STBYM Halftober Monsterfest Playlist, Episode 5: Cambrian Monsters

Let's go back to 2017. Heck, let's go back 500 million years to the monster-haunted waters of the Cambrian period. Halftoberfest now.

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Episode Transcript

Speaker 1 (00:04):
Hello, Dr Jessup. Anybody here? Well, hello, good sir. I'm
glad to see you have arrived. I apologize I can't
be there to greet you in person, but please know
that I have most appreciative of your attendance. It's so
hard to find good volunteers these days. It's it's just

(00:26):
just every undergraduate with even a bit of backbone and
simply vanished in the past six months. Uh huh okay,
So am I in the right place? Ah? Well, well,
perhaps instead you should ask whether you were in the
right time? Uh huh. Well, the flyer said you were
doing six for test subjects in something called Middle Cambrian exposure.

(00:52):
I'm not sure what that is, but if you're paying cash,
I'm still on board. Excellent. Now tell me do you
have any experience with time displacement? I don't think so,
of course, not, of course not. You can tell me.
Can you swim? You know I can, but it's one
of those things I wouldn't say I'm a great swimmer. Okay,

(01:14):
nobody's perfect. Do you see the throbbing lightness of the
world text in the center of the room there, Well, yeah, yeah,
I do, except go to it right, Yes, yes, closer,
closer doesn't feel right? What's that feeling? What's the matter,

(01:36):
my little vertebrate? Haven't you ever wanted to feel? Five
hundred miran years loved? What is that? Is? That? Is
that an ocean? Oh? My god, It's like the whole
planet's an ocean. It's full of monsters. Welcome to Stuff

(01:59):
to blow your Mind from housework dot com. Hey, welcome
to stuff to blow your mind. My name is Robert
Lamb and I'm Joe McCormick and Robert. That was obviously
a reference to some kind of journey we may be
taking to the Cambrian period. That's right. Yeah, we had
a little cameo by the late great Anton Jess late

(02:23):
did he die? I don't know. I mean there are
there are rumors of his death, but who knows for sure?
They always exaggerated. Is well? Anyway, today I've got a
little story I want to tell the lead us into
our topic. Now. Obviously it is October. It's our favorite
time of year to talk about monsters. We talked about
monsters anyway, but this is the time where we really
double down. Its clear mandate for monsters, and I got
to take a monster science adventure this past month. So

(02:47):
this this past month, early on one Sunday morning, my
wife Rachel and I were in Canada and we woke
up before dawn on this Sunday morning in the town
of Golden British Columbia. It's in western Canada, the Canadian Rockies,
and we had some coffee and bagels, and we filled
up our backpacks with a bunch of layers of warm clothes,
bottles of water, all that hiking stuff, and we drove

(03:08):
along the steep mountain sides to this tiny town called
Field in British Columbia. And there we parked beside a
gas station and we waited to meet our guide and
the rest of this tour group. So the guide was
a paleontologist named David, and the hiking group was mostly
French speaking families, some really lovely people and some very

(03:29):
intelligent children with great questions like why do animals die? Uh?
And so we hiked through the town of Field and
along this uphill path through the forest up the side
of Mount Stephen. And as we went on throughout the day,
the trail got steeper and steeper, and we could see
through the trees the town. We came from was becoming

(03:49):
this tiny miniature model in the distance. And then right
around midday we came out of the tree line and
we walked up on this bare plane of flat rocks
and they were pieces of the underlying shale formation that
had chipped and broken off, and they had gathered in
this relatively flat part of the mountain side. And on
this plane of rocks, you walk around and you pick

(04:10):
up these mineral fragments and they're full of fossils. It's
just fossils everywhere. Almost every other rock you find has
the shape of an animal from millions of years ago
printed into it. You're literally walking on thousands and thousands
of fossils. So you're in this this mountainous environment and David,

(04:31):
who by the way, i'm picturing as the Android from
Prometheus and Alien Covenant, is guiding you and showing you
these these prehistoric remnants in the rock. David was not
Michael Fastbender, but David was excellent. He was a really
really good guide. And this place we came to where
we were walking on fossils, this was the Mount Stephen
Trio bite beds. It is a graveyard of organisms from

(04:53):
the Cambrian period about five hundred million years ago. Now.
Mount Stephen is in an area that's home to the
Urgess Shale geological formation, which is one of the most
important sites of Cambrian Period fossils in the world. And
if you ever get a chance to do one of
these hikes, I highly highly recommended. I think it literally
might be the coolest thing I've ever done. You have

(05:14):
to book them through this organization called the Burgess Shale
Geoscience Foundation, and they pair you with a guide. Our guide, David,
the paleontologist, was an excellent science communicator. He was really
good with the kids on the group, and he was
a great hiking guide. So if you get a chance
to go with David, big thumbs up to him. Be
warned if you do try to do this, it's a
tough hike. It's like eight kilometers round trip horizontally with

(05:37):
a seven hundred and ninety five meter elevation gain, which
is like two thousand, six hundred feet and uh and
that's starting at like twelve hundred or th hundred meters
of elevation at the at the base of the mountain.
Uh So the air is thin and it's worth doing
some other hikes at higher elevation to get yourself accustomed
to the lack of oxygen. But I also don't want

(05:58):
to scare you too much. Obviously I will. I am
no kind of athlete or experienced altitude hiker or anything
like that, and I survived so beer advising listeners to
wear their best flip flops this particular, just be prepared,
have some layers, have some water, do a little practice.
If you can make the trip, it is absolutely worth
it to see these fossils firsthand. You can pick them up,

(06:21):
you can feel the ribs of these Cambrian organisms. You
can you can feel the contours of their bodies as
they printed on this ancient shale. But also it's really
cool to be there, just because the area around field,
including Mount Stephen, trial By Beds and the Burgess Shale
quarry quarries, are just arguably the most important Cambrian fossil

(06:41):
sites in the world. They are a geological window into
a time stranger, I would argue than any alien planet
in any movie, any book, any video game, any Star
Trek episode. I think the real alien monsters h And
of course, as you if you know the show, you
know use the term monster affectionately. It's not a pejorative.

(07:03):
The real alien monsters are not out there on some
exo planet. They were right here five million years ago,
and in this one amazing place you can sort of
crunch through their frozen graveyard and it's awesome. Now, Joe,
do you find yourself falling into the same admittedly dumb
trap that I do when I when I think about

(07:24):
about the nationalities that are sort of overlaid regarding a
fossil uh findes like these are Canadian Cambrian monsters and
stuff like that. Like, yeah, because I was recently reading
to my son about Terra saurs and was reading about
the about about Bavarian fossils of Terra saurs, and is

(07:45):
as silly as it is, I couldn't help but think
of of Bavarian Terra stars thinking about the Varian rhistoric creature,
like wearing later hosen the big big stein of beer,
And it's so unfair. You know, I've done the same
thing thinking of Mongolian fossil finds. In our previous episode
we talked about various raptors I believe remember it was

(08:06):
the velociraptor or Dononicus. But I could not help but
then think about them in terms of like human history
regarding that area and part of his pack. Uh yeah, yeah,
I know exactly what you're talking about. And that does
highlight the need to sort of explain how the Cambrian

(08:27):
world was so different than our world, not just that
it had different animals in it, but that planet Earth
was different then. So when I say it was an
alien planet, I mean that quite literally. It's not just
that it had different fauna, it was a It was
a totally different place to live. And so before we
get into exploring these monsters of the Cambrian Period, these

