Where’s my eternal youth? Part 1

crappy towards mortals? Uh not. I don't know if it's on purpose. You do get Zeus being a jerk, but it might be like he's a jerk by accident, or maybe he's a jerk on purpose. It's kind of hard to tell because being a jerk is kind of Zeus is default thing in general. Yeah, Zeus in this myth acts kind of like the Monkeys Paul and the classic short story where you get the wish but not quite in the way you wanted it. So here's how it goes.

And this is the version that's in the Homeric Hymn to Aphrodite So the myth involves the goddess aos Aus is the goddess of Dawn, and she falls in love with a mortal man from Troy named Tiffanus. And this is horrible, right, It's horrible for a goddess to fall in love with a mortal because while the gods may live eternally, dining on the ambrosia and just going on into the future, of course, mortal people, as the name implies,

will die. And she hates this idea. She hates the idea that the man she's fallen in love with will someday die while she gets to go on living forever. She can't bear the thought of it. So she goes to Zeus and she makes a request, well you grant my lover, Tiffannus, eternal life, and Zeus does it. Usually, you know, usually Zeus is a jerk, but here he's like, yes, yes,

I will do that for you. Aos. Well, maybe he was busy and he's just like, okay, yeah, I'll just go ahead and check this off the list because I've I've got this, uh, this other torment in mind for another mortal, right, don't have time to be a jerk. Just bam eternal life, you will not perish and die like the other mortals. But then it takes a dark turn. So let me read from the translation of the home Eric him to Aphrodite, And this is translated by Hugh

Evelyn White quote. So also golden throned Aos wrapped away tithan Us, who was of your race and like the deathless gods. And she went to ask the dark clouded son of Chronos that he should be deathless and live eternally. And Zeus bowed his head to her prayer and fulfilled her desire. Okay, so he's granting the wish. Too simple, was queenly Aos. She thought not in her heart to ask youth for him and to strip him of the

slough of deadly age. So while he enjoyed the sweet flower of life, he lived rapturously with golden throned Aos, that early born by the streams of ocean at the ends of the earth. But when the first gray hairs began to ripple from his comely head and noble chin, queenly Aos kept away from his bed, though she cherished him in her house and nourished him with food and ambrosia, and gave him rich clothing, but when loathsome old age pressed full upon him, and he could not move nor

lift his limbs. This seemed to her in her heart the best counsel. She laid him in a room and put to the shining doors. There he babbles endlessly, and no more has strength at all such as once he

had in his supple limbs. M Okay, well, this makes me think Zeus probably just agreed to her request because all the gods know that mortals are going to ask for immortality at some point or the other, and it's probably not going to phrase the question properly, and you should let them have it because it will teach them a lesson. Well, yeah, he'll learn when he's old and babbling and decrepit but cannot die. Because global myth cycles

are filled with stories of of immortality gone wrong. You know, it's either a wandering immortal who's doomed or or lovers who you know, obtain a portion of immortality and it's mishandled. There's a there's a wonderful example of this in the in Chinese myth with the the Elixir of Immortality and the and the Woman of the Moon. Oh does it come back to bite her or come back to bite the person who wants it um it gets. There are a few different versions of the tale, but essentially, you know,

one person is immortal and the other is not. That sort of thing this this this mismatch that we see president in the Greek tale as well. Man, why are there so many myths and folk tales where people get punished for wanting better than their lot in life? Well, because you can't have it, I mean, especially when it comes to things like avoiding death and avoiding aging. You're

not gonna get it. So there's something refreshing about stories in which people do get it, and it backfires because that way we think, oh, well, this this thing that I cannot have is actually not that great, So thank goodness, I'm going to grow old and die. Yeah. I wonder if it makes you feel like you're not so bad off. It's like, well, I'm gonna die one day, but I could be like Tiffanius and that's even worse. Exactly, So, I think the myth is sort of an embodiment of

this cruel fact about human nature. It's not just that, as they say in Bravos, all men must die, but that all people must decline. I think Warren Zevon put it best. He said time treats everybody like a fool. And I think that's the case. And no amount of lawyers, guns, or money will get you out of this, that's right. So on one hand, you've got the idea of death. And death is a sort of unavoidable fact about biology because living organisms are these finely tuned factories of chemical reactions.

