April 10, 2014 • 56 mins
While evolution gets all the spotlight for moving species into better versions of themselves, but really it's natural selection that is the engine driving the process. Learn all about this elegant scientific observation that forms the basis of life.
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:01):
Welcome to Stuff you Should Know from House Stuffworks dot com. Hey,
and welcome to the podcast. I'm Josh Clark, There's Charles W.
Chuck Bryant, and there's no which makes us a very
special edition of Stuff you Should Know, harrier than Jerry. Yeah,
(00:22):
edition much harrier. No, let's see your hair man that
has a lot of hair hairsuite. He's like the original
Kings of Leon. I used to love those guys back
when they were like Tennessee hill Billy's. Yeah, and then
they got their glam makeover and I was like, it's
like Metallica after the Black album. Yeah, what happened? What
(00:46):
happened Metallica Lars. I think they enjoyed making loads of money,
truckloads of money. Didn't think more than being like heavy
metal parking lot guys. Yeah exactly. Um, hey Chuck. Before
we get started, we want to tell everybody you can
follow us on Twitter. That's why sk podcast. You can
hang out with us on Facebook, dot com, slash stuff.
You should know our YouTube channel search Josh and Chuck.
(01:06):
It's pretty awesome, and as always we have a wonderful website.
Stuff you Should Know dot com. That's right, you can
hang out with us outside of the podcast if you want,
if you want, no pressure. So how are you doing?
I'm great. I'm super excited about this topic because A
we're pairing it with our Charles Darwin show, Yeah, which
(01:27):
I guess came out last episode, right, aren't we pairing
the two? Yeah? I think we're doing Darwin first. Let's
do Darwin first, because I think in the Darwin episode
we say we should do natural selection. It's here we are.
But I'm just excited because to me, and I gushed
a little at Darwin's feet, this is my own personal statement.
(01:48):
I think natural selection is the most exciting and like
beautiful thing that exists. It's it's just it really turns
my crank. You know, you're like an old timey car. Yeah, yeah,
you know. I grew up this is again my personal story.
I grew up in churches most listeners now, uh, which
(02:11):
was heavy doses of of creation, the creation story. And
I remember, as a kid, even fully involved in in church,
thinking like I just this doesn't make sense to me.
I just it didn't add up. So natural selection it
just makes sense to you. Yeah. When I finally learned
about natural selection, like really really understood and learned it.
(02:32):
It just it made total sense because I can like
see it, it was tangible. I could make sense of it.
And again that's my own story. We don't poo poo
anyone or saying anyone should feel anyway, but we just
explain how things work exactly. You know. But I have
a personal attachment to this just because I think it's
(02:53):
like the grooviest thing going. Yeah, no, I know what
you mean. Like it it makes uttering complete sense. It's
almost um in capable of being appropriated to serve some agenda.
It just is what it is, you know, It's just there.
It's beautiful. I agree with you entirely. It's an elegant theory.
Its just super neat. Yeah. Um. And the wonderful thing
(03:13):
is is like there's even squabbles in the scientific community
over exactly how evolution works and processes, and regardless, everyone's
still like, yep, natural selection pretty much perfect. Yeah, it
just makes sense. I'm gonna have a t shirt natural selection.
It just makes sense. I have a feeling we'll be
(03:33):
getting an email with something like that eventually, So let's
talk about natural selection. I think a lot of people,
including myself, um, kind of had an idea of what
it was, pretty good idea, but not necessarily understanding the
ins and outs of it. And well, that's what we're
here for, is to explain the ins and outs of
natural selection. So, um, basically, a lot of people interchange
(03:56):
evolution and natural selection. That's incorrect. Um. Evolution is this
huge process by which species adapt and change to survive
in their environments, and the way that that moves along.
The mechanism that drives that is natural selection. So they're
not one and the same. Natural selection drives evolution. Yeah,
(04:20):
and who wrote this one? Was this? Uh? Grabowski? The
grabster I should have known. Uh, just very simply puts
it very early on the article. Organisms best suited to
survive in their particular circumstance have a greater chance of
passing their traits onto the next generation. That's right, it
just makes sense. I'm gonna try not to say that
(04:40):
every ten minutes, but just now that that's going on
in my head. Yeah, and and and um do you
want that on a T shirt? And natural selection is
like it's this ongoing, basically never ending process even when
organisms really kind of seemingly stopped developing, like they figured
it out. Yeah, but it's it isn't. It doesn't have
(05:02):
its own sentience. It isn't its own thing. Like you can't.
You can't attribute it to some sort of creator or
creation necessarily unless you believe that kind of thing. But
like if you're if you, it's very easy to give
it a personality, but it's not. It's the byproduct of
how organisms exist, and we exist by our genes and
(05:23):
by the fact that those genes change frequently within the
lifetime of a person thanks to what we understand now
is of the genetics, but also through reproduction. And from
these these moments, these periods where genes are up for
a change, they can completely or even just partially change
part of an organism, and that change may or may
(05:46):
not help the organism survive in the environment, like you
just quoted Grabanowski. And if it does, bay a natural
selection will root that out and it will propagate that. Yeah,
and uh. It also points out Darwin um he did
coin term natural selection and survival of the fittest. And
I do think that many people hear survival of the
fittest and they think of the lion eating the gazelle.
(06:09):
But it's also, like he says, the tree that can
disperse its seed where it needs to for those seeds
to grow or the bacteria that uh survives. It's not
you know, animal eating animal, although it can, right, And
so since we're on it, Chuck, fitness is basically um
like you say, like a tree's ability to spread seeds
(06:29):
and for those seeds to take rud because its grabs.
Her points out, it's not enough for a tree to
produce a bunch of seeds, which is its ability to reproduce, Yeah,
and its ability to survive long enough to even get
to the point to it where it reproduces. Right. That's
step one is to live long enough to be able
to reproduce. Step two, or the second part of it
(06:50):
is that that reproduction is as successful as it possibly
can be. Yeah, Like it says, not only you gotta
do it, you gotta do it well. So that tree,
it spreads tons and tons of seeds. If those seeds
um happen to um catch fire and sunlight, that's not
going to be a very good trait. But if they
(07:10):
have like a really hard husk that can survive the
elements but then disintegrates when it's digested by a raccoon
and then pooped out. You know, then all of a
sudden you've got that step two covered. Yeah, or if
it you know, if it's just dumb luck, if that
tree exists in a place where it's super windy and
can disperse the seeds better, uh, then it will propagate.
(07:33):
If not, then you may not even know that that
tree existed exactly unless you consult the fossil record. That's right. Um, Okay,
So I guess the whole point to natural selection is
that it is an agent of change, but it's also
a byproduct of change, and we kind of have to
take a step backward to figure out where this change
(07:57):
is happening. I already said it a little bit, but
it's in it's our DNA. It's in the DNA of
all living things to change. Yeah, well, traits were all
born with traits, and we inherent those traits from you
know who who made us our folks and um. But
(08:17):
it's not necessarily that's not necessarily natural selection at work
over like one generation to the next. Right, there can
be differences in traits. Like Darwin, as we'll see, points
that out himself. He's like, let's just get it out
of the way, Like just because you have brown eyes
and somebody else has blue eyes, that's not evolution. No,
and he uses a good example here of tall versus
short folks. Uh, tall people might be basketball players, people
(08:40):
might be jockeyscus the grabs are not Darwin. Yeah yeah, yeah,
Um did they have basketball? When was that advented? When
did the name sent in mid basketball? I want to
say eighteen forty eight, but it's probably eighteen seventy, not
too far off. So he makes the point that you know,
if something happened to where like jockeys could reproduce better
(09:01):
or basketball players could not reproduce anymore. Yeah, I was
trying to imagine, just make up anything, I know, I
was trying to and like I couldn't come up with it. Well,
just make make up something like being able to uh
dribble and dunk lowers your sperm count. Oh that's a
good one. See, that's what I'm saying. I think my
brain was in understand natural selection modes of my My
(09:25):
imagination grew less fertile, so it didn't survive, No, it didn't. Um,
And over time, basically basketball players don't reproduce as much
jockey's do, and over several generations, people are going to
be shorter on average. It sounds almost dumb, it's so simple,
but that's really the basis of it. It is, and
it's one of those things. It's like economics where it's
(09:46):
so simple that it's hard to wrap your mind around
it because you make it more complex necessarily than it is.
It's it's very similar for me. Um. And with that
basketball example which just happened, was humanity evolved to be shorter.
That was the end result. And that evolution took place
(10:07):
because there was a shift in the distribution of traits.
So before lots of basketball players, lots of jockeys, tallness
and shortness, which are traits or variations on the trade
of height in humans, Like we have height, we're not
too dimensional inherited by who bore you, right, not us,
(10:28):
your parents. We bore you in a different way. Um.
So the variations on the trade eventually gave rise to evolution.
So within just like our generation or even a couple
of generations, the differences in eye color, height or something
like that, it doesn't represent evolution, but changes like that
can lead to evolution over time. Yeah, if they are
(10:52):
changes that either aid or prevent your survival, right, Like
if something happens and all of a sudden human women
were all like, we're not gonna mate with anybody but
blue eyes. You can bet your bippy that within two
generations there's gonna be nothing but blue eyed kids. Yeah,
or grown adults getting blue contacts. That's a good idea
(11:12):
because they're tired of not having sex. But then maybe
our eyes would adapt to um the context and just
absorb them. Something has to happen. Your imagination is plenty fertill,
my friend, I guess so. Uh, and this all goes
back if we can go back a little further to
something called DNA um that is a chemical structure that
(11:35):
is the basis for everything that is. Is that a
good way to say it? And Uh? Within DNA are
sequences of traits, sets of traits, and those are the genes.
And then there's something called the LLL, which is really
where it all comes together. Is it all? Or allele?
Does I say ll adele? No? Adele allele? Okay? So
(12:01):
it's like a gene is like a specific sequence of
DNA that produces some trade. So height, like you have
a height gene like and when that gene is working
like you will grow. Yeah, the expression of the gene
is the allele. Yeah, that's the variation of that trait.
So imagine like as just a stretch of genes is
(12:21):
like a few boxes, say five of them, and three
are off the three that will encode to make brown eyes, uh,
and two are on the two that will encode to
make blue eyes. So each one's an allele, but the
one that's functioning gives you blue eyes. So in allal
is just a variation on a trade. And a trade
(12:43):
is produced by a gene, which is a sequence of DNA.
That variation is produced by an allele, which is a
sequence of the gene. And how often that allele shows
up in a population is the allele frequency. And it's
really simple. You hear alleal frequency and it sounds like,
oh that's science, but it's really pretty easy. That's what
they go to school force to learn the jargon. Yeah,
(13:05):
and uh, we did a really good episode on population
and uh, we're gonna be talking about here again though,
So we should just say that a population is a
group uh in one place that have sex with each other. Yeah. Um,
so like a zebra in Africa. He makes up he
(13:25):
should have used real examples because he said, let's say
there were zebras in South America. But I see his point,
that would be a different population because they can't have
sex with the zebras in Africa, because zebras can't swim
across the ocean. And a lion in Africa is in
a different population than a zebra in Africa because they
don't do it right. They can't. It's an abomination. It is.
(13:47):
You come up with a zion, that'd be kind of cool.
