Founder and Executive director of the Edelman Fossil Park of Rowan University Paleontologist Dr. Kenneth Lacovara joins WIRED to answer the internet's questions about the phenomenon of extinction.
Director: Justin Wolfson
Director of Photography: Ben Dewey
Editor: Richard Trammell
Expert: Kenneth Lacovara
Line Producer: Joseph Buscemi
Associate Producer: Brandon White
Production Manager: Peter Brunette
Production Coordinator: Anthony Wooten
Casting Producer: Nicholas Sawyer
Camera Operator: Caleb Weiss
Sound Mixer: Sean Paulsen
Production Assistant: Sonia Butt
Post Production Supervisor: Christian Olguin
Post Production Coordinator: Rachel Kim
Supervising Editor: Doug Larsen
Additional Editor: Paul Tael
Assistant Editor: Billy Ward
Director: Justin Wolfson
Director of Photography: Ben Dewey
Editor: Richard Trammell
Expert: Kenneth Lacovara
Line Producer: Joseph Buscemi
Associate Producer: Brandon White
Production Manager: Peter Brunette
Production Coordinator: Anthony Wooten
Casting Producer: Nicholas Sawyer
Camera Operator: Caleb Weiss
Sound Mixer: Sean Paulsen
Production Assistant: Sonia Butt
Post Production Supervisor: Christian Olguin
Post Production Coordinator: Rachel Kim
Supervising Editor: Doug Larsen
Additional Editor: Paul Tael
Assistant Editor: Billy Ward
Category
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TechTranscript
00:00I'm Dr. Kenneth LaQuivara, paleontologist and executive director of the Edelman Fossil
00:04Park Museum of Rowan University.
00:06I'm here to answer your questions from the internet.
00:09This is Extinction Support.
00:15Lindsey Kinsel 2 asks, How do we know an asteroid killed the dinosaurs?
00:20Well, dinosaurs dominated Earth's terrestrial ecosystems for 165 million years.
00:25They were cosmopolitan.
00:27You find them on every continent.
00:28And then we see this impact layer, this ash, the fallout from the asteroid.
00:32And nowhere on Earth has anyone found a single in-place dinosaur fossil one centimeter above
00:38this layer.
00:39We can see that there was a day in history when, poof, they were gone.
00:43Where is Brandon? writes, If asteroids killed the dinosaurs, how come every other animal
00:47that was alive at the same time as them that's still alive now survived?
00:52The biggest killer that day when the asteroid struck was the heat.
00:56So if you were on the surface of the Earth and had no place to hide, you died that day.
01:00If you could get underground like a little shrew-like mammal or a lizard or crocodiles
01:04or good burrowers or even birds, there were birds at the end of the Cretaceous period,
01:09if you could get under the ground that day, you had a chance at surviving.
01:12TheRealLemming asks, Where is the asteroid that killed the dinosaurs?
01:15Has it ever been found?
01:16It has been found, actually.
01:18And there's a crater off the Yucatan Peninsula, that's the east coast of Mexico, that's about
01:23110 miles across and 12 miles deep.
01:27It was published in 1991.
01:29That's when scientists knew about it, but actually petroleum companies knew about it
01:32since the 70s.
01:33And they didn't tell anyone because they're petroleum companies.
01:36The asteroid that wiped out the dinosaurs was about 18 kilometers across, traveling
01:41at about 45 times the speed of a bullet.
01:44And it probably landed in the springtime because there are some fish in North Dakota, some
01:49fossil fish, that have spring pollen trapped in their gills.
01:53Sunpei Tarku asks a good question, Which animal species came the closest to going extinct
01:58and then successfully recovered?
02:00Well, the best example I know of is the California condor.
02:05In 1972, it was down to about 22 individuals.
02:09The chemical DDT was causing their eggshells to be soft and to break, and so they couldn't
02:14reproduce.