And if you make substantial changes to the factory, say by jamming a rock through part of it, or biting part of it off, or filling it up with parasites that come up all the gears, the factory isn't gonna work the same anymore. It might not work at all were physical creatures were subject to physical disruption. So the potential for death is unavoidable. It's sort of part of what it means to be alive. But aging not quite so much. This steady time correlated decline in our biological fitness.

Why does that have to happen? That's not physically inevitable in the same way that death is. Yes, and this is going to be the question we're gonna be discussing in this pair of episodes. Now we do want to drive home. We're not going to get as much into some of the mechanics of aging, like we're not going to get into telomeres and telomerase and all and all of that, although that's a wonderfully insightful topic onto itself.

We're gonna be talking more about the these this sort of evolutionary function of aging, if it has one, right, aging is something that has such a cost for the organisms that undergo it, like tiffanus. What pays for it biologically? Why does it exist? Now? To underscore the fact that aging is not necessarily something that is inevitable, and especially not aging as early as we do, we should maybe look at some organisms that do not age in the same way we do. Yeah, they're there are a number

of organisms. I'm sure a number of them come to to everyone's mind here. You think of ancient hoary tortoises stumbling across the the ground, right, or perhaps your mind turns to the greenland shark. Will come back to that one in a second. But really one of the more insightful examples here is the hydra, or at least individuals in the hydra genus. So you're talking about the monster

that gets its head cut off and grows two more. No, as much as I do love the mythical hydra, now these are the natural world hydras, tiny tentacle creatures that need to continue to wow scientists because they they have a number of just wonderfully bizarre and monstrous capability. So they can reproduce through a sexual butting. They have these mouths that open up kind of like wounds in their body and then close. There's some fabulous videos of them

doing that. It looks like you're staring into the mouth of hell. And they have this seemingly natural inability to grow, grow old, and die of natural causes. They boast low mortality rates throughout their lives and apparently this is according to one Dr Owen Jones from the University of Southern Denmark. He has claimed that it would take four hundred years for of a hydro population to die of natural causes

in the lab. Wow, well, well that's a hardy species. Yeah, So let me let me back some of that up here with with some more facts about the life of the hydra. So their fertility rates remain constant their entire lives, which, as will discuss, is is pretty unique and according to um Pomona College biology researcher Professor Daniel Martinez. He has repeatedly found no evidence of sinescence in laboratory caddled hydra. Yeah, and he even goes so far as to state that

an individual hydra can live forever under the right laboratory circumstances. Well, now, of course that's the catch, right. The hydra's natural environment offers sufficient hostilities to make natural death by old age and impossibility. You got disease, predators, water contamination. These are the things that usually kill a hydra off in due time, and likewise, scientists have yet to create a hydra utopia

that can sustain them indefinitely. Now, this is a good point in the use of the word immortality, which sometimes comes up when people are covering organisms like these. There are a couple of different ways you could look at immortality. One would be the Highlander version or something like that, where there's just like nothing that can kill you except maybe one or two little things, but that you are

generally invulnerable to death. And then there'd be a different version of immortality that says, yeah, you're vulnerable to death by injury or disease. You just don't naturally grow old and die. You don't have a cap on your lifespan. That would be more like, what are are the elves of Middle Earth? Kind of like that, like they can

be killed in battle, but they don't grow old and die. Yeah. Well, I mean I would argue that the immortals of Highlander are much the same, Like there's a there's a very specific thing you can do to kill them. Uh, and technically anyone can do it. It's just you've got to get the drop on them. Right. We should mention that we're popping in little references to Highlander to get you ready for the fact that one day soon we're going to do a Science of Highlander two episode and I'm