I guess, sort of like a tiger. Probably maybe that's
what a tiger. I think. It's So you were talking
about populations and you're in a little frequency. So, um,
you could conceivably quantify the alleal frequency of blue eyes
(14:10):
and the human population because we transcended, like the difference
between Africa and South America. Like we have planes now,
so we we all have access to sex with one
another as a population, as long as you have a
passport and some money for a plane ticket. Um. So
speaking about a lieal frequency, Um, the point of that
(14:32):
whole thing is that with evolution, I guess another way
to put it, the way it grabs or puts it
is evolution is just a shift or a change in
alleal frequency. And the reason that that change takes places
because those alleles that become more and more widespread and
distributed it across the population, UM have made that organism
(14:58):
more likely to survive, to reproduce, and more likely to
successfully reproduce. Yeah, that's it. That's it. That's the evolution
driven by natural selection. Do you want to quit? I
don't think we could top at this point. Now it
does get more interesting. Um Alile's create are created in
a few different ways. UM. One is called a mutation,
(15:20):
which you probably heard of. Uh. These are random changes. Uh.
They are pretty rare, like the X men. Yeah, very rare,
very rare mutants are. That's why they got to hang
out with the president a lot. Yeah, but the president
was also a mutant, wouldn't he. Oh yeah, eventually Kelsey Grammer. No, no, no,
the president was the guy with the son with the wings.
(15:44):
I thought, ye, his son was the mutant and the
president the president. But I think Kelsey Grammer eventually was
elected president Blue president, Blue Harry President. So to me,
the cool thing about mutations is is they can be
completely new traits that are introduced that are completely different
(16:05):
than anything you've ever seen in that species, which is
pretty radical. Another way is just like we've been talking
about sex a lot reproduction just with animals humans. That
is the way that an aile can express itself. Right.
It's the mixing together when when your mom and your
dad love each other very much and they copulate. Um,
(16:28):
there sperm and egg mixed together, break down their DNA
and it's glorious, fantastic um little mini explosion inside the
womb and uh, and then it really it recombines into
a totally new form that shares part of the dad's
DNA and part of the mom's UNICH to make a
(16:48):
new human. Yeah, and you get all the bad traits
from each of them, right, hopefully you get all the
best traits. But that's the point of sexual reproduction, which
was itself naturally selected, because it increases the potential that
you're going to inherit uh, good traits that will let
you survive. That's right, there's just more traits out there.
(17:10):
It's like um. I think it was the Sense of
Smell episode we did where we talked about pheromones, the
idea that pheromones among humans, we we can still detect
them even though we don't know it. And the whole
reason we can is to smell out other people's immune
system and we want somebody with an opposite immune system
of RS. So when you put the two together, it
(17:32):
produces a little mini superhuman who can't be killed. There
was an interesting study I think where they just had
people smelling things, but the gauging attraction levels right. But
it's based on the premise of sexual reproduction, which is
the combining as many good traits as possible make somebody
with a lot of them. Uh. And then the final
(17:53):
way that um alile's are created is um genetic recombination,
and that would be in the case of like a
bacteria who obviously don't go out and have sex with
each other um, but they do absorb DNA that they
get from other bacteria and basically make it part of them. Yeah,
they think that's where the ukaryotes came from. Yeah, the
(18:15):
mitochondria was its own thing and it became absorbed by
some ancient cell to serve as like the power center
of the of the cell, and from that like gave
rise to everything with the backbone, everything that's not a
bacteria basically, so fish at first, I guess yeah, but eventually,
like it all, it all just came to that and
(18:36):
it's still going on today. It's just two organisms in
one neat yeah that's super neat, and then one other thing.
Like there are three ways that this could happen. That
um that new alliles could be introduced. But um, I
wonder if epigenetics will eventually be added to that. Yeah,
(18:56):
because think about it. I mean, it's a change in
gene expression, right, So yeah, I could see that leading
to I guess I guess it could be classified as
a spontaneous mutation. I guess it would fall under that umbrella. Yeah,
but so much leads up to it. I don't know.
I'm with you. What's out of fourth? Okay, et the
genetics is officially added as a change to Allele's I'm
(19:21):
sure we'll get an email from someone that's super smart
that will explain exactly why that won't happen there. Like,
first of all, Chuck was right, it's allows so Chuck
we um. You know we said that all of this
starts at DNA and the fact that it changes, we
actually should go back even further, um than that, uh,
(19:43):
into the backdrop of nature, the environment, the reason that
DNA changes, that traits change over time is because of
a little thing called death. Yeah, we all die and
how to avoid it exactly. It's it's the combination of
the two things. We're all going to die, and all
(20:04):
organisms appear to be driven by a desire to put
off that moment as long as possible, So we have
an instinct to survive. Right. The problem is is the
processes of nature are trying to put us down all
the time, so there is a inherent struggle to survive.
So when you combine our desire to live with nature
(20:28):
trying to kill us all the time, it forms that struggle.
The struggles have survived gives rise to the changes in genes,
which eventually are selected and convert to evolution. So it
all begins with the struggle to survive and the desire
to survive. Right, And this is spelled out by Darwin himself. Yeah,
(20:50):
should we read some of his quotes, Uh this is
These are from the on the Origin of the Species,
which if you just listen to the Charles Starwin, you know,
that was his most famous work that he put up,
one of many, but that's his uh you know, warrant Peace.
It's close second was my travels with Timmy about his
pet rabbit and he going around the county bothering neighbors.
(21:14):
So he here are you with the Here a few
of the basic tenants in on the origin of the
species and with some quotes from Darwin himself. One is
the organisms show variations of a variation of traits. Yeah,
that's him just getting it out of the way, like,
don't be dumb. If you think that your your dad's
blue eyes and your brow and eyes are revolution, you're wrong. Okay,
(21:37):
I like that better than his quote. Actually, let's do that.
Let's do Josh's take on his quote. I'll do what
I can, all right. Uh. Number two is more organisms
are born that could ever possibly be supported by the
resources here on the planet. That's right. Uh, stop being
such an idiot. There's such a thing as scarcity, don't
(21:57):
you know that. I mean this is great. Um, I
feel the birth of the new podcast coming. Number three. Therefore,
in conclusion, all organisms must struggle to live. You already
kind of covered that, okay. Um. Number four, some traits
offer advantages in the struggle. That's right. Uh, those are mutations,
(22:20):
and as Josh will eventually predict, epigenetics, not always mutations
though right changes to Allele's um. Organisms that have those
traits are the ones that will help you survive, are
more likely to be successful and reproduce and pass them on.
And then finally successful variations the ones that we have
(22:40):
just talked about that allow you to survive and reproduce more.
They accumulate over the years and the generations as they
are exposed to something we'll talk about in a minute
called population pressure. Right. And he points out too that
this is essentially specific and local. Like UM, if humans
had a right where you cooled extremely easily all the time, UM,
(23:04):
under under all conditions, it wouldn't play very well. When
you move to the northern latitudes, you die, so it
would be selected out of populations in the northern latitudes.
But if you lived in the tropics, it would probably
be selected um and propagated over time because you probably
have a lot more energy. You wouldn't just be laying
(23:24):
around fanning yourself with palm fronds. Well you do that too,
but you wouldn't need to. Yeah, but it's just it's
a nice experience. UM. So I mentioned population pressure, and
that's a key here to understanding this whole bowl of soup.
And we'll talk about that right after this message. All right,
(23:46):
So here we are in the stew I called it soup.
It's really a stew of evolution and that section. So
we need to talk about population pressure, which is basically
anything in a population that makes it tough for your species.
Are you, as an individual plant or animal to survive it? Yeah? Again,
(24:06):
because there's such things scarcity that means you compete with
people in your species or people outside of your species, right,
like a lion wants to eat you. Yeah, there's always
it's always going on, yes, um. And then even if
you lived in total harmony with all the plants and
animals around you and vice versa, nature is still shooting
(24:27):
lightning bolts at you, train your floods, droughts, famine, all
that stuff there is always in and is Darwin put
it like every organism struggles to survive one way or another. Yeah,
And that can really speed things up as far as
alleal frequency change, Like if you flood it out an
(24:47):
entire country, you're gonna see some big changes within a
generation or two. It's not necessarily over hundreds of years,
that's right, um. And that's because Uh. When you have
something especially like uh, a flood or drought or just
some severe increase sudden increase in population pressure, it goes
from just background population pressure to something very acute and pronounced.
(25:11):
I got a lot of the population dies off. Yeah,
Like his example is pretty great. Actually about the fire.
Let's say a fire killed all the vegetation under fifteen
feet and a population of giraffes, anything under fifteen feet
is gonna have a hard time reaching food, and so
they're gonna start reproducing and making taller giraffes pretty much
(25:34):
as fast as they can write. The ones that can't
reach food will die off, a lot of them before
they can reproduce. The ones that can reach food will
live to reproduce, which will produce those taller giraffes. Um,
And what just happened then in that giraffe example is
called a population bottleneck. Something happened that took a large population,
reduced it down to a smaller amount. And then usually
(25:55):
in that smaller group, there's going to be some traits
or whatever that used to be evenly distributed among the
population that are now really concentrated and clustered. And like
it could be something super rare that is now the
trade right exactly. So if you have a super rare
trait spread out very evenly among a large population, that
(26:19):
trait may or may not ever be selected, and if
it is selected, it may take a very long time
to be selected because there's so many other competing traits. Well,
when a lot of those other competing traits are narrow
we weeded out, and you have that population bottlenecked, those
traits are going to be very pronounced and they they're
going to be selected very quickly. So you have a
very quick change in evolution as a result of sudden
(26:42):
acute population bottlenecks. Yeah, it basically becomes the norm. So
in that area of where the fire ended up killing
shorter giraffes, the norm will now be super tall giraffes exactly.
And don't say chuck. All giraffes are super tall, super
super tall, super super tall. And this is apparently happened
to humans. Um there's a population bottleneck. Supposedly around seventy
(27:04):
tho years ago. Um uh, there was something called the
Toba eruption, huge supervolcano created like a six to ten
year long winner and dropped the number of humans Homo
sapiens down to something as low as possibly three thousand people. Yeah, so, uh,
the planet on the whole planet, and they're not quite
(27:25):
sure like what what um variations were selected out of that,
but you can bet there was an enormous change within
years of that event. Boy, I wonder what it was
like before that, right, it's pretty interesting. So let's say
the giraffes, like everything was hunky dory, no fires, no nothing,
but just some of them decided that they wanted to
(27:48):
see if there really are no such thing as zebras
in South America. So they hop on a boat and
they sailed to South America and they establish a new
little giraffe colony there. Yeah, well we'll result from that
is called the founder effect. And there is a band,
by the way, I already looked, no, yeah, I thought
there's gotta be one, and it is h and I
(28:09):
listen to their song. How is it? It was pretty good?
What kind of music, you know, sort of uh, giraffe
in the Giraffe shoegazy. Okay, not bad? Um so anyway, Yeah,
the founder effect is when you quite literally, when a
population founds a new area and don't have sex with
(28:29):
that other population anymore. Right, So, and you can have
very different traits from even if it's a giraffe, from
the ones in Africa, because they set up camp in
a new place, right, and it's almost like an unforced bottleneck. Yeah,
you know they have voluntary bottleneck. Yeah. Nature didn't kill
off a bunch of the population. The population just broke
(28:51):
off from from a larger group to a smaller group.
