Selects: How Extinction Works

Scientists believe that 99% of the estimated 50 billion species that have ever lived on Earth have disappeared through extinction. This is a natural process typically, but it can also be cataclysmic and it's becoming clear we are amid a massive one. Find out more with Josh and Chuck in this classic episode. See omnystudio.com/listener https://omnystudio.com/listener for privacy information.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:04Josh Clark?

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• 1:05Josh Clark?

  Introducing Voices of Vivgard. Vivgard is also known as its generic name, F. Gart Tigamod Alpha F-Cab, and this new show features firsthand stories from people living with a rare disease. Hosted by Andrew Stratton, these perspectives highlight that life is more than a moment, a condition, or a tough day. Living with a rare disease can be challenging, but it does not define the Voices of Vivgard. In these episodes, they share their stories, from diagnosis to working with their care team on their treatment plan. Listen to Voices of Vivgard on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hello, friends. It's Josh, and I'm back with the Select. And this week, I've selected

• 1:44Josh Clark?

  our 2014 episode on extinction. In this episode, we go over all the big extinctions and what probably caused them, including the one we're most likely in right now, which was probably caused by humans. And if you pay attention, you can start to notice the little glimmers, the little beginnings of what would become my side podcast, The End of the World with Josh Clark. And although we don't talk about any movies, I'm betting there's some glimmers of Chuck's long-running side podcast, Movie Crush, in here, too. Hope you enjoy this episode. It's a good one.

• 2:23Speaker 00

  Welcome to Stuff You Should Know, a production of iHeartRadio.

• 2:33Josh Clark?

  Hey and welcome to the podcast. I'm Josh Clark. There's Charles W. Chuckers Bryant. Jerry is over there. I almost said your last name, Jerry. How weird. And then today, we have a fourth character in the, um, in the studio with us. Chuck. This ascent.

• 2:48Speaker 03

  Yeah.

• 2:49Josh Clark?

  Scent.

• 2:51Josh Clark?

  Coming together to make like a tangible human being. So you are wearing patchouli.

• 2:57Speaker 03

  Uh, not wearing.

• 2:58Josh Clark?

  Well, you have patchouli on you as a result of one of Emily's sugar scrubs, right?

• 3:02Speaker 03

  Yeah.

• 3:03Josh Clark?

  Mama?

• 3:04Speaker 03

  Yeah.

• 3:04Josh Clark?

  And it's loveyourmama.com?

• 3:06Speaker 03

  Yeah.

• 3:06Josh Clark?

  Okay. And then Jerry is contributing to that with an enchilada. So the, all of them combined, I would say there's like, there's an extra person in this seat right here.

• 3:19Speaker 03

  Uh, what kind of person is that?

• 3:21Josh Clark?

  Just another person.

• 3:22Speaker 03

  Okay.

• 3:23Josh Clark?

  A viable, living organism. One that when we leave the studio will probably become extinct.

• 3:33Speaker 03

  That's a good one. Did you like that?

• 3:35Josh Clark?

  Yeah. I've had that plan since probably two weeks ago.

• 3:39Speaker 03

  Nice.

• 3:40Josh Clark?

  Uh, how are you doing, man?

• 3:42Speaker 03

  I'm good. I've been thinking of Busta Rhymes all day.

• 3:45Josh Clark?

  Why? Did he have a song about extinction?

• 3:47Speaker 03

  He had an album called Extinction Level Event.

• 3:50Josh Clark?

  Oh, yeah?

• 3:51Speaker 03

  Yeah. And that was in one of the songs.

• 3:52Josh Clark?

  That sounds super 90s.

• 3:55Speaker 03

  Well, it's Busta Rhymes. It has to be 90s.

• 3:57Josh Clark?

  But I mean, even those words, extinction level event. People were worried about stuff because of like the turn of the millennium. You remember? X-Files is a huge hit.

• 4:06Speaker 03

  Sure.

• 4:07Josh Clark?

  Deep Impact and Armageddon.

• 4:10Speaker 03

  Oh, yeah.

• 4:10Josh Clark?

  Came out at like, on the same day, basically. And both were hits. Like, people were just nervous.

• 4:16Speaker 03

  Yeah.

• 4:17Josh Clark?

  And, um, as a result... Buster Rhymes was very popular.

• 4:21Speaker 03

  That's right, although he's not anymore.

• 4:24Josh Clark?

  Uh, he's still good, though.

• 4:26Speaker 03

  He hadn't been doing much.

• 4:27Josh Clark?

  No, but his body of work is still good.

• 4:30Speaker 03

  Oh, sure, yeah, leaders in the new school.

• 4:32Josh Clark?

  And his early work with Tribe Called Quest?

• 4:36Speaker 03

  Oh, yeah, he guested on one of my favorite songs.

• 4:38Josh Clark?

  Yeah, what's the scenario?

• 4:41Speaker 03

  Was that the one?

• 4:42Josh Clark?

  I think so, I mean, he was definitely on that one.

• 4:44Speaker 03

  Yeah.

• 4:44Josh Clark?

  But that was the one also where I think, um, yeah, he makes fun of people with saggy pants. Cause it was so new.

• 4:52Speaker 03

  Right.

• 4:53Josh Clark?

  Apparently Buster Rhymes wasn't down with it yet.

• 4:55Speaker 03

  Yeah.

• 4:56Josh Clark?

  Which is pretty ironic because he got hardcore into that.

• 4:58Speaker 03

  That was raw, raw like a dungeon dragon, right?

• 5:01Josh Clark?

  Right, right.

• 5:02Speaker 03

  It was pretty awesome.

• 5:03Josh Clark?

  It's a good song.

• 5:04Speaker 03

  Yeah.

• 5:05Josh Clark?

  So extinction is clearly what we're talking about.

• 5:08Speaker 03

  Right.

• 5:09Josh Clark?

  Today, uh, and I guess we should probably give a shout out to some of the extra reading material.

• 5:15Speaker 03

  Yeah, man.

• 5:16Josh Clark?

  We picked up on, um, there's a woman named Elizabeth Colbert, or Colbert, depending on if you watch The Colbert Report.

• 5:25Speaker 03

  Yeah.

• 5:26Josh Clark?

  Um, she is basically a leading expert as far as journalists go on extinction. She wrote a book called The Sixth Extinction.

• 5:36Speaker 03

  That's a good, it's a good article.

• 5:37Josh Clark?

  Yeah, and like she wrote an article in The New Yorker, she's a New Yorker journalist. That was basically the predecessor to the book, you know how they do?

• 5:44Speaker 03

  Sure.

• 5:44Josh Clark?

  They're like, oh, I need an extra 20 grand, so I'll just write a synopsis of the book I'm writing.

• 5:49Speaker 03

  Yeah.

• 5:50Josh Clark?

  Um, and it's a good article, and we work from that. There's another one from the New Yorker Review of Books called They're Taking Over about the explosion of jellyfish.

• 5:58Speaker 03

  Yeah.

• 5:59Josh Clark?

  Um, on how stuff works, there's one that I wrote years back called Will We Soon Be Extinct?

• 6:04Speaker 03

  Yeah.

• 6:04Josh Clark?

  And there's another How Stuff Works one that we've done an episode on called Why Is Biodiversity Important?

• 6:10Speaker 03

  Yeah, and I found one in I O nine.

• 6:13Josh Clark?

  Uh huh.

• 6:14Speaker 03

  For animals that we thought were extinct, but miraculously popped back up.

• 6:20Josh Clark?

  Nice.

• 6:21Speaker 03

  Which is always a good story.

• 6:22Josh Clark?

  Oh, yeah, it's a, it's a heartwarming story of triumph over adversity and coming back when everybody thought you were down.