02:15Plus, they're scavengers, so they would eat a dead deer that had been shot by a hunter
02:20with lead shot, and they were getting lead poisoning.
02:22And so through an amazing effort, zoos and other conservation organizations, they captured
02:27every single remaining condor, all 22.
02:29They had an intensive breeding program, and then they started to release them back into
02:34the wild.
02:35They are not out of danger.
02:36They are still a critically endangered species, but right now there are about 550 California
02:41condors in the world.
02:43Some of them have actually made their way from California to Zion National Park, and
02:47there's now a small breeding population of California condors there.
02:51So they seem to be moving in the right direction because we took action, because we banned
02:55DDT, because California banned lead shot.
02:57So it's not like we're helpless in these cases.
03:00There are things that we can do to help pull these organisms back from the brink, but the
03:04time to act is now.
03:06Noman Densele asks, What's the worst that could happen if mosquitoes and flies were
03:10to be extinct?
03:11Well, although they are pests, small insects like that are really down pretty close to
03:16the base of the food chain.
03:17And you think about all the things that eat mosquitoes and flies, a lot of birds, frogs,
03:22other amphibians, small mammals.
03:25And so you know what?
03:26If you want to precipitate an extinction event, if you want to wipe out big animals, kill
03:29off the insects.
03:30That's the best way to do it.
03:32Ambre Del Queso, or Cheese Man, how many animals have humans hunted to extinction?
03:38Actually we have examples.
03:39When the government of Australia put a bounty on the Tasmanian tiger, people went out and
03:44shot every single one of them.
03:45There's a heartbreaking film of the last Tasmanian tiger circling wearily in this cage, and that
03:53was the last of its species.
03:54Passenger pigeons, we killed all of them just for sport.
03:58They used to block out the sun for hours with flocks of billions.
04:02Dodos, Dutch sailors, would club them to death.
04:05They wouldn't eat them.
04:06They would just stack them up and use them for firewood.
04:08The same thing happened to the great auk, which was sort of the penguin of the North
04:12Atlantic.
04:13And then if you go back a little further in time to Stone Age humans, the woolly mammoth
04:17and the woolly rhino and the giant ground sloth and all those amazing Pleistocene creatures
04:23that all of a sudden died when humans showed up.
04:26Base Shiver states, invasive species are bad.
04:28They outcompete native ones.
04:30Yes, so?
04:31It's called the free market.
04:32It's true in that there's natural selection that is occurring, but invasive species for
04:38the most part are able to invade those places because of us, because of our transportation
04:42systems or sometimes intentionally humans releasing them into the environment.
04:47And the result of that is that native species go extinct, native species that are important
04:52in the ecosystem or important to us as maybe a food crop.
04:56And so, you know, I don't think we want to really be playing planetary engineer with
05:01the Earth's biosphere.
05:03Death by Kool-Aid Man writes, what extinct animals do you think is really just hidden
05:08away from humans?
05:09I would be surprised if us paleontologists have discovered 1% of the species that have
05:15ever lived.
05:16And if you look at just the group that we call dinosaurs, if you go back to the early
05:20part of the last century, there was a new dinosaur species published about once every
05:25year.
05:26By the seventies, it was about a half a dozen a year, and now it's about one a week.
05:31Now there are some animals that were at one point believed to have gone extinct that are
05:35later found alive.
05:36It's very, very rare.
05:37They're actually called Lazarus species.
05:39And a good example of that would be the coelacanth, which is a very ancient fish.
05:43It lived alongside of the dinosaurs and it was believed to be extinct until the one was
05:47dredged up off the coast of South Africa in the 1930s.
05:51There's a pine tree called the Wallamie pine that was thought to have been extinct since
05:54the Cretaceous period.
05:56And in the nineties, it was discovered alive in a valley in Australia.
06:00So this can happen, but it's, it's very, very rare.
06:02Most things that we determine are extinct in the fossil record.
06:06We never see again.
