Stuff You Should Know - How Fossils Work

Episode Date: March 4, 2011

A fossil is a piece of once-living organic material that has undergone a transition from an organic state to an inorganic state. But what exactly is fossilization? Listen in as Josh and Chuck break down the process of fossilization. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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They just have way better names for what they call, like what we would call a jackmove or being robbed. They call civil acid. Be sure to listen to the war on drugs on the iHeart Radio App, Apple Podcast, or wherever you get your podcasts. Brought to you by the reinvented 2012 Camry. It's ready, are you? Welcome to Stuff You Should Know from HowStuffWorks.com. Hey, and welcome to the podcast. I'm Josh Clark. With me as always is the intrepid paleontologist, Charles W. Chuck Bryant.

It's terrible, isn't it? No, I like it. I wish I was a paleontologist. Well, it's your new nickname, though. Or intrepid, at least. Let's just go with paleontologists. That'd be great. Okay, we're talking fossils today, dude. This is really interesting stuff. It really is. And you can tell that Tracy Wilson, our esteemed head of the writing editor. I think she's site director now for us, the Ford director, right? You can tell that she was very, very excited. She took her time and really doled this one out. I think savor is the right word. You can feel that her smiling through the keyboard.

Yeah, she's very happy to write how fossils work. And we're happy to do it because it's one of those very comprehensive articles on the site that you just, it has everything you need. Sedimentary rock, flat bones versus round bones, leaf impressions. It has it all. Unless you're an intrepid paleontologist, then we'll get an email saying, it actually wasn't very comprehensive. You guys royally screwed this up. We just wait until we get into a punctuated versus gradual evolution. Chuck, you've heard of Lucy, right? The Australopithecus. Yeah. Okay. Well, she was, I think, 3.2 million years old. That's one old lady. It really is. The earliest hominid we've found as far as I know.

But there is a part of her foot missing. It's always been missing that we've never found before. So this thing, this bone was so essential that we couldn't tell how she walked until recently. Why? Because the missing bone, we couldn't tell how she walked. Exactly. Wow. We can tell so much from bones that when we don't have the right bones, we can't tell anything. So she may have been in a knuckle dragger. Sure. She may have hopped. We didn't know. Well, recently, some people from the University of Missouri or Missouri, depending on whether or not you live in the state, found the group of foot bones needed to show what kind of walker Lucy was. And she walked upright. How was her gait upright?

Upright. Just like a human. Did she have a hitch in her get along? She had a pepper in her step. Possibly. She knew she'd be famous one day. Sure. She used some love with Tuck Tuck. But consider this, right? Okay. 3.2 million year old foot bones were found. And we could tell from them how she walked. This is the state of the field that you remember, paleontology. Pretty cool. This is how advanced it is. And yet, it's really just kind of using common sense to figure out what all bones mean. Yeah. Common sense in science. Fossils. Go. Let's talk about it, Chuck. What are some of the different kinds of fossils? Well, one of my favorite kinds is a trace fossil. Yeah. That's actually one of my favorites,

too. It's like that Jesus footprint thing. Footprints in the sand. Yeah. It sort of is, Josh. That is when it's actually not part of the organism at all, but it's like tooth marks in a chunk of wood from a saber tooth tiger. Or footprints. Or footprints. Or trackways, as Tracy calls them. Yes. Footprints, trackways. It's just unnecessary, but it has a pleasant tone. You know science. Yeah. They're not footprints. They're trackways. I'm bored in Ethiopia. Let's call them trackways. So trace fossils is one. Of course, there's bone fossils, right? The most famous fossils. Yeah, those are great, too. They got nothing on trace fossils, though. Actually bone fossils. That's what you really want. If you're going to reconstruct

a dinosaur for your museum, you can't do it with footprints. No, you can't. You need the bones. You do. And the bones are of course the most famous ones. And the dinosaur bones are the most famous of all the bone types, right? So there's something that I think is often missed by lay people such as myself. In that when you find a bone, right? So you find like a big old dinosaur bone. It's really geologically speaking. It's not a bone any longer. Yes. Not like you find a bone buried in your yard that was an animal from like, you know, 35 years ago. You could, but that's not a fossil. Well, no, it's still bone. A fossil is a bone or a piece of once living organic material that's undergone a transition from an organic state to an inorganic state. That's what a fossil is.

