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How Natural Selection Works · Stuff You Should Know

0:01
Speaker 1: Welcome to Stuff you Should Know from House Stuffworks dot com. Hey,
0:11
Speaker 1: and welcome to the podcast. I'm Josh Clark, There's Charles W.
0:14
Speaker 1: Chuck Bryant, and there's no which makes us a very
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Speaker 1: metal parking lot guys. Yeah exactly. Um, hey Chuck. Before
0:57
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1:06
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Speaker 1: Stuff you Should Know dot com. That's right, you can
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Speaker 1: hang out with us outside of the podcast if you want,
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Speaker 1: if you want, no pressure. So how are you doing?
1:21
Speaker 1: I'm great. I'm super excited about this topic because A
1:24
Speaker 1: we're pairing it with our Charles Darwin show, Yeah, which
1:27
Speaker 1: I guess came out last episode, right, aren't we pairing
1:30
Speaker 1: the two? Yeah? I think we're doing Darwin first. Let's
1:33
Speaker 1: do Darwin first, because I think in the Darwin episode
1:36
Speaker 1: we say we should do natural selection. It's here we are.
1:40
Speaker 1: But I'm just excited because to me, and I gushed
1:43
Speaker 1: a little at Darwin's feet, this is my own personal statement.
1:48
Speaker 1: I think natural selection is the most exciting and like
1:52
Speaker 1: beautiful thing that exists. It's it's just it really turns
1:57
Speaker 1: my crank. You know, you're like an old timey car. Yeah, yeah,
2:04
Speaker 1: you know. I grew up this is again my personal story.
2:07
Speaker 1: I grew up in churches most listeners now, uh, which
2:11
Speaker 1: was heavy doses of of creation, the creation story. And
2:15
Speaker 1: I remember, as a kid, even fully involved in in church,
2:20
Speaker 1: thinking like I just this doesn't make sense to me.
2:23
Speaker 1: I just it didn't add up. So natural selection it
2:26
Speaker 1: just makes sense to you. Yeah. When I finally learned
2:29
Speaker 1: about natural selection, like really really understood and learned it.
2:32
Speaker 1: It just it made total sense because I can like
2:36
Speaker 1: see it, it was tangible. I could make sense of it.
2:39
Speaker 1: And again that's my own story. We don't poo poo
2:44
Speaker 1: anyone or saying anyone should feel anyway, but we just
2:48
Speaker 1: explain how things work exactly. You know. But I have
2:51
Speaker 1: a personal attachment to this just because I think it's
2:53
Speaker 1: like the grooviest thing going. Yeah, no, I know what
2:55
Speaker 1: you mean. Like it it makes uttering complete sense. It's
2:58
Speaker 1: almost um in capable of being appropriated to serve some agenda.
3:03
Speaker 1: It just is what it is, you know, It's just there.
3:07
Speaker 1: It's beautiful. I agree with you entirely. It's an elegant theory.
3:10
Speaker 1: Its just super neat. Yeah. Um. And the wonderful thing
3:13
Speaker 1: is is like there's even squabbles in the scientific community
3:16
Speaker 1: over exactly how evolution works and processes, and regardless, everyone's
3:23
Speaker 1: still like, yep, natural selection pretty much perfect. Yeah, it
3:28
Speaker 1: just makes sense. I'm gonna have a t shirt natural selection.
3:31
Speaker 1: It just makes sense. I have a feeling we'll be
3:33
Speaker 1: getting an email with something like that eventually, So let's
3:37
Speaker 1: talk about natural selection. I think a lot of people,
3:39
Speaker 1: including myself, um, kind of had an idea of what
3:42
Speaker 1: it was, pretty good idea, but not necessarily understanding the
3:45
Speaker 1: ins and outs of it. And well, that's what we're
3:48
Speaker 1: here for, is to explain the ins and outs of
3:50
Speaker 1: natural selection. So, um, basically, a lot of people interchange
3:56
Speaker 1: evolution and natural selection. That's incorrect. Um. Evolution is this
4:02
Speaker 1: huge process by which species adapt and change to survive
4:09
Speaker 1: in their environments, and the way that that moves along.
4:12
Speaker 1: The mechanism that drives that is natural selection. So they're
4:16
Speaker 1: not one and the same. Natural selection drives evolution. Yeah,
4:20
Speaker 1: and who wrote this one? Was this? Uh? Grabowski? The
4:24
Speaker 1: grabster I should have known. Uh, just very simply puts
4:28
Speaker 1: it very early on the article. Organisms best suited to
4:31
Speaker 1: survive in their particular circumstance have a greater chance of
4:35
Speaker 1: passing their traits onto the next generation. That's right, it
4:38
Speaker 1: just makes sense. I'm gonna try not to say that
4:40
Speaker 1: every ten minutes, but just now that that's going on
4:43
Speaker 1: in my head. Yeah, and and and um do you
4:47
Speaker 1: want that on a T shirt? And natural selection is
4:50
Speaker 1: like it's this ongoing, basically never ending process even when
4:54
Speaker 1: organisms really kind of seemingly stopped developing, like they figured
4:58
Speaker 1: it out. Yeah, but it's it isn't. It doesn't have
5:02
Speaker 1: its own sentience. It isn't its own thing. Like you can't.
5:06
Speaker 1: You can't attribute it to some sort of creator or
5:09
Speaker 1: creation necessarily unless you believe that kind of thing. But
5:12
Speaker 1: like if you're if you, it's very easy to give
5:14
Speaker 1: it a personality, but it's not. It's the byproduct of
5:18
Speaker 1: how organisms exist, and we exist by our genes and
5:23
Speaker 1: by the fact that those genes change frequently within the
5:26
Speaker 1: lifetime of a person thanks to what we understand now
5:30
Speaker 1: is of the genetics, but also through reproduction. And from
5:34
Speaker 1: these these moments, these periods where genes are up for
5:38
Speaker 1: a change, they can completely or even just partially change
5:43
Speaker 1: part of an organism, and that change may or may
5:46
Speaker 1: not help the organism survive in the environment, like you
5:49
Speaker 1: just quoted Grabanowski. And if it does, bay a natural
5:52
Speaker 1: selection will root that out and it will propagate that. Yeah,
5:56
Speaker 1: and uh. It also points out Darwin um he did
5:59
Speaker 1: coin term natural selection and survival of the fittest. And
6:03
Speaker 1: I do think that many people hear survival of the
6:05
Speaker 1: fittest and they think of the lion eating the gazelle.
6:09
Speaker 1: But it's also, like he says, the tree that can
6:12
Speaker 1: disperse its seed where it needs to for those seeds
6:15
Speaker 1: to grow or the bacteria that uh survives. It's not
6:19
Speaker 1: you know, animal eating animal, although it can, right, And
6:22
Speaker 1: so since we're on it, Chuck, fitness is basically um
6:26
Speaker 1: like you say, like a tree's ability to spread seeds
6:29
Speaker 1: and for those seeds to take rud because its grabs.
6:32
Speaker 1: Her points out, it's not enough for a tree to
6:35
Speaker 1: produce a bunch of seeds, which is its ability to reproduce, Yeah,
6:39
Speaker 1: and its ability to survive long enough to even get
6:41
Speaker 1: to the point to it where it reproduces. Right. That's
6:43
Speaker 1: step one is to live long enough to be able
6:46
Speaker 1: to reproduce. Step two, or the second part of it
6:50
Speaker 1: is that that reproduction is as successful as it possibly
6:54
Speaker 1: can be. Yeah, Like it says, not only you gotta
6:57
Speaker 1: do it, you gotta do it well. So that tree,
7:00
Speaker 1: it spreads tons and tons of seeds. If those seeds
7:03
Speaker 1: um happen to um catch fire and sunlight, that's not
7:08
Speaker 1: going to be a very good trait. But if they
7:10
Speaker 1: have like a really hard husk that can survive the
7:14
Speaker 1: elements but then disintegrates when it's digested by a raccoon
7:18
Speaker 1: and then pooped out. You know, then all of a
7:21
Speaker 1: sudden you've got that step two covered. Yeah, or if
7:24
Speaker 1: it you know, if it's just dumb luck, if that
7:26
Speaker 1: tree exists in a place where it's super windy and
7:29
Speaker 1: can disperse the seeds better, uh, then it will propagate.