(08:48):
beautiful and bizarre creatures that you couldn't even dream up
if you tried, I think we should take a look
at the Cambrian Period itself and explain what it was
like to be Terra five hundred million years ago. So
the Cambrian Period lasted from about five hundred forty to
about four hundred and eighty five million years ago, and
if you were dropped from today straight into the Cambrian period,

(09:12):
you would not recognize planet Earth. The Earth, for one thing,
revolved faster than it does now, So days were only
about twenty one hours long, and there were about four
hundred and twenty of them in a year. The air
would be hot, so the average global surface temperature would
have been about ten degrees celsius hotter than today. That's
a good bit hotter. The atmosphere, while it did have

(09:35):
significant free oxygen, at this point, was not quite what
it is today. It would have felt a little bit
thick with carbon dioxide in your lungs. If you happen
to see dry land, it would probably look more like
the surface of Mars than Earth today. Because land dwelling
plants didn't exist yet. It's kind of hard to imagine

(09:55):
Earth that way. And without plant roots to hold the
soil in place, lands surfaces eroded very easily in the
wind and the churning water. So you know, the continents
are constantly just kind of burning away into the oceans
and being reformed. So to call back to a previous
episode we did, was this was definitely a world before fire.
Oh yeah, because what would it what would it burn? Right? Yeah,

(10:18):
I mean I can't be sure it was totally without fire,
but I mean, yeah, obviously not fire on the scale
we see of wildfires in forests today. Because there was
oxygen in the atmosphere at this point, but yeah, what
what would burn? What would the fuel be? All Right,
So we have this alien world with just a barren
land when visible, and then we have this this ocean,

(10:39):
this strange ocean, and the Cambrians Earth that that's not
a story about land at all. That is a story
about ocean. It was the ocean planet at that point.
You could probably make the argument it's the ocean planet
right now, but it definitely was then. According to Cambrian
Ocean World Ancient Sea Life of North America by John
Foster uh the love all of the seas rose steadily

(11:01):
in this saw tooth rise and fall pattern throughout the
Cambrian period. So at the beginning of the period sea
level was actually a little bit lower than it is today,
But by the end of the Late Cambrian sea level
was about a hundred and sixty meters or five and
thirty feet higher than it is today. So in today's terms,
New York underwater, Rome underwater, Paris underwater, Baghdad underwater, even

(11:26):
parts of Moscow underwater, and the high sea level in
the Cambrian led to flooding of about forty percent of
the area of Earth's continental masses. Compared that to today,
we're only about five percent of that continental area is
covered in water, so most of our planets dry land
mass was gathered together closer to the south pole, and

(11:46):
the continent that became North America was then called Laurentia,
not then called by people who have been people today
called that continent than Laurentia, and you sort of have
to imagine North America turned sideways, mostly flooded, straddling the equator.
Also adding to the alien quality in the Cambrian astronomy

(12:07):
would have been a little bit different. So the Moon
was more than twenty kilometers closer to Earth than meaning
that its gravity was stronger, meaning the high and low
tides on Earth were higher and lower. Okay, you know
my son was just talking to him to me the
other day about the size of the moon and prehistoric times.
Oh yeah, like he knew that the moon was bigger

(12:29):
in prehistoric times. Yeah, and uh, and knows that it
will be it will be smaller in future times. Did
he into it that or did he find that out somewhere?
He consumes a lot of dinosaur train and he really
likes this podcast, Wow in the World. That's a great
science podcast for for kids. So and then you know,
we talked to him a lot about science. Man, I

(12:50):
wish I was that cool when I was, I probably
just would have told you about like which ninja turtle
was bigger in prehistoric times. Yeah, so far ninja turtles
will probably come in and wash it all the way.
But for now, he's really really into the thing, like
an alien ocean driving away the continents. Okay, So if
we looked under that ancient ocean, that's where the real
craziness comes in, because we would find this vast realm

(13:14):
of gorgeous, terrifying, surreal monsters that would look completely unlike
the kind of Earth life we're familiar with today. Because
the Cambrian period is the geological layer where we see
evidence of one of the most fascinating and mysterious events
in the history of life on Earth, known as the
Cambrian Explosion. So explosion. What exploded? Was this like a

(13:36):
bunch of volcanoes or something? No, the Cambrian explosion is
a story about biodiversity. So, Robert, how old is the Earth? Oh,
it's so at four and a half billion years old. Yeah,
that's the general astronomical idea. So four and a half
billion years old. We've had this planet roughly, and we
know there's been single celled life on the planet for

(13:56):
at least maybe three and a half billion years or so,
based on fossil traces left behind by these organisms. And
new findings keep pushing the debatable frontier of earliest life
farther and farther back into the darkness of Earth time.
One example, I just came across So the other day,
just earlier this year, in March seventeen, there was an
article published in Nature arguing that apparent microbe fossils in

(14:20):
the New Vue Agatuck Belt in Quebec are about three
point eight billion and possibly four point three billion years old,
somewhere in that range, and these single celled life forms
would have been surviving around hydrothermal vents and had this
biochemistry based on eating and excreting iron. That's that's like

(14:42):
a comic book film, right, yeah, the iron eater. And
the crazy thing is that if these findings are correct,
life on Earth would have began within just a few
hundred million years of the planet first accreting together in space.
It's kind of hard to believe, but whether life on
Earth began like four point two billion years go or
more recently. We know that for a long long time,

(15:04):
life on Earth wasn't becoming much more complex, right. There
was no serious multicellular life, So no animals, no fish
and reptiles, no birds, no plants, no mushrooms, just microbial
organisms like bacteria and archaea floating around in the oceans,
forming mats and films and occasionally occasionally building these giant

(15:26):
mineral brains in the surf called strummtallites. So this would
be if this were a science fiction film, this would
be the least cinematic alien life form encounter unless it
made people like, you know, horribly sick obviously, or possessed them.
Biofilm planet, yeah, yeah, the planet of slime. Yeah, it
was would be the episode of of Star Trek that

(15:47):
that does not does not make it to the series. Yeah,
and that's you know, that would have been the story
of Earth for most of Earth's history, not having any
kind of interesting animals or anything like that. Not to
say that microbes aren't interesting in themselves, but maybe less
interesting to look at. It would have been slime planet. Yeah. Generally,
this is the stuff that occupies one, maybe two pages

(16:08):
of a of a large prehistoric life book before you
get onto the more exciting things, the things that children
can imagine fighting each other. But it's most of the
life that's ever happened. And then billions of years later,
at the beginning of the Cambrian Period, something happens very suddenly.
Loads of insane animals show up. And when I say suddenly,

(16:30):
I have to qualify that that's suddenly from a geological
point of view, which in reality means it took millions
of years about five hundred and forty million years ago
to about five hundred million years ago. But that's still
pretty suddenly compared to the age of the Earth. And
this geologically rapid spike in animal diversity delivers creatures with
bilateral symmetry, with large bodies, with eyes, with legs, with shells,

(16:56):
with segmented body parts. You've got all of these crazy
different types of creatures suddenly showing up, and it's like
where did they all come from? Yeah, it's like all
these prototypes are rolled out at once. It's like the
segment in is it is a RoboCop one or two
where we get all the crazy prototypes that, oh, that's
a RoboCop two. Yes, yeah, it's one of our favorite

(17:17):
points of comparison on the show for biology. Uh yeah,
you have suddenly all these different, you know, seemingly crazy
examples of life, and many of many of which don't
seem to to fall in easily into that category of well,
this is a precursor to something we have later on.
It's a precursor to something we have today now. Of course,
for some people with negative attitudes towards evolutionary science, this