It's gone through the process of fossilization. And most of these fossils, the vast majority of fossils are found in sedimentary rock. Before we go any further, we should probably do a little brief primer on sedimentary rock, right? Which is awesome. Yeah, it's pretty easy, too. We've talked about the earth's core and layers when I think we talked about earthquakes and maybe some other stuff. We all know that there's the inner core, outer core. We got the crust. Crust is the thinnest layer, and that's where the fossils are. That's where the goods are. Yes. And most of the rocks in the crust are sedimentary rocks that you've been talking about often on for the past eight minutes. Right. And that's like silty, sandy stuff that hardened over the years.

Right. I mean, the earth, remember we talked about, oh, what was it, clouds? Sure. I can't remember what podcast it was, but we talked about how much sand is transferred from Africa to South America annually. Yeah, when clouds, but yeah. You remember the one I'm talking about? Okay. So the earth's biogeochemical process is equal a lot of movement of particulate matter, right? The earth is dynamic, baby. It is. It's also very fluid, too, right? A lot of that matter is at one point as suspended particles in water that's moving around, right? Yeah. So as this, as the water leaves and the sediment is deposited, it builds up and up and up over time, it hardens into rock, and eventually we have sedimentary rock, which is below our feet. We don't normally see it unless

say the Colorado River winds over it for, you know, millions and millions and millions of years, revealing the sedimentary rock that's in the earth's crust. Alla Grand Canyon. Exactly. So you're talking about? Yeah, I forgot the Grand Canyon part. So you know how I said the earth was dynamic, baby? Yeah. That's important. I didn't just throw that in there as a factoid. It's important because when these plates shift around, that's how fossils are on earth. Things can be moved great distances and pushed to the surface eventually or close enough to where a dig can unearth it. And it's like just because it's fossilized doesn't mean it's stuck in that one spot forever because earth is always moving. So the point of all this is sedimentary rock

is like you said dynamic. It moves around, sometimes fossils pop up or it becomes exposed all of the Colorado River. Yeah. And that is where fossils are, right Chuck? Yes. So let's say that at some point in time there was a dinosaur or a saber-toothed tiger or a cyanobacteria. Woolly mammoth? Woolly mammoth, sure. And it's hanging out around a riverbed and it has a massive heart attack and falls over in the riverbed. And very quickly it becomes covered with sediment and silt, right? Yeah. And that's important because once it starts getting covered up with stuff, it's sort of being protected from like all of us. Let's just break the news. Alla fossil means is that something has been protected from the natural decomposition process. Otherwise

it would just decompose like everything else and you wouldn't see it anymore. You've just totally betrayed Tracy in the tone she went to this, the whole drama, drawing out suspense. But that's true. So what you said was right. So you'd fall over in a riverbed, you start getting covered up with the sediment and silt and it's immediately starting to protect you in a way. Right. Not you, but whatever. The woolly mammoth. The woolly mammoth. The thing is that in this sediment, in this silt, you can't really hide from macro bacteria and other forms of life that are basically dedicated to breaking down organic matter, soft tissue, hair, eyeballs, genitalia, all that kind of stuff. It eventually becomes broken down. And what's left is the hard stuff, the bone, right?