And that smaller groups probably going to have some weird
trader too that are going to be select and and
push evolution along faster than usual. Yeah, alright, let's talk
about this then. Okay, let me pose a question to you, sir,
that I know the answer to. Uh, what about things
(29:14):
that don't evolve anymore? Buddy? What about like the shark
that's been about the same for millions of years? Show
me your natural selection? There? I got this, Okay. So
sharks are a great example, um, because they haven't changed
in millions of years because they don't need to. Well,
because basically they became apex predators a long time ago
(29:37):
in their environments, and their environments went unchanged enough so
that sharks didn't need to change. They are basically as
far as natural selection goes perfect. Yeah, they early on
figured it out. It's like, all right, I've got my
my teeth and are great. My my gills are working.
I can send electrical impulses from can swim super fast,
(29:58):
I can kill everything I see. As long as something
doesn't punch me in the nose, I'm pretty much good.
Or kill me for my sharks, then well that's yeah.
It makes you wonder how sharks you are gonna evolve now.
But let's say pre human fishing, so, uh, two hundred
years ago up to from several million, maybe tens, I
don't remember how long sharks have been around virtually unchanged. Yeah,
(30:23):
so uh, let's say from millions and millions, millions and
millions and millions and millions and millions of years ago
up to two hundred years ago. Sharks are virtually unchanged
because they hit their peak and they're fine. But that
doesn't mean that they have gone unchanged or that natural
selection hasn't exerted an effect on them. Basically, what happens
(30:45):
is they're still undergoing mutations through reproduction. There's new allele's
showing up, but none of them are holding it. Can
hold a candle to the perfection. That's been achieved by
the shark, so they get selected out. They don't get
a chance to um to reproduce in the population or
become distributed amongst the population. So if you still have
(31:08):
natural selection weeding out, but rather than changing the shark
population or the shark species um our family family you have,
you have a natural selection as an agent of stability. Yeah,
or I guess if let's do a hypothetical, if we
were going to use shark finn shark finning as an example,
(31:30):
Let's say only sharks with you know, perfectly triangular gray
fins were selected out right to be finned and cut
off for shark fin soup. So that means sharks that
have like weird spots on their fins would not get killed.
So theoretically, hypothetically, over generations, we might see sharks with
(31:53):
only spotted fins, and that probably will happen because of
the sudden and acute population pressure being exerted on sharks
by humans. There has to be some sort of forced
adaptation that's gonna occur. Yeah. I don't know what the
criteria for a good fin though is, or if they
just take them all like whatever they can catch, but
(32:13):
I mean it could be as simple as something like
UM figuring out that they like just swimming deeper and
not coming up and like within the humans grass like
just yeah just stay. Yeah, we should say that that's
a really good point. UM. A trait isn't necessarily something
that is um visibly apparent, like it like height or
(32:35):
something like that. It can be an ability or a
proclivity like grabster uses the example of UM dogs have
evolved UM the trait of UM hanging out with humans
and chuck, UM tell them about the elephants because that's
a pretty good example of what we're talking about. Sharks. Yeah. Yeah, Well, elephants,
(32:57):
as we know, are killed many times for their ivory tusks.
And it's sort of a no, it's a good news
bad news scenario. You would think, hey, good news, there's
some elephants that were being born without tusks at all,
so they're not being hunted. And over the years, now
there it went from like like close, now are not
(33:22):
born with tusks, So you think that's awesome because now
they're not being hunted, but they need those tusks for
digging in defense and things like that, so they're they're
losing a valuable trait which is going to put stress
on the population as a whole, I would think over time.
But in the near term it's been selected out because
it's keeping the elephants alive because the ones that were
(33:43):
naturally without tusks weren't being killed by poachers, so they
were allowed to reproduce more frequently than ones with tusks
that were being killed. So, yeah, you have a within
a human lifetime, within seventy years or so, the population
has evolved. Yeah, that's what I mean by like you
can see it happening in front of us, right, And
(34:05):
this is where the debate comes from. Where I was saying, like,
scientists even debate on how evolution changes or happens um.
And there's basically the difference between um gradualism or punctuated
equilibrium and gradualism is just over time, very slowly new
ah lials appear, and some of them tend to make
(34:27):
organisms fitter, and so they'll eventually, over very long stretches
of time, be selected out and then uh, punctuated equilibrium
is like we're talking about with the African elephants, where
there's a sudden population pressure and all of a sudden,
this organism or species is forced to evolve, and they do,
(34:48):
and then after that everything evens out for a little
while and stays the same until the next catastrophic event. Yeah,
I don't get it. There A it says there's an
ongoing debate about that. Can't they both exist? I don't
understand why they don't both exist. It seems like one
is just constant background evolution and the other one is
um like evolution as a result of you know, sudden
(35:09):
acute crises. Why wouldn't they both think? I don't understand
it either, if the looking at them. Okay, Chuck, So
let's go a little further and well, I guess we'll
go back to jeans. But um, remember you know a
guy named Richard Dawkins, Right, He wrote a book in
the seventies called The Selfish Gene, and it basically we
(35:30):
were talking about, you know, the debate between gradualism and
equilibrium punctuated equilibrium. Well, Dawkins came along and said, you guys,
shut up for a little bit, let's talk about this
the Selfish Gene, And he just basically reframed the entire
way that people look at evolution. Yeah, I thought, I
think it's pretty interesting. Uh. The essence of it is
that as long as you reproduce, then natural selection doesn't
(35:55):
care about you after that, right after you've passed on
your genes. That's the important part. Uh. In the case
of spiders is one great example. Sometimes the male gets
eaten right afterward. Yeah, or like praying manness. This didn't
the female eat the the male's head, like bite the
male's head off, And we're talking about praying mannesses, So
(36:15):
it's okay to say female um in that case. Though
both those cases, natural selection doesn't care. The male has
done his job. He is propagated and passed down the
allele and it doesn't matter if he dies or not.
Right afterward. It doesn't put any stress on the population. No.
And that's like a really there was a tricky thing
(36:36):
before Dawkins came along. It was like, wait a minute,
there's a real problem with natural selection if if the
whole point is for something to be able to reproduce
and reproduce successfully, like, why would there be um adaptations
that kills Yeah, where like the organism is killed like
as a result of reproduction. That doesn't make any sense.
(36:57):
And Dawkins came along and said, it doesn't make sense
if you stop look king at organism and start looking
at the genes. Basically, like none of that matters, right,
So he he made his point so well that it
actually got a little bit out of hand. Um and
it came to be known as well. It was the
selfish team before, but basically it was. He characterized it
(37:18):
so well that it became a character. Jeans became a
character almost like they had hijacked organisms and we're using
them as husks to pass along themselves, like a virus
or something like that. Um and Dawkins came out a
number of times and it's like, no, that's the wrong interpretation,
that's not what I mean. But it's still essentially the
(37:38):
same thing. It's just m yeah, yeah, we are we
we we are a means of passing along our genes.
And if you look at it through the lens of
natural selection, the the as long as the genes are
able to be passed along, the vessel is no longer necessary.
So therefore the head can be bitten off by the woman.
(37:59):
That's right. But like we said, this isn't widespread, but
it does help explain things like spiders, right, you know,
But there's a big flaw in this selfish gene theory right, well,
and Dawkins theories as a whole. Right, there's the flaw
is is that there's such a thing as altruism. Yeah,
and this is you know, humans and animals that, for
(38:22):
no reasons based on natural selection, desire to help each
other doesn't benefit you in the least at all. Know it.
As a matter of fact, it can harm you before
you're able to reproduce. So even from the genetic level
of the selfish gene um, it doesn't make any sense
because you're the genes are allowing the organism to be
(38:42):
harmed before it could possibly reproduce. What why Why does
someone have an instinct to jump in an icy river
to save somebody? And they have found that it is
instinctual and that it happens in infants with like zero
cultural training. It's like part of us. Yeah, and it's
not a human it's either. There are plenty of animals
that um that display altruism as well, like mere cats
(39:07):
are big on altruism. Yeah, and I like the explanation.
It makes again total sense to me. Something called kinship.
If you've got a couple of different families, took Tuk's
family and and Bartok's family. Well, Bartok is a composer.
But what's another good cave man name. Uh, yeah, that's
(39:29):
a great one. So Mango's family is very selfish. They
don't like to share their their stuff. They're all competing
for the same food. Tuktok's family is very generous. They
like to share things. So over time they will be
a more successful family because they have been altruistic and
shown that kinship and they're they're improving their chances of
success by combining their their efforts into a group effort um,
(39:52):
which is kind of like that Paleolithic warlessness we talked
about in the Cave Dwellers episode. Oh yeah, where everybody
just kind of figured out that, like they could be
more successful if they stopped fighting and started harvesting together. Um,
and if you kind of look at it like that,
like everybody coming together as a group for a common goal.
You're also looking at super organisms. Yeah, have we done
(40:15):
one on ants specifically? No? I think we should. I agree,
because they are about the best example of a super organism.
It's basically the little worker ants aren't doing the reproducing.
They can't even reproduce their that goes to the top dogs.
They only get to do that. So all those little
worker ants aren't even passing on their genes, but they're
still busting their little aunt butts for the colony. And
(40:38):
um a super organism basically then is to step back
and say, let's not look at ants, but let's look
at the ant colony as an organism, as one organism,
And that explains the altruism in that ant sacrificing its
own ability to pass along its genes in order to
serve the colony as a whole. Then it makes sense
like Papa aunt is going to pass down the jenes.
I just need to make sure Papa aunt has food
(41:00):
and water, right, And you can also use that same
um argument to explain why, Like it would make sense
if um, you know, you jumped in to save your
son from a river. That kinship explains that. But why
would you jump in to save someone else's son. Well,
if you look at it like, well, this kid's part
of the same species and shares a lot of the
(41:22):
same genes as you, you're ensuring that your species genes
are passed along. Yeah, and you get to humble brag
on Facebook Yeah, how bad big time? Oh pretty boring day.
Just saved the kid from the river and the icy river. No, biggie,
just helped ensure as jeans get passed along. I guess
a humble brag that would be, um, well, it looks
like my shoes are ruined that I just bought, jumped
(41:44):
into an icy river, and saved the kid. Yeah, that'd
be good one. We should start this doing fake humble
brags on Twitter, Facebook. Oh, this brand new BMW I
got has the windshield wipers are busted. Not a day
for it. It's raining. That's just being a jerk, Okay,
all right, So now we should talk about something that
(42:06):
also excites me. Vestigial and attavistic traits. Um. All organisms
carry some trait that is really no benefit and really
is no longer expressing itself as a means to help
you survive. But it's not harming you either, so it
hasn't been selected out, so it's just there. And UM,
I've got some pretty good examples in the human body.
(42:29):
UM one summer behavioral summer actual organs like the appendix.
Many people think the appendix is of this vestigial organ
I heard that it might fight cancer. Well now that
now scientists are starting to say, we think it might
fight cancer, or it might house um like bacteria that
(42:50):
helps you aid in digestion. So everybody who's a pendics
we took out get inline. We're gonna put them back in.