06:07Great blue panda asks, what if supervolcano Yellowstone erupts?
06:11What happens to all species?
06:12Well, probably bad things.
06:14Yellowstone is a giant supervolcano.
06:16In fact, it wasn't discovered until just a few decades ago because it's so big, geologists
06:21didn't know they were inside a volcano.
06:23It was when satellite imagery started to become available that we saw Yellowstone as this
06:27huge, huge volcanic caldera.
06:29The last time it had a really huge eruption was about 600,000 years ago.
06:34And parts of the West were covered with 600 feet of ash, 600 feet.
06:39If that were to ever happen again, it would take out a lot of the United States.
06:43Even here in New York, a couple thousand miles away, there would be terrible effects.
06:46The ash would reach New York aviation here and probably globally would shut down.
06:52Probably not going to erupt tomorrow, but there is going to be a tomorrow someday.
06:56Maverick8358 writes, would we as humans be extinct if another Chicxulub asteroid hit
07:02Earth?
07:03Probably not, not at least initially.
07:05And when an asteroid hits, the most deadly moment is when the fallout comes in.
07:09The rock and the dust that's blasted from the impact zone goes into space and then resettles
07:14back through the atmosphere.
07:15You can imagine the energy released by the impact.
07:18In the case of the asteroid that wiped out the dinosaurs, a body of rock the size of
07:22Massachusetts times 12 miles deep was blasted into space.
07:26So that day when the dinosaurs died, global temperatures got up to probably somewhere
07:30between toaster oven and pizza oven.
07:33And that means if you were on the surface of the Earth that day, you were dead.
07:36Now, if that happened in today's world, it would surely be calamitous.
07:40But a lot of humans are underground.
07:42They work underground.
07:43There's tunnels underground.
07:44There's subways.
07:45There are defense facilities underground.
07:47So certainly some humans would survive that day.
07:50We'd probably be in a Mad Max situation for some time.
07:53Whether we pull out of that or not, who knows?
07:56How strong is the evidence for an alternative hypothesis for the dinosaur extinction?
08:00Well, I would say weak at this point.
08:03There are other hypotheses that have been out there for decades.
08:07For example, maybe volcanoes wiped out the dinosaurs.
08:10Well, that sort of thing takes hundreds of thousands or millions of years and it would
08:15unfold gradually around the planet and doesn't look like the instantaneous extinction that
08:20we see in the fossil record.
08:22Some people have said, well, the dinosaurs weren't doing so well leading up to the extinction.
08:26So they really died of multiple causes.
08:29And A, we have no evidence that they weren't doing well.
08:31We don't have that kind of resolution in the fossil record.
08:34And actually it looks more like they were doing great and their biodiversity was flourishing.
08:38But to say that they died of multiple causes would be something like saying Bob had a cold
08:43and he got shot by a bazooka.
08:45So he died of multiple causes.
08:47Smudgy90 asks, what stopped dinosaurs re-emerging as the dominant species after the meteor event?
08:53Well, death.
08:54Death is hard to come back from.
08:56But birds tried.
08:57We call birds avian dinosaurs.
08:59A flamingo or a hummingbird is a dinosaur to the same degree that a stegosaurus or a
09:04triceratops is.
09:05We have certain anatomical features that you have to have to be considered a dinosaur.
09:10And if we go back to the very first creature that satisfies those criteria, 237 million
09:16years ago, fossil found in Africa that we call Nyasasaurus.
09:20A hundred percent of that species' descendants, that's the group that we call dinosaurs.
09:25So when I say the dinosaurs went extinct 66 million years ago, what I'm really talking
09:30about is the non-avian dinosaurs.
09:32But some avian dinosaurs survive until today.
09:35Swen Roeschla asks, would human evolution, the evolution of higher intelligence, ever
09:40been possible without this mass extinction event or would it have taken a different course?
09:46I think it would have almost certainly taken a different course.
09:49Earth history is so contingent.