But the bone also has organic material within it as well. Yeah. And that'll break down. We're talking blood cells, collagen, fat. That's going to break down too. The key here is the inorganic parts of the bone remain intact. Right. And it's the other keyword here is porous. Yes. Well, you take calcium, I imagine for your hips. Me? Yeah. Sure. Glucosamine calcium. Sure. And so what you're doing is you're fortifying the calcium that's already in your hips supposedly. Right. Because the bone is made in large part of calcium, which is a mineral, which is inorganic. So as all the organic stuff dies out, what's left is, like you said, the inorganic, calcium, whatever minerals, and that holds the shape, right? Yeah. The initial structure is kept intact. Right. But like you said,

this bone is also porous. Yeah, that's the key. And over time, other mineral sediment kind of enters into these microscopic pores. Iron. Right. Carbonate. Yeah. And fortifies this, ultimately turning what was once an organic bone into an inorganic rock in the shape of the bone. Yeah. But for all intents and purposes, it's still the bone. It still has that original calcium. Yeah. It's still the same thing. It's not like a replica of it. It's just become fossilized. Yeah. And Tracy, in the article, uses a pretty good example. I thought it's like filling a sponge with glue. The sponge is going to keep the shape, but the glue is going to ooze through all the spots that it can ooze, harden. Right. And there you go. You've got a hard sponge. A hard sponge.

Which is basically what a fossil is. And this takes place, Josh, over the course of millions of years. The sediment reinforcing the bones eventually becoming rock. It's not the kind of thing that happens willy-nilly over thousands of years. It takes a long time. And this isn't just happening by itself. All the surrounding area is being deposited with sediment as well. It's also turning into rock. And then the ultimate test of time for a fossil is that it can withstand the pressure of the that's mounted by the hardening rock, sedimentary rock, that's growing around it. So it can be crushed. Is that how? Sure. I imagine a lot of fossils are definitely crushed. Crushed to death.

Poor guys. But if it survives and you can find this, you will eventually be able to get to it. And then you remove the rock from around the fossil and there's your bone, that you can take to the Natural History Museum and get at least $500 for. When you were a kid, Josh, let me ask you this. Did you ever go into the woods on a little nature course from like a science center, let's say, and do a cast, plaster cast of an animal footprint? Did you ever do that? No. Really? Really? I did that. We went and found like deer hoof prints. You fill it with plaster and there was some way of doing it where you got an inverse plaster cast of a deer hoof print. That can happen actually in a way with trace fossils.

So you can, you know, sediment can act the same way in one of these, let's say, the woolly mammoth makes a footprint in some loose but sturdy soil. That fills up with sediment and creates basically a mold just like I did as a kid with the plaster cast. Yeah, as long as the sediment that fills it in is lighter or thinner than the soil that the impressions made in, then yeah, it would preserve that track. Yeah, and plants can do the same thing. It's not just bones we're talking about. Right. It can also fill in in a different way, I guess, the opposite way to where it makes basically a cast of the foot that made the track. Oh yeah. And then so it's like a kind of like a fossil of a ghost foot that's not really there, but it makes the foot,

it's like an inverse cast of not the track but the foot that made the track. Yeah, yeah, gotcha. Pretty cool. You know what other, another, my favorite trace fossil is? It's not a trackway. It's copper light. I changed my mind. That is a good one. That's done. It's poop. Fossilized poop. That's right. It can tell you a lot about an animal. It can tell you about its fiber intake. Yeah. It can tell you about what size its poop was. Yeah. Chuck, you know in the 80s, the CIA found out much about Gorbachev and his health. They found out he had like cancer or some sort of chronic illness by stealing his poop. Really? When he was, when he came on a state visit to the US, they took his poop and analyzed it and when Reagan, he was in the US, they just grabbed

it from the toilet. Did he not flush? I just want more specifics that you probably don't have. As far as I understand. Okay. They probably, his hotel room or wherever he was staying, they were prepared to do this. This wasn't like... Toilet rigged probably. Yes. Okay. But wherever Reagan went, they had a portable toilet that he used. It was the only one he was allowed to use. I'm not kidding. So no one could steal his poop? Yep. Wow. Talk about paranoid. Yeah, seriously. When you point one finger, there's three pointing back at you. You know what I mean? Yeah, yeah. So Josh, that is sedimentary rock and that's to me one of the cooler ways you can get a fossil. Petrified wood too. Don't leave that one out. Oh yeah, sure. It's basically the same thing that we just described