• 6:29Speaker 03

  Yeah, some of them like.

• 6:30Josh Clark?

  Basically rocky.

• 6:31Speaker 03

  Hundreds of millions of years later even.

• 6:33Josh Clark?

  Yeah.

• 6:34Speaker 03

  It's crazy.

• 6:34Josh Clark?

  Like the silicon?

• 6:36Speaker 03

  Uh, I think that's one, was that the big fish?

• 6:38Josh Clark?

  Mm-hmm.

• 6:38Speaker 03

  Yeah. They just caught that thing one day.

• 6:43Josh Clark?

  Yeah.

• 6:44Speaker 03

  And said, hey, wait a minute.

• 6:45Josh Clark?

  Yeah.

• 6:46Speaker 03

  This thing's extinct.

• 6:47Josh Clark?

  It's supposed to be.

• 6:49Speaker 03

  Exactly.

• 6:49Josh Clark?

  We'll talk about how and why things fall off. But things do fall off and it seems that there is a um that the whole thing is a very natural process, extinction is. But for a very long time, I guess scientists um believed that the God created all of the animals.

• 7:14Speaker 03

  Yeah.

• 7:14Josh Clark?

  On earth and that his will was too perfect, his creation was too divine to even allow for extinction. So because they were aware of the fossil record, they rationalized these huge bones of animals they didn't see anywhere as we just haven't found them yet.

• 7:31Speaker 03

  Well, yeah, and this was all the way up and you know, into the 19th century and some really smart people like Thomas Jefferson thought, for instance, when he sent Lewis and Clark out west, that they might come across the great mastodon.

• 7:43Josh Clark?

  Right.

• 7:43Speaker 03

  He's like, it's bound to be out there somewhere, guys. So be careful. Uh, but there were some other smarter people um like George Cuvier. In 1812, he was pretty ahead of his time. In fact, in 1812, he was way ahead of his time because he published an essay called Revolutions on the Surface of the Globe.

• 8:01Josh Clark?

  Yeah.

• 8:02Speaker 03

  And he kind of asserted that now things can go extinct. Uh, and he called them uh species perduce, lost species.

• 8:11Josh Clark?

  Right.

• 8:12Speaker 03

  And basically hypothesized that there have been cataclysmic events that have caused extinctions.

• 8:19Josh Clark?

  Right.

• 8:19Speaker 03

  In so many words.

• 8:20Josh Clark?

  This is basically flew in the face of this that like not only was there extinction, but there were, there were huge events that caused it. And so the, the religious thinkers of the day said, okay, wait, wait, wait. We can work with this because buddy, what you're talking about is like Noah's flood. So you, my friend, just proved the Bible correct using science.

• 8:41Speaker 03

  Yeah, Darwin wasn't on board, though, although he did believe in extinction. He thought it was the only way it could happen is the gradual extinction.

• 8:48Josh Clark?

  Right.

• 8:49Speaker 03

  That is also true and we'll talk about that as well.

• 8:51Josh Clark?

  And of course Darwin is this huge hero of biology.

• 8:54Speaker 03

  Yeah.

• 8:55Josh Clark?

  So everybody's like, well, Darwin's right about just about everything. So literally until the 1990s, Darwin's view that extinction happens extremely slowly.

• 9:06Speaker 03

  Yeah.

• 9:07Josh Clark?

  Slower than speciation events, so ultimately you should always have more species, new species coming up than you have going extinct.

• 9:16Speaker 03

  Yeah.

• 9:17Josh Clark?

  Until the 1990s, that's the way that it was, that's the way it seemed.

• 9:20Speaker 03

  Yeah.

• 9:21Josh Clark?

  So Chuck, like I said, all of this stayed around until 1991.

• 9:26Speaker 03

  Yeah.

• 9:27Josh Clark?

  And it was a result of, like, think about it, think about how you think of mass extinctions now. You think of an asteroid hitting Earth, destroying everything. And it wasn't until 1991 that that view became widely accepted. And it was because of this dude named Alvarez. He was a geologist, I believe, Walter Alvarez. And in the 70s, he started studying this clay layer that was basically in the fossil record right at the time the dinosaurs suddenly died out.

• 9:59Speaker 03

  Right.

• 10:00Josh Clark?

  And no one could quite explain what was going on here. They just knew that this must have happened gradually, so it must be a problem with the actual fossil record, not our way of thinking.

• 10:10Speaker 03

  Yeah, and there are plenty of problems with the fossil record, which we'll get into as well.

• 10:13Josh Clark?

  Right. But Walter Alvarez said, "Let me, let me look at this in a little more detail." And he looked at the iridium and found that the iridium levels were off the charts, which shouldn't be, because it's very, very rare. And we associate iridium on Earth as being brought here by, say, like, an asteroid or whatever.

• 10:30Speaker 03

  Yeah, it's super abundant in asteroids.

• 10:31Josh Clark?

  So all of a sudden, this guy goes, "Oh, wait a minute. Maybe we can explain this dying out of dinosaurs, where the dinosaurs went 65 million years ago, by an asteroid." And that was in 1980 that they proposed this hypothesis, and they ran into a lot of resistance.

• 10:48Speaker 03

  Sure.

• 10:49Josh Clark?

  And then finally, in 1991, a year after, a crater was discovered under the Yucatan Peninsula in Mexico, they dated it and said, "Yeah, it just so happens that this crater was formed just at the moment the dinosaurs died out."

• 11:07Speaker 03

  Yeah.

• 11:08Josh Clark?

  So the Alvarez hypothesis is probably right, and extinction can happen on a mass, sudden scale, just as it can also happen on a very long-term scale, too.

• 11:18Speaker 03

  Yeah, that crater was 112 miles wide, so it fit the profile. And basically ended the Cretaceous period in the Mesozoic era. And for a while, they called it the Cretaceous-Tertiary event. But now they call it the Cretaceous Paleogene Event.

• 11:34Josh Clark?

  And did you notice that they-

• 11:35Speaker 03

  Or the KPG.

• 11:36Josh Clark?

  Right. They noticed the, that, or did you notice the Cretaceous, which is spelled with a C, is denoted with a K?

• 11:44Speaker 03

  Yeah, it did.

• 11:44Josh Clark?

  Did you see why? It's just German. It's just a German translation for it.

• 11:49Speaker 03

  I figured it was something like that.

• 11:50Josh Clark?

  Yeah. It was just bugging me.

• 11:52Speaker 03

  So now, we now believe an asteroid brought us into the Cenozoic Era that we, that we enjoy today.

• 11:59Josh Clark?

  Love the Cenozoic.

• 12:00Speaker 03

  It's pretty good. It's pretty awesome.

• 12:02Josh Clark?

  It's a good era.

• 12:02Speaker 03

  I mean, it's our era.

• 12:03Josh Clark?

  Yeah. So you gotta love it.

• 12:05Speaker 03

  You gotta love it.

• 12:07Josh Clark?

  So Chuck, like I said, the extinction, extinction can happen, and it does happen, and it's a natural process. If you talk to people about extinction today, though, they say, "Yeah, we're kind of in a huge extinction event."

• 12:25Speaker 03

  Yeah, and it makes sense. I mean, when you look at the, our past, they estimate maybe up to 5 billion species have lived on Earth, and more than 99% of those are gone. And I love how The New Yorker put it. I think that, there's an old joke that all of life on Earth today could be accounted for with a simple rounding error.

• 12:44Josh Clark?

  Yeah.

• 12:44Speaker 03

  Like, everything we know. So yeah, we've lost 99% of things that have ever lived on this planet due to extinction.

• 12:53Josh Clark?