(17:41):
provides some kind of rhetorical ammunition, right indeed, I mean
the explosion is often exploited by evolution of niers, even Darwin,
we have to note thought that the explosion was at
odds with the normal evolutionary process, which in a funny
way could be true, but not in the way an
evolution denier would mean. A couple of thoughts. Evolution is
we're familiar with it today, tends to take place within

(18:03):
ecosystems in which every niche is already filled. So basically,
every way there is for a creature to make a living,
there's already something trying to do that. So if you
want to compete, you've got to outcompete these other organisms.
The global ocean of the Cambrian on the other hand,
represented a world in which it seems like there was
still tremendous ecological opportunity to occupy, Like there was territory

(18:26):
in the ecology that didn't have any existing competition. So
it was a time in which an animal could start
doing something to eat or to otherwise survive, and no
other species was already doing that thing. There was just
sort of like free land to grab. Yeah, like yeah,
land grab call the frontier, except without other organisms already

(18:46):
occupying it. So that there could be one explanation for
why evolution seems to be working differently at this one
period in history than it has since. But also the
Young Earth creationist who exploits ongoing abates in biology to
sort of resort to the supernatural. They're employing a fallacy
in rhetoric known as the argument from ignorance fallacy, which

(19:09):
means like, I don't know what caused something, therefore the
cause is x uh. Example, you don't know who committed
the Jack the Ripper murders, therefore it was interdimensional sasquatches. Now,
the version employed here, of course, says, you can't all
agree we don't know on what caused the sudden or
geologically sudden biodiversity of the Cambrian explosion. Therefore, the cause

(19:31):
is supernatural. Now, this line of thinking obviously doesn't get
you anywhere once you examine it, but the disagreement and
debate over the cause is a fascinating, outstanding question, and
it's something I think we want to entertain a few
answers to today. Now, some of the hypotheses are primarily
environmental and chemical. Right, so some scientists have proposed that

(19:52):
the cause of the camera and explosion could be a
rise in the content of oxygen in the atmosphere, which
leads to an increase in the level of dissolved oxygen
and the oceans. Now, of course, remember that Earth's original
atmosphere did not have free oxygen, right, That was added
to the atmosphere gradually as a waste product of photosynthesis.
You have all these microbes out there and they're eating

(20:14):
the sunlight and then their geoengineering the atmosphere with their
waste products, which included oxygen. The gradual natural terraforming of
our world. Yeah, the microbial terraforming of Earth, which absolutely
did happen in the past, and that's where we get
our oxygen. Now, when you think about it. Large, fast
moving animals need lots of oxygen to feed their energy

(20:35):
hungry tissues. Like think of the way that when you
move your muscles a lot, your body starts greedily gulping
down more and more air. In the same way, if
you think about these organisms in the past, suddenly you
wanted to have organisms with large bodies. They would have
needed access to oxygen. So maybe when that oxygen became available,
suddenly you could build these big, fast moving bodies and

(20:58):
you get all this animal biodiversity. So previously the the
oxygen economy would not support this kind of growth, right,
But the idea is then it would. So did a
sudden increase in oxygen drive the explosion? Well, some recent
studies have cast doubt on this hypothesis, including one published
in Nature by Spurling at all uh and it basically

(21:18):
did not find evidence of a significant increase of oxygen
in ocean water at the beginning of the Cambrian So
evidence shows that if there was an increase in oxygen
at the Cambrian transition, it was kind of a small one.
Al Right, Well, what else do we have? Well, other
hypotheses are more biological and ecological, like what if there
was one type of biological innovation, some new way for

(21:42):
animals to make a living or new thing. Animals could
do that rapidly accelerated competition with an ecosystems, which would
speed up natural selection and cause new species to form
much more rapidly. How about the example of site. Oh yeah,
this is a big yeah. So previous animals they might
have had some kind of photosensitive spots or receptors that

(22:06):
would have allowed them to, for example, move towards the sunlight.
But the Cambrian is the first period in history where
we have evidence of complex site organs, you know, eyes.
It's the age of organisms with compound eyes. So imagine
how much adaptive pressure would be put on you if
you lived in a world where all creatures were basically
blind and then suddenly some of your competitors could see. Yeah,

(22:30):
this is this is a crazy thing to try to imagine,
but yeah, just just think of sight coming online in
a world and all the additional stuff that this entail.
Suddenly pigmentation begins to matter. I mean, it's hard to
even apply. You're one is tempted to apply this to
human arms race um, which is which is often an
an apt comparison. But I mean, what can we even

(22:54):
look to in human technology and human weapons systems. I mean,
I'm just thinking maybe you could apply it. You can
compare it to flight and say that, well, once, once
human technology allowed us to take to the air, that
created an entire new theater of war, and they also
changed the existing theaters of war. And I think you

(23:14):
could make that comparison pretty well, like flight changed the
nature of warfare forever, Like suddenly just having like lots
of ground troops didn't didn't matter a whole lot, right,
But this, this seems more extensive than that. You know,
It's like it's it's the opening of another dimension of
competition in a way. Yeah, and yeah, and you think

(23:35):
so you you mentioned pigmentation. Suddenly the colors you are matter,
like blending in matters. But also think about the way
it would make movement matter. It would make the shapes
of bodies matter. It would just completely change all the
dynamics of how creatures interacted with one another. Yeah, not
only prey predator interactions, but of course just interspecies of communication, uh,

(23:56):
and as well as mating, etcetera. I mean, every thing
changes because of this. Yeah, So We'll come back to
look at more of these answers to this question throughout
the episode, but I think we should take our first
break and then we come back. We will look at
one of the first major inhabitants of our Cambrian monster House.
All right, we're back. So as we roll through these,

(24:18):
I also want everyone to think of potential Halloween costume ideas,
because I think we have some We have some wonderful
prehistoric monsters here that I think are more inventive listeners
might be able to turn into a mask or a
full body cost Okay, So I want you Starship Troopers
fans out there to get a little bit excited about
stone Bug Planet fans of the book or the movie, well,

(24:41):
I mean they both got bugs. Okay. So in eight
six there's a Canadian geologist by the name of Richard McConnell,
and he's visiting the town of Field, the same town
I went to when I began the walk up Mount
Stephen Field, British Columbia, where some railroad workers told him
they had found so then creepy on the slopes of

(25:02):
nearby Mount Stephen. They were these things that they called
quote stone bugs, and these were in fact, trilobytes the
best known inhabitants of the Cambrian oceans. Now, trialobytes are
not a single species, but there are a class of
extinct animals from the phylum Arthropoda, and so that would
be the same phylum that includes, for example, insects and crustaceans,

(25:25):
lobsters or arthropods. Insects and spiders or arthropods. These exoskeleton creatures,
now trialobytes were an enormously successful form of life, beginning
in the Cambrian and surviving for about three hundred million
years until they were wiped out about two hundred and
fifty million years ago in the Permian Triassic extinction event
also known as the Great Dyeing, which was the biggest

(25:48):
mass extinction in the history of planet Earth. About nent
of all marine species went extinct. It's kind of hard
to imagine, but until then, trial bites were like sort
of like the insects of today, just this enormously successful,
the type of creature found everywhere. They were a swarm

(26:08):
upon the face of the deep or as I kind
of want to think of them as the infinity bugs.
I like it. So the trio byte body structure kind
of resembles like a roly poly or a pill bug,
maybe crossed with a horseshoe crab. It's got these articulated
segments lining its back, and if you look at it
from the top down, you'll see this flat, hard shell

(26:30):
made of a matrix of tiny calcite needles. And if
you look at it on the vulnerable underside, you'll see
the legs and the gills and the mouth. And actually
it does kind of look like a like a roly
poly or a pill bug on the underside too, if
you ever see them. Yeah, I have to say the
Trilobyte of all the creatures were going to discuss today, Well,
first of all, it's the most famous, I think, so

(26:51):
most of you have probably seen images of it before.
But it also does look a lot more like existing creatures.
It doesn't if you, if you didn't know better, you
could easily see an image of this and think that
it could be something living today. Yeah. I think the
creepiness of the triobyte world comes not from seeing their

(27:11):
body plans, because you can see stuff that looks kind
of like them, Like you say, it's just how many
of them there were, and thinking of this being one
of the dominant body plans on the planet or the
dominant body plan on the planet. And if you're still
drawing a blank as to what this looks like, I'm
going to include images of of all the species that
we're discussing here on the landing page for this episode.