for bone, but for wood. Yeah. Hard as a rock because it is a rock. Here you go. All right. So like I just said, that was sedimentary rock and that's kind of fun, but you can also get a fossil. Why is that funny? Because one dies in a cave that's really dry. Yeah, desiccation. Yeah, desiccation is basically sort of a mummification, but it's not like we think of with mummification with the Egyptian tombs or anything like that. Well, that's because there's no preservation techniques that have been undertaken. It's just natural. Basically, it dries out. It's like throwing an orange in a dehydrator. So when it's really dry, there's not going to be any place for bacteria to thrive. It's the reason beef jerky is not refrigerated. If you refrigerate your beef jerky,

you're you're doing something wrong. Yeah, that's true. Well, if you have beef jerky long enough to need refrigeration, then you're doing something wrong or something really, really right. The war on drugs impacts everyone. Whether or not you take America's public enemy. Number one, this drug abuse. This podcast is going to show you the truth behind the war on drugs. They told me that I would be charged for conspiracy to distribute 2200 pounds of marijuana. Yeah, and they can do that without any drugs on the table. Without any drugs, of course, yes, they can do that. And on the prime example, the war on drugs is the excuse our government uses to get away with absolutely insane stuff. Stuff that'll piss you off. The property is guilty. Exactly. And it starts as

guilty. It starts as guilty. The cops. Are they just like looting? Are they just like pillaging? They just have way better names for what they call like what we would call a jack move or being robbed. They call civil asset for it. Be sure to listen to the war on drugs on the iHeart Radio app, Apple Podcasts or wherever you get your podcasts. I'm Jordan Klepper, Daily Show contributor, Trump rally pass holder, and as of today, my most daring title yet, podcast host. This is Jordan Klepper Fingers the Conspiracy, an all new limited series podcast from the Daily Show. Now, normally when I hear Trump's supporters bring up these, let's just call them what they are 100% unverified banana gram conspiracy theories.

We grab the sound bites, pack them in the segment for the Daily Show and move on to the next person. I feel like cult is such a native word. We are not a cult. If you go online, there's a whole list of pedophile symbols. Really? Yes. What's on your back? Q flag. Q and non. One of those crazy people. Now, we're doing it differently. I'm finally diving into some of the most incredible conspiracy theories that have been pitched to me at Trump rallies. Like, did you know that Osama bin Laden is a guy named Tim? Yeah, we're doing a whole episode on that one. JFK Jr., coming back from the dead, that's an episode. The deep state, that too. We're going way down the rabbit hole. Listen to Jordan Klepper Fingers the Conspiracy on the iHeart Radio app, Apple Podcasts or wherever

you get your podcasts. So, desiccation actually works so well sometimes that it can preserve the skin and soft tissues as well, which is something that sedimentary rot cannot do. Have you been to the Smithsonian? I have. They have a very cool, I guess, a prehistoric cow or a musk ox. I can't remember, but it's a thing's head. Much of its back, I guess, the cape. Wow. Two of its legs. And the skin's still there. It's just right there. It's probably, it's tens of thousands of years old and it's just sitting right there. Did they rebuild it or just put the parts up? It's just the parts, but it's laid out so that it gives you the impression of what you're looking at. But its face is still there. It's very cool. Wow. My favorite kind of fossil though, Josh,

is, I'm going to say that every five minutes, is a frozen fossil because if you get trapped, let's say you're a woolly mammoth trapped in ice, not only is that going to keep other like vultures and things from picking at your bones and skin, but it's also going to keep it from breaking down and you can get hair fully preserved sometimes, hair and skin and like a big mammoth. Have you seen pictures of Leuba? No. Leuba is a baby woolly mammoth that was found by a reindeer herder in Siberia and it weighs 92 pounds or something like that, but it would have gotten up to several tons. It is adorable because it is a fully preserved woolly mammoth baby with the wrinkles in the skin and everything yet. It spent 45,000 years in the permafrost,