7:33
Speaker 1: If not, then you may not even know that that
7:35
Speaker 1: tree existed exactly unless you consult the fossil record. That's right. Um, Okay,
7:41
Speaker 1: So I guess the whole point to natural selection is
7:46
Speaker 1: that it is an agent of change, but it's also
7:49
Speaker 1: a byproduct of change, and we kind of have to
7:52
Speaker 1: take a step backward to figure out where this change
7:57
Speaker 1: is happening. I already said it a little bit, but
7:59
Speaker 1: it's in it's our DNA. It's in the DNA of
8:02
Speaker 1: all living things to change. Yeah, well, traits were all
8:08
Speaker 1: born with traits, and we inherent those traits from you
8:11
Speaker 1: know who who made us our folks and um. But
8:17
Speaker 1: it's not necessarily that's not necessarily natural selection at work
8:20
Speaker 1: over like one generation to the next. Right, there can
8:23
Speaker 1: be differences in traits. Like Darwin, as we'll see, points
8:26
Speaker 1: that out himself. He's like, let's just get it out
8:28
Speaker 1: of the way, Like just because you have brown eyes
8:30
Speaker 1: and somebody else has blue eyes, that's not evolution. No,
8:33
Speaker 1: and he uses a good example here of tall versus
8:35
Speaker 1: short folks. Uh, tall people might be basketball players, people
8:40
Speaker 1: might be jockeyscus the grabs are not Darwin. Yeah yeah, yeah,
8:44
Speaker 1: Um did they have basketball? When was that advented? When
8:47
Speaker 1: did the name sent in mid basketball? I want to
8:49
Speaker 1: say eighteen forty eight, but it's probably eighteen seventy, not
8:53
Speaker 1: too far off. So he makes the point that you know,
8:56
Speaker 1: if something happened to where like jockeys could reproduce better
9:01
Speaker 1: or basketball players could not reproduce anymore. Yeah, I was
9:04
Speaker 1: trying to imagine, just make up anything, I know, I
9:09
Speaker 1: was trying to and like I couldn't come up with it. Well,
9:12
Speaker 1: just make make up something like being able to uh
9:15
Speaker 1: dribble and dunk lowers your sperm count. Oh that's a
9:19
Speaker 1: good one. See, that's what I'm saying. I think my
9:21
Speaker 1: brain was in understand natural selection modes of my My
9:25
Speaker 1: imagination grew less fertile, so it didn't survive, No, it didn't. Um,
9:31
Speaker 1: And over time, basically basketball players don't reproduce as much
9:34
Speaker 1: jockey's do, and over several generations, people are going to
9:37
Speaker 1: be shorter on average. It sounds almost dumb, it's so simple,
9:42
Speaker 1: but that's really the basis of it. It is, and
9:44
Speaker 1: it's one of those things. It's like economics where it's
9:46
Speaker 1: so simple that it's hard to wrap your mind around
9:49
Speaker 1: it because you make it more complex necessarily than it is.
9:53
Speaker 1: It's it's very similar for me. Um. And with that
9:57
Speaker 1: basketball example which just happened, was humanity evolved to be shorter.
10:02
Speaker 1: That was the end result. And that evolution took place
10:07
Speaker 1: because there was a shift in the distribution of traits.
10:12
Speaker 1: So before lots of basketball players, lots of jockeys, tallness
10:16
Speaker 1: and shortness, which are traits or variations on the trade
10:20
Speaker 1: of height in humans, Like we have height, we're not
10:23
Speaker 1: too dimensional inherited by who bore you, right, not us,
10:28
Speaker 1: your parents. We bore you in a different way. Um.
10:33
Speaker 1: So the variations on the trade eventually gave rise to evolution.
10:36
Speaker 1: So within just like our generation or even a couple
10:40
Speaker 1: of generations, the differences in eye color, height or something
10:43
Speaker 1: like that, it doesn't represent evolution, but changes like that
10:48
Speaker 1: can lead to evolution over time. Yeah, if they are
10:52
Speaker 1: changes that either aid or prevent your survival, right, Like
10:56
Speaker 1: if something happens and all of a sudden human women
10:58
Speaker 1: were all like, we're not gonna mate with anybody but
11:01
Speaker 1: blue eyes. You can bet your bippy that within two
11:04
Speaker 1: generations there's gonna be nothing but blue eyed kids. Yeah,
11:08
Speaker 1: or grown adults getting blue contacts. That's a good idea
11:12
Speaker 1: because they're tired of not having sex. But then maybe
11:16
Speaker 1: our eyes would adapt to um the context and just
11:19
Speaker 1: absorb them. Something has to happen. Your imagination is plenty fertill,
11:25
Speaker 1: my friend, I guess so. Uh, and this all goes
11:28
Speaker 1: back if we can go back a little further to
11:29
Speaker 1: something called DNA um that is a chemical structure that
11:35
Speaker 1: is the basis for everything that is. Is that a
11:37
Speaker 1: good way to say it? And Uh? Within DNA are
11:42
Speaker 1: sequences of traits, sets of traits, and those are the genes.
11:46
Speaker 1: And then there's something called the LLL, which is really
11:50
Speaker 1: where it all comes together. Is it all? Or allele?
11:53
Speaker 1: Does I say ll adele? No? Adele allele? Okay? So
12:01
Speaker 1: it's like a gene is like a specific sequence of
12:04
Speaker 1: DNA that produces some trade. So height, like you have
12:09
Speaker 1: a height gene like and when that gene is working
12:12
Speaker 1: like you will grow. Yeah, the expression of the gene
12:14
Speaker 1: is the allele. Yeah, that's the variation of that trait.
12:18
Speaker 1: So imagine like as just a stretch of genes is
12:21
Speaker 1: like a few boxes, say five of them, and three
12:25
Speaker 1: are off the three that will encode to make brown eyes, uh,
12:29
Speaker 1: and two are on the two that will encode to
12:33
Speaker 1: make blue eyes. So each one's an allele, but the
12:37
Speaker 1: one that's functioning gives you blue eyes. So in allal
12:41
Speaker 1: is just a variation on a trade. And a trade
12:43
Speaker 1: is produced by a gene, which is a sequence of DNA.
12:46
Speaker 1: That variation is produced by an allele, which is a
12:49
Speaker 1: sequence of the gene. And how often that allele shows
12:53
Speaker 1: up in a population is the allele frequency. And it's
12:57
Speaker 1: really simple. You hear alleal frequency and it sounds like,
13:00
Speaker 1: oh that's science, but it's really pretty easy. That's what
13:02
Speaker 1: they go to school force to learn the jargon. Yeah,
13:05
Speaker 1: and uh, we did a really good episode on population
13:09
Speaker 1: and uh, we're gonna be talking about here again though,
13:12
Speaker 1: So we should just say that a population is a
13:15
Speaker 1: group uh in one place that have sex with each other. Yeah. Um,
13:21
Speaker 1: so like a zebra in Africa. He makes up he
13:25
Speaker 1: should have used real examples because he said, let's say
13:28
Speaker 1: there were zebras in South America. But I see his point,
13:31
Speaker 1: that would be a different population because they can't have
13:33
Speaker 1: sex with the zebras in Africa, because zebras can't swim
13:36
Speaker 1: across the ocean. And a lion in Africa is in
13:39
Speaker 1: a different population than a zebra in Africa because they
13:41
Speaker 1: don't do it right. They can't. It's an abomination. It is.
13:47
Speaker 1: You come up with a zion, that'd be kind of cool.
13:51
Speaker 1: I guess, sort of like a tiger. Probably maybe that's
13:56
Speaker 1: what a tiger. I think. It's So you were talking
14:00
Speaker 1: about populations and you're in a little frequency. So, um,
14:06
Speaker 1: you could conceivably quantify the alleal frequency of blue eyes
14:10
Speaker 1: and the human population because we transcended, like the difference
14:15
Speaker 1: between Africa and South America. Like we have planes now,
14:18
Speaker 1: so we we all have access to sex with one
14:21
Speaker 1: another as a population, as long as you have a
14:23
Speaker 1: passport and some money for a plane ticket. Um. So
14:29
Speaker 1: speaking about a lieal frequency, Um, the point of that
14:32
Speaker 1: whole thing is that with evolution, I guess another way
14:37
Speaker 1: to put it, the way it grabs or puts it
14:39
Speaker 1: is evolution is just a shift or a change in
14:42
Speaker 1: alleal frequency. And the reason that that change takes places
14:46
Speaker 1: because those alleles that become more and more widespread and
14:51
Speaker 1: distributed it across the population, UM have made that organism
14:58
Speaker 1: more likely to survive, to reproduce, and more likely to
15:02
Speaker 1: successfully reproduce. Yeah, that's it. That's it. That's the evolution
15:06
Speaker 1: driven by natural selection. Do you want to quit? I
15:09
Speaker 1: don't think we could top at this point. Now it
15:12
Speaker 1: does get more interesting. Um Alile's create are created in
15:17
Speaker 1: a few different ways. UM. One is called a mutation,
15:20
Speaker 1: which you probably heard of. Uh. These are random changes. Uh.
