are really closely related to vestigial organs and traits, I think are pretty fascinating too. And they're a little bit different in that an atavism is basically a trait from a distant, distant evolutionary ancestor. We're not talking about your great, great grandfather. We're talking like 50,000 years ago where that particular piece of DNA gets expressed again and the thing that comes straight to mind of the difference I guess between a vestigial and atavistic are babies that are born with tails which is so crazy in the first place.

Robert Lamb: Yes, actually happens; it's not just a -

Julie Douglas: National Enquirer headline.

Robert Lamb: - Bat Boy or anything.

Julie Douglas: Yeah exactly, it's not Bat Boy with a tail. So if you think about turkeys which are flightless birds and you see their wings, those are vestigial, right?

Robert Lamb: Yes.

Julie Douglas: Because they're sort of imperfect versions of what they might have had when they were taking flight.

Robert Lamb: Right, the ostrich is another example of that.

Julie Douglas: Yeah, and so if you look at a baby born with a tail, that's just sort of more of an evolutionary oddity.

Robert Lamb: Um-hum, but - yeah, and kind of - but kind of like as if suddenly there was a turkey that had - like of all the turkeys, suddenly there's a turkey that has maybe larger wings, kind of a deal because it's not like the baby's growing a tail for balance, but in a prior evolutionary form, it would have needed a tail for balance and that's where that comes from.

Julie Douglas: Yeah, exactly. Perhaps there were prehensile - it was prehensile tail that you could use to wrap around a tree limb to support yourself even, so there are different ways that a tail could have been used in evolution, but every once in a while, there it goes.

Robert Lamb: So it's kinda like there's an on/off switch with a dimmer in our genes. And over the years, the evolutionary force decided, "Hey, we don't really need this tail anymore. Let's dim that down to the bare minimum." But every now and then, the dimmer switch gets brought up just a little bit.

Julie Douglas: Right, and if you were unlucky enough to be born in the ninth century with a tail, well, it just wouldn't have been good news for you. By the way, I just wanted to point that out. Your mother would have been branded a witch and you would both have been disposed of because obviously, a tail looks as though it's something from the dark arts or from the beast.

Robert Lamb: Yeah, you're some sort of a changeling left in the crib.

Julie Douglas: Exactly. So that's one of the really interesting things about vestigial and atavistic traits. They just don't behave the way that you think they're going to.

Robert Lamb: Yeah. Now a lot of this really comes out of the work of Charles Darwin; not the actual [inaudible] traits in the actual appearance of things like tails, etc, but our understanding of what these things are comes from his 1871 book, The Descent of Man. And in this, he identified about a dozen different anatomical features that he thought were useless in tha t we don't use them the same way that other people or creatures do. So for Darwin, this was also proof that we evolved from a primitive ancestor - from primitive ancestors. And it's interesting, there's another guy that came after Darwin who - he really took hold of this idea and ran with it, and his name was Robert Wiedersheim and he was an anatomist.

This is 1893 and he put together a list that had like 90 different things on it, which I find just amazing. And not to say that this was not a very learned guy; this guy was pretty - this was a very bright guy. He was on the cutting edge of science.

Julie Douglas: In 1893.

Robert Lamb: In 1893; yeah, important to note. And he was just very - well, he was just a little ambitious maybe and just a little too eager to classify things. So you see this mentioned a lot, especially by people who want to defend say creationism against evolution because people who are proponents of evolutionary theory will often point out vestigial organs and limbs as proof that we've evolved and there's not some sort of divine force dictating what a body looks like. And - but they'll - creationists will sometimes throw this back - if you do a search for this guy's name on the internet, you will find pretty much nothing but random blog entries or message board posts attacking evolution.

Julie Douglas: So what was the - sort of the meat of his theory or the -?

Robert Lamb: Well, that's the thing. The important - something that's not really mentioned in any of these lists is that the list itself is pretty particular. There are some glaring things where he was like, "People don't need three toes, the three end toes like the pinky toe and the other two." I forget which pigs those are.

Julie Douglas: I was about to say the piggy that ate and the one that didn't and then the one that went wee, wee, wee all the way home.