but it's like completely intact. It's very cute. That's why it's my favorite. It's one of the cutest dead things you'll ever see. Another couple of ways you can get a fossil, Josh, which are not my favorite, are tar. Lebrea tar pits. Although that is one of my favorites. Which Lebrea tar pit is actually redundant because Lebrea means the tar, so it's calling it the tar tar pit and not the tarter. Did they ever tell you about when I shot a commercial there? Did you go by there in LA? No, I went to. I forgot about it when we were there last. Well, for those of you who haven't been, it's right in the middle of Los Angeles, like south of Hollywood on Wilshire Boulevard. The main tar pit is tar pits are fenced off, obviously, and they have

little recreations. It's actually the saddest thing you'll ever see. The recreation they have in there is of a, I guess it's a mother woolly mammoth trapped in the tar, trying to get out, and the father and the baby on shore howling. It's awful, but it's still active. All this tar is bubbling up and everything. I shot a commercial there once, and I was on the other side of the property far away from the main pit, and I looked down and there was a little mini tar pit, a little tar puddle about a foot wide bubbling right beneath my feet. I could have scooped it up with my finger if I'd been so inclined. Yeah. Instead, you're like, that stinks. Well, it's just crazy to think that that's still like it's happening. Apparently, I looked it up.

There's like you said, main pits that are chained off and that are still being excavated, but they have them like in neighborhoods all around the area and parks. They're just kind of all over the place around there. That's like parts of Stone Mountain popping up all over the place. Yeah. We had a big chunk of Stone Mountain in our backyard growing up. Yeah. All right. For those of you who don't know, Stone Mountain is the world's largest exposed piece of granite, and it is right here in our home state. And it takes like 30 minutes to hike, but you still get to get to the top and be like, I just hiked a mountain. Yeah. Which I have. Josh, you can also get Pete. Mossy Pete can preserve life forms, including human beings. Like tolin man. Who was

that? Tolin man. I don't know about him. How do you know all these people? Two people. The first multi-syllable word I could spell was archaeology. Really? I've always been interested in that. I could see that. Yeah. Tolin man also, you can hate archaeology like some people hate art, and you'll still be interested in tolin man. Yeah. He was found in Denmark. He lived 2400 years ago, and he was murdered sacrificially, they think, and cast into the peat bog, which Pete is just decomposing moss and lots of it. But it has a tendency, I think it's anaerobic. So tissues preserve really well. But it's this guy that they dug up, and he's so well preserved that when they found him in the 1950s, they called the cops because they thought they'd found a murder

victim. Really? Like a recent one. He looks kind of funny, but he's got his whiskers are preserved. Wow. He's wearing a cap. He still has the garret around his neck. It's really awesome. So what is he dated at? Like 300 to 400 BC. That's when he was killed. And he's wearing a hat? Yeah, a sheepskin leather cap. Really? Yeah. No last chance garage for him? No. Well, and then my favorite way, Josh, that you can get a fossil is you're joking. Did you say it again? I did. It's amber. They just keep getting better and better, like the movie Jurassic Park. Yeah, that's how we get dinosaurs again. Yeah, dino DNA. So you found something on whether or not that's feasible, right? Yeah, because I always wondered, you know, when you see Jurassic Park, you see the

little video they made clearly to explain to the movie going on. It's how this is done. Right. It's better than Ellen Page running around. What was that movie? Inception. Inception. So the mosquito flies in tree resin, tree resin eventually becomes hard as copal, then it eventually becomes inert as amber. You get the little mosquito in there. They extracted the dino DNA from the blood of the mosquito filled in the gaps with, I think, frog DNA. Yeah. And that was all there was to it. And at the time, I thought boom, bada bing, banjiovi. Yeah. At the time, I thought that seems plausible and it sort of is, but I did look up today and there was a researcher that was interviewed at the, or closer to that time, I think, that basically debunked it and said, we could potentially