15:25
Speaker 1: They are pretty rare, like the X men. Yeah, very rare,
15:29
Speaker 1: very rare mutants are. That's why they got to hang
15:31
Speaker 1: out with the president a lot. Yeah, but the president
15:34
Speaker 1: was also a mutant, wouldn't he. Oh yeah, eventually Kelsey Grammer. No, no, no,
15:39
Speaker 1: the president was the guy with the son with the wings.
15:44
Speaker 1: I thought, ye, his son was the mutant and the
15:46
Speaker 1: president the president. But I think Kelsey Grammer eventually was
15:50
Speaker 1: elected president Blue president, Blue Harry President. So to me,
15:57
Speaker 1: the cool thing about mutations is is they can be
16:01
Speaker 1: completely new traits that are introduced that are completely different
16:05
Speaker 1: than anything you've ever seen in that species, which is
16:08
Speaker 1: pretty radical. Another way is just like we've been talking
16:12
Speaker 1: about sex a lot reproduction just with animals humans. That
16:17
Speaker 1: is the way that an aile can express itself. Right.
16:20
Speaker 1: It's the mixing together when when your mom and your
16:24
Speaker 1: dad love each other very much and they copulate. Um,
16:28
Speaker 1: there sperm and egg mixed together, break down their DNA
16:32
Speaker 1: and it's glorious, fantastic um little mini explosion inside the
16:37
Speaker 1: womb and uh, and then it really it recombines into
16:42
Speaker 1: a totally new form that shares part of the dad's
16:46
Speaker 1: DNA and part of the mom's UNICH to make a
16:48
Speaker 1: new human. Yeah, and you get all the bad traits
16:51
Speaker 1: from each of them, right, hopefully you get all the
16:54
Speaker 1: best traits. But that's the point of sexual reproduction, which
16:59
Speaker 1: was itself naturally selected, because it increases the potential that
17:04
Speaker 1: you're going to inherit uh, good traits that will let
17:07
Speaker 1: you survive. That's right, there's just more traits out there.
17:10
Speaker 1: It's like um. I think it was the Sense of
17:13
Speaker 1: Smell episode we did where we talked about pheromones, the
17:17
Speaker 1: idea that pheromones among humans, we we can still detect
17:21
Speaker 1: them even though we don't know it. And the whole
17:23
Speaker 1: reason we can is to smell out other people's immune
17:27
Speaker 1: system and we want somebody with an opposite immune system
17:30
Speaker 1: of RS. So when you put the two together, it
17:32
Speaker 1: produces a little mini superhuman who can't be killed. There
17:35
Speaker 1: was an interesting study I think where they just had
17:37
Speaker 1: people smelling things, but the gauging attraction levels right. But
17:41
Speaker 1: it's based on the premise of sexual reproduction, which is
17:44
Speaker 1: the combining as many good traits as possible make somebody
17:49
Speaker 1: with a lot of them. Uh. And then the final
17:53
Speaker 1: way that um alile's are created is um genetic recombination,
17:57
Speaker 1: and that would be in the case of like a
17:59
Speaker 1: bacteria who obviously don't go out and have sex with
18:02
Speaker 1: each other um, but they do absorb DNA that they
18:06
Speaker 1: get from other bacteria and basically make it part of them. Yeah,
18:11
Speaker 1: they think that's where the ukaryotes came from. Yeah, the
18:15
Speaker 1: mitochondria was its own thing and it became absorbed by
18:18
Speaker 1: some ancient cell to serve as like the power center
18:23
Speaker 1: of the of the cell, and from that like gave
18:27
Speaker 1: rise to everything with the backbone, everything that's not a
18:29
Speaker 1: bacteria basically, so fish at first, I guess yeah, but eventually,
18:34
Speaker 1: like it all, it all just came to that and
18:36
Speaker 1: it's still going on today. It's just two organisms in
18:40
Speaker 1: one neat yeah that's super neat, and then one other thing.
18:44
Speaker 1: Like there are three ways that this could happen. That
18:46
Speaker 1: um that new alliles could be introduced. But um, I
18:51
Speaker 1: wonder if epigenetics will eventually be added to that. Yeah,
18:56
Speaker 1: because think about it. I mean, it's a change in
18:58
Speaker 1: gene expression, right, So yeah, I could see that leading
19:03
Speaker 1: to I guess I guess it could be classified as
19:06
Speaker 1: a spontaneous mutation. I guess it would fall under that umbrella. Yeah,
19:11
Speaker 1: but so much leads up to it. I don't know.
19:14
Speaker 1: I'm with you. What's out of fourth? Okay, et the
19:16
Speaker 1: genetics is officially added as a change to Allele's I'm
19:21
Speaker 1: sure we'll get an email from someone that's super smart
19:23
Speaker 1: that will explain exactly why that won't happen there. Like,
19:26
Speaker 1: first of all, Chuck was right, it's allows so Chuck
19:32
Speaker 1: we um. You know we said that all of this
19:34
Speaker 1: starts at DNA and the fact that it changes, we
19:37
Speaker 1: actually should go back even further, um than that, uh,
19:43
Speaker 1: into the backdrop of nature, the environment, the reason that
19:47
Speaker 1: DNA changes, that traits change over time is because of
19:52
Speaker 1: a little thing called death. Yeah, we all die and
19:57
Speaker 1: how to avoid it exactly. It's it's the combination of
20:01
Speaker 1: the two things. We're all going to die, and all
20:04
Speaker 1: organisms appear to be driven by a desire to put
20:07
Speaker 1: off that moment as long as possible, So we have
20:10
Speaker 1: an instinct to survive. Right. The problem is is the
20:15
Speaker 1: processes of nature are trying to put us down all
20:18
Speaker 1: the time, so there is a inherent struggle to survive.
20:24
Speaker 1: So when you combine our desire to live with nature
20:28
Speaker 1: trying to kill us all the time, it forms that struggle.
20:31
Speaker 1: The struggles have survived gives rise to the changes in genes,
20:34
Speaker 1: which eventually are selected and convert to evolution. So it
20:40
Speaker 1: all begins with the struggle to survive and the desire
20:43
Speaker 1: to survive. Right, And this is spelled out by Darwin himself. Yeah,
20:50
Speaker 1: should we read some of his quotes, Uh this is
20:53
Speaker 1: These are from the on the Origin of the Species,
20:55
Speaker 1: which if you just listen to the Charles Starwin, you know,
20:58
Speaker 1: that was his most famous work that he put up,
21:02
Speaker 1: one of many, but that's his uh you know, warrant Peace.
21:06
Speaker 1: It's close second was my travels with Timmy about his
21:10
Speaker 1: pet rabbit and he going around the county bothering neighbors.
21:14
Speaker 1: So he here are you with the Here a few
21:19
Speaker 1: of the basic tenants in on the origin of the
21:21
Speaker 1: species and with some quotes from Darwin himself. One is
21:25
Speaker 1: the organisms show variations of a variation of traits. Yeah,
21:29
Speaker 1: that's him just getting it out of the way, like,
21:31
Speaker 1: don't be dumb. If you think that your your dad's
21:34
Speaker 1: blue eyes and your brow and eyes are revolution, you're wrong. Okay,
21:37
Speaker 1: I like that better than his quote. Actually, let's do that.