  Right, which again, is, like, it has such a terrible connotation these days, extinction, extinction. But it happens naturally. Apparently, what they've found from looking at the fossil record and from studying life on Earth, is that a species tends to have about a 10 million year lifespan. And there, a speciation event occurs where it branches off from one species and produces an entirely new species, and that species, on average, will stick around for about 10 million years, and then something happens and it dies out, and other species take its place. This is the natural course of life, from what we can tell.

• 13:31Josh Clark?

  The thing is, it normally happens on a very slow time scale, like when it's what's called background extinction, right?

• 13:40Speaker 03

  Yeah, the background rate is supposed to be between 1 and 5 species per year, but they think that now it could be like 100 times that.

• 13:49Josh Clark?

  I've seen up to 1,000 times the normal rate, and I saw another study from 2014, so it's fresh.

• 13:57Josh Clark?

  And it said that they, these researchers calculated the normal rates and they found that there's between .023 and .135 extinct species per million species per year.

• 14:11Speaker 03

  That doesn't really mean much.

• 14:13Josh Clark?

  It means so much that it boggles the mind.

• 14:15Speaker 03

  Yeah.

• 14:16Josh Clark?

  You know, like, that's a really strange way of putting it, but basically, they're saying like, for every million species on earth, at any given point in time, during a year, as low as .023 species will die out.

• 14:30Speaker 03

  Yeah.

• 14:31Josh Clark?

  So in a year, you shouldn't necessarily have that many species. In, in current times, though, like you said, between 100 and 1,000 times that rate is what we're seeing right now, which is, you could say alarming.

• 14:44Speaker 03

  It is alarming. The reason they don't have hard numbers on this stuff is because, like we said, it's a tough thing to study because the fossil record is, well, there's a lot of problems. One is it's incomplete. We don't really know how many fossils, or species there have been on earth since the beginning of Earth. It's just impossible to tell. Fossils form under, you know, really specific conditions, so you may think something is gone because it has disappeared from the fossil record, but all that means is there wasn't a fossil. It doesn't necessarily mean it's gone.

• 15:18Josh Clark?

  Right.

• 15:18Speaker 03

  So that's why things will pop back up. They'll think, hey, we haven't seen a fossil of this guy in 2,000 years, but here it is all of a sudden.

• 15:26Josh Clark?

  And even if it has gone extinct, just where it stopped showing up in the fossil record doesn't mean, like you said, that's when it went extinct, right then. It could have been millions of years later.

• 15:37Speaker 03

  Well, because then you're supposing that the last thing of that species happened to make a fossil.

• 15:42Josh Clark?

  Yes.

• 15:43Speaker 03

  Which is just silly.

• 15:43Josh Clark?

  Yeah. And also, it makes you wonder how many species have lived and died on earth that just never showed up in the fossil record.

• 15:50Speaker 03

  Yeah, just weren't fossils at all.

• 15:51Josh Clark?

  Right.

• 15:52Speaker 03

  Yeah. Well, if it never crawled into amber, or, you know, was buried by ash or something. That's luck.

• 16:00Josh Clark?

  Or got trapped in brontosaurus poop.

• 16:03Speaker 03

  I don't know if that's good luck or bad luck.

• 16:05Josh Clark?

  It's just, it is what it is.

• 16:07Speaker 03

  It's nature. So because of all these gaps in the fossil record, these researchers that love this topic tend to do a lot of math.

• 16:16Josh Clark?

  Right.

• 16:16Speaker 03

  And a lot of speculating with algorithms and mathematical formulas.

• 16:21Josh Clark?

  They love those.

• 16:22Speaker 03

  Figure this stuff out.

• 16:22Josh Clark?

  Sure.

• 16:23Speaker 03

  And that's the only way to do it, really, is to speculate with numbers. It also helps them define things like the minimum viable population, which if you go below that, then it's bad news for the species. It's the minimum amount you can have to still be considered to have a bright future.

• 16:40Josh Clark?

  Right.

• 16:41Speaker 03

  As a thing.

• 16:42Josh Clark?

  Or to just survive as a species, right?

• 16:45Speaker 03

  Yeah, that's what I mean.

• 16:45Josh Clark?

  Yeah.

• 16:47Speaker 03

  Dim future if you're not surviving.

• 16:48Josh Clark?

  Yeah, math is pretty grim.

• 16:50Speaker 03

  It can be, in this case, for sure.

• 16:53Josh Clark?

  So we'll talk about exactly what makes an extinction and then what makes up mass extinctions. But first, let's do a little breakage, huh?

• 17:10Speaker 04

  Hello, hello. I'm Malcolm Gladwell, host of Smart Talks with IBM. I spoke with IBM's Ana Paula Assis about what digital sovereignty actually means in the age of AI.

• 17:21Speaker 05

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• 18:23Josh Clark?

  Okay, so Chuck, you've been talking about animals, animal species going extinct and then showing up again, like the coelacanth.

• 18:33Speaker 03

  Yeah, or at least disappearing.

• 18:34Josh Clark?

  Right.

• 18:35Speaker 03

  From the record.

• 18:35Josh Clark?

  But we as humans assume they were extinct, like, again, the coelacanth, there's this fish that they caught off the coast of South Africa. When did we talk about it? Was it in this day in history?

• 18:45Speaker 03

  I don't remember. We definitely have hit on that, though.

• 18:47Josh Clark?

  I think it was.

• 18:48Speaker 03

  Because it's huge, right?

• 18:49Josh Clark?

  Yeah, it's a big, ugly fish.

• 18:51Speaker 03

  Yeah.

• 18:52Josh Clark?

  And it looks like an old dinosaur, but they thought it had died out like 50, 60 million years ago.

• 18:59Speaker 03

  Actually, way longer. They thought it disappeared 400 million years ago.

• 19:02Josh Clark?

  Even more impressive.

• 19:03Speaker 03

  Yeah.

• 19:04Josh Clark?

  So then they caught one off the coast of South Africa in the 30s, then they caught another one a couple decades later in Madagascar, or Mauritius or something, and that made the coelacanth a Lazarus species.

• 19:18Speaker 03

  Yes.

• 19:19Josh Clark?

  Even though it hadn't really gone anywhere, we just thought it did. So, we humans, having the most important perspective on the entire planet, possibly in the entire universe.

• 19:27Speaker 03

  Yeah.

• 19:28Josh Clark?

  It was a Lazarus species to us.

• 19:30Speaker 03

  Yeah, Lazarus from the Bible.

• 19:31Josh Clark?

  Right.

• 19:32Speaker 03

  Raised from the dead.

• 19:33Josh Clark?

  Yeah.

• 19:33Speaker 03

  Like the coelacanth.

• 19:34Josh Clark?

  Again, with the biblical connotations with extinction.

• 19:38Speaker 03

  Yeah.

• 19:38Josh Clark?

  There's a lot at stake here.

• 19:39Speaker 03

  That's true. Another way something might disappear, and you might think it's gone, is if it actually evolves into a new species. That's called pseudo-extinction.

• 19:48Josh Clark?

  Mm-hmm.

• 19:49Speaker 03

  And that's a great success story as well.

• 19:51Josh Clark?

  It is, but it also, I don't understand why that's not just a speciation event. I mean, why is that pseudo-extinction? Why is that any different from regular extinction?

• 20:01Speaker 03

  Um, yeah, maybe just because it's, uh, it's, didn't die out.

• 20:07Josh Clark?

  Right.

• 20:07Speaker 03

  It actually just changed and evolved. Those are two different things.

• 20:11Josh Clark?

  Yeah, it seems like a gray area to me.

• 20:13Speaker 03

  Yeah.

• 20:14Josh Clark?

  But for the most part, when an animal just disappears, and we should say like even today, we're still finding things that we thought were extinct.