09:51If you run the movie of life on Earth back, it never turns out the same way twice.
09:56If you can imagine that asteroid that wiped out the dinosaurs, well, that formed the same
10:00time the solar system did, four and a half billion years ago.
10:03Go out to the asteroid belt at that time and hit that asteroid with a piece of popcorn
10:07and then 66 million years ago, it doesn't hit the Earth.
10:10And our mammalian ancestors during the entire reign of the dinosaurs were little tiny nocturnal
10:15shrew-like creatures living in the hidden and forgotten recesses of the dinosaur world.
10:20They could never really get anywhere until the dinosaurs went extinct.
10:23And then the dinosaurs went extinct and almost immediately early primates evolved.
10:27Some mammals returned to the sea.
10:29They become whales.
10:30Some mammals become big predators, big herbivores.
10:33None of that happens, I think, including intelligent species such as us, without the extinction
10:39of the dinosaurs.
10:40A Reddit user asks, 99% of all living things that ever lived on Earth are now extinct.
10:46Fact or fiction?
10:48It's fact-ish.
10:49We don't know the exact percentage, but certainly the vast, vast majority of creatures that
10:54ever lived, something approaching 99% have evolved.
10:58They persisted for some amount of time and then they went extinct.
11:02Extinction is a natural process, but it generally happens gradually over geological time, not
11:07in rapid succession as is happening today.
11:10SanCancelGuru opines, pandas are so bloody useless they deserve to go extinct.
11:16Well, that's pretty judgy there, Guru.
11:20Pandas have a place in this world just like we do and they fulfill a role in their ecosystem.
11:26And pandas, like every creature, have an unbroken chain of ancestry stretching back 3.8 billion
11:32years to their microbial forebears.
11:34This is a lineage that survived all five mass extinctions, including the one that wiped
11:39out the dinosaurs, but they're having trouble surviving us.
11:42So what does that tell you?
11:44Lynn Irwin wants to know, how did cockroaches survive the dino-killing asteroid strike?
11:48Well, have you ever tried to kill a cockroach?
11:51It's not that easy.
11:52Cockroaches are small, their knees are meager, and they can get underground, and that is
11:57a formula for success.
11:59Barnado12 writes, what will cause the extinction of life on the planet next time?
12:04Volcanoes erupting, asteroid impacts, sunspots, or developing fatal diseases in a lab?
12:10Well, here's what we know from history.
12:12There have been five past mass extinctions and everyone was caused by a climate crisis.
12:17The last, a climate crisis caused by an asteroid impact.
12:21We are experiencing a sixth extinction right now.
12:24We're not quite at the levels, obviously, that happened when the dinosaurs were wiped
12:27out.
12:28But the rate of extinction that's happening right now, if it persists, will cause Earth's
12:32sixth extinction.
12:33Yaboy asks, what if there was a mass extinction so big it wiped away all evidence of anything
12:39being there?
12:40Well, there was actually a time in early Earth history called the Age of Bombardment, four
12:44and a half billion years ago to 3.8 billion years ago, when there was still a lot of debris
12:48in the solar system.
12:50And so planet sterilizing impacts happened commonly.
12:54It might well be possible that microbial Earth got started several times, but was wiped
13:00out by asteroid bombardment.
13:03And that wouldn't leave a record that we would ever find.
13:06Stigmatronic writes, the whole concept of the sixth mass extinction is bogus for the
13:12most part.
13:13And you know what, Stigmatronic, I appreciate your skepticism.
13:16That's essentially the basis of science.
13:19But we have data for the assertion that a sixth extinction is underway right now.
13:23The background extinction rate of vertebrate animals over the last two million years is
13:28to lose about nine species per century.
13:31Well, just in the last century, we have lost 615 species of vertebrate animals.
13:38Some people think the rate might be as much as a hundred times higher than the normal
13:41background rate.
13:42If you look at not species, but populations of wild animals today, this is shocking.