21:40
Speaker 1: Let's do Josh's take on his quote. I'll do what
21:43
Speaker 1: I can, all right. Uh. Number two is more organisms
21:46
Speaker 1: are born that could ever possibly be supported by the
21:50
Speaker 1: resources here on the planet. That's right. Uh, stop being
21:55
Speaker 1: such an idiot. There's such a thing as scarcity, don't
21:57
Speaker 1: you know that. I mean this is great. Um, I
22:01
Speaker 1: feel the birth of the new podcast coming. Number three. Therefore,
22:05
Speaker 1: in conclusion, all organisms must struggle to live. You already
22:08
Speaker 1: kind of covered that, okay. Um. Number four, some traits
22:13
Speaker 1: offer advantages in the struggle. That's right. Uh, those are mutations,
22:20
Speaker 1: and as Josh will eventually predict, epigenetics, not always mutations
22:25
Speaker 1: though right changes to Allele's um. Organisms that have those
22:31
Speaker 1: traits are the ones that will help you survive, are
22:33
Speaker 1: more likely to be successful and reproduce and pass them on.
22:37
Speaker 1: And then finally successful variations the ones that we have
22:40
Speaker 1: just talked about that allow you to survive and reproduce more.
22:43
Speaker 1: They accumulate over the years and the generations as they
22:47
Speaker 1: are exposed to something we'll talk about in a minute
22:49
Speaker 1: called population pressure. Right. And he points out too that
22:53
Speaker 1: this is essentially specific and local. Like UM, if humans
22:58
Speaker 1: had a right where you cooled extremely easily all the time, UM,
23:04
Speaker 1: under under all conditions, it wouldn't play very well. When
23:08
Speaker 1: you move to the northern latitudes, you die, so it
23:11
Speaker 1: would be selected out of populations in the northern latitudes.
23:15
Speaker 1: But if you lived in the tropics, it would probably
23:18
Speaker 1: be selected um and propagated over time because you probably
23:22
Speaker 1: have a lot more energy. You wouldn't just be laying
23:24
Speaker 1: around fanning yourself with palm fronds. Well you do that too,
23:27
Speaker 1: but you wouldn't need to. Yeah, but it's just it's
23:31
Speaker 1: a nice experience. UM. So I mentioned population pressure, and
23:35
Speaker 1: that's a key here to understanding this whole bowl of soup.
23:40
Speaker 1: And we'll talk about that right after this message. All right,
23:46
Speaker 1: So here we are in the stew I called it soup.
23:48
Speaker 1: It's really a stew of evolution and that section. So
23:53
Speaker 1: we need to talk about population pressure, which is basically
23:57
Speaker 1: anything in a population that makes it tough for your species.
24:02
Speaker 1: Are you, as an individual plant or animal to survive it? Yeah? Again,
24:06
Speaker 1: because there's such things scarcity that means you compete with
24:09
Speaker 1: people in your species or people outside of your species, right,
24:14
Speaker 1: like a lion wants to eat you. Yeah, there's always
24:17
Speaker 1: it's always going on, yes, um. And then even if
24:20
Speaker 1: you lived in total harmony with all the plants and
24:23
Speaker 1: animals around you and vice versa, nature is still shooting
24:27
Speaker 1: lightning bolts at you, train your floods, droughts, famine, all
24:32
Speaker 1: that stuff there is always in and is Darwin put
24:35
Speaker 1: it like every organism struggles to survive one way or another. Yeah,
24:40
Speaker 1: And that can really speed things up as far as
24:43
Speaker 1: alleal frequency change, Like if you flood it out an
24:47
Speaker 1: entire country, you're gonna see some big changes within a
24:50
Speaker 1: generation or two. It's not necessarily over hundreds of years,
24:53
Speaker 1: that's right, um. And that's because Uh. When you have
24:58
Speaker 1: something especially like uh, a flood or drought or just
25:02
Speaker 1: some severe increase sudden increase in population pressure, it goes
25:06
Speaker 1: from just background population pressure to something very acute and pronounced.
25:11
Speaker 1: I got a lot of the population dies off. Yeah,
25:14
Speaker 1: Like his example is pretty great. Actually about the fire.
25:17
Speaker 1: Let's say a fire killed all the vegetation under fifteen
25:21
Speaker 1: feet and a population of giraffes, anything under fifteen feet
25:27
Speaker 1: is gonna have a hard time reaching food, and so
25:31
Speaker 1: they're gonna start reproducing and making taller giraffes pretty much
25:34
Speaker 1: as fast as they can write. The ones that can't
25:36
Speaker 1: reach food will die off, a lot of them before
25:38
Speaker 1: they can reproduce. The ones that can reach food will
25:41
Speaker 1: live to reproduce, which will produce those taller giraffes. Um,
25:44
Speaker 1: And what just happened then in that giraffe example is
25:47
Speaker 1: called a population bottleneck. Something happened that took a large population,
25:52
Speaker 1: reduced it down to a smaller amount. And then usually
25:55
Speaker 1: in that smaller group, there's going to be some traits
25:58
Speaker 1: or whatever that used to be evenly distributed among the
26:02
Speaker 1: population that are now really concentrated and clustered. And like
26:08
Speaker 1: it could be something super rare that is now the
26:11
Speaker 1: trade right exactly. So if you have a super rare
26:14
Speaker 1: trait spread out very evenly among a large population, that
26:19
Speaker 1: trait may or may not ever be selected, and if
26:21
Speaker 1: it is selected, it may take a very long time
26:24
Speaker 1: to be selected because there's so many other competing traits. Well,
26:27
Speaker 1: when a lot of those other competing traits are narrow
26:29
Speaker 1: we weeded out, and you have that population bottlenecked, those
26:34
Speaker 1: traits are going to be very pronounced and they they're
26:36
Speaker 1: going to be selected very quickly. So you have a
26:38
Speaker 1: very quick change in evolution as a result of sudden
26:42
Speaker 1: acute population bottlenecks. Yeah, it basically becomes the norm. So
26:46
Speaker 1: in that area of where the fire ended up killing
26:50
Speaker 1: shorter giraffes, the norm will now be super tall giraffes exactly.
26:55
Speaker 1: And don't say chuck. All giraffes are super tall, super
26:57
Speaker 1: super tall, super super tall. And this is apparently happened
27:00
Speaker 1: to humans. Um there's a population bottleneck. Supposedly around seventy
27:04
Speaker 1: tho years ago. Um uh, there was something called the
27:08
Speaker 1: Toba eruption, huge supervolcano created like a six to ten
27:12
Speaker 1: year long winner and dropped the number of humans Homo
27:16
Speaker 1: sapiens down to something as low as possibly three thousand people. Yeah, so, uh,
27:22
Speaker 1: the planet on the whole planet, and they're not quite
27:25
Speaker 1: sure like what what um variations were selected out of that,
27:30
Speaker 1: but you can bet there was an enormous change within
27:35
Speaker 1: years of that event. Boy, I wonder what it was
27:38
Speaker 1: like before that, right, it's pretty interesting. So let's say
27:41
Speaker 1: the giraffes, like everything was hunky dory, no fires, no nothing,
27:45
Speaker 1: but just some of them decided that they wanted to
27:48
Speaker 1: see if there really are no such thing as zebras
27:51
Speaker 1: in South America. So they hop on a boat and
27:54
Speaker 1: they sailed to South America and they establish a new
27:57
Speaker 1: little giraffe colony there. Yeah, well we'll result from that
28:01
Speaker 1: is called the founder effect. And there is a band,
28:04
Speaker 1: by the way, I already looked, no, yeah, I thought
28:06
Speaker 1: there's gotta be one, and it is h and I
28:09
Speaker 1: listen to their song. How is it? It was pretty good?
28:12
Speaker 1: What kind of music, you know, sort of uh, giraffe
28:15
Speaker 1: in the Giraffe shoegazy. Okay, not bad? Um so anyway, Yeah,
28:22
Speaker 1: the founder effect is when you quite literally, when a
28:24
Speaker 1: population founds a new area and don't have sex with
28:29
Speaker 1: that other population anymore. Right, So, and you can have
28:33
Speaker 1: very different traits from even if it's a giraffe, from
28:36
Speaker 1: the ones in Africa, because they set up camp in
28:40
Speaker 1: a new place, right, and it's almost like an unforced bottleneck. Yeah,
28:46
Speaker 1: you know they have voluntary bottleneck. Yeah. Nature didn't kill
28:48
Speaker 1: off a bunch of the population. The population just broke
28:51
Speaker 1: off from from a larger group to a smaller group.