• 20:23Speaker 03

  Yeah, yeah.

• 20:24Josh Clark?

  So-called Lazarus species, which goes to make the point, we have no idea how many living species there are on the planet today.

• 20:33Speaker 03

  Yeah, or have been. It's all just a good guess.

• 20:37Josh Clark?

  It is, using math.

• 20:38Speaker 03

  Yeah.

• 20:39Josh Clark?

  Grim, grim math. But for the most part, we understand that when a species goes away suddenly, it went extinct. And as we've been saying again and again, extinction is kind of this natural process, or it is a very natural process. And it typically results from a change in the habitat.

• 21:00Speaker 03

  Yeah.

• 21:01Josh Clark?

  Of a species, and its inability to adapt. So it dies out.

• 21:06Speaker 03

  Yeah, competition with other species, hunting by humans, or perhaps the environment has been tainted by humans.

• 21:15Josh Clark?

  Humans, or a new bacteria, or a new virus. The thing is, though, is, so these big factors, habitat loss, competition with new species, hunting, and contaminants in the environment, those are the big four reasons that something goes extinct, right?

• 21:29Speaker 03

  Yeah.

• 21:30Josh Clark?

  Humans can and are responsible for all four of those.

• 21:34Speaker 03

  Yeah, and this is the extinction that happens over time, obviously. Not a big asteroid hitting the planet.

• 21:40Josh Clark?

  No, but it can happen pretty quickly. And this is a Tracy Wilson joint. And in the introduction, she mentions the stellar sea cow, which was an Arctic resident. It was a big old manatee, basically.

• 21:55Speaker 03

  Yeah.

• 21:56Josh Clark?

  And they were first described by Arctic explorers in 1741. By 1768, they were extinct. So it can happen on a pretty rapid. Um, scale.

• 22:09Speaker 03

  Yeah.

• 22:10Josh Clark?

  Especially when you introduce humans.

• 22:12Speaker 03

  Yeah, and it, you know, it has a domino effect too, because we talked about, and everyone knows about the dangers of losing bees. It's not just like, oh, well, there are no more bees.

• 22:20Josh Clark?

  Right.

• 22:21Speaker 03

  That's going to affect pollination and plants, and those plants are being fed on by other animals. And it tends to have a snowball effect.

• 22:30Speaker 03

  Like, for example, at the end of the last ice age, mammals, small mammals, started to go extinct. And because of that, large animals started to go extinct because they like to eat the small animals.

• 22:39Josh Clark?

  Exactly, which is the answer to the question, why is biodiversity important? Well, because ecosystems thrive and survive on a wide number of species that are, exist pretty much naturally in balance.

• 22:52Speaker 03

  Yeah.

• 22:53Josh Clark?

  You know, a pretty good example of that stuff falling out of balance is the passenger pigeon. You familiar?

• 23:02Speaker 03

  Yeah, they're trying to de-extinct that thing.

• 23:06Josh Clark?

  Yeah, you want to talk about de-extinction?

• 23:08Speaker 03

  Yeah, well, de-extinction is exactly what it sounds like. It is sort of Jurassic Park-y. It is, in 2003, some scientists revived the Burcado, Bukardo, and that's a Spanish mountain goat. And they did it just sort of like Jurassic Park, from DNA that was frozen in time. Unfortunately, although it did work initially, the DNA only survived a matter of minutes. But they did, it did count as a de-extinction.

• 23:38Josh Clark?

  I think it, there was a live birth that survived a few minutes, wasn't it?

• 23:42Speaker 03

  Yeah, the animal itself only survived a few minutes, though.

• 23:45Josh Clark?

  Right. It was like, I should not be.

• 23:50Speaker 03

  That's true. And, I mean, they basically said, it's happening now, and we have the capabilities, and we may not be able to bring the woolly mammoth back, but we might be able to bring back something kind of close.

• 24:03Josh Clark?

  Right, so, and that raises, in this article that you sent, this moral question, like, should we be doing this? Just because we can, does that mean we should? And so, like, if you bring back an animal that has been extinct for so long that its habitat is now gone.

• 24:19Speaker 03

  Yeah, where are they going to live?

• 24:20Josh Clark?

  Exactly, where are you going to put it? A zoo? That doesn't seem like a good reason to bring an animal back, so we could put it in a zoo.

• 24:26Speaker 03

  Yeah, and just, uh, Mike, maybe it, this is my opinion here, which we don't do a lot of, but it seems like concentrating on the problems we face now with the extinction rates is something that we should concentrate on, not bringing back the woolly mammoth.

• 24:40Josh Clark?

  Right, and that also kind of dovetails with the point that if we have this ability and routinely, um, exercise it, we may be less inclined to protect the stuff we have now for like, "Well, it's important enough, we'll just genetically re-engineer it and bring it back later."

• 24:57Speaker 03

  Yeah, I think they, in the CNN article, they liken it to just thinking we have an undo button.

• 25:01Josh Clark?

  Right.

• 25:02Speaker 03

  On the world.

• 25:03Josh Clark?

  Control Z.

• 25:04Speaker 03

  Yeah, no good.

• 25:05Josh Clark?

  No. And it's funny because the author doesn't realize that Control Z works outside of Microsoft Word, too.

• 25:11Speaker 03

  I don't, I'm not sure.

• 25:13Josh Clark?

  He specifically mentioned Control Z in Microsoft Word.

• 25:17Speaker 03

  Oh, Word specifically?

• 25:19Josh Clark?

  Microsoft Word, he said it.

• 25:21Speaker 03

  Yeah, that's a little weird.

• 25:22Josh Clark?

  He could be a shill, and he was just working it in.

• 25:24Speaker 03

  Maybe.

• 25:25Josh Clark?

  You know?

• 25:26Speaker 03

  Well, on Macs, though, it's not Control, um, maybe he just meant Microsoft and awkwardly put in Word.

• 25:32Josh Clark?

  Maybe.

• 25:33Speaker 03

  Or maybe that's the only program he knows.

• 25:35Josh Clark?

  Maybe.

• 25:36Speaker 03

  You know?

• 25:37Josh Clark?

  How do I work this? Um, so you were saying that they're trying to bring back the carrier, the passenger pigeon, right?

• 25:44Speaker 03

  Yeah.

• 25:45Josh Clark?

  So the passenger pigeon is this really neat example of what happens when, um, you have a lack of biodiversity.

• 25:52Speaker 03

  Yeah.

• 25:53Josh Clark?

  Um, there were, when, uh, European settlers came to the New World, apparently like one out of every four birds in North America was a passenger pigeon. A quarter of the entire bird population was passenger pigeons.

• 26:10Speaker 03

  That's a lot of pigeons.

• 26:11Josh Clark?

  There's a ton of pigeons. There are so many that you could just like shoot into like a flock and you would kill a couple hundred. Literally, it was, there were that many. The thing is, is, um, if you, if you read 1493 or 1491, I can't remember which one it is, but both are excellent books by Charles C. Mann. He talks about the passenger pigeon and how they've recently realized that there are so many passenger pigeons because a century before...

• 26:37Josh Clark?

  Their, one of their great predators, the Native American,

• 26:41Speaker 03

  Yeah.

• 26:41Josh Clark?

  had been wiped out by disease that had been introduced to the continent about a century before that. So by the time the Europeans got here and really started to settle and encounter the passenger pigeon, they're like, "God, look at all these pigeons," and didn't realize that the pigeon population had exploded because their natural predator had died off.

• 27:00Speaker 03

  Right.

• 27:01Josh Clark?

  And so, we in turn hunted them into extinction. So because of one near extinction, another species was allowed to thrive and explode. And then that, when they were faced with their predator again, humans, they were eventually wiped out and went extinct.