maybe get some DNA, even though it's really fragile and loses its signature really quickly. Even if you could get the DNA, he said that you couldn't construct a dinosaur. It's just you can't fill in the blanks like that. There's way too many blanks. You'd have a giant frog with little tiny arms, forearms. But Steven Spielberg made us believe when you saw those dinosaurs walk across that field. That guy can make me believe in anything, that aliens came to the American Southwest, that there was a World War II that- Yeah, sure. E.T. phone home. Yeah. Good stuff, though. Where are we here? Chuck, we're kind of painting this picture where, if you just stick a shovel anywhere on the earth, you're going to yield all sorts of bones and

fossils. Not true. No, it's not. First of all, a mere fraction that I don't think could possibly be calculated because we rely on the fossil record to show us what existed back when, and it's incomplete. Therefore, we've entered a catch-22, but there's just a mere fraction of all of the species and organisms that's ever lived that become fossilized. Basically, a perfect storm of chance has to occur for a fossil to be created. As we've seen, even when it is created, it can still be crushed into oblivion. They're few and far between. Yeah, to begin with. We have to figure out where to find them. Then you've got to find it. That's the other problem. The way we find it is by identifying rock that will likely have the type of fossil that we're looking for.

Yeah, so you want something from that year. If you know that this animal lived 30 million years ago, you're going to go find rock that you know is 30 million years old and start poking around and looking. It's sort of a very chance thing. We know that a layer of rock or strata of rock is 30 million years old because of a technique we have called radiocarbon dating. You want to do this one? Well, sure. Carbon 14 dating is what a lot of people toss around because that's probably the most well-known, but that can only take you back 60,000 years. We're talking millions and billions of years, so they need to study isotopes like potassium 40 and uranium 238 because that goes back millions of years, evidently, to half-life. Yeah, and half-life is where an atom

loses half of its life isotopes to decay. Yeah. Okay, and this radioactive decay takes place at a predictable rate depending on the atom, the type of atom, right? Yeah, that's how I understand it. So if we find a type of atom missing x number of isotopes, we can say, well, this is roughly 30 million to 31 million years old or 30 million to 30 million and 300 years old. I'm not sure what window we can date it to radiocarbon dating, but I think it's enough so that we have a rough estimate of when this fossil lived and the sediment was buried around it. So Josh, let's say that you're lucky enough and skilled enough as an intrepid paleontologist to come across your fossil. What do you do? Well, as I said, you dig it up and take it to the museum and sell it for 500

simoleons. Well, I don't know about that, but you should call a museum. Even if you think you know what you're doing, you're probably going to need some help if it's something major. I think you should probably go on the assumption that you don't know what you're doing. Okay. Unless you're a trained paleontologist, part of the problem is we assume that these fossils being rocks or sturdy, that's not always the case. So there's a lot of danger of damage in just an average Joe trying to excavate them. Also, if you just pull a bone up and walk away with it, it immediately loses context. Yeah, it's like removing a piece of evidence from a crime scene. Exactly. You can't do that. Well, you're not supposed to. So they have these huge cranes and digging tools where

they can remove huge slabs of earth, which is a really good way to do it. And sometimes if it's something that could be fragile, they'll remove the entire slab, cast it in plaster, and just go ahead and ship that thing off to a facility to handle it from there. Right. And the cool thing is, is even though rock has formed around this bone, yeah, that's key right up right all up on it, all up in it. If you flake it away properly, if you flake the surrounding sedimentary rock away, you're going to find that there's what's called a plane of weakness, which is where the bone and the rock are still on this very microscopic level. They're not fused together. You're going to hit that and the rock should chip right away. Right. And leave the bone. Yeah. And I think sometimes

they missed it with water, too, to soften it up and help the whole process. Yeah. Another thing, too, if they find that it's really brittle, they can actually reinforce the bone with resin and thin glue. The war on drugs impacts everyone, whether or not you take drugs. America's public enemy, number one is drug abuse. This podcast is going to show you the truth behind the war on drugs. They told me that I would be charged for conspiracy to distribute 2200 pounds of marijuana. Yeah, and they can do that without any drugs on the table. Without any drugs, of course, yes, they can do that. And I'm the prime example. The war on drugs is the excuse our government uses to get away with absolutely insane stuff. Stuff that'll piss you off. The property is guilty. Exactly. And