28:54
Speaker 1: And that smaller groups probably going to have some weird
28:57
Speaker 1: trader too that are going to be select and and
29:02
Speaker 1: push evolution along faster than usual. Yeah, alright, let's talk
29:07
Speaker 1: about this then. Okay, let me pose a question to you, sir,
29:10
Speaker 1: that I know the answer to. Uh, what about things
29:14
Speaker 1: that don't evolve anymore? Buddy? What about like the shark
29:17
Speaker 1: that's been about the same for millions of years? Show
29:20
Speaker 1: me your natural selection? There? I got this, Okay. So
29:25
Speaker 1: sharks are a great example, um, because they haven't changed
29:29
Speaker 1: in millions of years because they don't need to. Well,
29:33
Speaker 1: because basically they became apex predators a long time ago
29:37
Speaker 1: in their environments, and their environments went unchanged enough so
29:40
Speaker 1: that sharks didn't need to change. They are basically as
29:44
Speaker 1: far as natural selection goes perfect. Yeah, they early on
29:49
Speaker 1: figured it out. It's like, all right, I've got my
29:52
Speaker 1: my teeth and are great. My my gills are working.
29:54
Speaker 1: I can send electrical impulses from can swim super fast,
29:58
Speaker 1: I can kill everything I see. As long as something
30:00
Speaker 1: doesn't punch me in the nose, I'm pretty much good.
30:03
Speaker 1: Or kill me for my sharks, then well that's yeah.
30:06
Speaker 1: It makes you wonder how sharks you are gonna evolve now.
30:09
Speaker 1: But let's say pre human fishing, so, uh, two hundred
30:14
Speaker 1: years ago up to from several million, maybe tens, I
30:18
Speaker 1: don't remember how long sharks have been around virtually unchanged. Yeah,
30:23
Speaker 1: so uh, let's say from millions and millions, millions and
30:26
Speaker 1: millions and millions and millions and millions of years ago
30:30
Speaker 1: up to two hundred years ago. Sharks are virtually unchanged
30:33
Speaker 1: because they hit their peak and they're fine. But that
30:36
Speaker 1: doesn't mean that they have gone unchanged or that natural
30:41
Speaker 1: selection hasn't exerted an effect on them. Basically, what happens
30:45
Speaker 1: is they're still undergoing mutations through reproduction. There's new allele's
30:51
Speaker 1: showing up, but none of them are holding it. Can
30:55
Speaker 1: hold a candle to the perfection. That's been achieved by
30:58
Speaker 1: the shark, so they get selected out. They don't get
31:01
Speaker 1: a chance to um to reproduce in the population or
31:04
Speaker 1: become distributed amongst the population. So if you still have
31:08
Speaker 1: natural selection weeding out, but rather than changing the shark
31:11
Speaker 1: population or the shark species um our family family you have,
31:20
Speaker 1: you have a natural selection as an agent of stability. Yeah,
31:24
Speaker 1: or I guess if let's do a hypothetical, if we
31:26
Speaker 1: were going to use shark finn shark finning as an example,
31:30
Speaker 1: Let's say only sharks with you know, perfectly triangular gray
31:38
Speaker 1: fins were selected out right to be finned and cut
31:41
Speaker 1: off for shark fin soup. So that means sharks that
31:44
Speaker 1: have like weird spots on their fins would not get killed.
31:48
Speaker 1: So theoretically, hypothetically, over generations, we might see sharks with
31:53
Speaker 1: only spotted fins, and that probably will happen because of
31:56
Speaker 1: the sudden and acute population pressure being exerted on sharks
32:00
Speaker 1: by humans. There has to be some sort of forced
32:05
Speaker 1: adaptation that's gonna occur. Yeah. I don't know what the
32:08
Speaker 1: criteria for a good fin though is, or if they
32:11
Speaker 1: just take them all like whatever they can catch, but
32:13
Speaker 1: I mean it could be as simple as something like
32:15
Speaker 1: UM figuring out that they like just swimming deeper and
32:21
Speaker 1: not coming up and like within the humans grass like
32:24
Speaker 1: just yeah just stay. Yeah, we should say that that's
32:27
Speaker 1: a really good point. UM. A trait isn't necessarily something
32:30
Speaker 1: that is um visibly apparent, like it like height or
32:35
Speaker 1: something like that. It can be an ability or a
32:39
Speaker 1: proclivity like grabster uses the example of UM dogs have
32:43
Speaker 1: evolved UM the trait of UM hanging out with humans
32:48
Speaker 1: and chuck, UM tell them about the elephants because that's
32:53
Speaker 1: a pretty good example of what we're talking about. Sharks. Yeah. Yeah, Well, elephants,
32:57
Speaker 1: as we know, are killed many times for their ivory tusks.
33:01
Speaker 1: And it's sort of a no, it's a good news
33:06
Speaker 1: bad news scenario. You would think, hey, good news, there's
33:09
Speaker 1: some elephants that were being born without tusks at all,
33:12
Speaker 1: so they're not being hunted. And over the years, now
33:15
Speaker 1: there it went from like like close, now are not
33:22
Speaker 1: born with tusks, So you think that's awesome because now
33:24
Speaker 1: they're not being hunted, but they need those tusks for
33:27
Speaker 1: digging in defense and things like that, so they're they're
33:31
Speaker 1: losing a valuable trait which is going to put stress
33:34
Speaker 1: on the population as a whole, I would think over time.
33:37
Speaker 1: But in the near term it's been selected out because
33:40
Speaker 1: it's keeping the elephants alive because the ones that were
33:43
Speaker 1: naturally without tusks weren't being killed by poachers, so they
33:47
Speaker 1: were allowed to reproduce more frequently than ones with tusks
33:51
Speaker 1: that were being killed. So, yeah, you have a within
33:55
Speaker 1: a human lifetime, within seventy years or so, the population
34:00
Speaker 1: has evolved. Yeah, that's what I mean by like you
34:03
Speaker 1: can see it happening in front of us, right, And
34:05
Speaker 1: this is where the debate comes from. Where I was saying, like,
34:08
Speaker 1: scientists even debate on how evolution changes or happens um.
34:12
Speaker 1: And there's basically the difference between um gradualism or punctuated
34:17
Speaker 1: equilibrium and gradualism is just over time, very slowly new
34:22
Speaker 1: ah lials appear, and some of them tend to make
34:27
Speaker 1: organisms fitter, and so they'll eventually, over very long stretches
34:31
Speaker 1: of time, be selected out and then uh, punctuated equilibrium
34:36
Speaker 1: is like we're talking about with the African elephants, where
34:39
Speaker 1: there's a sudden population pressure and all of a sudden,
34:43
Speaker 1: this organism or species is forced to evolve, and they do,
34:48
Speaker 1: and then after that everything evens out for a little
34:50
Speaker 1: while and stays the same until the next catastrophic event. Yeah,
34:54
Speaker 1: I don't get it. There A it says there's an
34:57
Speaker 1: ongoing debate about that. Can't they both exist? I don't
35:00
Speaker 1: understand why they don't both exist. It seems like one
35:02
Speaker 1: is just constant background evolution and the other one is
35:06
Speaker 1: um like evolution as a result of you know, sudden
35:09
Speaker 1: acute crises. Why wouldn't they both think? I don't understand
35:12
Speaker 1: it either, if the looking at them. Okay, Chuck, So
35:16
Speaker 1: let's go a little further and well, I guess we'll
35:18
Speaker 1: go back to jeans. But um, remember you know a
35:22
Speaker 1: guy named Richard Dawkins, Right, He wrote a book in
35:26
Speaker 1: the seventies called The Selfish Gene, and it basically we
35:30
Speaker 1: were talking about, you know, the debate between gradualism and
35:33
Speaker 1: equilibrium punctuated equilibrium. Well, Dawkins came along and said, you guys,
35:37
Speaker 1: shut up for a little bit, let's talk about this
35:40
Speaker 1: the Selfish Gene, And he just basically reframed the entire
35:43
Speaker 1: way that people look at evolution. Yeah, I thought, I
35:46
Speaker 1: think it's pretty interesting. Uh. The essence of it is
35:50
Speaker 1: that as long as you reproduce, then natural selection doesn't
35:55
Speaker 1: care about you after that, right after you've passed on
35:58
Speaker 1: your genes. That's the important part. Uh. In the case
36:01
Speaker 1: of spiders is one great example. Sometimes the male gets
36:05
Speaker 1: eaten right afterward. Yeah, or like praying manness. This didn't
36:08
Speaker 1: the female eat the the male's head, like bite the
36:12
Speaker 1: male's head off, And we're talking about praying mannesses, So
36:15
Speaker 1: it's okay to say female um in that case. Though
36:20
Speaker 1: both those cases, natural selection doesn't care. The male has
36:24
Speaker 1: done his job. He is propagated and passed down the
36:28
Speaker 1: allele and it doesn't matter if he dies or not.