• 27:19Speaker 03

  Yeah, the American buffalo, we almost hunted them out of existence.

• 27:23Josh Clark?

  Yeah, were it not for Ted Turner.

• 27:24Speaker 03

  Yeah, we tried our best to. They were just shooting those things for fun.

• 27:27Josh Clark?

  Yeah.

• 27:28Speaker 03

  At one point.

• 27:28Josh Clark?

  Man, that's disgusting.

• 27:29Speaker 03

  It is disgusting. You hear about the, like, trains.

• 27:32Josh Clark?

  Yeah.

• 27:33Speaker 03

  Just going through the west and just shooting out the windows at the buffalo for no reason.

• 27:36Josh Clark?

  Yeah, and doing nothing, just leaving them there to rot.

• 27:38Speaker 03

  Unbelievable.

• 27:39Josh Clark?

  Remember, we did an episode on the buffalo. That was a good one.

• 27:42Speaker 03

  So sad.

• 27:43Josh Clark?

  No, it was good.

• 27:45Speaker 03

  Well, it was sad too, though.

• 27:47Josh Clark?

  Oh, gotcha.

• 27:47Speaker 03

  So, if you want to talk about extinction-level events, that's a whole different deal.

• 27:53Josh Clark?

  You want to talk Buster Rides.

• 27:55Speaker 03

  That's not a slow, gradual extinction. That is some big thing that happens that wipes out a lot of living things all at once. And they estimate there's been more than 20 of these in the history of the world. But five of them, they call them the big five.

• 28:13Josh Clark?

  Right.

• 28:14Speaker 03

  For a reason.

• 28:15Josh Clark?

  For good reason.

• 28:15Speaker 03

  And we'll just go through those kind of quickly now. The Ordovician extinction, it's about 490 million years ago. And that wiped out about half of all animal families.

• 28:28Josh Clark?

  And the reason it wiped out about half is because, at the time, most of the stuff on earth still lived in the sea. Glaciers formed at this time, lowering sea levels, which meant that animals that lived in a certain depth of the sea, usually toward the surface, Lost their habitat.

• 28:44Speaker 03

  Boiled.

• 28:45Josh Clark?

  Yeah.

• 28:46Speaker 03

  Maybe.

• 28:46Josh Clark?

  Yeah. Or were brought down to the level where their predators like to hang out and were eaten en masse. But that accounted for that extinction, which is kind of rare because as you'll see, when we're talking about the big five or mass extinctions in general, it's very difficult to pinpoint exactly what happened. So that's one of the rare ones that we're like, pretty sure this is why all of these, all this life went extinct all of a sudden.

• 29:09Speaker 03

  Yeah, and one reason it's difficult is because it was almost 500 million years ago.

• 29:12Josh Clark?

  That's another reason.

• 29:14Speaker 03

  It's kind of tough here in 2014. Uh, number two, I feel like Letterman. Number two on the top five extinction. Um, the late Devonian extinction, um, they're still debating about that. And about a quarter of the marine families. And by the way, we should mention when they research these things, they home in on family and genera in the big, um, uh, classification group.

• 29:38Josh Clark?

  Right.

• 29:39Speaker 03

  They don't say like, oh, look at these kingdoms that have disappeared or these phylum. They go down to the smaller levels.

• 29:45Josh Clark?

  Right, and family and genus are just above species as far as the taxonomy is concerned.

• 29:51Speaker 03

  Exactly. Um, so what I say about half of the marine genera, and that was 360 million years ago.

• 29:58Josh Clark?

  Right. No idea what caused that one.

• 30:01Speaker 03

  No idea.

• 30:01Josh Clark?

  At least you and I have no idea.

• 30:03Speaker 03

  Yeah, I don't think they care about that one too much.

• 30:05Josh Clark?

  Yeah. The Permian Triassic extinction, this is, um, this is a pretty big one.

• 30:11Speaker 03

  This is the biggest one ever.

• 30:12Josh Clark?

  This is the one they call the great dying, right?

• 30:14Speaker 03

  Uh, I think so.

• 30:16Josh Clark?

  I've seen estimates of as much as 95 to 96% of all life.

• 30:21Speaker 03

  That's crazy.

• 30:22Josh Clark?

  Died off during this, this extinction event.

• 30:25Speaker 03

  Yeah.

• 30:25Josh Clark?

  Um, in this article, it says 85% of marine genera and 70% of land species went extinct. And that was 250 million years ago. There's a lot of people who have different ideas about what did it, but they think it's possible as volcanic activity creating acid rain.

• 30:43Speaker 03

  Yeah.

• 30:44Josh Clark?

  Um, that's a big one. That possibly happened more than once.

• 30:47Speaker 03

  Was that the one where, I don't know, I think that was the... The KPG event was the one where they think, they're not exactly how it happened, but they may have been just broiled.

• 30:56Josh Clark?

  Isn't that awesome?

• 30:58Speaker 03

  Broiled on the face of the earth.

• 30:59Josh Clark?

  Yeah. Which would have happened pretty quickly, too, actually.

• 31:02Speaker 03

  And I think that one is if, because they think it may have burst through the atmosphere, right?

• 31:07Josh Clark?

  Yeah, so.

• 31:08Speaker 03

  And just rained hot debris everywhere.

• 31:09Josh Clark?

  That's the one that got rid of the dinosaurs.

• 31:11Speaker 03

  Yeah.

• 31:12Josh Clark?

  Sixty-five million years ago. What is it called? The K hyphen PG?

• 31:16Speaker 03

  Yeah, the Cretaceous Paleogene event now.

• 31:18Josh Clark?

  And that's the one where they, they are pretty sure that an asteroid hit Central America.

• 31:24Speaker 03

  Yeah.

• 31:25Josh Clark?

  And sent all of this rock.

• 31:28Speaker 03

  Yeah.

• 31:29Josh Clark?

  Like, basically vaporized rock, away from Earth with so much force that this stuff made it out of the atmosphere.

• 31:36Speaker 03

  Yeah.

• 31:37Josh Clark?

  And then started to come back down. And as it did, it generated thermal heat enough to bring the broil down on Earth.

• 31:45Speaker 03

  Yeah, and that's the, one of two sub-explanations. The other is that the old familiar ash, basically, kept photosynthesis from it, like it blacked out the sun.

• 31:56Josh Clark?

  Yeah, like in nuclear winter.

• 31:57Speaker 03

  Yeah.

• 31:58Josh Clark?

  Yeah. Pretty nuts, though.

• 32:00Speaker 03

  But we skipped number four.

• 32:01Josh Clark?

  Yeah.

• 32:02Speaker 03

  For no good reason. The end triassic extinction killed about twenty percent of marine families, about half of marine genera, and that was two hundred million years ago.

• 32:12Josh Clark?

  Yeah. And again, like, with a mass extinction, there's, there's no real definition for it, I found. I was looking to see, okay, who's, who's the body that says, like, okay, a mass extinction event took place? It's, again, the, the fossil record is incomplete enough, and we're making guesses, and mathematical guesses, but still guesses, to the extent that we don't have a real definition for what constitutes a mass extinction. But those five were so massive.

• 32:43Speaker 03

  Yeah.

• 32:44Josh Clark?

  That there's virtually no debate whatsoever that those account for mass extinction events.

• 32:49Speaker 03

  Yeah.

• 32:50Josh Clark?

  Um. It's kind of like a you know it when you see it kind of thing. But there's no agreement on how fast.

• 32:57Speaker 03

  Pornography?

• 32:57Josh Clark?

  Pretty much.

• 32:58Speaker 03

  Yeah.

• 32:58Josh Clark?