But for many years, and I think the debate is
still out whether or not it is a remnant from
primate ancestors when um we had to digest like plants
like super rich in cellulose or something. Yeah, I got that.
We don't anymore. So that's why the appendix really does nothing.
(43:10):
Back when we were giant termite men, scary time sinuses,
that was what we were like. On the other side
of the population bottleneck, giant termite people. Sinuses supposedly may
um there. It's also debated. But their pockets of air
in your face, and no one really knows if they
serve any kind of biological function or not. Yeah, and
(43:32):
they kind of suck too, because they get infected. They
can't get infected the coxics. It's pretty exciting because it's
a tailbone that used to be a tail, and some
people are still born with them. Yeah, and the people
who are born with tails are atavistic because they're out
of atavisms. It's it's a vestigial remnant that UM expresses
(43:57):
itself very closely to the way it actually used to be.
It's not just a trace of it anymonger. It is
like it's like that Alleale saying, hey, maybe we should
go back to tails again. What do you think? But yeah,
it's not um. Just so you don't picture like a
human with a big four ft long monkey tail, it's
usually like a bumper or something. Didn't George Costanza have
(44:20):
a tail? And uh what was that one? Jack Black
Fairly brothers? Oh yeah, yeah, shallow, yeah, yeah, I think
you're right, and you could wag it. I don't remember that.
Uh what else? Um? Oh, here's a behavior um of
this digital behavior of the palmer grasp reflex. Oh yeah,
(44:41):
I thought this is cool. It's pretty neat. When you
go up to a little uh stinky, dirty human baby
and you put your finger in their hand or their
foot even it's gonna grab it like super hard and
super strong. Yeah, like Popeye basically, or like a little
baby monkey trying to hang onto mama, cruising through the
jungle through the grabbing onto the coat their mom's coat. Yeah,
(45:04):
so basically that's a behavior they think is is like
a human baby now doesn't need to grasp hold of
something that hard at six weeks old, So it's a behavior. Maybe.
So we we played tennis thanks to a vestigial behavior
and ability, I don't oh got it being able to
grip that racket? Yeah? What's what article is this from?
(45:27):
Is it? Um? Was it? Ion nine? Yeah? I think so.
It was kind of silly, But these are some pretty
decent examples. We we've talked about in male nipples before,
you know, we did. We did a whole episode on
um goose bumps, the erector pilly. I've never heard of this?
Oh I did it? Dump be dumb on it? You
want to explain what it is real quick? There you
go ahead, okay, Um, everyone has had goose bumps. The
(45:50):
erector pilly are those muscle fibers that give you goose
bumps when you don't even necessarily want them or need them. Right,
there's little musts that are attached to your hair follicles,
whether you have hair there or not any longer, and
they press it up so that your hair stands on end,
either to make yourself look bigger, so you're scary, or
(46:12):
because you're cold, to make your coat fluff out, as
in when we used to have coats because we were animals.
Another vestigial trait, and uh, my favorite one aside from tonsils,
is the like a similar nearus. Did you like how
you asked me if I wanted to do it? And
(46:32):
I was like no, And then I did it anyway.
I knew it. I knew that was coming. If you
look in your mirror and you look at your eyeball,
and you look in the little inside corner of your eyeball, um,
you're gonna see a little fold of tissue and it's
not the little bump, but it's that little thing in
the inside corner of your eye that is a remnant
(46:55):
of a third eyelid. What's it called? What kind of eyelid?
The p L I C A plica or like a
similar nearis And uh, apparently we had third eyelids that
would that were clear, so you could like wash your
eye and still keep an eye out for predators. And
they would come from the side rather than up and down.
(47:17):
They moved horizontally. Yeah, like a snake or a reptile, yeah,
or a bird. They still have them, Man, we do not,
but we still have that in the corner of our
eye even though it does nothing. So here's the thing.
We have the jenes then to make that. Yeah, if
we needed it again, so that Allele could possibly come back,
(47:38):
like we could have people who were born with that,
and like if it ended up helping us, Um, like
if we could sleep with our eyes upen to watch
the zombie invasion or to watch TV better twenty four
hours a day. Uh. Just the fact that we can
wiggle our ears, that's a vestigial trait. There's no reason
why we should be able to wiggle our ears. I
can wiggle, mind, can you do them one at a time,
(47:59):
you're wiggling you're eyebrows. I'm gonna go in my whole face,
I know. Can you do one at a time? Like
that's pretty Actually, well that means like human's going bananas
right now. So, uh, that means that maybe Josh's ancestors, Uh,
we're a little closer than mine. And as far as uh,
(48:22):
monkeys directing their ears to listen out for predators. Yeah, no,
it means I'm less evolved as a human being. I have,
like the ability to move ears, so I can hear
things that I don't need to anymore. And I'm fairly harry,
So this has been a depressing episode for me in
that respect. I didn't want to mention any of that stuff. So, Chuck,
(48:42):
we talked about um African elephants. You want to give
a couple more examples of uh natural selection and action.
The ball worm. Sometimes it happens super fast. In the
case of the ball worm, it's happening faster than we
can create toxins to kill them. Yeah, like they treat
now with no the genetically engineered so cotton produces it itself. Yeah,
(49:04):
I guess it's not treating I guess it is originally
treated cotton. But now cotton is growing with this toxin
that is supposed to kill bullworms. But enough bulworms h
were immune to that that they were the ones that
went on to do the most reproducing to eat the cotton.
I'm sure that that first generation of bullworms were like,
(49:26):
I'm so wasted off this cotton, but I'm alive. Uh.
And then the clovers. Some species of clover have mutation
that made poison cyanide leak from its cells, causing it
to be bitter. Therefore it wouldn't be eaten. Isn't that weird? Yeah,
just that the clovers like don't eat me. Yeah. I
make cyanide somehow. Yeah, but unfortunately, when the temperature drops
(49:50):
blow freezing that sells rupture releases that cyanide into the
plant and it kills itself. However, in warm climates that
doesn't happen. So what you end up with is clover
in warmer climates that's completely different structurally cellularly than the
one in the colder climate. Yeah, the warmer ones produced sanide,
the ones in the colder climates don't same clover. It's
(50:11):
very much like that example of Um, you know the
humans that can cool constantly playing well in the tropics
but not in north Pretty cool stuff. Yea, man, I
love this. You got anything else? I got nothing else?
Oh well, let's talk about ourselves a little bit real quick. Really, Yes,
(50:33):
what's your sign from the Pisces? I can't wiggle my ears? Um? No,
humans like we have, like I was saying, we have
jets now, so like we're one large population right. Um.
That's just one example of how we've essentially taken ourselves
out of the evolution game. We even more to the point,
we have such thing as birth control, artificial birth control. UM,
(50:55):
we have a lot of different things that we do
inadvertently or advert only to UM, to adapt, to change ourselves,
to change our ability to reproduce whatever. So I wonder, then,
are we UM out of the evolution game already forever?
(51:16):
Will we ever be able to if we're not? Yeah?
And I mean is that the case? Like I know,
it's the goal of trans humanism is to say so long,
suckers the evolution and just be totally in charge. But
I also wonder, like UM with birth control, birth control
is an artificial it's it's unnatural selection. Yeah, it's artificial
(51:39):
black aide to reproducing, right, which flies in the face
of natural selection. My question is is natural selection enough
of a UM powerful process that eventually UM women are
going to start evolving an immunity to birth control, or
is human ingenuity so strong that it's like we've got
(52:00):
natural selection beaten. It's just gone now, it's done for
us aside from fires and floods and famines and droughts
and all that. But I mean, like on that graduated
or gradual background natural selection, or we have we taken
ourselves out of that I wonder or is it enough
of a population pressure to have the effect to begin with? Yeah,
(52:21):
just from the fact that there's so many humans that
that that there's scarcity exists. So I guess not. I
guess we just answered my question. Man. I really didn't
think it was going to get answered, but it just did.
We're still under the effects and influence of natural selection.
It's a podcast miracle bow before natural selection humans. I
(52:42):
want to take a second to say hi to all
the sixth through ninth grade science classes who are listening
to this right now. I assume there's at least one
or two Hi. Okay, so natural selection right, all right? Uh,
if you want to learn more about natural selection, you
can type those words into the search par at how
stuff works dot com. It will bring up a world
(53:03):
class article by the Grabster. Uh. And since I said
search part, it means it's time for a listener mail.
I'm gonna call this We're curing people of disease. Nice, Hi,
guys and Jerry, you have a very large in a
very large way to help cure my six year old
niece Eva of lyme disease. For several months, he experienced
a series of strange symptoms that didn't seem to relate
(53:25):
to one another, including infection, muscle weakness, double vision. After
months of testing, her doctors were at a complete loss
as to what to do and what was wrong. Because
the once cheerful, enthusiastic little girl began to withdraw. She
was unable to go to school for periods of time
and quit all her beloved after school activities. Um one day,
she said to my sister, Mommy, there are two of you.
(53:47):
One is up here, one is down there. Which one
is the real you? Another alarming and creeping creepy statement was,
my legs don't work anymore. Enter Uncle Josh and Uncle Chuck.
After listening to the podcast on how ticks Work, I
encourage my sister to have my niece tested for lime disease.
Despite not having any evidence of being bitten or being
in a region known for dear ticks. She was tested
(54:08):
and indeed did have lime disease. That is awesome, Uncle
Josh and Uncle Chuck really saved the day on this one.
Ava was in pain, confused, and very afraid because she
didn't understand what was happening. None of the doctors suspected
lime disease. And I never would have pushed for it
without or even tested for it in the first place,
if your podcast hadn't tipped me off to the possibility.
That is so cool that the girl owas like her
(54:29):
well being to us, uh and to the doctors that
have helped her to a lesser extent. After the treatment,
she's back to her old, happy, studious and energetic self.
She's a brilliant young girl and we'll have a bright
future thanks to you guys having her back and making
her full recovery possible. Much love, Michelle Marianni. That's awesome.
(54:50):
Thanks for letting us know that, Michelle. Ava. Right, Yeah,
it's really neat way to go Ava, way to beat
that Lime disease. Stupid ticks hate ticks, even hate the episode.
That was a great one. We need to do aligned
disease episode when they're supposedly it is very controversial and
I've never really looked into it. Okay, I've heard you
could make money selling your blood. I don't know if
(55:10):
that's true. Oh it is okay. Uh. You have to
do on the black market though, because they don't pay
on the regular market. It's all like, well, I'm a
do gooder. Um, So if you want to get in
touch with Chuck and I to let us know how
we helped you or a relative out, we love hearing
that kind of stuff, or you can just get in
touch to say hi or whatever you want. You can
(55:32):
tweet to us at s Y s K podcast, hang
out at our happening Facebook page, Facebook dot com, slash
Stuff you Should Know, send us an email to Stuff
Podcast at Discovery dot com, check out our YouTube channel,
look for Josh and Chuck, and as always, joined us
at our home on the web. Stuff you Should Know
dot com for more on this and thousands of other topics.
(55:56):
Is it how Stuff Works dot com
Welcome to Stuff you Should Know from House Stuffworks dot com. Hey,
and welcome to the podcast. I'm Josh Clark, There's Charles W.