Robert Lamb: Yeah. He was like, "We don't need those guys," but it was other stuff like there was the lumbar rib. A lot of things on this list are kind of in medicalese and I'm not really sure what they are to be honest, but it was very particular. And they were all things that he said they don't actually have a function in the body, and therefore, they're just remnants of evolutionary past. Of course over time, we looked at it at more detail and we realized, "Oh wait, we actually do need this. This does serve a purpose." And I imagine anybody that's missing three toes on each foot would probably be able to tell you that it's not ideal.

Julie Douglas: No, particularly in heels.

Robert Lamb: Yeah. So let's go through some of these more common - because the list is not 90 strong anymore. It's - there are really only a handful of really good examples. And even some of those, as we'll discuss, you can go back and forth on. So wisdom teeth: do you have them?

Julie Douglas: Yes, I - well, no. I have one.

Robert Lamb: Okay.

Julie Douglas: Three have been extracted. And of course, like anyone, they were the bane of my existence. And the interesting thing about wisdom teeth, I think, is the moniker and it is so called wisdom teeth because they usually emerge between the ages of 17 and 25, which I think back in the day was thought to be when you had gained a good amount of knowledge and you had become wise. Of course, we know otherwise; that the brain itself isn't even fully developed until age 25, but I digress.

So wisdom teeth: there are a couple of different schools of thought on this, on why they're vestigial now. One is hygiene. If you were living 20,000 years ago, you certainly weren't brushing your teeth twice a day and particularly not with fluoride. So you were probably missing a good amount of your teeth by the time you turned 18, which is probably about half of your life span anyway. So it'd be really helpful if you got some wisdom teeth in to kinda get an upgrade to your chompers. So that's one theory.

Robert Lamb: Wow, so basically, by the time your wisdom teeth came in, some of your other teeth would be ready to go.

Julie Douglas: Right.

Robert Lamb: This is kind of like the second row of shark teeth coming in.

Julie Douglas: Exactly, right. Right, you are wise and toothless at this point.

Robert Lamb: And getting on in years I guess in looking - if yo u're considering just like ancient, ancient man.

Julie Douglas: Right, right. How else are you gonna be able to eat your tiger meat? So you've gotta get - you've gotta have something there in the wings. The second school of thought is that as we evolve, that our jaws have actually gotten a lot smaller. So it's pretty simple. Your wisdom teeth are getting crowded out. They're extraneous. They're a pain in the butt. They're unpleasant and they must be removed.

Robert Lamb: Okay. Well, I probably will have to remove mine eventually, or have them removed professionally rather because mine are generally rather quiet, but then occasionally, they'll just be really painful for like a week.

Julie Douglas: Yeah, they seem to do some sort of flare up, some sort of evolutionary like, "Hey, remember me?"

Robert Lamb: Well, another example is body hair. This is - this one's rather obvious when you look at it. A good head of hair can help maintain cranial temperatures, but obviously, it's not mandatory as any bald person will be able to tell you or just somebody who likes to shave their head. But body hair used to be very important. Back in way prehistoric days when we were just naked creatures wondering a frigid landscape, we depended on really furry bodies to maintain temperature. But of course, over time, we wondered into areas that weren't as cold. We went into warmer climates. We developed the ability to sweat. And eventually, we figured out how to make clothes.

Julie Douglas: And build mansions.

Robert Lamb: And build mansions, yeah. So yeah, body hair is a great example of something that we really do not need. A lot of people get rid of it through one - or regularly purge themselves of it. And it's just an evolutionary trait from the old days.

Julie Douglas: Hum. And yet it's so nice to have a stylish head of hair.

Robert Lamb: Yeah. Well, I'm thinking back to sort of evolution sort of never throwing something out just in case it needs it again. It's kind of an example of where they're saying, "Hey, you may have sweaters and big mansions today, but what about next year? What about 100 years from now? It might get pretty cold."

Julie Douglas: Yeah, that nuclear winter.

Robert Lamb: Yeah. There might be another ice age coming. It's like don't - it's like I know all you humans wanna be nice pink and hairless, but just calm down. You might need it again.

Julie Douglas: That's right. It's saying, "Hey, I'm in here for the long haul."

Robert Lamb: Yeah.

Julie Douglas: I'm keeping it. It's something to think about.