not kidding. Yeah, you have advanced warnings so you can all go review at least the first two films. Well, I would say just the first two films actually, Okay, But back to the hydra and biological immortality in the real world. Yeah, so this is a major point really for all organisms. The natural world is generally sufficient to ensure mortality. It's dangerous, it's filled with competitors, predators, pathogens, accidents,

and all manner of additional hazards. Now, humans and their captives tend to live in a very privileged space, largely removed from the threat of predation. At least you'll find other creatures with no natural predators as well. Typically these are apex predators, but that doesn't mean they don't have

to deal with all these other dangers. Well. No, when you think about an apex predator, just because there's nothing that tackles it and tears it apart and eats it, that doesn't mean that it's not subject to attacks from its environment, right. I mean, it of course is subject to disease. But one of the other things to think about with an apex predator is these creatures are very

often constantly at the edge of starvation. And so when you see the antelope running from the cheetah or something, of course the cheetahs trying to kill the antelope, but by escaping, the antelope is sort of also trying to kill the cheetah. It is starving the cheetah to death by a escaping. The cheat is a great example too, because either cheetah injures itself in the pursuit of a prey, especially if it tackles prey that is a little beyond

its ability or or is potentially beyond its ability. It can sustain an injury that results in death, not because it becomes infected or what have you, but because say, a wounded limb on a cheetah can mean it cannot pursue prey and it starves. Right, This is another thing we often fail to appreciate in the natural world is how how absolutely damning a small injury can be to an organism that has to hunt or escape hunters to survive.

You also, of course have read about large cats that have turned man killer and uh in some of these cases, if remember correctly, sometimes it has to do with the decline of dental health, like that their their inability to depend on their their teeth for their traditional prey and it leads to sort of a desperate switch in their their selection of prey. So anyway, most most individuals are going to die or be killed before they can grow old, so there's already a low probability of being alive and

reproductive at an advanced stage. Still, hyders are are really interesting because it give us a real world of the world example of how how undying creatures would work on a biological level. They're hardy, they're regenerative. They have they have evolved to thrive in the harsh environments, and it actually reminds me of an alien species that shows up

in an Ian em banks. The Culture series, of course, go into the Culture Yeah, I mean he he always managed to work so many wonderful scientific topics into his his books, and one of these topics is biological immortality. Alright, So we meet in the really the very first Culture book, we meet the Dherens. And here's just a quick quote. The Adherens themselves had evolved on their planet a deer as the top monster from a whole planet full of monsters.

The frenetic and savage ecology of a deer in its early days had long since disappeared, and so had all the other homeworld monsters except those in zoos. But the Adherens had retained the intelligence that made them winners, as well as the biological immortality, which, due to the viciousness of the fight for survival back then, not to mention, a deer's high radiation levels had been an evolutionary advantage

rather than a recipe for stag nation. Now, I think that might be something interesting to come back to maybe in the second episode and consider whether it would actually work that way and what the effect of high mortality at different stages of life would have on the life span of an organism. Alright, well, on that note, let's take a quick break, and when we come back, we're gonna roll through just a few other long living organisms, uh that are not a hydra or an adheran. Thank

thank Alright, we're back. So I mentioned the greenland shark earlier. This one is pretty impressive because greenland sharks live where we understand now about four hundred years uh. And this is an exclusively wild species as well. This is not something you're gonna find growing old and fat in an aquarium. These are sharks generally don't do very well in aquariums. Correct, yeahs, And no one has a greenland shark that I am

aware of as of this recording. At two thousand sixteen, University of Copenhagen study estimated that one female greenland shark uh had it was it was at least four hundred years old, and that the species doesn't even reach sexual maturity until one d and fifty. So think of that, not until they've reached an age that exceeds every human being who has ever lived, and that's counting unverified but not mythic individual humans, right, not the Highlanders or you know,

like you know, biblical days. Right. Yeah. Now, of course that's still not the oldest animal because there was a clam named me. Was this the first line of a children's book? I know it should be, well, I would be. I would actually be surprised if there's not a children's book about Ming. There was a clam named Ming. Yeah, and Ming did love to sing. Yeah. This here it rights itself. So technically Ming was a qua hog clam.