Chuck Bryant, and there's no which makes us a very
special edition of Stuff you Should Know, harrier than Jerry. Yeah,
(00:22):
edition much harrier. No, let's see your hair man that
has a lot of hair hairsuite. He's like the original
Kings of Leon. I used to love those guys back
when they were like Tennessee hill Billy's. Yeah, and then
they got their glam makeover and I was like, it's
like Metallica after the Black album. Yeah, what happened? What
(00:46):
happened Metallica Lars. I think they enjoyed making loads of money,
truckloads of money. Didn't think more than being like heavy
metal parking lot guys. Yeah exactly. Um, hey Chuck. Before
we get started, we want to tell everybody you can
follow us on Twitter. That's why sk podcast. You can
hang out with us on Facebook, dot com, slash stuff.
You should know our YouTube channel search Josh and Chuck.
(01:06):
It's pretty awesome, and as always we have a wonderful website.
Stuff you Should Know dot com. That's right, you can
hang out with us outside of the podcast if you want,
if you want, no pressure. So how are you doing?
I'm great. I'm super excited about this topic because A
we're pairing it with our Charles Darwin show, Yeah, which
(01:27):
I guess came out last episode, right, aren't we pairing
the two? Yeah? I think we're doing Darwin first. Let's
do Darwin first, because I think in the Darwin episode
we say we should do natural selection. It's here we are.
But I'm just excited because to me, and I gushed
a little at Darwin's feet, this is my own personal statement.
(01:48):
I think natural selection is the most exciting and like
beautiful thing that exists. It's it's just it really turns
my crank. You know, you're like an old timey car. Yeah, yeah,
you know. I grew up this is again my personal story.
I grew up in churches most listeners now, uh, which
(02:11):
was heavy doses of of creation, the creation story. And
I remember, as a kid, even fully involved in in church,
thinking like I just this doesn't make sense to me.
I just it didn't add up. So natural selection it
just makes sense to you. Yeah. When I finally learned
about natural selection, like really really understood and learned it.
(02:32):
It just it made total sense because I can like
see it, it was tangible. I could make sense of it.
And again that's my own story. We don't poo poo
anyone or saying anyone should feel anyway, but we just
explain how things work exactly. You know. But I have
a personal attachment to this just because I think it's
(02:53):
like the grooviest thing going. Yeah, no, I know what
you mean. Like it it makes uttering complete sense. It's
almost um in capable of being appropriated to serve some agenda.
It just is what it is, you know, It's just there.
It's beautiful. I agree with you entirely. It's an elegant theory.
Its just super neat. Yeah. Um. And the wonderful thing
(03:13):
is is like there's even squabbles in the scientific community
over exactly how evolution works and processes, and regardless, everyone's
still like, yep, natural selection pretty much perfect. Yeah, it
just makes sense. I'm gonna have a t shirt natural selection.
It just makes sense. I have a feeling we'll be
(03:33):
getting an email with something like that eventually, So let's
talk about natural selection. I think a lot of people,
including myself, um, kind of had an idea of what
it was, pretty good idea, but not necessarily understanding the
ins and outs of it. And well, that's what we're
here for, is to explain the ins and outs of
natural selection. So, um, basically, a lot of people interchange
(03:56):
evolution and natural selection. That's incorrect. Um. Evolution is this
huge process by which species adapt and change to survive
in their environments, and the way that that moves along.
The mechanism that drives that is natural selection. So they're
not one and the same. Natural selection drives evolution. Yeah,
(04:20):
and who wrote this one? Was this? Uh? Grabowski? The
grabster I should have known. Uh, just very simply puts
it very early on the article. Organisms best suited to
survive in their particular circumstance have a greater chance of
passing their traits onto the next generation. That's right, it
just makes sense. I'm gonna try not to say that
(04:40):
every ten minutes, but just now that that's going on
in my head. Yeah, and and and um do you
want that on a T shirt? And natural selection is
like it's this ongoing, basically never ending process even when
organisms really kind of seemingly stopped developing, like they figured
it out. Yeah, but it's it isn't. It doesn't have
(05:02):
its own sentience. It isn't its own thing. Like you can't.
You can't attribute it to some sort of creator or
creation necessarily unless you believe that kind of thing. But
like if you're if you, it's very easy to give
it a personality, but it's not. It's the byproduct of
how organisms exist, and we exist by our genes and
(05:23):
by the fact that those genes change frequently within the
lifetime of a person thanks to what we understand now
is of the genetics, but also through reproduction. And from
these these moments, these periods where genes are up for
a change, they can completely or even just partially change
part of an organism, and that change may or may
(05:46):
not help the organism survive in the environment, like you
just quoted Grabanowski. And if it does, bay a natural
selection will root that out and it will propagate that. Yeah,
and uh. It also points out Darwin um he did
coin term natural selection and survival of the fittest. And
I do think that many people hear survival of the
fittest and they think of the lion eating the gazelle.
(06:09):
But it's also, like he says, the tree that can
disperse its seed where it needs to for those seeds
to grow or the bacteria that uh survives. It's not
you know, animal eating animal, although it can, right, And
so since we're on it, Chuck, fitness is basically um
like you say, like a tree's ability to spread seeds
(06:29):
and for those seeds to take rud because its grabs.
Her points out, it's not enough for a tree to
produce a bunch of seeds, which is its ability to reproduce, Yeah,
and its ability to survive long enough to even get
to the point to it where it reproduces. Right. That's
step one is to live long enough to be able
to reproduce. Step two, or the second part of it
(06:50):
is that that reproduction is as successful as it possibly
can be. Yeah, Like it says, not only you gotta
do it, you gotta do it well. So that tree,
it spreads tons and tons of seeds. If those seeds
um happen to um catch fire and sunlight, that's not
going to be a very good trait. But if they
(07:10):
have like a really hard husk that can survive the
elements but then disintegrates when it's digested by a raccoon
and then pooped out. You know, then all of a
sudden you've got that step two covered. Yeah, or if
it you know, if it's just dumb luck, if that
tree exists in a place where it's super windy and
can disperse the seeds better, uh, then it will propagate.
(07:33):
If not, then you may not even know that that
tree existed exactly unless you consult the fossil record. That's right. Um, Okay,
So I guess the whole point to natural selection is
that it is an agent of change, but it's also
a byproduct of change, and we kind of have to
take a step backward to figure out where this change
(07:57):
is happening. I already said it a little bit, but
it's in it's our DNA. It's in the DNA of
all living things to change. Yeah, well, traits were all
born with traits, and we inherent those traits from you
know who who made us our folks and um. But
(08:17):
it's not necessarily that's not necessarily natural selection at work
over like one generation to the next. Right, there can
be differences in traits. Like Darwin, as we'll see, points
that out himself. He's like, let's just get it out
of the way, Like just because you have brown eyes
and somebody else has blue eyes, that's not evolution. No,
and he uses a good example here of tall versus
short folks. Uh, tall people might be basketball players, people
(08:40):
might be jockeyscus the grabs are not Darwin. Yeah yeah, yeah,
Um did they have basketball? When was that advented? When
did the name sent in mid basketball? I want to
say eighteen forty eight, but it's probably eighteen seventy, not
too far off. So he makes the point that you know,
if something happened to where like jockeys could reproduce better
(09:01):
or basketball players could not reproduce anymore. Yeah, I was
trying to imagine, just make up anything, I know, I
was trying to and like I couldn't come up with it. Well,
just make make up something like being able to uh
dribble and dunk lowers your sperm count. Oh that's a
good one. See, that's what I'm saying. I think my
brain was in understand natural selection modes of my My
(09:25):
imagination grew less fertile, so it didn't survive, No, it didn't. Um,
And over time, basically basketball players don't reproduce as much
jockey's do, and over several generations, people are going to
be shorter on average. It sounds almost dumb, it's so simple,
but that's really the basis of it. It is, and
it's one of those things. It's like economics where it's
(09:46):
so simple that it's hard to wrap your mind around
it because you make it more complex necessarily than it is.
It's it's very similar for me. Um. And with that
basketball example which just happened, was humanity evolved to be shorter.
That was the end result. And that evolution took place
(10:07):
because there was a shift in the distribution of traits.
So before lots of basketball players, lots of jockeys, tallness
and shortness, which are traits or variations on the trade
of height in humans, Like we have height, we're not
too dimensional inherited by who bore you, right, not us,
(10:28):
your parents. We bore you in a different way. Um.
So the variations on the trade eventually gave rise to evolution.
So within just like our generation or even a couple
of generations, the differences in eye color, height or something
like that, it doesn't represent evolution, but changes like that
can lead to evolution over time. Yeah, if they are
(10:52):
changes that either aid or prevent your survival, right, Like
if something happens and all of a sudden human women
were all like, we're not gonna mate with anybody but
blue eyes. You can bet your bippy that within two
generations there's gonna be nothing but blue eyed kids. Yeah,
or grown adults getting blue contacts. That's a good idea
(11:12):
because they're tired of not having sex. But then maybe
our eyes would adapt to um the context and just
absorb them. Something has to happen. Your imagination is plenty fertill,
my friend, I guess so. Uh, and this all goes
back if we can go back a little further to
something called DNA um that is a chemical structure that
(11:35):
is the basis for everything that is. Is that a
good way to say it? And Uh? Within DNA are
sequences of traits, sets of traits, and those are the genes.
And then there's something called the LLL, which is really
where it all comes together. Is it all? Or allele?
Does I say ll adele? No? Adele allele? Okay? So
(12:01):
it's like a gene is like a specific sequence of
DNA that produces some trade. So height, like you have
a height gene like and when that gene is working
like you will grow. Yeah, the expression of the gene
is the allele. Yeah, that's the variation of that trait.
So imagine like as just a stretch of genes is
(12:21):
like a few boxes, say five of them, and three
are off the three that will encode to make brown eyes, uh,
and two are on the two that will encode to
make blue eyes. So each one's an allele, but the
one that's functioning gives you blue eyes. So in allal
is just a variation on a trade. And a trade
(12:43):
is produced by a gene, which is a sequence of DNA.
That variation is produced by an allele, which is a
sequence of the gene. And how often that allele shows
up in a population is the allele frequency. And it's
really simple. You hear alleal frequency and it sounds like,
oh that's science, but it's really pretty easy. That's what
they go to school force to learn the jargon. Yeah,
(13:05):
and uh, we did a really good episode on population
and uh, we're gonna be talking about here again though,
So we should just say that a population is a
group uh in one place that have sex with each other. Yeah. Um,
so like a zebra in Africa. He makes up he
(13:25):
should have used real examples because he said, let's say
there were zebras in South America. But I see his point,
that would be a different population because they can't have
sex with the zebras in Africa, because zebras can't swim
across the ocean. And a lion in Africa is in
a different population than a zebra in Africa because they
don't do it right. They can't. It's an abomination. It is.
(13:47):
You come up with a zion, that'd be kind of cool.