Robert Lamb: Yeah, I don't know about wisdom teeth though. If it is a - if it's like actually the jaw has shrunk, I can't imagine there being a case where - maybe it is where eventually our jaw would get bigger. Or it's like nature's way of saying, "Hey, you can brush your teeth every day and live until 80 now, but call me in 100 years and see if that's the case."

Julie Douglas: Yeah, it's possible. I do think there's a logic behind it. And another one of these traits, which I don't know if it would come back or not; we'll have to think about that, is called Darwin's Point. And it's also known as Darwin's tubercle. And it's basically a small, thick nodule on the upper ear lobe that we think was meant to help focus sounds to kind of hone in. So it's essentially a little fleshy antennae.

Robert Lamb: I'm having a hard time picturing it since we're both wearing headphones. I can't feel it or see it.

Julie Douglas: Well, I now wanna peel back your headphones and see if you have it, but it actually - in some people it looks kind of pronounced. It looks like little elfin - like a little elfin ear bump. It's actually kinda cute, but not everybody has this. This is more like an atavistic trait. So in some populations it only shows up like ten percent of the time and others, 50 percent of the time. It just sort of depends on where you live, what your genetics are and so on and so forth. But again, maybe in the future we will need some little antennae device to help us with sound. You never know .

Robert Lamb: Yeah. Or it's kind of a case where it's like you're not using it, but hey, it's not like it's inconveniencing you. So nature's kinda like, "Don't freak out. We're just gonna keep this around in case you need it. It's not like you're tripping over it."

Julie Douglas: No, you can dress it up for Halloween; make it even more pronounced.

Male Speaker

This presentation is brought to you by Intel, sponsors of tomorrow.

Robert Lamb: Now another interesting vestigial trait is the vomeronasal organ which sounds pretty cool.

Julie Douglas: Sounds pretty serious, yeah.

Robert Lamb: And this is a structure in the nose that would ideally be used to detect pheromones emitted by potential mates. In humans though, this - like cats and dogs are big on this and various other animals, which is why I actually have a little spray can of cat pheromone to use -

Julie Douglas: Just on your desk?

Robert Lamb: Just when I want cats attacking me and coming and laying all over me.

Julie Douglas: Okay.

Robert Lamb: No to try and keep ours from urinating where it's not supposed to.

Julie Douglas: Oh.

Robert Lamb: Which we're not sure she does, but just in case: cat pheromones in spray form.

Julie Douglas: That's good to have around.

Robert Lamb: Yeah, I did get myself in the face with it one day because I was spraying it on a vent and I didn't realize the vent was on and so it's like three squirts of cat pheromone and then [noise] right back up in my face. So I was followed all day by strays.

Julie Douglas: Yeah, your eyeball was licked a lot.

Robert Lamb: Yeah, their scratchy tongue is so weird on the eyeball.

Julie Douglas: I know.

Robert Lamb: But no, so in humans though it doesn't even appear to be connected to the brain in any way, the vomeronasal organ. It's like it's not even plugged in. It's like the - if you have a toaster oven in your kitchen and you haven't used it in ages. It's not even plugged in, but it's taking up counter space.

Julie Douglas: So if it were plugged in, does that mean we would all be sniffing each other?

Robert Lamb: Maybe, maybe. I don't know.

Julie Douglas: I just - sorry, I had to ask.

Robert Lamb: Let's hope it doesn't turn on. That would be - it would certainly change the culture a bit.

Julie Douglas: It would be awkward.

Robert Lamb: So apparently, embryos, embryonic humans actually develop this organ and it's the - and at one point in thei r development, it's very much like the vomeronasal organs in other animals, but then it displaces and it's pretty much just set aside for the remainder. So we always end up keeping it. It's there, but it's just never plugged in.

Julie Douglas: Huh. Do you mind if I talk about nipples?

Robert Lamb: Go for it.

Julie Douglas: Okay. So male nipples -

Robert Lamb: Male nipples.

Julie Douglas: You know the question always comes up every once in a while.

Robert Lamb: Yeah, what are they for?

Julie Douglas: Yeah, why? I just wanted to say and I hope this doesn't get too sensitive, but it's completely normal and the short answer, the reason why men have nipples is because women do. And actually, in other non-humans, this is true as well.