  Um, there, there's no agreement on how fast it hap- it has to happen. Or how widespread it has to happen. But typically, it's like a large percentage of all of the animals alive.

• 33:10Speaker 03

  Yeah.

• 33:10Josh Clark?

  Something like 20% say of all living animal species. Not just animals, animal species just die off.

• 33:17Speaker 03

  Yeah.

• 33:17Josh Clark?

  Um, and it's worldwide. That's another, that seems to be another, um, factor in defining a mass extinction.

• 33:24Speaker 03

  Yeah, like how widespread.

• 33:25Josh Clark?

  Yeah.

• 33:25Speaker 03

  Sure.

• 33:26Josh Clark?

  So, um, these events were pretty big.

• 33:28Speaker 03

  Yeah, and one of the, um, I think one of the researchers in the article you sent made a pretty good point that the current mass extinction, extinction that we're in now, which we're going to talk about in depth here in a minute. Uh, he said, these are way more dangerous because in the event of an asteroid, let's say, while it might really suck, it's one bad event. And right afterward, the world starts to try and recoup. It may take a million years, but it tries its best to start reforming life and get going again.

• 33:58Josh Clark?

  Right.

• 33:58Speaker 03

  Where in now, there's no stress relief. It's just a constant, there's no recuperation because it's not over.

• 34:05Josh Clark?

  Right, or the recuperation will come, but we won't be around to see it because it, the, the breaking point will be us wiping ourselves out by wiping out the biodiversity.

• 34:15Speaker 03

  Ooh.

• 34:16Josh Clark?

  And there is a kind of this whole moralistic thing to the, to the idea of extinction. This, there's this whole human guilt. But if you just kind of take a step back and look at mass extinction, um, intellectually, it doesn't wipe out life, it just changes.

• 34:33Speaker 03

  Everything.

• 34:34Josh Clark?

  Uh, right, so for, for one species, it might be a boom time. For everybody else, it's a dying off time, but it's all in your perspective.

• 34:45Speaker 03

  Well, yeah, this, this beautiful earth that we know and love now isn't anything like it was 100 million years ago.

• 34:51Josh Clark?

  Exactly, and there's not necessarily a set level that, or a baseline that earth is supposed to be at.

• 34:58Speaker 03

  Right, because nature doesn't care.

• 35:01Josh Clark?

  Right.

• 35:01Speaker 03

  And nature's not like, oh, we got all these people here now and, uh, things seem pretty modern and they got smartphones. So maybe we should just protect this version.

• 35:10Josh Clark?

  Yeah.

• 35:10Speaker 03

  Uh, they're like, what, what's the cycle, every what, 10 million years?

• 35:13Josh Clark?

  For a species.

• 35:15Speaker 03

  For a species, okay.

• 35:15Josh Clark?

  That's a lifespan of a species on average.

• 35:18Speaker 03

  So basically, every- What, 10,000?

• 35:21Josh Clark?

  10 million.

• 35:22Speaker 03

  10 million years, the Earth, it just doesn't care.

• 35:25Josh Clark?

  No, the point is, is for a species, its lifespan is 10 million years and the Earth is not caring every day of that.

• 35:31Speaker 03

  Yeah.

• 35:32Josh Clark?

  It doesn't care.

• 35:33Speaker 03

  It's just stumbling toward the next event, basically.

• 35:36Josh Clark?

  Exactly.

• 35:37Speaker 03

  That will one day probably happen.

• 35:38Josh Clark?

  The thing is, is all of this is not to say that humans are off the hook. All evidence that's coming in now is showing that we are doing a lot to speed up extinction events and create a mass extinction, so much so that the big five is possibly the big six. And we may be in the very beginning stages of the sixth one, and we'll talk about that right after this.

• 36:10Speaker 04

  I'm Malcolm Gladwell, host of Smart Talks with IBM. I spoke with Dr. Laura Jayhai of Cleveland Clinic about how advanced computing is helping shorten the path from medical discovery to treatment.

• 36:23Speaker 07

  The moment that there is a compound that someone in a lab thinks it would be effective to treat a certain disease, it takes about 10 to 13 years from that moment to when that drug is on a shelf for a patient. A big part of that gap could be computationally solved. Better simulation of compounds, designing drug trials that are more efficient, that would finish faster. That was the motivation to bring computational tools and technology closer to biomedical researchers.

• 36:57Speaker 04

  Learn more about how Cleveland Clinic and IBM are using AI and quantum computing to revolutionize biomedical research at ibm.com/smarttalks.

• 37:09Speaker 08

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• 37:49Josh Clark?

  So Chuckers, we've been talking about mass extinction events.

• 37:52Speaker 03

  Yeah.

• 37:52Josh Clark?

  There's a big five, and a lot of people are saying, no, there's six. And the sixth one is human-caused. So much so that geologists are proposing that we call our current epoch the Anthropocene.

• 38:06Speaker 03

  Yeah.

• 38:06Josh Clark?

  Because humans are having such an impact on Earth that they imagine 10,000 years from now, geologists will be able to look and point to this layer and say, here's where humans started.

• 38:17Speaker 03

  Yeah, let's get in the wayback machine.

• 38:20Josh Clark?

  Oh, yeah.

• 38:20Speaker 03

  Let's crank this baby up.

• 38:21Josh Clark?

  Does it have enough kerosene?

• 38:23Speaker 03

  Oh, it's got enough kerosene, buddy, because we're going back about 50,000 years.

• 38:27Josh Clark?

  You got enough, okay. I'm gonna bring a spare key.

• 38:29Speaker 03

  And we're gonna go to Australia even, because it's just nice down there. And what I see around me are these huge wombat-like things that are as big as hippos.

• 38:39Josh Clark?

  Huge.

• 38:40Speaker 03

  And I see a tortoise over there that's the size of a VW Beetle.

• 38:44Josh Clark?

  Yeah.

• 38:45Speaker 03

  And this weird, short-faced kangaroo, and he's 10 feet tall.

• 38:49Josh Clark?

  10-foot-tall kangaroo, look at the size of that thing.

• 38:52Speaker 03

  And everything is crazy, but let's just unpack here and let's start propagating, you and me.

• 38:58Josh Clark?

  Okay, I'm gonna make a spear, just for safety.

• 39:01Speaker 03

  All right.

• 39:01Josh Clark?

  And it sounds like I need to defend you off, too.

• 39:03Speaker 03

  And you know what? It's weird. Things are starting to disappear around us as we grow and as we expand. And, uh, and scene.

• 39:14Josh Clark?

  That was nice. Can we get out of here, because that 10-foot-tall kangaroo's eyeing us?

• 39:25Speaker 03

  Well, not anymore, buddy, he's dead.

• 39:26Josh Clark?

  Oh, wow.

• 39:27Speaker 03

  Because they believe, a lot of people think that around 50,000 years ago, when humans started expanding their footprint, there was a very inconvenient...

• 39:38Speaker 03

  Uh, correlation with species dying out as we spread about the earth.

• 39:44Josh Clark?

  Yeah, the, the, this sixth mass extinction, I apologize for not being able to say sixth correctly.

• 39:51Speaker 03

  That's, that's right.

• 39:52Josh Clark?

  But, um, there, there's a huge debate and it's still, it's not settled. Both sides are like, ah, we're right.

• 39:59Speaker 03

  Right.

• 39:59Josh Clark?

  Another one is like, we're right. The thing is, both sides agree like, yeah, we're in the midst of a sixth mass extinction.

• 40:06Speaker 03

  And isn't that what matters?

• 40:07Josh Clark?

  But is it human cause or is the result of climate change? And just because it's the result of climate change doesn't mean that if you take the trail back far enough, it isn't necessarily human caused.