(27:32):
It's stuff to blow your mind dot com. All right,
So we've had to look at the creature's legs. Let's
turn this puppy around. Okay, turn it so if you
look at it from the top down, you can basically
divide a trialobyte in three both ways, so if you
look at it lengthwise, you're looking at it head on. Lengthwise,
there is bilateral symmetry, and this is the cameraan period.

(27:54):
We see these animals with bilateral symmetry really taking over.
You can fold them in half and they're like a book.
They match on both sides. And in that lengthwise direction,
the trilobyte is divided into three lobes. You've got the
axial lobe, which runs down the middle from the head
to the tail, kind of like the spine of the
book or like the spine of a vertebrate. And then

(28:14):
you've got the two plural lobes on each side. Which
you're shielding the legs from above. There were these you know,
shelled lobes stick out on the side and they cover
up where the legs would be moving underneath. Now you
rotate at ninety degrees, and then you've got another three sections.
You've got the head known as the cephalon, the middle
section known as the thorax, and the rear section known

(28:36):
as the pigidium. Now, one thing you might wonder, why
do we see these articulated segments on the shell of
a trilobyte, Like, why doesn't it have something more like
a big solid turtle shell? You know, why why the
different plates overlapping? Well, there are multiple answers, but one
is that apparently some trilobytes were able to partially curl

(28:58):
up and protect their soft or bellies, like an armadillo
or a pillbug. Yeah, it's so. Do you do you
use the word pillbug or roly poly? Do I think
they're the same thing, the same creature or the same
you know, classification of creatures at the very least. But yeah,
I grew up with roly poly. I think I did too,
And somehow in my adulthood transition to pillbug, I've sold

(29:21):
out my childhood wonders. It does sound significantly less silly. Well, anyway,
trial bite fossils are that. That's what you're walking on
in the Mount Stephen trial by beds, right. So you
walk around, you crunch through these things, you pick up
these rocks and they've got these little shells in them,
and the trial bite fossils are so common you can
get the sense that these animals must have been stacked

(29:41):
a mile high when they actually existed, right. There were
a lot of them in the Cambrian but they're perhaps
overrepresented in the fossil record because many of the fossilized
shells we find are not the animals themselves, but the
discarded shells left over from the molting process. So, like
Arthur pods today, trial bytes were himmed in by this

(30:03):
protective shell, and if they wanted to grow bigger, they
had to molt, which meant discarding that protective outer layer
and temporarily risking a soft bodied existence in order to
grow that larger, harder shell. It would be like if
there were a prehistoric hominid creature that left multiple skeletons,
you know, which is of course impossible, but with an

(30:24):
exoskeleton is is completely is very possible. Well, the vulnerability
of molting makes me think about the comparison to a
human newborn. You know, when when babies are born, they
don't necessarily have all their their hard protective skeletal parts yet,
and I have a lot of unfused together the unfused
skull for example, and the soft cartilaginous body parts where

(30:45):
you really do make yourself vulnerable when you're first born.
But of course they're depending on the fact that mammals
have protective parents that will try to prevent injury to
their offspring when they're young and vulnerable trial bites. I
don't know if they're they're quite so protective of their
I mean you could say that puberty is kind of
a molting period where where where we tend to be

(31:06):
soft and vulnerable, if not in if not in mentally,
at least mentally. Yeah. Uh so, that's interesting to think
of the molting process having an impact on the sheer
number of fossilized remains. But but then on top of that,
of course, it makes you analyze, and we've discussed this
on the show before, like what makes a creature more

(31:28):
liable to be fossilized and I mean, you look at
the creatures that are fossilized in any great number. It's
not going to be an apex predator living in a
dry region. It's going to be something like a low
level and bird invertebrate that lives in the muck, something
that gets buried quickly. Uh, and that leaves behind hard
body parts near water, especially right. So the great the

(31:49):
great land squid of old right, has not been preserved.
But their beaks are many. Oh, yes, that's right. We
would get the beaks. Yeah, these beds of beaks. We've
under what they are. Yeah. But because there are so
many triobyte fossils, and because they're so strange and so
alien to the modern life forms we encounter in our
day to day lives, I mean they might be they

(32:11):
might bear some resemblance to insects, for example, right, and
this is why railroad worker might call them stone bugs.
But it's no surprise that they show up in human
culture too. I wanted to mention one cool example I
came across. Remember Adrian Mayor, who wrote the first fossil Hunters.
We talked about her in our in our what was
it the geomethology? Yes, yes, this had to do with

(32:32):
how did ancient people look at fossil life remains? Didn't
I think they were monsters? That they think they were dragons? Yeah? Yeah?
And did did these ideas of mythical monsters come from
people finding fossils? So she's got another boat called Fossil
Legends of the First Americans, and she writes of how
triobyte fossils were apparently used as protective amulets by some

(32:52):
of the Ute people of Utah. So this one story
is that in the early nineteen hundreds there was an
amateur natural historian named Frank back With, and he noticed
a trial bite necklace at a Ute burial site. So
he asked some friends of his name, Joseph and Tedford
pick of It, who were members of the tribe, what
this meant, and they told him that the fossil was

(33:13):
called Timpei kansavaci, which meant little water bug in stone
and Beckwith also records that the men told him that
their elders believed that wearing the trial bites could protect
against sickness and bullets. But I thought that's kind of
cool that look somehow the fossils were intuited to have
been water dwelling creatures, and I wonder how people would

(33:35):
have figured that out back then. I thought that was
really interesting. Yeah, especially given that there would be there
would be plenty of terrestrial invertebrates to compare it to.
I guess maybe they maybe they saw more of the
of the crab in this creature than they did, uh,
you know, terrestrial bugs. I know, I wouldn't have been
that perceptive. I would have called it like roly Poly

(33:55):
or something. Well, anyway, considering that all the there are
all these shells everywhere, another possible answer to the question
of what caused the Cambrian explosion comes up? What if
the Cambrian explosion is an illusion? What if it is
not so much an event in history where all these
animals suddenly emerged, but a misperception created by the types

(34:19):
of evidence available to us, a reporting error exactly, It
would be a sampling bias. How would that be. Well,
like we've been talking about, we know fossilization has this
serious preference for hard body parts, and it appears to
be around the Cambrian period that biomineralization, right, the forming
of these mineral based body parts like skeletons and shells,

(34:41):
that that became common in many different animals. It's the
age of shells and exoskeletons. So it could be that
many animal forms had precedent in the Precambrian era, that
there were there were animals sort of like them living before,
and it's simply that we don't have good records of
them because they were aren't making hard body parts yet. Okay,

(35:03):
so this makes sense. So it's not it's it's not
that just suddenly there are all these creatures around with
their hard shells. There were plenty of creatures around beforehand.
It's just those were not preserved. Those are not as
president the fossil record, right, because they didn't have the
hard shells. Yeah. On the other hand, even soft animals
leave some fossil traces like tracks and burrows, And generally,

(35:25):
I think paleontolog just think that these types of fossils
are not as abundant as they would seem to be
if the Precambrian world was basically a soft, flappy copy
of the Cambrian. But either way, this leads us to
a kind of new way of framing the Cambrian question.
If the Camerian explosion is characterized as this explosion of
animal body plans, and especially those with hard body parts.