This is um, an Arctic variety of clam, and it was discovered off the coast of Iceland in two thousand and six. Now, at the time they thought it was around four hundred and five years old, so they named it after the Ming dynasty that would have ruled China at this time. Later estimates, and this is supported by carbon dating, would boost that age to five hundred and

seven years half a millennium. So this means that the creature was born in fourteen and that's still within the Ming dynasty, which went to four And to throw another point of context in there, this was around the time that Leonardo da Vinci completed the Last Supper. It's the year Portuguese explorer Vasco da Gama reached India. That's when this this thing was was born and then it died. In two thousand and six, there was a clam named Ming,

and Ming remembered everything. There you go now the plant where the world of course has all of this beat. Uh. There's the great Basin bristle cone Pine or Pinus long gava, and it can only lived to over five thousand years of age, and that takes us back to the very end of the Neolithic period. Work on Stonehenge had begun. This was the age of the Pharaoh, so it lived through the rise and the fall of the Roman Empire. Now, of course this highlights that different kinds of organisms have

massively different potential when it comes to life span. Yeah, and of course plants are very different from animals. This reminds me that one of the ideas that was brought up recently. I believe on our discussion module on Facebook or Facebook group, that we should do something just on plants, like what is a plant? To sort of strip it down to its basics. I kind of like that idea.

It's a really lazy animal. Well I've got a really lazy one then for you here, Uh, there's at least one step beyond the great base in Bristle Cone Pine. And this is something you'll find in fish Lake National Park in Utah here in the United States. Uh, the quaking aspen tree, which is also the state tree by the way, also known as the trembling Giant or pando, which means I spread. So what we have here, and this is this is one where not everybody necessarily agrees with.

This might be sort of bending the definition a little bit of what is a long living organism. But what we have here is a single clone of quaking aspen connected by a single extensive roots system that's roughly the size of Vatican City, a hundred and six acres, thirteen million pounds, and it's all eighty thousand years old. So what you're talking about is a forest that is all sort of in some way the same organism, right, you could. It's it's not as simple as the clam was born

in this century and it died in this one. But if you if you've been the deaf Issian enough and you accept this as an example, we're talking about a thing that has lived since humans first left Africa to colonized the world. Wow. Yeah, now, Robert, here's something I've always wondered about dinosaurs. You got to wonder how long they lived, especially because this gets warped by our sense

of history. I think, because they lived so long ago, you just naturally go to this completely illogical place where they must have lived a long time. Like, Okay, tyrannosaurs Rex lived maybe three hundred years. I mean they got they got very big, so you have to imagine it took them a while to grow as big as they did. This would take a lot of years of eating and cell division and all that. So so so surely they had very long lifespans. Well, this used to be the

main theory. And this was in part because of either size or at least the size of many of the specimens, and the fact that we thought, well, they were essentially giant reptiles, and so based on slow reptile growth rates and their size, they said, well, big dinos probably lived several hundred years. But today paleontolo just believed they grew more like birds and mammals, and this cuts back on

their lifespans somewhat. So for instance, the Field Museum of Chicago, they have this, uh, this these t rex remains that they named Sue. Sue. She is great. Yeah, she's a wonderful specimen. You get to look right up at her and get a sense of the true size of this, this amazing species. Can I say something embarrassing? Go for it. I cried a little bit at Sue. Yeah, I'm not kidding. When we were in Chicago and I'm just sitting there looking at Sue for a while, I did something to me,

like a little misty. That's that's beautiful. I I can understand it because it is like looking back in time to encounter, you know, a fossil like that. So Sue is a rather big specimen, or at least the fossil remains are rather large and speak to a large specimen. They We think now that she probably achieved adult size at age twenty and lived to a ripe old age of twenty. Wow, so I am now older than than

this Tyrannosaurus rex was when it dies exactly. Yeah, and uh, and it just underlines that what you had with the dinosaurs was likely rapid growth but short lives. Now, one sort of side question that we won't fully explore. But this this may raise the question, well, dinosaurs have cancer because you're thinking about rapid growth, right of course. Well, basically this is the question we have to come back to.