• 40:18Speaker 03

  Yeah.

• 40:19Josh Clark?

  But these are the two debates. So one is the theory of overkill, which is the one you were just describing.

• 40:24Speaker 03

  Yeah, and that was, uh, describing Australia 50,000 years ago. Um, if we wanna get back in the wayback machine and go to North America 11,000 years ago, uh, three quarters of our largest animals started to die out, like the mastodon and the woolly mammoth and the giant beaver, saber tooth tiger. And not coincidentally, probably that's right around the time where we first walked over the Bering Land Bridge and set up shop here in North America.

• 40:50Josh Clark?

  Yeah, the thing is, is you can also say, well, that kinda gives or takes a few thousand years. And yeah, you can, it's definitely stretchable, but it's just not been proven. So it, there is a huge correlation between the spread of humans and the death of what are called megafauna, huge land animals.

• 41:07Speaker 03

  Yeah.

• 41:08Josh Clark?

  And they say that, that theory of overkill says that we came along with our smart little toolkits, which included like spearheads and arrows and axes and clubs and domesticated dogs after a certain point in time.

• 41:21Speaker 03

  Sure.

• 41:21Josh Clark?

  And overhunted either these huge, uh, like hippo sized marsupials.

• 41:28Speaker 03

  Yeah.

• 41:29Josh Clark?

  Or we hunted things that were slightly smaller that the huge hippo sized marsupials ate. Either way, we contributed directly to their mass extinction.

• 41:40Speaker 03

  Yeah, and they think, um, generally that overhunting isn't, at the very least, it's not the sole cause because you probably just can't hunt enough, the amount of people that we had, especially in a place like Australia, which wasn't super heavily, uh, founded. You know, it wasn't like 10 million people moved to Australia overnight. You know.

• 41:59Josh Clark?

  Right.

• 42:00Speaker 03

  So they say overhunting is probably not the sole cause, but maybe a factor. But other things humans did, like maybe in Australia, they started burning shrubs to clear land and maybe those shrubs were eaten by a certain species.

• 42:14Josh Clark?

  Right.

• 42:14Speaker 03

  And then that caused that domino effect again.

• 42:16Josh Clark?

  Another, the other camp that basically says, no, it's climate change and it's fairly natural, other people might say it's human caused climate change, but for the most part, if you are a climate change extinction proponent, you're probably just believe that this is a natural process that the earth is undergoing and humans didn't have enough of an impact early on to account for the loss of a lot of these species.

• 42:42Speaker 03

  Yeah.

• 42:42Josh Clark?

  This one study pointed to a place called Sahel, which was Australia, New Guinea and Tasmania all joined together in this mega continent.

• 42:52Speaker 03

  That was a crazy place.

• 42:53Josh Clark?

  It was, several tens of thousands of years ago. And they were saying that by the time humans arrived in Sahel or Australia, most of the megafauna was already gone. It was gone as a result of climate change and there's no evidence that we had a toolkit capable of killing these animals, you know, at this time.

• 43:13Speaker 03

  Yeah, true.

• 43:14Josh Clark?

  So the debate still rages on.

• 43:15Speaker 03

  Yeah, and you know, there's been several ice ages that didn't make things go extinct.

• 43:20Josh Clark?

  Right.

• 43:21Speaker 03

  So people point to that as maybe another counter argument.

• 43:24Josh Clark?

  Yeah.

• 43:24Speaker 03

  But the researchers you sent along did this pretty cool thing. They did the first global analysis of mapping large animals during this period, 132,000 to 1,000 years ago.

• 43:38Josh Clark?

  Right.

• 43:38Speaker 03

  And it was the first time they were able to really get a fine point on this geographical variation and the, and species loss. And they did find that 177 species of large mammals disappeared during that period where we were starting to spread out as a species.

• 43:54Josh Clark?

  Right.

• 43:55Speaker 03

  And.

• 43:56Josh Clark?

  Which apparently is, as it's put in this article, a massive loss.

• 44:01Speaker 03

  Yeah, and they said, you know, they they expect these kind of things to happen on an island, like if you go to Hawaii or, you know, any island, they say that that survival is the exception when humans invade an island.

• 44:11Josh Clark?

  Exactly.

• 44:12Speaker 03

  But for to happen on like a continent, it's it's pretty uh it's pretty amazing to think about the human impact.

• 44:17Josh Clark?

  Still an island.

• 44:19Speaker 03

  Well, yeah, I guess that's a good point.

• 44:22Josh Clark?

  Um, the but the jury is still out, though, on exactly what's causing this. Most scientists agree that we are in in a mass extinction event, and it's happening pretty quickly.

• 44:36Josh Clark?

  Something like, I think, a third of all coral reefs are in danger of extinction, a third of amphibians, I believe.

• 44:45Speaker 03

  Yeah, and a quarter of all mammals and an eighth of all birds are all classified as threatened with extinction and um.

• 44:50Josh Clark?

  And this is happening around the world, so it's fitting the criteria for a mass extinction.

• 44:55Speaker 03

  Yeah, they're basically chalking up to the the pace of human expansion and, you know, if you consider that farming and logging and building roads and buildings and most of the world's waterways have been diverted or dammed at this point or manipulated somehow.

• 45:11Josh Clark?

  Right.

• 45:11Speaker 03

  Um, only 2% of rivers in the United States run unimpeded, 2%. Everything else has been altered in some way.

• 45:20Speaker 03

  Chemical plants affecting, you know, CO2 in the atmosphere, it's having an effect.

• 45:26Josh Clark?

  And the CO2, actually, in the atmosphere is having another effect called ocean acidification, which has been described as global warming's evil twin. As more and more CO2 gets released in the atmosphere, um, the oceans scramble to keep up by absorbing more and more.

• 45:44Speaker 03

  Yeah.

• 45:45Josh Clark?

  And it stores some of that by turning some of it into acid, which lowers the pH of the ocean, which is making the ocean unfit for a lot of life. But as to kind of demonstrate how. Mass extinction is bad for one species, but great for another. Jellyfish populations are booming.

• 46:05Speaker 03

  Oh, really?

• 46:06Josh Clark?

  So probably-

• 46:06Speaker 03

  Because they like the lower pH?

• 46:08Josh Clark?

  Yeah.

• 46:08Speaker 03

  Yeah.

• 46:08Josh Clark?

  They like it more acidic and they're like seriously starting to cause some real problems and we're just seeing the beginning of this. So it's entirely possible that the next thousand years we'll see the rise of the jellyfish as the rest of the life on Earth starts to die off.

• 46:22Speaker 03

  Well, here's a staggering stat. The drop in ocean pH levels that have occurred in the past fifty years, they think might exceed what has happened in the past previous fifty million years.

• 46:33Josh Clark?

  Wow.

• 46:34Speaker 03

  So in the past fifty years, they've changed the, basically changed the chemical makeup of the ocean more than the past fifty million.

• 46:40Josh Clark?

  And speaking of fifty years, apparently in the next fifty years, an estimated half, half of all species on Earth could be extinct.

• 46:54Speaker 03

  Sucks, man. I want to see a sloth as big as an elephant.

• 46:57Josh Clark?

  Hey, get into de-extinction.

• 46:59Speaker 03

  Well, here, um-

• 47:00Josh Clark?

  You just saw one. We were in, we were in Suhul.

• 47:04Speaker 03

  Well, yeah, it was nice. But I wanted like, I wanted to come in the Wayback Machine and bring it to Atlanta.

• 47:10Josh Clark?

  No, I don't think that's a good idea, man. That thing looked like it would go berserk.

• 47:15Speaker 03

  Uh, and finally, unless you have anything else.