Robert Lamb: Does this fall back on the idea that the female is actually the species and the male is just a mutation of the species necessary for procreation?

Julie Douglas: I'd like to think so, but actually, this has to do with nature sort of - again, law of probability, sort of creating this in both males and females. So it's called genetic correlation and it really is a game of probability. So even though sex is determined at the time of fertilization, the gonads actually don't turn into testes or into ovaries until the seventh week and they don't start expressing the gender until then. Yeah, so it's just a just in case scenario.

Robert Lamb: So it's kind of like if you have a - I don't know if they do this anymore, but used to - it's like if you purchase an automobile that didn't have a cigarette ashtray - sometimes there would be - you could see the space where it would be. So it's like the default car body or just interior body or shell or whatever had the place for it just in case it was there.

Julie Douglas: Right, exactly. So just in case nature is like, "You know what? This is a gamble here. We'll go ahead and give nipples to everybody; all mammals, they get them." And you might have actually even heard of something called witch's milk. And this is actually produced in newborn infants.

Robert Lamb: No.

Julie Douglas: No? Yeah. And people kinda get freaked out about that because they think, "Whoa. Why is my son lactating?"

Robert Lamb: Whoa, a baby will lactate?

Julie Douglas: Yeah, it's rare.

Robert Lamb: Oh my goodness. I did not - I knew about men lactating of course, but babies; witch's milk?

Julie Douglas: Yeah. Yeah, witch's milk. But the reason is because their breasts are actually stimulated when they're in their mother's womb because the mother's hormones are crossing the placenta. So they're basically kinda - they come out and they still have some of those hormones in their system and they start lactating. So if this happens, it's actually not abnormal. It's fine.

Robert Lamb: Wow.

Julie Douglas: Yeah.

Robert Lamb: So if you were - if you happened to have been born in ye olden times as a baby with a tail lactating -

Julie Douglas: I'm sorry. Yeah, you were toast.

Robert Lamb: Wow.

Julie Douglas: Yeah. It just wasn't looking good for you or your mom. So what - there's a debate here. There are some people who say that -actually that nipples aren't vestigial because it's more like again, that game of probability. They would be active if you were a female or at least actively lactating. So let's talk a little bit about the - what is vestigial - what's not vestigial; some of the things that are up in the air?

Robert Lamb: Yeah, because it's like we said, some of these things just are in a process of maybe being phased out for the time being. And some of the - there are also cases - it's kind of like that list of 90 odd things. We came back around to some of those and said, "Well, wait. Actually, you do need this. Actually, this does have a purpose."

Julie Douglas: Toes are helpful.

Robert Lamb: Right. Yeah, so yeah, some of the items that we have considered vestigial in the past, some scientists are saying, "Well, hold on. We think it might actually have this purpose during this particular situation." So yeah, we're actually gonna come to two of the biggies and the first of which is the - just the superstar of vestigial organs, the appendix.

Julie Douglas: That's right. It's something that in humans, is sometimes reviled only because appendectomies. We perform something like 300,000 of them a year, but in small plant eating vertebrates, the appendix is actually pretty large and it helps to digest food. If you look at humans, it's just kind of a small lonely pouch and it's hanging out next to the large intestine and the small intestine.

Robert Lamb: And then sometimes, needs to be removed.

Julie Douglas: And it's - yeah, exactly. That's appendicitis. So - but the thing is that it's sort of a third wheel to digestion. It doesn't do anything. And the thought is that like the plant eating vertebrates, at one point it did actually break down food and aid in digestion. So that's what we know about it.

Robert Lamb: Yeah, countless people have this - do you have yours?

Julie Douglas: I do have mine.

Robert Lamb: In your body; not in a jar or anything?

Julie Douglas: No; no, not in a jar; not yet.

Robert Lamb: Yeah, I have mine still.

Julie Douglas: In a jar?

Robert Lamb: Inside me.

Julie Douglas: Okay, good.

Robert Lamb: In a jar.

Julie Douglas: Yeah.

Robert Lamb: But yeah, it's like millions of people have this removed and everybody goes on just fine. Nobody's like, "Oh, I wish I hadn't had that appendix removed."

Julie Douglas: Exactly. So a lot of people have thought, "Okay, it must be vestigial. It has absolutely no purpose."