But based on the research I was looking at, we only have evidence of the hadrosaurs, the duck build dinosaurs developing any form of cancer. Now that's the caveat that's the only the only ones we have evidence of that that occurring in. But it is interesting to think of like the late model dinosaur as being the place where we see the cancer showing up. We gotta come back

and do an episode on dinosaur cancer in the future. Yeah, by all means, well, I want to do something that we often end up having to do, which is that after we've explored a concept for a while, it becomes more and more complicated and our lay definition starts to get a little less useful. So I think maybe we should ask the question what actually is aging? Now? We we have a pretty uh intuitive, gut level understanding of what aging is. We know when we see it, But

how would you define it? I mean, it's it is something different from death, and it is something different from just like, I don't know your skin getting wrinkles or something like that. What what is the actual scientific thing that all of the stuff we call aging has in common. Well,

this is a great question. I mean, on one hand, it is closely tied to death, and I think one of the stumbling blocks is that will will alreadily admit that aging is something that our body does, but we tend there's tends to tend to be a cultural barrier in place to saying that death is something our body does. We like to push that off onto some sort of external force of of fade or anthropomorphy, eyes dread, you know,

or some sort of limit imposed on us by the gods. Well, yeah, yeah, death is something that we more often characterize as happening to us. Death happens to you. It's not something you do. Though. There you can kind of see that the division between the death and the aging death I was talking about at the beginning of this episode comes into focus, because of course, death can happen to you if you get a rock jammed through your you know, through your body

or something like that. But the body does seem to naturally progress toward death over time. And that's kind of

a weird question, like why would it do that. We will definitely explore the science behind that question in the second episode that we will look at some archaic answers to it in this one, because when especially with the human, with the human experience of aging and death, it seems completely illogical that in many cases a human being would spend the majority of its life progressing towards death, like

the majority of your life. His decline, Uh, that just feels either gross or cruel or just like a horrible design flaw, or yeah, or nonsensical. But where's my eternal youth doesn't make any sense? Um. So in his nine book The Evolutionary Biology of Aging, published by Oxford University Press, the biologist Michael R. Rose defined aging in the following way quote a persistent decline in the age specific fitness

components of an organism due to internal physiological deterioration. Now Rose actually has offered has said that in some ways we might need to update that understanding a little bit to accommodate for some new discoveries. But I think this is a good place to start. So let's look at the parts of that definition. Number one, it's persistent decline,

which means aging only goes one way. It's not characterized by say decline and rebound, and some organisms do have patterns like this, it is not quite aging, like you can think about the jellyfish that have regenerative capabilities where they can revert to a younger stage of life. But then so it's persistent decline. And then in the quote age specific fitness components biological fitness meaning the ability to survive and reproduce. So these are the things that are

persistently in decline. You become less able to survive and less able to reproduce. And then it's due to internal physiological deterioration. So it's saying that this persistent decline in the ability to survive and reproduce is not due to disease or injury, but to something deteriorating within the body tissues themselves. Yeah, this is this makes me think, of course, of the phrase cradle to the grave and with it

with the hydra. The cradle to the grave is kind of a straight line with reproduction taking place at all levels until something happens to kill it. Whereas most of them models that that we look at, most of the models we looked at in researching this episode, it's more of a of a rise rising and lowering. There's a rise towards like peak sexual maturity, peak reproductive maturity, and then a decline. Yeah uh yeah, And then it gets even stickier, right because we we've just tried to be

very careful and how we're defining this. But then I realized that I said the it's a decline in the ability to survive and reproduce, not due to disease or injury. But a lot of the things that are the characteristic signals of aging are sometimes thought of as diseases, even