(35:47):
Why do the hard body parts show up? Like? Where
do they come from? Why evolve shells? And this leads
us to another possible answer to the to the cause
of the Cambrian explosion. What if it was caused by
a by aological innovation like predation? Oh so like you,
So you have all of these creatures that have that
have evolved and then suddenly they realized, Hey, we can

(36:10):
just eat each other. I can I can just eat
these guys. Why should I compete for the same same
meal when I can make them my meal and then
I'm essentially eating what they already ate, Right, Why would
I waste my time filter feeding when I can just
eat ted over there? Yeah. So Eric Spurling, the Stanford
paleontologist who is the lead author on one of the

(36:30):
papers I mentioned earlier in this episode, he explained in
a Nature News article earlier this year, or actually know
it was last year, that he thinks a very modest
increase in dissolved oxygen could have been enough to push
the the ocean chemistry over the edge to allow for
the emergence of predation and carnivory. As an ecological niche,

(36:54):
which would have thereafter driven evolution across the animal spectrum
as this arms race between predator and prey emerged. In
a world of predators, you need shells and you need
to be able to move. Yeah, alright, well this this
sounds the sounds plausible, and there's some evidence that this
is what was happening. Here's an odd fact. Sometimes trialobyte

(37:16):
fossils are missing chunks, not because the fossils have been damaged,
but apparently because the animals were One example, a specimen
of the trial trialobyte illinoid is found in Walcott's Quarry
at the Burge of Shale, has this distinct W shape
missing from its left side, as if something took this
kind of two fanged bite out of it. So in

(37:38):
this alien ocean, and you have to imagine me, uh,
in the voice of Ripley and aliens, who's laying the eggs?
What's taking the bites out of these trilobytes. Maybe it's
less dramatic if if you put it that way, but
but yeah, there's got to be something something else out there,
some sort of predator that is that is chopping down

(38:00):
of these guys. And this leads us to the second
monster in our Cambrian monster House, the weird shrimp. Alright,
hold that thought, because we're gonna take a quick break,
and when we come back, we will we will get
to know the weird shrimp, which is truly unless you're already,
you know, super familiar with this time period, I would
say it's the first really alien creature of the Cambrian period.

(38:24):
All right, we're back. Okay. So in Ewo, a British
Canadian paleontologist named Joseph Frederick Witty Eves was trying to
figure out how to classify some odd Cambrian fossils that
looked like headless shrimp shells. You can look at pictures
of these online, but um, you could see these five

(38:46):
hundred million year old imprints of these clawed tails and bodies,
but the heads were always missing. Yeah, they look they
basically look like entrees. Yeah. Yeah, it's like somebody pulled
the head off the shrimp and served it to you
in a little cocktail glass. Now, he named the organism
Anomala carus, which means weird shrimp or strange shrimp or

(39:08):
odd shrimp, however you prefer. Meanwhile, Burgess shale pioneer Charles Walcott,
which who is the guy who the Walcott's Quarry at
the Burgess Shield was named after, he collected and described
a fossil of a different animal. These preserved remains only
showed a large, disembodied mouth, a thick muscular ring shape,

(39:29):
surrounded by a circle of jagged teeth facing inward, and
Walcott believed this mouth to be the remains of a
jellyfish that he named Patoya. Al Right, so this would
be the mouth of an otherwise soft creature, that was
his argument. And all we have left is the mouth, right.
And it wasn't until many decades later that researchers Harry
Whittington and Derek Briggs figured out that these two weird

(39:51):
anomalous animals were weird and anomalous because they were different
parts of the same creature, a huge Cambrian editor that
retained the name of Anomala carus. The weird shrimp were
actually a pair of clawed appendages basically mouth tentacles for
snatching up prey and shoving it into the mouth parts,

(40:13):
and the mouth parts where the toothy ring, which had
previously been identified as patoya. If you've never seen an
image of Anomala carus. This is another thing to look
up well, or maybe we'll try to include a picture
on the landing. Yeah, we'll include a picture of this
this creature, because it's just too it's too weird. If
it need be, we will draw one and uploaded to
the side. It's sort of like impossible to make yourself

(40:36):
believe that this thing really existed on Earth. But I've
seen the fossils now, and so the reason these disembodied
parts were originally misidentified was a common problem in paleontology.
As we've mentioned several times now, fossilization is strongly biased
toward hard body parts like shells and bones. Anomala carus
did not have a hard exoskeleton covering its whole body,

(40:59):
but probably had a very light kitanous outer layer like
a shrimp shell on some parts of its body, and
when it died and decomposed, its body probably fell apart
into different pieces, and not all of those pieces were
preserved at the same rate. So it's rare to find
fossils that preserve any information about soft body parts, and

(41:19):
even rarer still to find soft bodies intact all in
one place. Rare, but not entirely impossible because since the
original discovery of what amounted to Anomala cars is killing equipment,
more fully preserved Anomala cars specimens have been discovered. For example,
one fossil discovered in nineteen two shows the spiked feeding

(41:41):
arms branching off of the head, within reach of the
crushing mouth ring, and all contained within the imprint of
this elongated soft body lined with lateral lobes that probably
undulated to power swimming. So if you're trying to imagine
this thing right now, you have to picture a kind
of wide, flat at lobed jellyfish snake undulating along through

(42:04):
the ancient seas, with a gaping mouth ring on the
underside that could squeeze with teeth but never fully close,
and then sticking out of its face a couple of
hooked fang tentacles lined with spikes. Yeah this this looks
like a creature that belongs in a Star Wars cantina. Yeah. Yeah,
it should be like having a drink and telling you

(42:25):
it doesn't like you, and it probably doesn't like you.
Now you you might be thinking, okay, so how big
were these things? Right? Like? A few inches long? Parts
found in fossil sites in China indicate that Anomalo carras
type organisms may have grown to almost two meters long,
which is around six feet. You know, people do those

(42:46):
like booking a swim with the dolphins thing. I think
people should book swim with the anomalo carras. They should
use some kind of DNA engineering to bring these things back,
you know, and then have you swim with them at
the resort the per day shouldn't explosion hypothesis is correct? Especially,
I mean, this was eating other animals was a growth industry,

(43:06):
so it it does make sense that that the the
successful model for eating other creatures would produce larger and
larger organisms, right yeah. So, but the question I guess
is if these things are preying on the you know,
the widespread triobittes of the ancient seas, I don't know,
would they take a bite out of you if they could.
So you're in the water with them. You obviously don't

(43:28):
look or smell like their normal prey. But then again,
they might just want to see what it tastes like.
It's hard to know. We kind of get into that
whole shark and gorilla area. I don't know if I've
mentioned this on the podcast, but I don't think so well.
Every time I go to the ocean, I comfort myself
regarding the risk or apparent risk of sharks and and