Robert Lamb: Right. And yet, there's a growing debate on this. And some people have pointed out that well, first of all, when that appendix is still in your body, it is a producer of white blood cells and antibodies. So it's not just necessarily along for the ride. It may not be meeting the same purpose it was originally there for, but it's still doing something. Of course, it could still be considered vestigial given that, but then there's also this - where it really gets interesting is the idea that the appendix can repopulate the gut with microbes needed to stave off infection.

And where this is key: it comes down sadly , to the topic of diarrhea and dysentery. In the developed world, if you - first of all, you're probably less likely to get some strains of dysentery and diarrhea. And then when you do, you can go to your doctor or you can go to your drugstore and get something to deal with it. In the past and indeed still in many parts of the world, those options aren't necessarily on the table or as readily available. And so there's this belief to really understand the appendix's role, we need to be able to look at developing countries and look at - because we have the facts on its removal in the developed world.

We can say, "Millions of people have it done every day no problem," but they say we really need to look at people in the developing world, like portions of war-torn Africa, etc and see if there are people there with appendix removed; how they would fare given their conditions?

Julie Douglas: Okay, so their exposure to many more diseases and so on and so forth.

Robert Lamb: Right. So in this case, it would be - this would be an organ, this would be vestigial to some, but not to others and again, it's kinda like nature saying, "Hey, you have a Rite Aid down the road now and clean drinking water in your house, but 100 years from now, maybe not. And then you're gonna come running to me, the appendix, wanting me to pump you full of microbes to stave off your dysentery."

Julie Douglas: "And if you're lucky and I haven't burst, I will help you."

Robert Lamb: Yeah.

Julie Douglas: That's what I imagine the appendix to say. Another vestigial I guess you would say trait or structure in this case would be the tailbone, yeah?

Robert Lamb: Yeah, the coccyx.

Julie Douglas: Coccyx.

Robert Lamb: Coccyx, okay. I always get that and the frozen lake in Dante's Inferno confused. What is that called?

Julie Douglas: I don't know.

Robert Lamb: I don't know. I can't say it either. You're the one that knows Italian.

Julie Douglas: Yeah, but that doesn't mean that I know the frozen lake; sorry.

Robert Lamb: Yeah, got you.

Julie Douglas: I will check into it though.

Robert Lamb: All right. It's on the tip of my tongue. I can picture the word in my head.

Julie Douglas: [Italian] go on.

Robert Lamb: But anyway, the - we mentioned some of this earlier about the growth of a tail that will happen occasionally, and so the tailbone is kind of the same deal. What does it really do for us aside occasionally getting broken if you fall on your butt hard enough? Maybe not all that much. There is - the whole idea is these are smaller and smaller vertebrae leading up to the tail that isn't even there. So it's kind of an evolutionary road to nowhere.

Julie Douglas: Right. Yeah, but there are some people who say that coccyx helps to anchor minor muscles and helps support pelvic organs. And they say that there's some evidence, but it's kinda weak evidence, I have to say because you can have the coccyx removed or - excuse me, the tailbone and you can have little or no adverse effects. You can live without it if need be.

Robert Lamb: Yeah. It's kind of like - to use an example, you're at work in one of our meeting rooms. This is called the cool room. There is a cardboard box in the corner that apparently contains -

Julie Douglas: A cat.

Robert Lamb: No, not a cat. It contains - I think it contains lid rocks or something like a prod uct from another age. And - but it's been in there forever. This product is not to my - I have no idea, but evidently, it's not going anywhere. This package just has no delivery information on it. Whatever purpose it was originally intended for, it's obviously not meeting.

Julie Douglas: Right. And it's survived renovation.

Robert Lamb: Right, renovation after renovation, but I sit on it, every meeting that we have in the cool room, at least for the big editorial meetings. So while it's original purpose is long gone, it has found a new purpose and it works very well in that regard.

Julie Douglas: So it's adapted.

Robert Lamb: Yeah, exactly.

Julie Douglas: Yeah, that's very Darwinian of it.

Robert Lamb: Yeah, you could remove it now and say, "Hey, this is pointless," but then where am I gonna sit?

Julie Douglas: Right. You would miss it.