though maybe they're not caused by say a germ or something. Uh. There are all kinds of things like diabetes melitas, or like rheumatoid arthritis that are totally characteristic signs of aging and human beings, and they're thought of as diseases, but they're not so much something that gets done to the body by external forces. There are a thing that happens when the body is around for a long time under

certain conditions. It makes me think back to our episode on Chinese immortality and about the the idea of the the older body being kind of an alien body, Like it's a different biology we're changing into a different being with different physical characteristics. Generally characterists that that leaned towards towards weakness. Absolutely, But then again, you can also look at aging through the microscope, look at it on the cellular level, and this is where you'll often see people

using words like sinescence. Defined by by Nature's scientific glossary quote, senescence is the process by which sells irreversibly stop dividing and inter a state of permanent growth arrest without undergoing cell death. Senescence can be induced by unrepaired DNA damage or other cellular stresses. So this is looking at it on the microscopic level and saying in essence, often used as as a synonym for aging, happens when the cells stop making new rejuvenated cells. This is kind of the

lack of upkeep keep model. It's the idea that well, the house is falling apart because nobody's working on it, nobody's maintaining, or at least the maintenance has really been scaled back or it's all. It's it's been my experience thus far with aging that you find the maintenance requests are are kind of rolled out in in a logical way where you're you're like, you may think to yourself, well, why am I still sore from this injury I sustained

last month? But my my, what my body is really trying to do is like grow a bunch of nose hair. You know, It's like, why why is that the the main operative that's been passed down to my body? You know, everything is beginning to get out of whack. It's as if it's as if there's nobody in charge anymore. Uh,

and they're just letting the house fall apart. Yeah. If you were the super tendon of an apartment building, it would be like, there's a water leak in the basement that has not been fixed for months, and your repair person is busy building hundreds of kitchen cabinets on the roof. Yeah yeah, And you think, well, in the old days, we we didn't have all these kitchen cabinets on the roof, and things got fixed. Why did things not got to

get fixed anymore? That is a great question, and I guess we should try to look at some answers to that when we come back from this next break. Thank alright, we're back, all right, So let's look at some historical and lay answers to the question why do we age? What's the point? Why does it happen? One common example that seems to make sense to people is the idea

that our body is, over time quote get worn out. Uh. So in his nine seven paper Pleotropy, Natural Selection and the Evolution of Senescence, which we will definitely come back to in the second episode, here, the American biologist George C. Williams pointed out that one problem explaining the true biological reason behind aging is that many people think they already understand what aging is and why it happens, and they're wrong.

They're wrong. But if you think you've already got the answer, you'll never go asking the question and writing of these kind of folk explanations for aging. He says, quote the most injurious of these is the identification of sinescence with the quote wearing out that is shown by human artifacts. And doesn't this seem very sensical? Right? Our tools get worn out over time. If you use a knife a whole lot, eventually it'll lose the sharpness of its blade.

Uh any tool you use too much. I'm thinking about a broom that we used to have for years around our house that eventually got worn down to nubs. There were just really no bristles on it anymore. Shouldn't our bodies be the same. This reminds me I've had to explain this to my my son recently, where he'll get some sort of cheap toy, you know, as a prize or something, and he'll be really into it. I'll have to explain to him that this is not the sort

of toy that lasts very long. You know, toys like this may last a week or so, and and he's like, no, if some some toys last forever. And I'm like, well, they don't. They don't really, And you have to try to explain how pretty much everything that is made by man is going to fall apart. Okay, after I finished my children's book about ming the Clam, I'm writing a second children's book called Toys Die. What it reminds me of the short story that that A I was was

based on. Oh yeah, I forget the exact title, but to believe it was super Toys Last All Summer, which I always thought was a rather fun title. That is great, but knowing knowing that we also know that they won't last forever, like you, like you say, so, going back to what Williams wrote, quote, A moment of serious consideration should convince a biologist of the fundamental dissimilarity between these two processes, meaning the body wearing out and tools wearing out.