36:31
Speaker 1: Right afterward. It doesn't put any stress on the population. No.
36:34
Speaker 1: And that's like a really there was a tricky thing
36:36
Speaker 1: before Dawkins came along. It was like, wait a minute,
36:39
Speaker 1: there's a real problem with natural selection if if the
36:41
Speaker 1: whole point is for something to be able to reproduce
36:44
Speaker 1: and reproduce successfully, like, why would there be um adaptations
36:50
Speaker 1: that kills Yeah, where like the organism is killed like
36:54
Speaker 1: as a result of reproduction. That doesn't make any sense.
36:57
Speaker 1: And Dawkins came along and said, it doesn't make sense
36:59
Speaker 1: if you stop look king at organism and start looking
37:01
Speaker 1: at the genes. Basically, like none of that matters, right,
37:06
Speaker 1: So he he made his point so well that it
37:08
Speaker 1: actually got a little bit out of hand. Um and
37:12
Speaker 1: it came to be known as well. It was the
37:14
Speaker 1: selfish team before, but basically it was. He characterized it
37:18
Speaker 1: so well that it became a character. Jeans became a
37:21
Speaker 1: character almost like they had hijacked organisms and we're using
37:25
Speaker 1: them as husks to pass along themselves, like a virus
37:29
Speaker 1: or something like that. Um and Dawkins came out a
37:33
Speaker 1: number of times and it's like, no, that's the wrong interpretation,
37:36
Speaker 1: that's not what I mean. But it's still essentially the
37:38
Speaker 1: same thing. It's just m yeah, yeah, we are we
37:42
Speaker 1: we we are a means of passing along our genes.
37:45
Speaker 1: And if you look at it through the lens of
37:47
Speaker 1: natural selection, the the as long as the genes are
37:51
Speaker 1: able to be passed along, the vessel is no longer necessary.
37:54
Speaker 1: So therefore the head can be bitten off by the woman.
37:59
Speaker 1: That's right. But like we said, this isn't widespread, but
38:03
Speaker 1: it does help explain things like spiders, right, you know,
38:07
Speaker 1: But there's a big flaw in this selfish gene theory right, well,
38:11
Speaker 1: and Dawkins theories as a whole. Right, there's the flaw
38:15
Speaker 1: is is that there's such a thing as altruism. Yeah,
38:18
Speaker 1: and this is you know, humans and animals that, for
38:22
Speaker 1: no reasons based on natural selection, desire to help each
38:27
Speaker 1: other doesn't benefit you in the least at all. Know it.
38:30
Speaker 1: As a matter of fact, it can harm you before
38:32
Speaker 1: you're able to reproduce. So even from the genetic level
38:36
Speaker 1: of the selfish gene um, it doesn't make any sense
38:40
Speaker 1: because you're the genes are allowing the organism to be
38:42
Speaker 1: harmed before it could possibly reproduce. What why Why does
38:47
Speaker 1: someone have an instinct to jump in an icy river
38:49
Speaker 1: to save somebody? And they have found that it is
38:52
Speaker 1: instinctual and that it happens in infants with like zero
38:56
Speaker 1: cultural training. It's like part of us. Yeah, and it's
38:59
Speaker 1: not a human it's either. There are plenty of animals
39:02
Speaker 1: that um that display altruism as well, like mere cats
39:07
Speaker 1: are big on altruism. Yeah, and I like the explanation.
39:12
Speaker 1: It makes again total sense to me. Something called kinship.
39:15
Speaker 1: If you've got a couple of different families, took Tuk's
39:19
Speaker 1: family and and Bartok's family. Well, Bartok is a composer.
39:23
Speaker 1: But what's another good cave man name. Uh, yeah, that's
39:29
Speaker 1: a great one. So Mango's family is very selfish. They
39:31
Speaker 1: don't like to share their their stuff. They're all competing
39:33
Speaker 1: for the same food. Tuktok's family is very generous. They
39:36
Speaker 1: like to share things. So over time they will be
39:41
Speaker 1: a more successful family because they have been altruistic and
39:45
Speaker 1: shown that kinship and they're they're improving their chances of
39:48
Speaker 1: success by combining their their efforts into a group effort um,
39:52
Speaker 1: which is kind of like that Paleolithic warlessness we talked
39:55
Speaker 1: about in the Cave Dwellers episode. Oh yeah, where everybody
39:58
Speaker 1: just kind of figured out that, like they could be
40:00
Speaker 1: more successful if they stopped fighting and started harvesting together. Um,
40:05
Speaker 1: and if you kind of look at it like that,
40:07
Speaker 1: like everybody coming together as a group for a common goal.
40:11
Speaker 1: You're also looking at super organisms. Yeah, have we done
40:15
Speaker 1: one on ants specifically? No? I think we should. I agree,
40:18
Speaker 1: because they are about the best example of a super organism.
40:21
Speaker 1: It's basically the little worker ants aren't doing the reproducing.
40:25
Speaker 1: They can't even reproduce their that goes to the top dogs.
40:29
Speaker 1: They only get to do that. So all those little
40:31
Speaker 1: worker ants aren't even passing on their genes, but they're
40:34
Speaker 1: still busting their little aunt butts for the colony. And
40:38
Speaker 1: um a super organism basically then is to step back
40:41
Speaker 1: and say, let's not look at ants, but let's look
40:43
Speaker 1: at the ant colony as an organism, as one organism,
40:46
Speaker 1: And that explains the altruism in that ant sacrificing its
40:50
Speaker 1: own ability to pass along its genes in order to
40:53
Speaker 1: serve the colony as a whole. Then it makes sense
40:55
Speaker 1: like Papa aunt is going to pass down the jenes.
40:58
Speaker 1: I just need to make sure Papa aunt has food
41:00
Speaker 1: and water, right, And you can also use that same
41:02
Speaker 1: um argument to explain why, Like it would make sense
41:07
Speaker 1: if um, you know, you jumped in to save your
41:10
Speaker 1: son from a river. That kinship explains that. But why
41:14
Speaker 1: would you jump in to save someone else's son. Well,
41:16
Speaker 1: if you look at it like, well, this kid's part
41:19
Speaker 1: of the same species and shares a lot of the
41:22
Speaker 1: same genes as you, you're ensuring that your species genes
41:25
Speaker 1: are passed along. Yeah, and you get to humble brag
41:27
Speaker 1: on Facebook Yeah, how bad big time? Oh pretty boring day.
41:31
Speaker 1: Just saved the kid from the river and the icy river. No, biggie,
41:36
Speaker 1: just helped ensure as jeans get passed along. I guess
41:39
Speaker 1: a humble brag that would be, um, well, it looks
41:41
Speaker 1: like my shoes are ruined that I just bought, jumped
41:44
Speaker 1: into an icy river, and saved the kid. Yeah, that'd
41:47
Speaker 1: be good one. We should start this doing fake humble
41:51
Speaker 1: brags on Twitter, Facebook. Oh, this brand new BMW I
41:56
Speaker 1: got has the windshield wipers are busted. Not a day
41:59
Speaker 1: for it. It's raining. That's just being a jerk, Okay,
42:03
Speaker 1: all right, So now we should talk about something that
42:06
Speaker 1: also excites me. Vestigial and attavistic traits. Um. All organisms
42:12
Speaker 1: carry some trait that is really no benefit and really
42:16
Speaker 1: is no longer expressing itself as a means to help
42:18
Speaker 1: you survive. But it's not harming you either, so it
42:21
Speaker 1: hasn't been selected out, so it's just there. And UM,
42:25
Speaker 1: I've got some pretty good examples in the human body.
42:29
Speaker 1: UM one summer behavioral summer actual organs like the appendix.
42:36
Speaker 1: Many people think the appendix is of this vestigial organ
42:40
Speaker 1: I heard that it might fight cancer. Well now that
42:43
Speaker 1: now scientists are starting to say, we think it might
42:46
Speaker 1: fight cancer, or it might house um like bacteria that
42:50
Speaker 1: helps you aid in digestion. So everybody who's a pendics
42:53
Speaker 1: we took out get inline. We're gonna put them back in.