(43:49):
of course just shark media in general by thinking about
the just like a brief clip on The Simpsons where
shark jumps out of the water and grabs a gorilla
out of a tree, just ridiculous for several reasons, but
it drives home like this is this is something that
does not happen, is not part of the the the

(44:10):
the the energy model for either species, you know, uh
and and and that's essentially what I am. I am
a gorilla in the water, and the shark has not
evolved to eat me exclusively. It can if need be,
but it's not out there looking for gorillas. Right. It
might have also, though, evolved a sort of like prey
diversity curiosity. It might take a little nibble on you
to see what you're like, right, right, So I guess

(44:32):
that would be the main concern. But I'm guessing you
would have this element of surprise because, by the way,
I don't mean to be promoting like fear of sharks.
Obviously we're not their primary prey, right. But but I'm
guessing with with humans, if if we were to go
with our opening scenario and you were just dropped into
the waters among these things, I would hope you would
have this this element of surprise over them and they

(44:55):
would be a bit shocked and uncertain and hesitant to
approach you. So another thing that's really cool about Anomala
carres is that they have these amazing eyes. For a
long time, detailed evidence of non biomineralized arthropod eyes had
been hard to find, but in two thousand eleven there
was a letter to Nature that detailed this amazing find

(45:16):
at the Emu Bay Shale of South Australia, and what
they had found was preserved Anomala carus eyes, and they
found that they had a pair of two to three
centimeter eyes about five fifteen million years old, and they
were compound eyes made of at least sixteen thousand hexagonally
packed lenses, meaning these eyes would have been about as

(45:37):
acute as the most powerful arthropod eyes today, like dragonfly eyes.
And the authors think that this is uh that this
evidence of acute vision lends support to the idea that
Anomala carreras was a powerful, fast moving apex predator going
all throughout the water column, which and this would have
accelerated the arms race that triggered Cambrian biodiversity and i

(46:00):
O mineralization. You know, this also just makes me wonder, though,
would a creature like this have anything to fear? Well,
I mean probably not. I mean if it's the apex
predator of an ancient ocean. What, it's the biggest thing
out there and it's got the most powerful killing equipment.
What does it have to worry about? Nothing? Until you know,
the time traveling human shows up and starts clubbing them.

(46:21):
I guess that club they brought. You'd have to bring
your own club. That's the key here. But nothing dead
will go. Ah, well, you know maybe it's still living.
Tree branch will work. Oh yeah, maybe that. Somebody should
have told kyleys about that. I guess that wouldn't have
been all that effective against the determinator. Yeah, where are
they going to get a tree branch? And the desolate
post apocalypture? Okay, we're on a tangent here, so we're

(46:45):
gonna look at some more uh Cambrian monsters. But one
more thing about Anomala carress before we move on, there
is still a fascinating debate going on about how and
what Anomala carress ate. So some of these wounded trial
bytes that we discussed earlier have injuries. It really seemed
to match the two pronged grasping appendages of the anomal
caress and some experts believe that its mouth parts would

(47:08):
not have been powerful enough to prey upon TRIALO bytes
with their hard outer shells. So that kind of creates
a question like what was was it eating something else?
Like how could it have gotten through these hard outer shells.
There are a few options. Maybe maybe they were just
really beefy and they could crunch through those shells. Maybe

(47:28):
they had some method of prying the shells off of
weaker trialo bytes and sucking up all the soft parts inside.
Or there's also an interesting possibility I learned about from
the guide on our hike, David. Maybe they took a
tip from the crab shack down the shore and they
sought out soft shells trialo bytes who were in the
process of molting. So you you release your hard shell,

(47:52):
put that aside to be fossilized for people to find
millions of years later, and then you stay soft for
a little bit while you, you know, you grow. What
if they sought those out, the molten trial bytes and
nominoomb oh man, Yeah, I mean that could be. That
could be the very uh niche that they are exploiting.
When you turn to the model of of of eating

(48:13):
other creatures, what better time than the molting period. Okay,
So the trialo bytes and anomal carrass type creatures are
some of the main players that we see in UH
in Cambrian evolution, but there are also all of these
fascinating bizarre periphery organisms. Like Robert, would you like to
take us on a tour of the rest of the

(48:34):
Cambrian monster house? Sure? Yeah, we have some wonderful UH
specimens here to discuss here, and there's not there's not
necessarily as much data behind all of them. I mean
there's data, but it's maybe not as as sexy as
such as a trilobyte. However, they still have some some
fascinating features, and I think many of them would make

(48:54):
excellent Halloween costomes. I would say they're much sexier than
the trial byte, maybe just not as a robust step.
So the first one here I want to discuss is
um opabinia. I've often called the stock eyed vacuum cinabite.
That's a good description one that I think evokes the
alien qualities of this creature. So if you're not looking

(49:17):
at a picture of this right now and stuff to
blow your mind dot com, I want you to imagine
something like a shrimp or a lobster, but with rows
of side lobes along its sides, paddling along like the
ores of a like a galley spiking ship. You's got
these lobes on the sides, kind of like we described,
with anomalocras that undulate to move it along throughout the water. Right.

(49:38):
And you know, it is not that remarkable at the
the end, Like I said, if you were just catching
it a glimpse of it out of the corner of
your eye, that the back portion doesn't look that different
from again, like a lobster or shrimp or something. But
it's the front end of the creature that is is
rather interesting because it has a long, flexible proboscis tipped
with grasping spines, and the creature itself was about three

(50:01):
inches long, not counting this uh weird cool richie tentacle. Yeah.
Five eyes to right, five eyes on stalks. Yes, five eyes,
just standing right at you on stalks like they put
them on stalks. It's like just a mess with us. Yeah,
and I think this all sounds very love crafty and
but but according to the Smithsonian National Museum of Natural History,

(50:25):
a reconstructed image of the creature resulted in laughter at
a nineteen seventy two scientific meetings. So instead of looking
at this thing and thinking, oh, this sounds horrific, it's like,
got this reaching arm that you know is up to
no good with its spikes on the end. But yeah,
apparently when it was first presented, uh, other other scientists

(50:45):
laughed at the prospect of something this ridiculous looking. So
you have to think, so, it's got this reaching appendage
that's sort of like its mouth appendage thing, So what's
sort of like maybe sort of like an ant eater,
I guess, but it's obviously not a vertebr at, not
a mammal. Yeah, it was. The idea here is that
this would have haunted the soft sea bed and it

(51:05):
would would have reached into sand burrows with this, so
this spiked terminating wriggly arm to grab delicious worms and
uh and actually have a quote here. This is from HB.
Whittington from the enigmatic animal Opabinia regalis Middle Cambrian Burgess Shale,

(51:26):
British Columbia. This was presented the Royal Society b quote.
Opabinia regalius may have plowed shallowly in the bottom mud,
propelled by movement of the lateral lobes. The eyes are
presumed to have been capable of detecting movements in the
surrounding waters, and the frontal process to have been used
to explore the mud for food and bring it to

(51:47):
the backward facing mouth. The frontal process. That is the
most amazing euphemistic term for killing equipment. And then they
put the frontal process through the thorax the way that
my son Uh describes it with the animals when he's
like drawing dinosaurs. He says that this is the part
that makes the animal's eyes close and then die. Yeah,

(52:12):
so you know, the frontal process is the part that
makes the trial by its eyes closed. So this is
a this is a cool specimen. It's it's unique, it's enigmatic,
it's silly looking, but it's also you have to admit,
a very sensible organism when you really think about it
um it's it needs something to grab those worms. It
has a single you know, grabber to do it. Now.