The breakdown of human artifacts is strictly mechanical and is readily cured by mechanical repairs. The system is a static one, since the same material is continuously present and there is no endogenous change with the passage of time. An organism, on the other hand, is an open system in a state of material flux. Even such structures as bones maintain constant exchanges with the environment. Moreover, an organism produces itself

by a morphogenetic process. It is indeed remarkable that after a seemingly miraculous feat of morphogenesis, and that means like growing into the adult shape, a metazoan should be unable to perform the much simpler task of merely maintaining what is already formed. I think this is a fantastic point. I mean, it doesn't make sense to say we get old because over time our bodies just get worn out, because our bodies have the ability to rejuvenate tissues. They

built tissues in the first place. They could just keep building them as long as they wanted. Yeah, I mean, I think part of this is the I mean part of it is just that we are so close to the aging process. We experience it, and we see it in others. Uh, We're almost too close to it to have an objective view of it. And then to your point, we're informed by what happens to our tools. And then I also they're tying into the experience as well, and

the wearing out of things. I think dental health has a has a huge impact on it because we observe this happening with our very teeth, the teeth of others that you get that those adult teeth in and those are the ones you're gonna have for the rest of your life as long as you can keep them. You know, they are going to wear out, and unlike other organisms, there's not going to be an additional h set there

that are going to lock into place. Third children's book for when children get their baby teeth knocked out, it's called this is your Last Chance. Yeah. I've actually heard uh parents, I think half joking, we talk about not worrying with brushing that much for young children because now they're gonna gore gonna get that second pit. You know they're gonna be These are not even These are just the baby teeth. Wait till the adult teeth come in

and then start worrying. Yeah. Now, beyond these simple folk explanations, we know that there have been lots of thinkers throughout history who must have tried to explain why aging happens before we had modern modern genetics to really understand the true mechanisms. Right, Yeah, this is you know, aging is part of the human experience, and so some of the great thinkers and human history have pondered it. We have

a few examples here to run through. For instance, Lucretius through fifty five b c uh he wrote about it in his text on the Nature of Things, and he argued that aging and death are beneficial because they make room for the next generation. This is probably another folk explanation a lot of people would employ. Right, totally seems to make sense. You can't just keep living forever because

you've gotta make room for the next generation. Yeah. It especially makes a sort of sense, I think for human populations when you have, say, individuals who have over the course of their lifetime accumulated certain benefits and powers and possessions, and then the idea as well, when they fall away, those resources spread to someone else, you know, I mean we we we have always lived in a world of of finite resources. And I want to be clear, it

is good that that happens. The next generations actually do benefit from the fact that older generations grow old and die. Uh, But there are some serious problems with thinking about this as the reason biologically that they grow old and die. Yeah. Though this this observation persisted well up into the twentieth century.

For instance, nineteenth century German biologist August Weissmann also believe that the death mechanism created room for the next generation of young to thrive at And you know, I have to men as well that I always it always always kind of felt this was the case, you know, at a gut level, without putting a lot of serious thought behind it. Oh yeah, before I investigated this, I assumed something along these lines. But then I started to doubt myself because I was like, oh, wait a minute, that's

group selection, and I always feel iffy about that. The problem here is pointed out by Daniel Fabian of the Institute of Population Genetics in in the publication nature is that quote, the cost of death to individuals likely exceeds the benefit to the group or species. And because long lived individuals leave more offspring than short lived individuals given equivalent reproductive output, selection would not favor such a death mechanism. Yeah.