it starts as guilty. It starts as guilty. The cops, are they just like looting? Are they just like pillaging? They just have way better names for what they call like what we would call a jack move or being robbed. They call civil acid. Be sure to listen to the war on drugs on the iHeart radio app, Apple podcast, or wherever you get your podcasts. I'm Jordan Klepper, Daily Show contributor, Trump rally pass holder. And as of today, my most daring title yet, podcast host. This is Jordan Klepper fingers the conspiracy and all new limited series podcast from the Daily Show. Now normally when I hear Trump supporters bring up these, let's just call them what they are 100% unverified banana gram conspiracy theories.

We grab the sound bites, pack them in the segment for the Daily Show and move on to the next person. I feel like cult is such a native word. We are not a cult. If you go online, there's a whole list of pedophile symbols. Now we're doing it differently. I'm finally diving into some of the most incredible conspiracy theories that have been pitched to me at Trump rallies. Like, did you know that Osama bin Laden is a guy named Tim? Yeah, we're doing a whole episode on that one. JFK Jr., coming back from the dead, that's an episode. The deep state, that too. We're going way down the rabbit hole. Listen to Jordan Klepper fingers the conspiracy on the iHeart radio app, Apple Podcasts or wherever you get your podcasts. But you need to be careful there too. Which is

pretty much helping along the fossilization process. Yeah, I think so. I mean, it's the same thing. It's like reinforcing it with something sturdy. Well, then you can date it using your little mass spectrometer that's in your pocket or a CAT scan sometimes. They use CAT scans, computer imaging, stuff like that. Yeah, I didn't get how they were dating it from CAT scans. I don't know if they're dating it with a CAT scan or just sussing the whole thing out. Gotcha. I don't think it's a dating situation. Tracy was just throwing out some extra tools of the trade, huh? Yeah, exactly. Gotcha. So, Chuck, what is all this worth? I mean, we have a thirst for knowledge, obviously. Sure. And people think bones are very cool. Yeah. But ultimately, what's the pursuit

of paleontology? To put together the piece of the puzzle of how we got here, right? I mean, that's what I think. Yeah, that's my understanding as well. Yeah, you can learn a lot by not only finding the fossil, but finding what was with the fossil in that same strata. It can tell you like, hey, this is a T-rex bone and there's also a bit of pine tree. So, we know pine trees were around and they may have eaten pine trees. Well, not T-rex because they were carnivores, right? Yeah, they were. Herbivore, let's say. You know what I mean. A brontosaurus? Sure. And ultimately, all of these fossils come together, plant and well, everything that we can get our hands on to form what is called the fossil record, right? Yeah. And this is basically the record of life on

Earth. It's also used to support evolution big time. And it's here that paleontology gets most contentious, right? Yeah, sure. Because there's the idea that beings evolve if you go far enough back from a single common ancestor, right? And so, if we can put together a complete fossil record, we would be able to see how everything alive today evolved from this common ancestor or common ancestors, right? Yeah. The problem is fossil records incomplete. And one of the really key parts that it's often missing are called transitional fossils, right? My favorite kind of fossil, Josh, is a transitional fossil. And one example Tracy used was the baleen whale. There's a picture of one actually in the article, 25 million year old fossil of a baleen whale with

sharp teeth. Today's baleen whales don't have sharp teeth, but we know that ones before this had sharp teeth and legs. Right. So this is a transitional fossil that shows, well, they used to have legs and sharp teeth, and they just had sharp teeth. And now they don't have legs or sharp teeth. They're defenseless. Which is why they're baleen whales. Right. And not sharks or megalodons. Right. And so a transitional fossil is one that pops up between old and new. And it makes sense. Our understanding of evolution is that it takes a little while and something like teeth aren't just going to go away in one generation. Right. It's going to take more and more and more. And then we should be able to find them along the way where maybe the teeth get smaller or there's