I guess, sort of like a tiger. Probably maybe that's
what a tiger. I think. It's So you were talking
about populations and you're in a little frequency. So, um,
you could conceivably quantify the alleal frequency of blue eyes
(14:10):
and the human population because we transcended, like the difference
between Africa and South America. Like we have planes now,
so we we all have access to sex with one
another as a population, as long as you have a
passport and some money for a plane ticket. Um. So
speaking about a lieal frequency, Um, the point of that
(14:32):
whole thing is that with evolution, I guess another way
to put it, the way it grabs or puts it
is evolution is just a shift or a change in
alleal frequency. And the reason that that change takes places
because those alleles that become more and more widespread and
distributed it across the population, UM have made that organism
(14:58):
more likely to survive, to reproduce, and more likely to
successfully reproduce. Yeah, that's it. That's it. That's the evolution
driven by natural selection. Do you want to quit? I
don't think we could top at this point. Now it
does get more interesting. Um Alile's create are created in
a few different ways. UM. One is called a mutation,
(15:20):
which you probably heard of. Uh. These are random changes. Uh.
They are pretty rare, like the X men. Yeah, very rare,
very rare mutants are. That's why they got to hang
out with the president a lot. Yeah, but the president
was also a mutant, wouldn't he. Oh yeah, eventually Kelsey Grammer. No, no, no,
the president was the guy with the son with the wings.
(15:44):
I thought, ye, his son was the mutant and the
president the president. But I think Kelsey Grammer eventually was
elected president Blue president, Blue Harry President. So to me,
the cool thing about mutations is is they can be
completely new traits that are introduced that are completely different
(16:05):
than anything you've ever seen in that species, which is
pretty radical. Another way is just like we've been talking
about sex a lot reproduction just with animals humans. That
is the way that an aile can express itself. Right.
It's the mixing together when when your mom and your
dad love each other very much and they copulate. Um,
(16:28):
there sperm and egg mixed together, break down their DNA
and it's glorious, fantastic um little mini explosion inside the
womb and uh, and then it really it recombines into
a totally new form that shares part of the dad's
DNA and part of the mom's UNICH to make a
(16:48):
new human. Yeah, and you get all the bad traits
from each of them, right, hopefully you get all the
best traits. But that's the point of sexual reproduction, which
was itself naturally selected, because it increases the potential that
you're going to inherit uh, good traits that will let
you survive. That's right, there's just more traits out there.
(17:10):
It's like um. I think it was the Sense of
Smell episode we did where we talked about pheromones, the
idea that pheromones among humans, we we can still detect
them even though we don't know it. And the whole
reason we can is to smell out other people's immune
system and we want somebody with an opposite immune system
of RS. So when you put the two together, it
(17:32):
produces a little mini superhuman who can't be killed. There
was an interesting study I think where they just had
people smelling things, but the gauging attraction levels right. But
it's based on the premise of sexual reproduction, which is
the combining as many good traits as possible make somebody
with a lot of them. Uh. And then the final
(17:53):
way that um alile's are created is um genetic recombination,
and that would be in the case of like a
bacteria who obviously don't go out and have sex with
each other um, but they do absorb DNA that they
get from other bacteria and basically make it part of them. Yeah,
they think that's where the ukaryotes came from. Yeah, the
(18:15):
mitochondria was its own thing and it became absorbed by
some ancient cell to serve as like the power center
of the of the cell, and from that like gave
rise to everything with the backbone, everything that's not a
bacteria basically, so fish at first, I guess yeah, but eventually,
like it all, it all just came to that and
(18:36):
it's still going on today. It's just two organisms in
one neat yeah that's super neat, and then one other thing.
Like there are three ways that this could happen. That
um that new alliles could be introduced. But um, I
wonder if epigenetics will eventually be added to that. Yeah,
(18:56):
because think about it. I mean, it's a change in
gene expression, right, So yeah, I could see that leading
to I guess I guess it could be classified as
a spontaneous mutation. I guess it would fall under that umbrella. Yeah,
but so much leads up to it. I don't know.
I'm with you. What's out of fourth? Okay, et the
genetics is officially added as a change to Allele's I'm
(19:21):
sure we'll get an email from someone that's super smart
that will explain exactly why that won't happen there. Like,
first of all, Chuck was right, it's allows so Chuck
we um. You know we said that all of this
starts at DNA and the fact that it changes, we
actually should go back even further, um than that, uh,
(19:43):
into the backdrop of nature, the environment, the reason that
DNA changes, that traits change over time is because of
a little thing called death. Yeah, we all die and
how to avoid it exactly. It's it's the combination of
the two things. We're all going to die, and all
(20:04):
organisms appear to be driven by a desire to put
off that moment as long as possible, So we have
an instinct to survive. Right. The problem is is the
processes of nature are trying to put us down all
the time, so there is a inherent struggle to survive.
So when you combine our desire to live with nature
(20:28):
trying to kill us all the time, it forms that struggle.
The struggles have survived gives rise to the changes in genes,
which eventually are selected and convert to evolution. So it
all begins with the struggle to survive and the desire
to survive. Right, And this is spelled out by Darwin himself. Yeah,
(20:50):
should we read some of his quotes, Uh this is
These are from the on the Origin of the Species,
which if you just listen to the Charles Starwin, you know,
that was his most famous work that he put up,
one of many, but that's his uh you know, warrant Peace.
It's close second was my travels with Timmy about his
pet rabbit and he going around the county bothering neighbors.
(21:14):
So he here are you with the Here a few
of the basic tenants in on the origin of the
species and with some quotes from Darwin himself. One is
the organisms show variations of a variation of traits. Yeah,
that's him just getting it out of the way, like,
don't be dumb. If you think that your your dad's
blue eyes and your brow and eyes are revolution, you're wrong. Okay,
(21:37):
I like that better than his quote. Actually, let's do that.
Let's do Josh's take on his quote. I'll do what
I can, all right. Uh. Number two is more organisms
are born that could ever possibly be supported by the
resources here on the planet. That's right. Uh, stop being
such an idiot. There's such a thing as scarcity, don't
(21:57):
you know that. I mean this is great. Um, I
feel the birth of the new podcast coming. Number three. Therefore,
in conclusion, all organisms must struggle to live. You already
kind of covered that, okay. Um. Number four, some traits
offer advantages in the struggle. That's right. Uh, those are mutations,
(22:20):
and as Josh will eventually predict, epigenetics, not always mutations
though right changes to Allele's um. Organisms that have those
traits are the ones that will help you survive, are
more likely to be successful and reproduce and pass them on.
And then finally successful variations the ones that we have
(22:40):
just talked about that allow you to survive and reproduce more.
They accumulate over the years and the generations as they
are exposed to something we'll talk about in a minute
called population pressure. Right. And he points out too that
this is essentially specific and local. Like UM, if humans
had a right where you cooled extremely easily all the time, UM,
(23:04):
under under all conditions, it wouldn't play very well. When
you move to the northern latitudes, you die, so it
would be selected out of populations in the northern latitudes.
But if you lived in the tropics, it would probably
be selected um and propagated over time because you probably
have a lot more energy. You wouldn't just be laying
(23:24):
around fanning yourself with palm fronds. Well you do that too,
but you wouldn't need to. Yeah, but it's just it's
a nice experience. UM. So I mentioned population pressure, and
that's a key here to understanding this whole bowl of soup.
And we'll talk about that right after this message. All right,
(23:46):
So here we are in the stew I called it soup.
It's really a stew of evolution and that section. So
we need to talk about population pressure, which is basically
anything in a population that makes it tough for your species.
Are you, as an individual plant or animal to survive it? Yeah? Again,
(24:06):
because there's such things scarcity that means you compete with
people in your species or people outside of your species, right,
like a lion wants to eat you. Yeah, there's always
it's always going on, yes, um. And then even if
you lived in total harmony with all the plants and
animals around you and vice versa, nature is still shooting
(24:27):
lightning bolts at you, train your floods, droughts, famine, all
that stuff there is always in and is Darwin put
it like every organism struggles to survive one way or another. Yeah,
And that can really speed things up as far as
alleal frequency change, Like if you flood it out an
(24:47):
entire country, you're gonna see some big changes within a
generation or two. It's not necessarily over hundreds of years,
that's right, um. And that's because Uh. When you have
something especially like uh, a flood or drought or just
some severe increase sudden increase in population pressure, it goes
from just background population pressure to something very acute and pronounced.
(25:11):
I got a lot of the population dies off. Yeah,
Like his example is pretty great. Actually about the fire.
Let's say a fire killed all the vegetation under fifteen
feet and a population of giraffes, anything under fifteen feet
is gonna have a hard time reaching food, and so
they're gonna start reproducing and making taller giraffes pretty much
(25:34):
as fast as they can write. The ones that can't
reach food will die off, a lot of them before
they can reproduce. The ones that can reach food will
live to reproduce, which will produce those taller giraffes. Um,
And what just happened then in that giraffe example is
called a population bottleneck. Something happened that took a large population,
reduced it down to a smaller amount. And then usually
(25:55):
in that smaller group, there's going to be some traits
or whatever that used to be evenly distributed among the
population that are now really concentrated and clustered. And like
it could be something super rare that is now the
trade right exactly. So if you have a super rare
trait spread out very evenly among a large population, that
(26:19):
trait may or may not ever be selected, and if
it is selected, it may take a very long time
to be selected because there's so many other competing traits. Well,
when a lot of those other competing traits are narrow
we weeded out, and you have that population bottlenecked, those
traits are going to be very pronounced and they they're
going to be selected very quickly. So you have a
very quick change in evolution as a result of sudden
(26:42):
acute population bottlenecks. Yeah, it basically becomes the norm. So
in that area of where the fire ended up killing
shorter giraffes, the norm will now be super tall giraffes exactly.
And don't say chuck. All giraffes are super tall, super
super tall, super super tall. And this is apparently happened
to humans. Um there's a population bottleneck. Supposedly around seventy
(27:04):
tho years ago. Um uh, there was something called the
Toba eruption, huge supervolcano created like a six to ten
year long winner and dropped the number of humans Homo
sapiens down to something as low as possibly three thousand people. Yeah, so, uh,
the planet on the whole planet, and they're not quite
(27:25):
sure like what what um variations were selected out of that,
but you can bet there was an enormous change within
years of that event. Boy, I wonder what it was
like before that, right, it's pretty interesting. So let's say
the giraffes, like everything was hunky dory, no fires, no nothing,
but just some of them decided that they wanted to
(27:48):
see if there really are no such thing as zebras
in South America. So they hop on a boat and
they sailed to South America and they establish a new
little giraffe colony there. Yeah, well we'll result from that
is called the founder effect. And there is a band,
by the way, I already looked, no, yeah, I thought
there's gotta be one, and it is h and I
(28:09):
listen to their song. How is it? It was pretty good?
What kind of music, you know, sort of uh, giraffe
in the Giraffe shoegazy. Okay, not bad? Um so anyway, Yeah,
the founder effect is when you quite literally, when a
population founds a new area and don't have sex with
(28:29):
that other population anymore. Right, So, and you can have
very different traits from even if it's a giraffe, from
the ones in Africa, because they set up camp in
a new place, right, and it's almost like an unforced bottleneck. Yeah,
you know they have voluntary bottleneck. Yeah. Nature didn't kill
off a bunch of the population. The population just broke
(28:51):
off from from a larger group to a smaller group.