This is one of the classic arguments against any kind of group level selection influence. And we can revisit this in more detail in the second episode. Now, of course, another great thinker is Aristotle, right, yeah, and he of course wrote about this as well in on Longevity and Shortness of Life. Aristotle tell us how it is all right? Well, before I go get going here, I do want to point out I I am going to be the last

person to to criticize Aristotle. Uh uh. I feel like he uh he did did a lot with the wisdom of the day, obviously, and that's an understatement. Uh, but he was not able. We're not going to take the opinion that Aristotle was dumb though I was talking. I was actually talking about this with my my wife last night when I was running through the material I'm about to uh to relate here, and she said, well, that would actually make a wonderful like BuzzFeed style article like

six things that dummy Aristotle got wrong. I mean, he got a lot of stuff wrong, but I mean everybody in the ancient world did. Yeah, I mean he people just didn't know what we knew today, right, And he was attempting and attempting to figure it out. He threw out a number of hypotheses that were not They did

not shake out. So here are just a few quotes from the work that will give you an idea of where he was going the re sa since for some animals being long lived and other short lived, and in a word, causes of the length and brevity of life, call for investigation. Fair enough, same question we're asking why does it happen? And then he goes on to say race is inhabiting warm countries have longer life, those living in cold climates have a shorter time. Likewise, there are

similar differences among individuals occupying the same locality. I don't know if that's true. I mean, we already touched on the greenland shark, and I think we've gone more in depth in the greenland shark in the past on this show. But part of it is its environment, which is quite cold. Uh. He also commented on the connection between the soul and the body. The soul must stand in a different case

in respect of its union with the body. And then this at least rings true, hints to all things are at all times in a state of transition and are coming into being and passing away. Okay, so this could be interpreted to mean something kind of like the fact that we're constantly undergoing cell division and our bodies maintain them I mean, obviously Aristotle didn't know this, but that our bodies maintain themselves through cell division and repair of tissues. Yes.

And then there's this quote speaking generally, the longest lived things occur among the plants, uh, example of the date palm. Next, in order we find them among the sanguineous animals rather than among the bloodless, and among those with feet rather than among the denizens of the water. Hence, taking these two characters together, the longest lived animals fall among sanguineous

animals which have feet. Uh. Men and elephants. Well, clearly we've learned how to make your aquarium fish live longer. You transplant some feet onto them. Uh. This at least as good quote. As a matter of fact. Also, it is a general rule that the larger live longer than the smaller. For the other long lived animals to happen to be of a large size are also those I have mentioned. Now, I'm sure this is not hard and fast rule, though I think there are probably some weak

correlations along these lines. I think so. I mean, we already touched on the dinosaur thing, but but certainly there are some examples of rather large animals that have longer lifespans within typical longevity. Now Aristotle's working theory, though, is that all of it revolves around moisture in an organism. Yes, quote, we must remember that an animal is by nature human and warm, and to live is to be of such a constitution, while old age is dry and cold, and

so is a corpse. I think Aristotle also tried to explain earthquakes by way of moisture, maybe misremembering them. And he also said that aquatic animals don't count here because they're not humid. Their watery and quote watery moisture is easily destroyed since it is cold and readily congealed. And finally, he also throws in four in animals, the males are

in general the longer lived. I don't think that's true either. Yeah, I believe in in in in many cases it is the it is the female that lives longer, certainly in humans, though that may be more pronounced in cases where we have been removed from the like when we've got modern medical care, because, for example, there is a lot of natural mortality during childbearing. So I don't know, you can maybe a point for Aristotle, there maybe a point for

modern science. We'll see, um. But anyway, that's that's that's what Aristotle had to say in the matter. And uh, and I like, I say, it's it's it's fascinating to look back on his writings and see how he's working this all out totally. So in the end, I think we're still left with this biological paradox of aging. Once we think about aging in a biological context, it's sort

of fails to make sense. Evolution selects for genes that increase biological fitness, meaning that increase the chances of survival and reproduction. Aging is characterized by an organ is m level decline in the chances of survival and reproduction. So why would organisms that have been evolving for billions of years still age, deteriorate, lose the ability to reproduce and eventually die. Shouldn't we have evolved to maximize survival and

reproduction as long as possible. Shouldn't we survive and keep making babies until a leopard bites our head off? But obviously this is not how things are. So what's the answer to this mystery? We'll explore that in the next episode. That's right, we have a cliffhanger. Will it be cruel twist of fate? Accident? Uh? Biological mechanism that serves a purpose? I don't know. We'll find out maybe our genome has

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