42:56
Speaker 1: But for many years, and I think the debate is
42:57
Speaker 1: still out whether or not it is a remnant from
43:00
Speaker 1: primate ancestors when um we had to digest like plants
43:05
Speaker 1: like super rich in cellulose or something. Yeah, I got that.
43:07
Speaker 1: We don't anymore. So that's why the appendix really does nothing.
43:10
Speaker 1: Back when we were giant termite men, scary time sinuses,
43:16
Speaker 1: that was what we were like. On the other side
43:18
Speaker 1: of the population bottleneck, giant termite people. Sinuses supposedly may
43:23
Speaker 1: um there. It's also debated. But their pockets of air
43:28
Speaker 1: in your face, and no one really knows if they
43:30
Speaker 1: serve any kind of biological function or not. Yeah, and
43:32
Speaker 1: they kind of suck too, because they get infected. They
43:35
Speaker 1: can't get infected the coxics. It's pretty exciting because it's
43:41
Speaker 1: a tailbone that used to be a tail, and some
43:46
Speaker 1: people are still born with them. Yeah, and the people
43:48
Speaker 1: who are born with tails are atavistic because they're out
43:52
Speaker 1: of atavisms. It's it's a vestigial remnant that UM expresses
43:57
Speaker 1: itself very closely to the way it actually used to be.
44:00
Speaker 1: It's not just a trace of it anymonger. It is
44:02
Speaker 1: like it's like that Alleale saying, hey, maybe we should
44:06
Speaker 1: go back to tails again. What do you think? But yeah,
44:09
Speaker 1: it's not um. Just so you don't picture like a
44:12
Speaker 1: human with a big four ft long monkey tail, it's
44:15
Speaker 1: usually like a bumper or something. Didn't George Costanza have
44:20
Speaker 1: a tail? And uh what was that one? Jack Black
44:24
Speaker 1: Fairly brothers? Oh yeah, yeah, shallow, yeah, yeah, I think
44:29
Speaker 1: you're right, and you could wag it. I don't remember that.
44:33
Speaker 1: Uh what else? Um? Oh, here's a behavior um of
44:38
Speaker 1: this digital behavior of the palmer grasp reflex. Oh yeah,
44:41
Speaker 1: I thought this is cool. It's pretty neat. When you
44:43
Speaker 1: go up to a little uh stinky, dirty human baby
44:47
Speaker 1: and you put your finger in their hand or their
44:49
Speaker 1: foot even it's gonna grab it like super hard and
44:52
Speaker 1: super strong. Yeah, like Popeye basically, or like a little
44:57
Speaker 1: baby monkey trying to hang onto mama, cruising through the
45:00
Speaker 1: jungle through the grabbing onto the coat their mom's coat. Yeah,
45:04
Speaker 1: so basically that's a behavior they think is is like
45:07
Speaker 1: a human baby now doesn't need to grasp hold of
45:09
Speaker 1: something that hard at six weeks old, So it's a behavior. Maybe.
45:13
Speaker 1: So we we played tennis thanks to a vestigial behavior
45:18
Speaker 1: and ability, I don't oh got it being able to
45:23
Speaker 1: grip that racket? Yeah? What's what article is this from?
45:27
Speaker 1: Is it? Um? Was it? Ion nine? Yeah? I think so.
45:31
Speaker 1: It was kind of silly, But these are some pretty
45:33
Speaker 1: decent examples. We we've talked about in male nipples before,
45:36
Speaker 1: you know, we did. We did a whole episode on
45:38
Speaker 1: um goose bumps, the erector pilly. I've never heard of this?
45:43
Speaker 1: Oh I did it? Dump be dumb on it? You
45:45
Speaker 1: want to explain what it is real quick? There you
45:47
Speaker 1: go ahead, okay, Um, everyone has had goose bumps. The
45:50
Speaker 1: erector pilly are those muscle fibers that give you goose
45:55
Speaker 1: bumps when you don't even necessarily want them or need them. Right,
45:59
Speaker 1: there's little musts that are attached to your hair follicles,
46:03
Speaker 1: whether you have hair there or not any longer, and
46:05
Speaker 1: they press it up so that your hair stands on end,
46:09
Speaker 1: either to make yourself look bigger, so you're scary, or
46:12
Speaker 1: because you're cold, to make your coat fluff out, as
46:15
Speaker 1: in when we used to have coats because we were animals.
46:18
Speaker 1: Another vestigial trait, and uh, my favorite one aside from tonsils,
46:26
Speaker 1: is the like a similar nearus. Did you like how
46:31
Speaker 1: you asked me if I wanted to do it? And
46:32
Speaker 1: I was like no, And then I did it anyway.
46:34
Speaker 1: I knew it. I knew that was coming. If you
46:36
Speaker 1: look in your mirror and you look at your eyeball,
46:39
Speaker 1: and you look in the little inside corner of your eyeball, um,
46:45
Speaker 1: you're gonna see a little fold of tissue and it's
46:47
Speaker 1: not the little bump, but it's that little thing in
46:51
Speaker 1: the inside corner of your eye that is a remnant
46:55
Speaker 1: of a third eyelid. What's it called? What kind of eyelid?
47:00
Speaker 1: The p L I C A plica or like a
47:03
Speaker 1: similar nearis And uh, apparently we had third eyelids that
47:08
Speaker 1: would that were clear, so you could like wash your
47:12
Speaker 1: eye and still keep an eye out for predators. And
47:14
Speaker 1: they would come from the side rather than up and down.
47:17
Speaker 1: They moved horizontally. Yeah, like a snake or a reptile, yeah,
47:23
Speaker 1: or a bird. They still have them, Man, we do not,
47:25
Speaker 1: but we still have that in the corner of our
47:27
Speaker 1: eye even though it does nothing. So here's the thing.
47:30
Speaker 1: We have the jenes then to make that. Yeah, if
47:34
Speaker 1: we needed it again, so that Allele could possibly come back,
47:38
Speaker 1: like we could have people who were born with that,
47:40
Speaker 1: and like if it ended up helping us, Um, like
47:42
Speaker 1: if we could sleep with our eyes upen to watch
47:44
Speaker 1: the zombie invasion or to watch TV better twenty four
47:48
Speaker 1: hours a day. Uh. Just the fact that we can
47:51
Speaker 1: wiggle our ears, that's a vestigial trait. There's no reason
47:53
Speaker 1: why we should be able to wiggle our ears. I
47:56
Speaker 1: can wiggle, mind, can you do them one at a time,
47:59
Speaker 1: you're wiggling you're eyebrows. I'm gonna go in my whole face,
48:02
Speaker 1: I know. Can you do one at a time? Like
48:06
Speaker 1: that's pretty Actually, well that means like human's going bananas
48:11
Speaker 1: right now. So, uh, that means that maybe Josh's ancestors, Uh,
48:18
Speaker 1: we're a little closer than mine. And as far as uh,
48:22
Speaker 1: monkeys directing their ears to listen out for predators. Yeah, no,
48:26
Speaker 1: it means I'm less evolved as a human being. I have,
48:29
Speaker 1: like the ability to move ears, so I can hear
48:32
Speaker 1: things that I don't need to anymore. And I'm fairly harry,
48:36
Speaker 1: So this has been a depressing episode for me in
48:39
Speaker 1: that respect. I didn't want to mention any of that stuff. So, Chuck,
48:42
Speaker 1: we talked about um African elephants. You want to give
48:45
Speaker 1: a couple more examples of uh natural selection and action.
48:49
Speaker 1: The ball worm. Sometimes it happens super fast. In the
48:52
Speaker 1: case of the ball worm, it's happening faster than we
48:55
Speaker 1: can create toxins to kill them. Yeah, like they treat
49:00
Speaker 1: now with no the genetically engineered so cotton produces it itself. Yeah,
49:04
Speaker 1: I guess it's not treating I guess it is originally
49:08
Speaker 1: treated cotton. But now cotton is growing with this toxin
49:11
Speaker 1: that is supposed to kill bullworms. But enough bulworms h
49:17
Speaker 1: were immune to that that they were the ones that
49:19
Speaker 1: went on to do the most reproducing to eat the cotton.
49:23
Speaker 1: I'm sure that that first generation of bullworms were like,
49:26
Speaker 1: I'm so wasted off this cotton, but I'm alive. Uh.