(52:35):
It's It's also interesting that this one remains unassigned to
any other extinct or currently living major group. That there
are some theories, but for the most part, this is
one of those um, you know, abandoned prototypes you can
think of. You know, there's there there's nothing out there
that that we know of that is a descendant of

(52:55):
this thing. That's interesting because when I think about organisms
like this, I think about the relationship between manipulation limbs
and the evolution of intelligence. I mean, there's one way
of looking at the evolution of hominid intelligence, and it's
to say that, Okay, one thing that may have driven
humans and other you know, great apes to have larger

(53:17):
brains and more intellectual power than the average mammal is
that they've got free limbs that they don't always have
to use for walking and stuff like that to manipulate objects,
and that the manipulation of objects allowed them to you know,
have advantages in the manipulation of tools and stuff like that. Yeah,
you can't help but imagine like what if this had

(53:39):
been the successful uh limb of of of evolutionary ascension,
and that ended up with all of these different like
monolimbed creatures, you know, plowing about in the seas, climbing
up onto land and maybe getting to the point where
they're using that that one spiky tentacle to to type
on computer keyboards. Yeah, yeah, you see it in octopi to,

(54:01):
you know, having these free, these free limbs that they
can manipulate things with. I wonder could Opabinia, if it
hadn't gone extinct yet, could it have become the tool
using creature before there were even mammals. But instead it
just remains this this weird dead end that looks it
looks like if you decided to make an animal out
of random Lego pieces and he stuck that. I think

(54:23):
they still have that, that sort of twisty grabber mechanism
and the Lego kids today. Alright, the next creature on
our list here is the Hallucigenia. Hallucigenia well named yeh,
it almost doesn't need a cool nickname, but I know
you have one thought up already. How about the creeping
headless spike worm. Yes, yeah, that's because it works because

(54:47):
we're essentially looking at a tube of flesh with two
rows of spines on one side and one row of
mouth tipped tentacles on the other. And on either end,
if we're keep in mind here we're working from the fossils.
Here on either end there's kind of a dark stain.
Presumably one of them is the head. And presumably the

(55:09):
idea here is that, at least the early ideas that
it walked about on those spines and it waved its
tentacles above it. Uh so you had this still walking
tentacle waiver something with no modern analogy, no modern analogy.
It looks like something that you would see illustrated in
a Wayne Barlow alien book. Yeah, yeah, absolutely, or like

(55:30):
something um, I don't know. It looks kind of like
one of those blobs that sometimes shows up in a
Gary Larson cartoon and he's just trying to create a
weird alien shape. Yeah. I mean, it looks like something
that would come out of a dream. Thus its name.
You know, it looks it's hallucigenia. It's something that is
that that seems like a fever dream of brought to
life in a fossil. Now. I think this was first

(55:52):
first put together by paleontologists in the seventies, right right,
and then they had there was a subsequent find from
Chi I know that showed a similar creature with a
second row of tentacles tipped with claws, and then they realized, oh,
we have it upside down. The creature walked on the
tentacles and the spikes provided an upward facing protective array.

(56:14):
So that's a lot. I mean, it's still a weird
looking critter, don't get me wrong, but that's a lot
more in keeping us what we might expect. You know,
that's not that different from say, a turtle with legs
on the bottom and the protective display on top, or
any you know, various examples from the invertebrate world. I
don't know, is that less weird? I'm trying to think. Okay,
so it's it's like a worm and it's got these

(56:36):
long tentacles with mouths on them that it walks on. Yeah,
I mean, it's still weird, and it's got spikes sticking up. Okay, Yeah,
I guess a little less weird than walking on the spikes. Yeah,
I guess. It's kind of a fun experiment you can
play anytime you see like a crazy alien illustration. Try
to decide is it more alien if you turn it
upside down? Uh? Because yeah, you can either improve upon

(56:58):
the design or figure about how they came up with
it to again with maybe. Alright, so let's talk about
it a little bit bit more here. So, University of
Durham invertebrate paleontologist Martin R. Smith, who was an interesting
chap He has a nice online presence. He placed the
fossil of one of these creatures in an electron microscope
in an attempt to, you know, figure out more about it.

(57:21):
And one of the pressing questions was name, like, which
which end is the head and which one is the anus? Well, yeah,
I mean that that's sort of. I knew there was
some problem with locating its head, and that comes through
in my name nomenclature of it, the headless spike worm.
Now I mentioned the stains earlier, right, like, basically from
the fossils we knew we knew that there was like
a big stain on one end and a smaller stain

(57:41):
on the other, and one was presumably the head. So
the larger stain was was for a long time interpreted
as a balloon like head on this creature. But it
turns out it was very much a stain. It was
the quote decay fluids that had been squeezed out of
one end of the guts of the organism grows. Yeah,
so this was the anus in the head was on
the other side. And when they looked to the head,

(58:05):
you know what, they found hockey mask. Close they found
a smiley face. Yeah, a pair of eyes with a
semicircular grin. Uh. And it so it was sort of
like a they say, it was sort of like a
caterpillar looking creature. Yeah. Now when I say smiley face,
it's it's kind of abstract. I'm looking at an image
of it here. But but we can't help but look

(58:26):
at it with our with our human failings and say, oh,
well that's a smiley face. Oh hallucigenia, you devil you. Yeah.
So hallucigenia is a fun one for sure. Stealing my heart.
Take me somewhere even weirder, Robert, All right, well the
next one is will Waxia, and uh, I believe you

(58:48):
did you? Did you come up with a name for
this one or did I? Okay, I think I actually
came up with a few different ones here. So it
looks kind of like a prehistoric iron maiden. It also
looks like an organic battle holm or perhaps a grim
dark Pokemon, and it provides another splash of of the
bizarre to the Cambrian seas. So two rows of long

(59:11):
spines and a kind of plate mail armor of leaf
shaped ribbed plates again on something that looks like a hat.
It it looks like a spiked hat like plate mail
kind of scenario. I can't stress the armor analogy enough.
It's kind of like a half of a walnut with
with plate mail on it and knives sticking out. Yeah,

(59:33):
it looks like something an orc would wear on its head.
And uh, A lot of the fossils here are essentially
that we have of this thing are essentially flattened remains
of this natural armor, because again it's the hard parts
that were left with and we just have to try
and interpret what the soft tissue would have consisted of.
And there are different interpretations here. Now Martin Smith, who

(59:54):
I just mentioned earlier, he favors the mollus interpretation. He
says that their mouth, which would have been a radula
bearing two rows of teeth, have several similarities with the
teeth of modern mollus and uh and and they look
nothing like worm teeth, because that's the other argument is
that these are essentially worm creatures. Specifically they would be

(01:00:16):
bristle worms. But that's more of a controversial interpretation. So
there's not a lot of depth for that particular organism
other than it just looks really strange. And when you
when you see illustrations of the Cambrian sea, you will
often find it'll get it will get in there somewhere.
It won't be the central organism, but it will it

(01:00:36):
will have a place in the in the in the illustration.
Now I've got a question around among this ancient Cambrian
monster house, this sea full of bizarre alien creatures, we
have to imagine that modern day life forms can trace
their roots back to organisms that inhabited these oceans, especially

(01:00:58):
when you think about very successful, whole modern philo like vertebrates. Yeah,
because the whole idea here is not that like everything
dies often and and life begins a new Uh, that
some of these models would would have descendants alive today,
I'll be you know, rather different to organisms. And we
have just such a case with Pekaia. Though it's a