13:47Since 1970, there are 69% fewer wild animals on the land.
13:53If that doesn't concern you, if that doesn't make you think that a sixth mass extinction
13:57is underway, I don't know what data you would need then.
14:00Lizway34 asks, why, why are they attempting to bring back the woolly mammoth?
14:06After six full Jurassic Park movies, my brain cannot fathom how anyone would possibly think
14:11this is a good idea.
14:13My gosh.
14:14A lot of people conflate recent creatures like the woolly mammoth with dinosaurs.
14:20Dinosaurs are truly ancient.
14:21Their world is gone.
14:23That's 66 million years ago.
14:25Mammoths were around only 3,300 years ago.
14:28Mammoths lived in a world that had the great pyramids, that had written stories, that had
14:32beer.
14:34That's this world today.
14:35And they had an important place in an ecosystem that still exists today.
14:40And so if we could bring back creatures, particularly ones that are the keystone species in their
14:44ecosystems, meaning species that lots of other species depend upon, then that would
14:49be a good thing for our environment, for our ecology, and it also has carbon sequestration
14:54ramifications.
14:55So in some cases, it could be a partial answer for the climate crisis as well.
15:00I happen to be on the board of scientific advisors of Colossal Biosciences, endeavoring
15:06to de-extinct the woolly mammoth and the Tasmanian tiger and the dodo.
15:11If there was a species that was on the brink today, if there were, say, only two of them
15:15left, let's say those two animals died, and it's two days later.
15:19Would you say, no, they're losers in Earth history, we're done with them?
15:23Probably not, right?
15:24Well, what if it was a week, or 10 years, or 100 years, or 1,000 years?
15:27I kind of have a Pottery Barn philosophy on this, which is, you break it, you bought it.
15:32I think if we're the agents of their demise, we have a moral and ethical responsibility
15:37to resurrect them and their ecosystems.
15:40Mauritiushotel7839 writes, have there been animals that were hunted to extinction by
15:45other animals and not humans?
15:47There are lots of examples.
15:49For example, in Hawaii today, exotic egg-eating snakes are wiping out many bird populations.
15:55In New Zealand, house cats, which are not indigenous, are wiping out ground-nesting
16:00birds.
16:01Rats are one of the things that push the dodo to extinction in Mauritius.
16:06In the fossil record, when we see landmasses connect, that often leads to extinction.
16:11One of the things that caused the worst mass extinction ever, this happened about a quarter
16:15billion years ago, we call it the Great Dying.
16:17We think it was caused by these giant volcanic fissures in Siberia, but it was exacerbated
16:21by the fact that all the continents just happened to bump into each other at that time, creating
16:26the supercontinent called Pangaea.
16:28When all the landmasses are connected to each other, then all the animals have to compete
16:32with the other animals, and it's very hard on life.
16:34When landmasses are fragmentary, when you have lots of islands and little continents,
16:38then there's lots of little niches that different species can occupy, and that usually leads
16:42to an increase in biodiversity.
16:44Bridget Howell writes,
16:45Species of least concern?
16:47What does that mean?
16:48It sounds so sad.
16:50It means that they're not threatened, and threatened includes vulnerable, endangered,
16:54and critically endangered, which is the worst category to be in.
16:57So least concern just means that the population is fairly stable.
17:01An example of a species of least concern would be the laughing gull.
17:04They're all over the country, really.
17:05They're doing just great.
17:06They love being around humans.
17:07They love eating your hot dogs and your popcorn on the beach, and they're doing just fine.
17:12A critically endangered species would be something like the northern right whale.
17:17There's probably only about 25 of them alive in the world.
17:21Saint Fiasco asks,
17:23What are the five mass extinctions?
17:25The first one that happens is at the end of the Ordovician period, around 400 million
17:29years ago.
17:30Life is confined to the oceans at this point, and most of that is in the shallow seas.
17:35Continents are drifting south.
17:36It initiates a glacial period.