And that smaller groups probably going to have some weird
trader too that are going to be select and and
push evolution along faster than usual. Yeah, alright, let's talk
about this then. Okay, let me pose a question to you, sir,
that I know the answer to. Uh, what about things
(29:14):
that don't evolve anymore? Buddy? What about like the shark
that's been about the same for millions of years? Show
me your natural selection? There? I got this, Okay. So
sharks are a great example, um, because they haven't changed
in millions of years because they don't need to. Well,
because basically they became apex predators a long time ago
(29:37):
in their environments, and their environments went unchanged enough so
that sharks didn't need to change. They are basically as
far as natural selection goes perfect. Yeah, they early on
figured it out. It's like, all right, I've got my
my teeth and are great. My my gills are working.
I can send electrical impulses from can swim super fast,
(29:58):
I can kill everything I see. As long as something
doesn't punch me in the nose, I'm pretty much good.
Or kill me for my sharks, then well that's yeah.
It makes you wonder how sharks you are gonna evolve now.
But let's say pre human fishing, so, uh, two hundred
years ago up to from several million, maybe tens, I
don't remember how long sharks have been around virtually unchanged. Yeah,
(30:23):
so uh, let's say from millions and millions, millions and
millions and millions and millions and millions of years ago
up to two hundred years ago. Sharks are virtually unchanged
because they hit their peak and they're fine. But that
doesn't mean that they have gone unchanged or that natural
selection hasn't exerted an effect on them. Basically, what happens
(30:45):
is they're still undergoing mutations through reproduction. There's new allele's
showing up, but none of them are holding it. Can
hold a candle to the perfection. That's been achieved by
the shark, so they get selected out. They don't get
a chance to um to reproduce in the population or
become distributed amongst the population. So if you still have
(31:08):
natural selection weeding out, but rather than changing the shark
population or the shark species um our family family you have,
you have a natural selection as an agent of stability. Yeah,
or I guess if let's do a hypothetical, if we
were going to use shark finn shark finning as an example,
(31:30):
Let's say only sharks with you know, perfectly triangular gray
fins were selected out right to be finned and cut
off for shark fin soup. So that means sharks that
have like weird spots on their fins would not get killed.
So theoretically, hypothetically, over generations, we might see sharks with
(31:53):
only spotted fins, and that probably will happen because of
the sudden and acute population pressure being exerted on sharks
by humans. There has to be some sort of forced
adaptation that's gonna occur. Yeah. I don't know what the
criteria for a good fin though is, or if they
just take them all like whatever they can catch, but
(32:13):
I mean it could be as simple as something like
UM figuring out that they like just swimming deeper and
not coming up and like within the humans grass like
just yeah just stay. Yeah, we should say that that's
a really good point. UM. A trait isn't necessarily something
that is um visibly apparent, like it like height or
(32:35):
something like that. It can be an ability or a
proclivity like grabster uses the example of UM dogs have
evolved UM the trait of UM hanging out with humans
and chuck, UM tell them about the elephants because that's
a pretty good example of what we're talking about. Sharks. Yeah. Yeah, Well, elephants,
(32:57):
as we know, are killed many times for their ivory tusks.
And it's sort of a no, it's a good news
bad news scenario. You would think, hey, good news, there's
some elephants that were being born without tusks at all,
so they're not being hunted. And over the years, now
there it went from like like close, now are not
(33:22):
born with tusks, So you think that's awesome because now
they're not being hunted, but they need those tusks for
digging in defense and things like that, so they're they're
losing a valuable trait which is going to put stress
on the population as a whole, I would think over time.
But in the near term it's been selected out because
it's keeping the elephants alive because the ones that were
(33:43):
naturally without tusks weren't being killed by poachers, so they
were allowed to reproduce more frequently than ones with tusks
that were being killed. So, yeah, you have a within
a human lifetime, within seventy years or so, the population
has evolved. Yeah, that's what I mean by like you
can see it happening in front of us, right, And
(34:05):
this is where the debate comes from. Where I was saying, like,
scientists even debate on how evolution changes or happens um.
And there's basically the difference between um gradualism or punctuated
equilibrium and gradualism is just over time, very slowly new
ah lials appear, and some of them tend to make
(34:27):
organisms fitter, and so they'll eventually, over very long stretches
of time, be selected out and then uh, punctuated equilibrium
is like we're talking about with the African elephants, where
there's a sudden population pressure and all of a sudden,
this organism or species is forced to evolve, and they do,
(34:48):
and then after that everything evens out for a little
while and stays the same until the next catastrophic event. Yeah,
I don't get it. There A it says there's an
ongoing debate about that. Can't they both exist? I don't
understand why they don't both exist. It seems like one
is just constant background evolution and the other one is
um like evolution as a result of you know, sudden
(35:09):
acute crises. Why wouldn't they both think? I don't understand
it either, if the looking at them. Okay, Chuck, So
let's go a little further and well, I guess we'll
go back to jeans. But um, remember you know a
guy named Richard Dawkins, Right, He wrote a book in
the seventies called The Selfish Gene, and it basically we
(35:30):
were talking about, you know, the debate between gradualism and
equilibrium punctuated equilibrium. Well, Dawkins came along and said, you guys,
shut up for a little bit, let's talk about this
the Selfish Gene, And he just basically reframed the entire
way that people look at evolution. Yeah, I thought, I
think it's pretty interesting. Uh. The essence of it is
that as long as you reproduce, then natural selection doesn't
(35:55):
care about you after that, right after you've passed on
your genes. That's the important part. Uh. In the case
of spiders is one great example. Sometimes the male gets
eaten right afterward. Yeah, or like praying manness. This didn't
the female eat the the male's head, like bite the
male's head off, And we're talking about praying mannesses, So
(36:15):
it's okay to say female um in that case. Though
both those cases, natural selection doesn't care. The male has
done his job. He is propagated and passed down the
allele and it doesn't matter if he dies or not.
Right afterward. It doesn't put any stress on the population. No.
And that's like a really there was a tricky thing
(36:36):
before Dawkins came along. It was like, wait a minute,
there's a real problem with natural selection if if the
whole point is for something to be able to reproduce
and reproduce successfully, like, why would there be um adaptations
that kills Yeah, where like the organism is killed like
as a result of reproduction. That doesn't make any sense.
(36:57):
And Dawkins came along and said, it doesn't make sense
if you stop look king at organism and start looking
at the genes. Basically, like none of that matters, right,
So he he made his point so well that it
actually got a little bit out of hand. Um and
it came to be known as well. It was the
selfish team before, but basically it was. He characterized it
(37:18):
so well that it became a character. Jeans became a
character almost like they had hijacked organisms and we're using
them as husks to pass along themselves, like a virus
or something like that. Um and Dawkins came out a
number of times and it's like, no, that's the wrong interpretation,
that's not what I mean. But it's still essentially the
(37:38):
same thing. It's just m yeah, yeah, we are we
we we are a means of passing along our genes.
And if you look at it through the lens of
natural selection, the the as long as the genes are
able to be passed along, the vessel is no longer necessary.
So therefore the head can be bitten off by the woman.
(37:59):
That's right. But like we said, this isn't widespread, but
it does help explain things like spiders, right, you know,
But there's a big flaw in this selfish gene theory right, well,
and Dawkins theories as a whole. Right, there's the flaw
is is that there's such a thing as altruism. Yeah,
and this is you know, humans and animals that, for
(38:22):
no reasons based on natural selection, desire to help each
other doesn't benefit you in the least at all. Know it.
As a matter of fact, it can harm you before
you're able to reproduce. So even from the genetic level
of the selfish gene um, it doesn't make any sense
because you're the genes are allowing the organism to be
(38:42):
harmed before it could possibly reproduce. What why Why does
someone have an instinct to jump in an icy river
to save somebody? And they have found that it is
instinctual and that it happens in infants with like zero
cultural training. It's like part of us. Yeah, and it's
not a human it's either. There are plenty of animals
that um that display altruism as well, like mere cats
(39:07):
are big on altruism. Yeah, and I like the explanation.
It makes again total sense to me. Something called kinship.
If you've got a couple of different families, took Tuk's
family and and Bartok's family. Well, Bartok is a composer.
But what's another good cave man name. Uh, yeah, that's
(39:29):
a great one. So Mango's family is very selfish. They
don't like to share their their stuff. They're all competing
for the same food. Tuktok's family is very generous. They
like to share things. So over time they will be
a more successful family because they have been altruistic and
shown that kinship and they're they're improving their chances of
success by combining their their efforts into a group effort um,
(39:52):
which is kind of like that Paleolithic warlessness we talked
about in the Cave Dwellers episode. Oh yeah, where everybody
just kind of figured out that, like they could be
more successful if they stopped fighting and started harvesting together. Um,
and if you kind of look at it like that,
like everybody coming together as a group for a common goal.
You're also looking at super organisms. Yeah, have we done
(40:15):
one on ants specifically? No? I think we should. I agree,
because they are about the best example of a super organism.
It's basically the little worker ants aren't doing the reproducing.
They can't even reproduce their that goes to the top dogs.
They only get to do that. So all those little
worker ants aren't even passing on their genes, but they're
still busting their little aunt butts for the colony. And
(40:38):
um a super organism basically then is to step back
and say, let's not look at ants, but let's look
at the ant colony as an organism, as one organism,
And that explains the altruism in that ant sacrificing its
own ability to pass along its genes in order to
serve the colony as a whole. Then it makes sense
like Papa aunt is going to pass down the jenes.
I just need to make sure Papa aunt has food
(41:00):
and water, right, And you can also use that same
um argument to explain why, Like it would make sense
if um, you know, you jumped in to save your
son from a river. That kinship explains that. But why
would you jump in to save someone else's son. Well,
if you look at it like, well, this kid's part
of the same species and shares a lot of the
(41:22):
same genes as you, you're ensuring that your species genes
are passed along. Yeah, and you get to humble brag
on Facebook Yeah, how bad big time? Oh pretty boring day.
Just saved the kid from the river and the icy river. No, biggie,
just helped ensure as jeans get passed along. I guess
a humble brag that would be, um, well, it looks
like my shoes are ruined that I just bought, jumped
(41:44):
into an icy river, and saved the kid. Yeah, that'd
be good one. We should start this doing fake humble
brags on Twitter, Facebook. Oh, this brand new BMW I
got has the windshield wipers are busted. Not a day
for it. It's raining. That's just being a jerk, Okay,
all right, So now we should talk about something that
(42:06):
also excites me. Vestigial and attavistic traits. Um. All organisms
carry some trait that is really no benefit and really
is no longer expressing itself as a means to help
you survive. But it's not harming you either, so it
hasn't been selected out, so it's just there. And UM,
I've got some pretty good examples in the human body.
(42:29):
UM one summer behavioral summer actual organs like the appendix.
Many people think the appendix is of this vestigial organ
I heard that it might fight cancer. Well now that
now scientists are starting to say, we think it might
fight cancer, or it might house um like bacteria that
(42:50):
helps you aid in digestion. So everybody who's a pendics
we took out get inline. We're gonna put them back in.
But for many years, and I think the debate is
still out whether or not it is a remnant from
primate ancestors when um we had to digest like plants
like super rich in cellulose or something. Yeah, I got that.
We don't anymore. So that's why the appendix really does nothing.