fewer and fewer baleen whale teeth in the average baleen whale mouth. Yeah. And you're putting together the puzzle. Exactly. Again, the fossil records are a little incomplete and there aren't as many transitional fossils as I think people would like to have. Yeah. Tied all together. Right. And then some of the explanations are probably the most famous explanation for this is that evolution isn't gradual. I think it's Stephen Jay Gould came up with the idea of punctuated equilibrium. And that is basically that evolution takes place suddenly in these huge quick bits and starts, which would explain why there's not teeth don't go away in a generation, but they go away a lot faster than we used to suspect. Gotcha. And that's why these fossils accompany

with the idea that not every animal that's ever died has become fossilized, explain why there's huge gaps in the fossil record, which will inevitably always be incomplete. Is that a hypothesis at this point? I guess it is. Not a theory yet. I don't think so. I think it is a hypothesis. I got one more thing. Okay. I'd like to finish with my favorite kind of fossil, and that is a living fossil. And that, Josh, is when you got a plant or animal that looks so much like ancient fossils that they consider a living fossil, a la the horseshoe crab. Right. Apparently the horseshoe crab has not changed. Didn't need to. It's perfect. Yeah, look at it. It's gorgeous. What else? Oh, ginkgo biloba plants. And then a word that I don't know.

Oh, the sealocanth. What is that? It's this horrid looking fish that they remember that VW commercial where he's like, it's like the sealocanth. And the guy's like, what? They're looking in the trunk and he's like a full-sized spare tire. It's like, it's like a sealocanth. They used to think it was extinct. There's a fish and then they found it like in the 1930s again. But it's this dinosaur looking fish that they thought was extinct for millions of years and they caught them, I think, in South America, off the coast of South America. And they're still around. And the horseshoe crab. And Steven J. Gould. And the ginkgo biloba. Well, that's it for fossils, right? That's all I have. I think we got the point across.

That's an overview. A fossil is a rock. Just remember that, okay? If you want to learn more about fossils, seriously, this is one of the better articles on the site. Tracy did a great job with it. Type fossils into the search bar, the handy search bar, and howstuffworks.com, which means it's time for listener mail. Josh, we made a young girl cry. That's what I'm going to call this one. Okay. It's probably happened more than once. Hi guys, and Jerry. My name is Allie. I'm from Indiana. I was in the ISSMA band contest playing a difficult marimba solo today. I was pretty nervous, but being first chair and the only female percussionist in my school really brought up my confidence. I went in, I choked,

and I stumbled through my piece. You get a gold silver bronze or a participation medal. I got the bronze, which is equivalent to a score of an F. 20%. I was really upset. Wait, what is participation then? That's sub F. I didn't even know they made medals. I thought it was just a ribbon. It's probably a ribbon. I was really upset. I got home. I was trying to cheer myself up by listening to your podcast on what's the deal with sinkholes. I really love the show and have listened almost everyone, but in the beginning you guys talked about how much the bronze medals suck. Remember that? Oh yeah. So we didn't lift our spears very much. Josh and Chuck, I just want to let you know that the two of you made me cry. That's from Allie, and I've since written Allie

back and apologized, and she said that she's feeling much better now, and it wasn't our fault, and I told her that I've choked under pressure many times in my life, and it happens, and it'll happen again, and it doesn't mean you don't have the goods with your marimbasola every single time. You pick yourself up. It sounds like you gave her some good advice, Chuck. I think so. She's been receptive to it. It sounds like a sweet girl. I think that's an excellent lead-in if you have a story about choking. Not physically choking, but there's something you're good at and you didn't do it well. Say you're a television reporter in Los Angeles and you're supposed to report on the Grammys. Something like that. Say you're a podcaster, and you have to do a show

about the sun. That's a good one too. We want to hear about it. You can send it to us via email. Just type in where it says to stuffpodcastathowstuffworks.com. 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 HowstuffWorks iPhone app has arrived. Download it today on iTunes. The War on Drugs is the excuse our government uses to get away with absolutely insane stuff. Be sure to listen to The War on Drugs on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts.

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