Robert Lamb: Yeah. So I think a number of these things, the appendix and the tailbone seem to fall into those - potentially fall into those categories where the original full blown purpose may not be applyable anymore, but they still have important roles to play.

Julie Douglas: Yeah, absolutely. Yeah, we don't want them to go away. So Robert, tell me about your toes and fingernails.

Robert Lamb: Well, my fingernails are fine. My toes, however -

Julie Douglas: Well, kept; they look good.

Robert Lamb: Yeah? Well, thank you.

Julie Douglas: Um-hum.

Robert Lamb: My toes - my toenails at times, have proven a problem to the point where I've wondered what's up with them; why do I have toenails if they're just going to break when they run into tables and ended up growing weird into the side of my toe? So I've had to have this procedure done. Forgive me; I don't know the name of it, but basically, the doctor goes in, cuts off - cuts out a side of the toenail and then kills the nail bed.

So I still have toenails. I'm not - I just wanna get that out there, but they've been altered so that they don't grow so mind numbingly painful anymore. And I've run into other people like a friend of mine, this guy, Michael. I was talking to him one day and he's like, "Oh, I had that procedure done." And then my actual podiatrist, he's had it done as well.

Julie Douglas: So you feel like maybe the toenails, they could - we could lose them maybe?

Robert Lamb: Well, I just think there's something up. Well, I don't know if we - well, maybe we could lose them. I haven't had to actually dig in the dirt with my toes before; maybe recreationally, but not for an actual survival purpose.

Julie Douglas: We don't wanna hear about your weekend [inaudible].

Robert Lamb: But seriously, it's like if I'm having to go the doctor to have them changed so that they don't hurt, there's something up. Maybe the design is a little outdated.

Julie Douglas: Yeah. Yeah, I'd go with that; that maybe we want them, but not necessarily the way that they are. I do say - I think that the fingernails are still pretty useful.

Robert Lamb: Yes, definitely.

Julie Douglas: In fact, I know one guy that uses his pinky nail to actually screw things in.

Robert Lamb: Oh yeah?

Julie Douglas: And you thought I was gonna go somewhere else with that, didn't you?

Robert Lamb: Oh, I don't know.

Julie Douglas: Long pinky nails, yeah. But so they can still be used as tools.

Robert Lamb: Yeah, anybody whose - you use them to pick up stuff all the time. Scratching; it may not be the ideal thing to do, but how would you - scratching would be a whole different ordeal if you could only rub a mosquito bite.

Julie Douglas: Yeah, can you imagine?

Robert Lamb: Yeah.

Julie Douglas: That would be torture.

Robert Lamb: So I think - yeah, nails are not going away any time soon.

Julie Douglas: No. And then I guess there's something too about keeping bacteria away or I don't even know. Or something about -

Robert Lamb: We're storing it for later.

Julie Douglas: Yeah -

Julie Douglas: I'll have this for later. But that does make me think what are we gonna look like in 500 years? What might become vestigial for us humans?

Robert Lamb: Yeah, again, we're not gonna develop new organs or limbs to tackle new problems, but some new problems may arise. Some problems will continue to disappear. So yeah, will we be completely hairless?

Julie Douglas: I'm going with that.

Robert Lamb: Will all of us lose these annoying wisdom teeth?

Julie Douglas: I hope so. I certainly do. Will we no longer have toenails?

Robert Lamb: Hum.

Julie Douglas: It's possible.

Robert Lamb: We'll see. So if you wanna know more about this topic, you should come to the howstuffworks.com website and check out the "How Vestigial Organs Work" by Molly Edmonds. You should read "How Atavism Works" by Katie Lambert. And we also have one on how natural selection works by Ed Grabianowski.

Julie Douglas: That's right.

Robert Lamb: I said it right?

Julie Douglas: Ed Grab as we call him.

Robert Lamb: Ed Grab.

Julie Douglas: Yeah.

Robert Lamb: So for more information on why you do or do not have a tail, check out those articles and we'll cat ch you next time.

Announcer: For more on this and thousands of other topics, visit howstuffworks.com. To learn more about the podcast, click on the podcast icon in the upper right corner of our homepage. The How Stuff Works iPhone app has arrived. Download it today on iTunes.