(01:01:20):
controversial example, right, yes, yeah, that this is not this
is not set in stone that the fossils, of course are. Um. Yeah,
you you referred to this as the ancestor fish slug
or potential potential ancestor. So if you're not looking at
an image of this creature, imagine a c slug that
swims like a modern fish, and you've got a clear

(01:01:42):
vision of Pecaia, or at least a clear vision as anyone.
The crazy thing about it is that that scientists point
to its not a chord, a precursor to the spinal cord,
and also a key aspect of this creature's swimming mechanics
as a reason that it could just be an ancestor
of all to bruts, including humans. But we're also throwing

(01:02:03):
a curve in all this because it has a two
lobed head that doesn't sound like any vertebrates I've ever
heard of. Yeah, scientists remain split on this now. A
nineteen discovery of a primitive fish in the Lower Cambrian
also suggests that it in Pecaya had an even more
ancient common ancestor. Okay, so it might be that this
thing wasn't a direct ancestor of existing vertebrates, but that

(01:02:27):
it might have been an offshoot of whatever was a
direct ancestor of living vertebrates. And I think it will
make a great Halloween costume for anyone out there who's
who's not sold on the previous specimens. Grandma fish slug. Yeah, yeah,
I mean I can just imagine it moving like you
you get used to seeing footage of sea slugs and uh,

(01:02:47):
similar creatures and the way they move, but this would
have moved if I'm if I'm reading it correctly, more
more like a fish, more like an eel. So imagine
like an eagle slug, and that's what you have here, totally.
Now there's one more. I thought it would be good
to mention because it's got a slightly love crafty in face, right,
Leon Coylia the blind whip Hunter. Yes, it looks kind

(01:03:09):
of This one's kind of hard to explain really, but
you know, it looks shrimpy, looks a little flea like.
But imagine a blind monster that stumbles around in the murk,
just bull whipping everything is vicinity with flails and then
just really whipping the heck out of potential prey. So
whips coming out of its face. Yes, and that's what

(01:03:30):
we have with leon Colia. Now we assume it was
blind because we haven't found evidence of IY stalks yet,
which if in the thing, of course, is that given
these previous examples, it's entirely likely that that that could occur.
At some point a future fossil find will reveal, oh, well,
they did have eye structures and they look like this,
but for the time being, the ideas that they were

(01:03:52):
seemingly blind. The creature here was about two inches long,
and it's usually classified as in as in our prode,
though sometimes it's thrown into the arachnomorph subgroups, which would
connect it, you know, more to scorpions and trilobytes. But
still it's a fascinating creature to try and imagine, especially

(01:04:13):
in this this changing time where eyesight is coming online
for various organisms and new new methods of exploiting other
organisms are becoming possible, and this one is just whipping
things with its face. I felt I can eat something. Yeah,
So I guess that's going to have to conclude our
tour of the Cambrian monsters. But I do want to

(01:04:34):
ask you, Robert, so clearly we have not exhausted all
of the fascinating questions about the Cambrian period and the
the emergence of biodiversity, animal biodiversity, especially in the Cambrian periods.
So I want to ask you which of the Cambrian
explosion theories we've discussed today appeals to you the most.

(01:04:55):
Obviously we haven't covered all of the possibilities. There are
other possible explanations out there. But what what? What What strikes
true to you? Like? What sounds right? Does it? Could
it have been cite as the thing that triggered all
of this biodiversity, or the innovation of predation and carnivary,
or the chemistry for biomineralization, or is it just this

(01:05:16):
sampling bias where you know, maybe that there isn't as
much bio innovation in this period as it seems just
from the fossil record. I mean, I guess I could
play it safe and say a little bit of all
of those, But but I guess I tend to buy
more into the predation and and cite arguments, with some
support by by by some of the additional arguments. But

(01:05:38):
but those are the two that I guess I feel
like they have the most meat for me. But then again,
I'm not a I'm not a scientist, you know, specializing
in this time period, but but those are the ones
that I feel like are the most Maybe it's just
calling to the five year old in me. The it's
the it's the explanation and involves creatures warring with each

(01:05:58):
other and battling each other and there for that's the
one that I can imagine. Yeah, it's hard to resist now,
I know, I've I think I read at some point
that one of the arguments against the site hypothesis is
just that site doesn't generally matter in the water and
especially in the deep water, as much as it does
on land. And not that it doesn't matter at all,

(01:06:19):
it does, but that you know, things like smell and
hearing and stuff like that are more useful in the ocean.
But yeah, I don't know, I'm not sure which I'm
most convinced by. The predation one seems very interesting to
me that if animals weren't really capitalizing on getting their
energy from other more large sized animals before and suddenly

(01:06:41):
they started doing that, that that could be you know,
a game changer. It's also kind of an original sin
type scenario too. It feels very mythic, right, like that
that the first creature to figure out that it can
it can prey on its fellow organisms. And how does
that occur? Like obviously it's it's not just a situation
of one day, uh this this creature just takes a

(01:07:02):
bite out of another one, Like it's going to be
a more gradual process and uh, you know, and and
likely begins with some sort of gray area of competition
for food, like for instance, a creature it becomes adept
at stealing food from either maybe stealing food from its mouth.
And what happens if you steal food from another creature's belly? Yeah, yeah,

(01:07:22):
you know, I mean that that is the difficulty of
this hypothesis is you have to imagine what's the process
that gets you there by gradual evolutionary change, Even if
it's geologically rapid, it still would have been gradual in
biological terms. Um, trying to you know, go from an
organism organisms that are all basically vegetarian to some organisms

(01:07:42):
eating other animals. Yeah yeah, Like another example that comes
to mind is, of course animals that will consume their
own young or their own eggs. We've talked about, you know,
the parental cannibalism. To sort of reabsorb essentially lost energy,
and how that could seemingly be an avenue into the

(01:08:03):
into interpredation, because if you're absorbing your own biomatter back
into yourself, then it becomes less of elite to absorb
the biomatter of another. I can also see a scavenging
to predation route that maybe, uh, the the gradual changes
that allow you to better and better extracts nutrition from

(01:08:23):
dead animals that you find on the bottom of the
ocean could eventually become useful in killing live animals right right.
Or you could just always do it and an angel
told you not to until a snake suggested otherwise, just
another possibility that could be it. Well, Robert, I don't
I don't get the feeling that we're done with the
Cambrian period. I think we may come back here in

(01:08:44):
the future to explore some other scientific issues and when
there may be other things to discuss with the burdge
of shale as well. Yeah, and and in general, I'd
love to do some more episodes in the future regarding
prehistoric creatures. I feel like this is something we come
back to time and time again. Well, I at least
on what a bi monthly uh, kind of pattern, I
guess so, I mean it's it's the seven year old

(01:09:05):
in me. I've I've never gotten over how much I
love dinosaurs and other weird organisms that don't exist today.
It's it's part of my love for monsters, and it's
part of what keeps bringing me back to paleontology. All right, well,
we'll leave it at that, but in the meantime, definitely
check out stuff to Blow your Mind dot com. I'll
check out the landing page for this episode because again

(01:09:26):
I'm gonna try to try to include images, illustrations of
fossil representations, whatever I can find for each of the
organisms presented here, so you can have some additional visual
idea of what we're talking about. And I'll include links
back to some of our other episodes that have dealt
with prehistoric organisms. And if you want to get in
touch with us directly with feedback about this episode or

(01:09:48):
any other to suggest a future episode topic, you can
always email us at blow the Mind at how stuff
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