(43:10):
Back when we were giant termite men, scary time sinuses,
that was what we were like. On the other side
of the population bottleneck, giant termite people. Sinuses supposedly may
um there. It's also debated. But their pockets of air
in your face, and no one really knows if they
serve any kind of biological function or not. Yeah, and
(43:32):
they kind of suck too, because they get infected. They
can't get infected the coxics. It's pretty exciting because it's
a tailbone that used to be a tail, and some
people are still born with them. Yeah, and the people
who are born with tails are atavistic because they're out
of atavisms. It's it's a vestigial remnant that UM expresses
(43:57):
itself very closely to the way it actually used to be.
It's not just a trace of it anymonger. It is
like it's like that Alleale saying, hey, maybe we should
go back to tails again. What do you think? But yeah,
it's not um. Just so you don't picture like a
human with a big four ft long monkey tail, it's
usually like a bumper or something. Didn't George Costanza have
(44:20):
a tail? And uh what was that one? Jack Black
Fairly brothers? Oh yeah, yeah, shallow, yeah, yeah, I think
you're right, and you could wag it. I don't remember that.
Uh what else? Um? Oh, here's a behavior um of
this digital behavior of the palmer grasp reflex. Oh yeah,
(44:41):
I thought this is cool. It's pretty neat. When you
go up to a little uh stinky, dirty human baby
and you put your finger in their hand or their
foot even it's gonna grab it like super hard and
super strong. Yeah, like Popeye basically, or like a little
baby monkey trying to hang onto mama, cruising through the
jungle through the grabbing onto the coat their mom's coat. Yeah,
(45:04):
so basically that's a behavior they think is is like
a human baby now doesn't need to grasp hold of
something that hard at six weeks old, So it's a behavior. Maybe.
So we we played tennis thanks to a vestigial behavior
and ability, I don't oh got it being able to
grip that racket? Yeah? What's what article is this from?
(45:27):
Is it? Um? Was it? Ion nine? Yeah? I think so.
It was kind of silly, But these are some pretty
decent examples. We we've talked about in male nipples before,
you know, we did. We did a whole episode on
um goose bumps, the erector pilly. I've never heard of this?
Oh I did it? Dump be dumb on it? You
want to explain what it is real quick? There you
go ahead, okay, Um, everyone has had goose bumps. The
(45:50):
erector pilly are those muscle fibers that give you goose
bumps when you don't even necessarily want them or need them. Right,
there's little musts that are attached to your hair follicles,
whether you have hair there or not any longer, and
they press it up so that your hair stands on end,
either to make yourself look bigger, so you're scary, or
(46:12):
because you're cold, to make your coat fluff out, as
in when we used to have coats because we were animals.
Another vestigial trait, and uh, my favorite one aside from tonsils,
is the like a similar nearus. Did you like how
you asked me if I wanted to do it? And
(46:32):
I was like no, And then I did it anyway.
I knew it. I knew that was coming. If you
look in your mirror and you look at your eyeball,
and you look in the little inside corner of your eyeball, um,
you're gonna see a little fold of tissue and it's
not the little bump, but it's that little thing in
the inside corner of your eye that is a remnant
(46:55):
of a third eyelid. What's it called? What kind of eyelid?
The p L I C A plica or like a
similar nearis And uh, apparently we had third eyelids that
would that were clear, so you could like wash your
eye and still keep an eye out for predators. And
they would come from the side rather than up and down.
(47:17):
They moved horizontally. Yeah, like a snake or a reptile, yeah,
or a bird. They still have them, Man, we do not,
but we still have that in the corner of our
eye even though it does nothing. So here's the thing.
We have the jenes then to make that. Yeah, if
we needed it again, so that Allele could possibly come back,
(47:38):
like we could have people who were born with that,
and like if it ended up helping us, Um, like
if we could sleep with our eyes upen to watch
the zombie invasion or to watch TV better twenty four
hours a day. Uh. Just the fact that we can
wiggle our ears, that's a vestigial trait. There's no reason
why we should be able to wiggle our ears. I
can wiggle, mind, can you do them one at a time,
(47:59):
you're wiggling you're eyebrows. I'm gonna go in my whole face,
I know. Can you do one at a time? Like
that's pretty Actually, well that means like human's going bananas
right now. So, uh, that means that maybe Josh's ancestors, Uh,
we're a little closer than mine. And as far as uh,
(48:22):
monkeys directing their ears to listen out for predators. Yeah, no,
it means I'm less evolved as a human being. I have,
like the ability to move ears, so I can hear
things that I don't need to anymore. And I'm fairly harry,
So this has been a depressing episode for me in
that respect. I didn't want to mention any of that stuff. So, Chuck,
(48:42):
we talked about um African elephants. You want to give
a couple more examples of uh natural selection and action.
The ball worm. Sometimes it happens super fast. In the
case of the ball worm, it's happening faster than we
can create toxins to kill them. Yeah, like they treat
now with no the genetically engineered so cotton produces it itself. Yeah,
(49:04):
I guess it's not treating I guess it is originally
treated cotton. But now cotton is growing with this toxin
that is supposed to kill bullworms. But enough bulworms h
were immune to that that they were the ones that
went on to do the most reproducing to eat the cotton.
I'm sure that that first generation of bullworms were like,
(49:26):
I'm so wasted off this cotton, but I'm alive. Uh.
And then the clovers. Some species of clover have mutation
that made poison cyanide leak from its cells, causing it
to be bitter. Therefore it wouldn't be eaten. Isn't that weird? Yeah,
just that the clovers like don't eat me. Yeah. I
make cyanide somehow. Yeah, but unfortunately, when the temperature drops
(49:50):
blow freezing that sells rupture releases that cyanide into the
plant and it kills itself. However, in warm climates that
doesn't happen. So what you end up with is clover
in warmer climates that's completely different structurally cellularly than the
one in the colder climate. Yeah, the warmer ones produced sanide,
the ones in the colder climates don't same clover. It's
(50:11):
very much like that example of Um, you know the
humans that can cool constantly playing well in the tropics
but not in north Pretty cool stuff. Yea, man, I
love this. You got anything else? I got nothing else?
Oh well, let's talk about ourselves a little bit real quick. Really, Yes,
(50:33):
what's your sign from the Pisces? I can't wiggle my ears? Um? No,
humans like we have, like I was saying, we have
jets now, so like we're one large population right. Um.
That's just one example of how we've essentially taken ourselves
out of the evolution game. We even more to the point,
we have such thing as birth control, artificial birth control. UM,
(50:55):
we have a lot of different things that we do
inadvertently or advert only to UM, to adapt, to change ourselves,
to change our ability to reproduce whatever. So I wonder, then,
are we UM out of the evolution game already forever?
(51:16):
Will we ever be able to if we're not? Yeah?
And I mean is that the case? Like I know,
it's the goal of trans humanism is to say so long,
suckers the evolution and just be totally in charge. But
I also wonder, like UM with birth control, birth control
is an artificial it's it's unnatural selection. Yeah, it's artificial
(51:39):
black aide to reproducing, right, which flies in the face
of natural selection. My question is is natural selection enough
of a UM powerful process that eventually UM women are
going to start evolving an immunity to birth control, or
is human ingenuity so strong that it's like we've got
(52:00):
natural selection beaten. It's just gone now, it's done for
us aside from fires and floods and famines and droughts
and all that. But I mean, like on that graduated
or gradual background natural selection, or we have we taken
ourselves out of that I wonder or is it enough
of a population pressure to have the effect to begin with? Yeah,
(52:21):
just from the fact that there's so many humans that
that that there's scarcity exists. So I guess not. I
guess we just answered my question. Man. I really didn't
think it was going to get answered, but it just did.
We're still under the effects and influence of natural selection.
It's a podcast miracle bow before natural selection humans. I
(52:42):
want to take a second to say hi to all
the sixth through ninth grade science classes who are listening
to this right now. I assume there's at least one
or two Hi. Okay, so natural selection right, all right? Uh,
if you want to learn more about natural selection, you
can type those words into the search par at how
stuff works dot com. It will bring up a world
(53:03):
class article by the Grabster. Uh. And since I said
search part, it means it's time for a listener mail.
I'm gonna call this We're curing people of disease. Nice, Hi,
guys and Jerry, you have a very large in a
very large way to help cure my six year old
niece Eva of lyme disease. For several months, he experienced
a series of strange symptoms that didn't seem to relate
(53:25):
to one another, including infection, muscle weakness, double vision. After
months of testing, her doctors were at a complete loss
as to what to do and what was wrong. Because
the once cheerful, enthusiastic little girl began to withdraw. She
was unable to go to school for periods of time
and quit all her beloved after school activities. Um one day,
she said to my sister, Mommy, there are two of you.
(53:47):
One is up here, one is down there. Which one
is the real you? Another alarming and creeping creepy statement was,
my legs don't work anymore. Enter Uncle Josh and Uncle Chuck.
After listening to the podcast on how ticks Work, I
encourage my sister to have my niece tested for lime disease.
Despite not having any evidence of being bitten or being
in a region known for dear ticks. She was tested
(54:08):
and indeed did have lime disease. That is awesome, Uncle
Josh and Uncle Chuck really saved the day on this one.
Ava was in pain, confused, and very afraid because she
didn't understand what was happening. None of the doctors suspected
lime disease. And I never would have pushed for it
without or even tested for it in the first place,
if your podcast hadn't tipped me off to the possibility.
That is so cool that the girl owas like her
(54:29):
well being to us, uh and to the doctors that
have helped her to a lesser extent. After the treatment,
she's back to her old, happy, studious and energetic self.
She's a brilliant young girl and we'll have a bright
future thanks to you guys having her back and making
her full recovery possible. Much love, Michelle Marianni. That's awesome.
(54:50):
Thanks for letting us know that, Michelle. Ava. Right, Yeah,
it's really neat way to go Ava, way to beat
that Lime disease. Stupid ticks hate ticks, even hate the episode.
That was a great one. We need to do aligned
disease episode when they're supposedly it is very controversial and
I've never really looked into it. Okay, I've heard you
could make money selling your blood. I don't know if
(55:10):
that's true. Oh it is okay. Uh. You have to
do on the black market though, because they don't pay
on the regular market. It's all like, well, I'm a
do gooder. Um, So if you want to get in
touch with Chuck and I to let us know how
we helped you or a relative out, we love hearing
that kind of stuff, or you can just get in
touch to say hi or whatever you want. You can
(55:32):
tweet to us at s Y s K podcast, hang
out at our happening Facebook page, Facebook dot com, slash
Stuff you Should Know, send us an email to Stuff
Podcast at Discovery dot com, check out our YouTube channel,
look for Josh and Chuck, and as always, joined us
at our home on the web. Stuff you Should Know
dot com for more on this and thousands of other topics.
(55:56):
Is it how Stuff Works dot com
Stuff You Should Know News
Hosts And Creators
Chuck Bryant
Josh Clark
Show Links
AboutOrder Our BookStoreSYSK ArmyRSSPopular Podcasts
40s and Free Agents: NFL Draft Season
Daniel Jeremiah of Move the Sticks and Gregg Rosenthal of NFL Daily join forces to break down every team's needs this offseason.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
Las Culturistas with Matt Rogers and Bowen Yang
Ding dong! Join your culture consultants, Matt Rogers and Bowen Yang, on an unforgettable journey into the beating heart of CULTURE. Alongside sizzling special guests, they GET INTO the hottest pop-culture moments of the day and the formative cultural experiences that turned them into Culturistas. Produced by the Big Money Players Network and iHeartRadio.