49:30
Speaker 1: And then the clovers. Some species of clover have mutation
49:34
Speaker 1: that made poison cyanide leak from its cells, causing it
49:40
Speaker 1: to be bitter. Therefore it wouldn't be eaten. Isn't that weird? Yeah,
49:43
Speaker 1: just that the clovers like don't eat me. Yeah. I
49:46
Speaker 1: make cyanide somehow. Yeah, but unfortunately, when the temperature drops
49:50
Speaker 1: blow freezing that sells rupture releases that cyanide into the
49:55
Speaker 1: plant and it kills itself. However, in warm climates that
49:58
Speaker 1: doesn't happen. So what you end up with is clover
50:01
Speaker 1: in warmer climates that's completely different structurally cellularly than the
50:06
Speaker 1: one in the colder climate. Yeah, the warmer ones produced sanide,
50:09
Speaker 1: the ones in the colder climates don't same clover. It's
50:11
Speaker 1: very much like that example of Um, you know the
50:13
Speaker 1: humans that can cool constantly playing well in the tropics
50:17
Speaker 1: but not in north Pretty cool stuff. Yea, man, I
50:22
Speaker 1: love this. You got anything else? I got nothing else?
50:28
Speaker 1: Oh well, let's talk about ourselves a little bit real quick. Really, Yes,
50:33
Speaker 1: what's your sign from the Pisces? I can't wiggle my ears? Um? No,
50:37
Speaker 1: humans like we have, like I was saying, we have
50:40
Speaker 1: jets now, so like we're one large population right. Um.
50:44
Speaker 1: That's just one example of how we've essentially taken ourselves
50:47
Speaker 1: out of the evolution game. We even more to the point,
50:51
Speaker 1: we have such thing as birth control, artificial birth control. UM,
50:55
Speaker 1: we have a lot of different things that we do
50:58
Speaker 1: inadvertently or advert only to UM, to adapt, to change ourselves,
51:05
Speaker 1: to change our ability to reproduce whatever. So I wonder, then,
51:11
Speaker 1: are we UM out of the evolution game already forever?
51:16
Speaker 1: Will we ever be able to if we're not? Yeah?
51:21
Speaker 1: And I mean is that the case? Like I know,
51:22
Speaker 1: it's the goal of trans humanism is to say so long,
51:26
Speaker 1: suckers the evolution and just be totally in charge. But
51:30
Speaker 1: I also wonder, like UM with birth control, birth control
51:34
Speaker 1: is an artificial it's it's unnatural selection. Yeah, it's artificial
51:39
Speaker 1: black aide to reproducing, right, which flies in the face
51:43
Speaker 1: of natural selection. My question is is natural selection enough
51:46
Speaker 1: of a UM powerful process that eventually UM women are
51:51
Speaker 1: going to start evolving an immunity to birth control, or
51:56
Speaker 1: is human ingenuity so strong that it's like we've got
52:00
Speaker 1: natural selection beaten. It's just gone now, it's done for
52:03
Speaker 1: us aside from fires and floods and famines and droughts
52:06
Speaker 1: and all that. But I mean, like on that graduated
52:09
Speaker 1: or gradual background natural selection, or we have we taken
52:15
Speaker 1: ourselves out of that I wonder or is it enough
52:17
Speaker 1: of a population pressure to have the effect to begin with? Yeah,
52:21
Speaker 1: just from the fact that there's so many humans that
52:25
Speaker 1: that that there's scarcity exists. So I guess not. I
52:29
Speaker 1: guess we just answered my question. Man. I really didn't
52:32
Speaker 1: think it was going to get answered, but it just did.
52:34
Speaker 1: We're still under the effects and influence of natural selection.
52:37
Speaker 1: It's a podcast miracle bow before natural selection humans. I
52:42
Speaker 1: want to take a second to say hi to all
52:44
Speaker 1: the sixth through ninth grade science classes who are listening
52:48
Speaker 1: to this right now. I assume there's at least one
52:51
Speaker 1: or two Hi. Okay, so natural selection right, all right? Uh,
52:57
Speaker 1: if you want to learn more about natural selection, you
52:59
Speaker 1: can type those words into the search par at how
53:01
Speaker 1: stuff works dot com. It will bring up a world
53:03
Speaker 1: class article by the Grabster. Uh. And since I said
53:06
Speaker 1: search part, it means it's time for a listener mail.
53:10
Speaker 1: I'm gonna call this We're curing people of disease. Nice, Hi,
53:15
Speaker 1: guys and Jerry, you have a very large in a
53:17
Speaker 1: very large way to help cure my six year old
53:19
Speaker 1: niece Eva of lyme disease. For several months, he experienced
53:23
Speaker 1: a series of strange symptoms that didn't seem to relate
53:25
Speaker 1: to one another, including infection, muscle weakness, double vision. After
53:29
Speaker 1: months of testing, her doctors were at a complete loss
53:32
Speaker 1: as to what to do and what was wrong. Because
53:35
Speaker 1: the once cheerful, enthusiastic little girl began to withdraw. She
53:38
Speaker 1: was unable to go to school for periods of time
53:40
Speaker 1: and quit all her beloved after school activities. Um one day,
53:44
Speaker 1: she said to my sister, Mommy, there are two of you.
53:47
Speaker 1: One is up here, one is down there. Which one
53:49
Speaker 1: is the real you? Another alarming and creeping creepy statement was,
53:53
Speaker 1: my legs don't work anymore. Enter Uncle Josh and Uncle Chuck.
53:57
Speaker 1: After listening to the podcast on how ticks Work, I
54:00
Speaker 1: encourage my sister to have my niece tested for lime disease.
54:03
Speaker 1: Despite not having any evidence of being bitten or being
54:05
Speaker 1: in a region known for dear ticks. She was tested
54:08
Speaker 1: and indeed did have lime disease. That is awesome, Uncle
54:11
Speaker 1: Josh and Uncle Chuck really saved the day on this one.
54:13
Speaker 1: Ava was in pain, confused, and very afraid because she
54:16
Speaker 1: didn't understand what was happening. None of the doctors suspected
54:19
Speaker 1: lime disease. And I never would have pushed for it
54:21
Speaker 1: without or even tested for it in the first place,
54:25
Speaker 1: if your podcast hadn't tipped me off to the possibility.
54:27
Speaker 1: That is so cool that the girl owas like her
54:29
Speaker 1: well being to us, uh and to the doctors that
54:33
Speaker 1: have helped her to a lesser extent. After the treatment,
54:36
Speaker 1: she's back to her old, happy, studious and energetic self.
54:39
Speaker 1: She's a brilliant young girl and we'll have a bright
54:41
Speaker 1: future thanks to you guys having her back and making
54:45
Speaker 1: her full recovery possible. Much love, Michelle Marianni. That's awesome.
54:50
Speaker 1: Thanks for letting us know that, Michelle. Ava. Right, Yeah,
54:52
Speaker 1: it's really neat way to go Ava, way to beat
54:55
Speaker 1: that Lime disease. Stupid ticks hate ticks, even hate the episode.
55:01
Speaker 1: That was a great one. We need to do aligned
55:02
Speaker 1: disease episode when they're supposedly it is very controversial and
55:05
Speaker 1: I've never really looked into it. Okay, I've heard you
55:07
Speaker 1: could make money selling your blood. I don't know if
55:10
Speaker 1: that's true. Oh it is okay. Uh. You have to
55:14
Speaker 1: do on the black market though, because they don't pay
55:16
Speaker 1: on the regular market. It's all like, well, I'm a
55:19
Speaker 1: do gooder. Um, So if you want to get in
55:23
Speaker 1: touch with Chuck and I to let us know how
55:25
Speaker 1: we helped you or a relative out, we love hearing
55:28
Speaker 1: that kind of stuff, or you can just get in
55:30
Speaker 1: touch to say hi or whatever you want. You can
55:32
Speaker 1: tweet to us at s Y s K podcast, hang
55:34
Speaker 1: out at our happening Facebook page, Facebook dot com, slash
55:38
Speaker 1: Stuff you Should Know, send us an email to Stuff
55:40
Speaker 1: Podcast at Discovery dot com, check out our YouTube channel,
55:43
Speaker 1: look for Josh and Chuck, and as always, joined us
55:46
Speaker 1: at our home on the web. Stuff you Should Know
55:48
Speaker 1: dot com for more on this and thousands of other topics.
55:56
Speaker 1: Is it how Stuff Works dot com