17:38Sea level drops, so it drops off of these shallow shelf areas, and it's just habitat
17:42loss.
17:43And so we have a mass extinction event.
17:45Life recovers, and then we're in the Devonian period after that.
17:49That seems to be a combination of climate change and bad ocean chemistry.
17:54There's a lot of evidence of anoxic water, water that doesn't have enough oxygen in it
17:59because it produces these black shale deposits in the Devonian.
18:02And so we have that mass extinction.
18:04And then the third mass extinction, the worst of all, is called the Great Dying.
18:07It happens at the end of the Permian period, about 250 million years ago.
18:11That is the result of these giant volcanic fissures in what is now Siberia, belching
18:16forth immense quantities of greenhouse gases, causing the planet to overheat, just like
18:21it's happening today.
18:22That in combination with Pangaea forming, making all the animals have to compete with
18:26all the other animals, it was really tough on life, and we lose about 95% of species.
18:32We lose these little guys.
18:34This is known as a trilobite.
18:37They almost look like underwater bugs, but they evolved about a half a billion years
18:41ago, and they were super successful for about a quarter billion years.
18:45But then by the end of the Permian period, their immense run across deep time is over,
18:50and they go extinct.
18:52And then we go into the Triassic period, really hard time for life on Earth.
18:56The world is recovering from this Great Dying event.
19:00And then those volcanic fissures in Siberia, they open up again, causing another mass extinction.
19:06And then after the Triassic, we really get into kind of the sweet spot of the dinosaur
19:10age.
19:11We're in the Jurassic period now.
19:12Things are going great.
19:13Dinosaurs are getting big.
19:14They're getting biodiverse.
19:16We get into the Cretaceous period.
19:17That's kind of the flower of the dinosaur world, and dinosaurs are cosmopolitan.
19:22They're in all kinds of niches.
19:23They're all kinds of sizes.
19:24And then an asteroid hits and murders them, and it's over that day.
19:28And then we get into the age that we are in now, the last 66 million years that becomes
19:32the age of mammals, only because the playing field was cleared by that asteroid.
19:36And now what's happening?
19:37Now we are causing the beginnings of the world's sixth mass extinction.
19:42Throwaway Simples writes the trolley question, I think deforestation is a good thing.
19:48Change my view.
19:49Well, Throwaway Simples, how do you like breathing?
19:52Because most of your oxygen comes from plants.
19:56The earth has two great lungs.
19:57One is the phytoplankton in the ocean.
19:59The other is really the Amazon rainforest.
20:02Rainforests such as the Amazon also have the highest biodiversity in the world.
20:06And where do you think your medicines come from?
20:08Well, they come from discoveries made from plants and animals and microorganisms that
20:12mostly live in tropical rainforests.
20:15So if you like not dying of horrible diseases, you should be pro-forest.
20:20Bill M. Foster says, I don't understand why sharks have to exist.
20:24Well, there's really no why in evolution.
20:28There's no forethought.
20:31Animals exist because they happened and sharks happened a long time ago.
20:35Sharks were around a couple hundred million years before the dinosaurs.
20:39They persisted through the entire reign of the dinosaurs.
20:42They survived the mass extinction that wiped out the dinosaurs.
20:45And obviously they exist today, but you know what they're having trouble with?
20:48Us.
20:49There are sharks that are critically endangered right now because they're being overfished
20:53and because their environments are being destroyed, such as the great hammerhead shark, which
20:58is endangered.
20:59And they are the apex predators in many of the ecosystems in which they live.
21:04And predators are important.
21:06It keeps actually the prey populations healthy because it winnows out the ones that are disease
21:13that could spread those diseases through the population.
21:16It causes natural selection, which causes the prey species to become faster, stronger,
21:21quicker.
21:22And so we really need sharks in this world.
21:25Okay, that's it.
21:26That's all the questions.
21:27I hope you learned something.
21:28Until next time.