• 47:18Josh Clark?

  I don't think so. I'm looking at everything.

• 47:20Speaker 03

  Um, we have a few highlights of extinct animals that have been rediscovered, which is not the same thing as being re-engineered.

• 47:28Josh Clark?

  What was this, an I O nine article?

• 47:29Speaker 03

  Yeah, this is I O nine, and some of those are pretty good.

• 47:31Josh Clark?

  Sure.

• 47:32Speaker 03

  Uh, the Bermuda Petrel and disappeared, they fought in the sixteen hundreds, but rediscovered in nineteen fifty-one. There's about a hundred and eighty of those alive today. Uh, let me see here, what else is good? Well, we also, we already talked about the coelacanth. The Cuban Solendon, Solenodon, excuse me, discovered in eighteen sixty-one, um, has only been- Caught 37 times in the history of the world. In 1970, they thought it was extinct. It's like a weird rat-like species. But then they found one in the 70s and then another one in 2003.

• 48:07Josh Clark?

  Huh.

• 48:08Speaker 03

  So like, welcome back, Cuban salinodon.

• 48:11Josh Clark?

  So it was like caught during the 70s and then during the period of the 70s revival in the early 2000s.

• 48:17Speaker 03

  That's right.

• 48:18Josh Clark?

  Nice.

• 48:18Speaker 03

  Gilbert's poturu. Man, these have weird names.

• 48:23Josh Clark?

  That's why they went extinct.

• 48:24Speaker 03

  Because you couldn't say sloth.

• 48:26Josh Clark?

  You know, we should save the, uh, the what?

• 48:30Speaker 03

  The Gilbert poturu.

• 48:31Josh Clark?

  Yeah.

• 48:32Speaker 03

  In 1841, this is a rabbit-sized marsupial in Australia. And it last appeared in 1879, and they thought, well, this thing's gone. Up until 1994, came back out and poked his head around and got caught in a few traps. But currently, less than 100 of those in the world.

• 48:49Josh Clark?

  Yeah.

• 48:50Speaker 03

  So those are just a few of the 10, and there's more than 10, obviously. But it's always a good story.

• 48:55Josh Clark?

  Sure, it is. Heartwarming.

• 48:57Speaker 03

  We think this thing's dead.

• 48:58Josh Clark?

  It's like, yeah, welcome back to the mass extinction.

• 49:01Speaker 03

  Yeah, exactly.

• 49:02Josh Clark?

  Still going on. If you want to know more about extinction, you should read each and every one of the articles we cited. And you can also read this article on HowStuffWorks.com by typing "extinction" into the handy search bar. And since I said that, it's time for listener mail.

• 49:19Speaker 03

  I'm going to call this Police Interrogation follow-up.

• 49:22Josh Clark?

  Okay.

• 49:22Speaker 03

  From Matt Pope. Hey, in Victoria, British Columbia.

• 49:26Josh Clark?

  All right.

• 49:27Speaker 03

  Thank you to Vancouver, by the way, for two great shows.

• 49:31Josh Clark?

  Yeah.

• 49:31Speaker 03

  After our great shows in Toronto.

• 49:33Josh Clark?

  Yep. Thanks to Toronto and Vancouver.

• 49:35Speaker 03

  Very supportive people. And boy, that second crowd in Vancouver was drunk and rowdy.

• 49:40Josh Clark?

  Yeah.

• 49:42Speaker 03

  Hey, guys, just listened to Police Interrogation. I thought I'd share a couple of quick personal stories to illustrate the pitfalls of relying on nonverbal cues to see if someone's guilty. I've never been in trouble with the law myself, but several years ago, I witnessed a crime. Called 911 to report it. Cops nabbed the perpetrator and a few days later asked me to come down to provide a witness statement. When I arrived, an officer led me into a tiny room that was every bit as bleak as the ones you see on TV. It was a weird experience. Even though I wasn't accused of a crime and the cop was polite in his questioning, the interrogation room setting and the power differential between the uniformed cop with a gun and my unarmed self made me feel really nervous. I started sweating, my voice shook, and if you had been watching my body language through the one-way mirror, you would have thought I was guilty.

• 50:24Josh Clark?

  Wow.

• 50:25Speaker 03

  And he was just a witness.

• 50:26Josh Clark?

  Yeah.

• 50:26Speaker 03

  The second story is very similar. Every year, our local courthouse has a public event where they give tours and put on a mock trial and actually hang someone. Kidding. I made up that part.

• 50:36Josh Clark?

  That was pretty good, Chuck.

• 50:38Speaker 03

  It's supposed to be educational and fun. My father is a lawyer and one year asked me if I'd like to play the defendant in the trial. I'm no actor, but I said, "Sure." My character was accused of a minor drug offense and I went through the whole ordeal being on trial and testifying in my own defense. I'll spare you the details, but afterward, my mom said, "Wow, you looked really guilty up there. I hope you never actually are on trial for anything because they'll lock you up and throw away the key." I learned from these situations, the very act of treating someone like a criminal can make him appear guilty.

• 51:07Josh Clark?

  Yeah.

• 51:08Speaker 03

  It reminds me of the Stanford prison study that we've talked about.

• 51:11Josh Clark?

  And there's a Psychology is Nuts about that. Psychology is Nuts video on our YouTube channel about the Stanford prison experiment.

• 51:18Speaker 03

  Yeah, that's a good one. You should check that out. I hope you guys never have to find out the hard way you'll react to police interrogation. If you do, I hope you find a good lawyer. That is from Matt Pope, once again, in Victoria, B.C.

• 51:30Josh Clark?

  Well, thanks a lot, Matt. That's kooky about your town doing mock trials and stuff like that.

• 51:36Speaker 03

  Yeah, and like hanging a guy?

• 51:37Josh Clark?

  Yeah. Crazy.

• 51:39Speaker 03

  He said it's fun.

• 51:40Josh Clark?

  The only thing that's OK about it is they make the guy look like Hitler.

• 51:44Speaker 03

  Right.

• 51:45Josh Clark?

  So it's like hanging Hitler every year, which everybody can get behind.

• 51:48Speaker 03

  Yeah, they call it the Hitler hang.

• 51:50Josh Clark?

  If you want to send us an email that Chuck feels the need to make up stuff about, you can send us an email to [email protected].

• 52:04Speaker 00

  Stuff You Should Know is a production of iHeartRadio. For more podcasts, MyHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.

• 52:20Josh Clark?

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• 52:51Speaker 09

  She's been thinking about this sleepover all week, but I think about her food allergies all the time. Fortunately, her doctor prescribed Zolair, omalizumab. It's proven to significantly reduce allergic reactions if a food allergy accident happens.

• 53:04Speaker 10

  Zolair 150mg is a prescription medication used to treat food allergy in people one year of age and older to reduce allergic reactions due to accidental exposure to one or more foods. While taking Zolair, you should continue to avoid all foods to which you are allergic. Don't use if you are allergic to Zolair. Zolair may cause a severe, life-threatening allergic reaction called anaphylaxis. Tell your doctor if you ever had anaphylaxis. Get help right away if you have trouble breathing or if you have swelling of your throat or tongue. Zolair should not be used for the emergency treatment of allergic reactions, including anaphylaxis. Zolair is for maintenance use to reduce allergic reactions, including anaphylaxis, while avoiding food allergens. Serious side effects, such as cancer, fever, muscle aches and rash, parasitic infection, or heart and circulation problems, have been reported. Please see zolair.com for full prescribing information. Ask an allergist about Zolair. This is an advertisement for Zolair,

• 53:49Speaker 10

  paid for by Genentech and Novartis.

• 53:51Speaker 00

  This is an iHeart Podcast. Guaranteed Human.