# Has human evolution stopped? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [November 5, 2016, 6:29pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732 "2016-11-05T18:29:16Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [November 6, 2016, 6:06pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/21 "2016-11-06T18:06:50Z")
Technology is a two edged sword … if we told someone in 1950 that someday some buttfuck nation like North Korea would have nuclear weapons and the means to deliver them … we’d get laughed in our faces … remember that when you laugh in my face when I say someday some radical group like ISIS hellbent on rapture will have the means to bio-engineer a deadly pathogen … Some time ago I read a prognostication that within 50 years we’ll find on the shelves of Toy-r-Us between the chemistry kits and electronic experimenters the gene-splicing labs … creating GMOs on your kitchen counter … sounds far-fetched? … maybe … just compare today’s smart phones with the communicators used on _Classic Trek_ … ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [November 6, 2016, 6:20pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/22 "2016-11-06T18:20:22Z")
> [@watchwolf49](#): > > Some time ago I read a prognostication that within 50 years we’ll find on the shelves of Toy-r-Us between the chemistry kits and electronic experimenters the gene-splicing labs … creating GMOs on your kitchen counter … sounds far-fetched? … maybe … just compare today’s smart phones with the communicators used on _Classic Trek_ … I’m not sure if you’re saying the progress of technology has been faster than forecast or slower? In any event, methods to splice genes have existed for decades, and grad students are routinely creating GMOs in a few days to a few months (depending on organism) with off-the-shelf kits and standardized protocols. Not quite on the kitchen counter yet, but not far off. One big obstacle has been efficient integration of DNA into a mammalian germline, but the celebrated recent development of [CRISPR](https://en.wikipedia.org/wiki/CRISPR) technology has solved that problem. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [November 6, 2016, 6:37pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/23 "2016-11-06T18:37:45Z")
I’m thinking along the lines of splicing the long infectious period of mono with the eventual symptoms of ebola all in a cell exactly shaped like a red blood cell … something specifically designed to wipe out the human population … something that will be widely distributed before symptoms start to show up, a certain and painful death and any testing that gives a positive all the time … how hard could it be? ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [November 6, 2016, 6:42pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/24 "2016-11-06T18:42:20Z")
> [@watchwolf49](#): > > I’m thinking along the lines of splicing the long infectious period of mono with the eventual symptoms of ebola all in a cell exactly shaped like a red blood cell … something specifically designed to wipe out the human population … something that will be widely distributed before symptoms start to show up, a certain and painful death and any testing that gives a positive all the time … how hard could it be? Well, the first thing you need to do is shake the vial of Ebola, open it and sniff it to see if it’s fresh. Then, don’t leave your house under any circumstances for the next few weeks in case the FBI are watching you. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [November 6, 2016, 8:42pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/25 "2016-11-06T20:42:15Z")
I guess I have the room now that I’ve ditched all those old smoke detectors … apparently Americium isn’t suitable for making nuclear bombs … but point taken, I’ll continue to avoid buying metric measuring spoons since that’s clearly a material step in some illegal direction … ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 7, 2016, 5:03pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/26 "2016-11-07T17:03:48Z")
> [@Mijin](#): > > Human evolution has slowed to a crawl thanks to increases in healthcare, food production and general quality of life for all. None of those things obviously slow evolution. They do change the environment we live in and affect who has children. But that’s not enough. To support the claim that evolutionary forces acting on our species has slowed, you need to show that the correlation between genetics and the number of children reaching adulthood (or some similar fitness metric) is smaller than it used to be. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [November 7, 2016, 5:32pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/27 "2016-11-07T17:32:14Z")
> [@Pleonast](#): > > None of those things obviously slow evolution. They do change the environment we live in and affect who has children. But that’s not enough. To support the claim that evolutionary forces acting on our species has slowed, you need to show that the correlation between genetics and the number of children reaching adulthood (or some similar fitness metric) is smaller than it used to be. Infant mortality is a terrible example to pick, since we trivially see this. We don’t need to match genes to mortality to know that overall the selection pressure must be falling: we can just observe that infant mortality has dropped to a minute proportion in the developed world, and is falling rapidly most everywhere else. (Yes, any infant mortality suggest that natural selection is still happening. And I’ve said as much. What I’ve said is the rate of selection is apparently slowing, and, in any case, the whole thing is an irrelevance vs the rate of human technological progress anyway). ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [November 7, 2016, 5:36pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/28 "2016-11-07T17:36:54Z")
And in any event, I think the question of whether natural selection is slowing is rather unimportant, since it is the _relative_ speed of evolutionary change that’s matters. If technology continues to advance, natural selection will play little role in future human evolution, which will be actively directed by we humans ourselves. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 7, 2016, 5:40pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/29 "2016-11-07T17:40:54Z")
> [@Mijin](#): > > Infant mortality is a terrible example to pick, since we trivially see this. > > We don’t need to match genes to mortality to know that overall the selection pressure must be falling: we can just observe that infant mortality has dropped to a minute proportion in the developed world, and is falling rapidly most everywhere else. I’m not sure how falling infant mortality affects the correlation between genetics and evolutionary fitness. If I recall, infant mortality used to be predominantly due to infectious disease. Those deaths are now greatly reduced. The remaining infant mortality rate would seem to be due to genetic conditions. That imply that reduced infant mortality has increased selective pressure, and presumably the correlation between genetics and reproductive success. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [November 7, 2016, 6:17pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/30 "2016-11-07T18:17:45Z")
> [@Broomstick](#): > > That’s just the tip of the iceberg. We still have pressures on us as a species, they’re just not as obvious as a tiger leaping out of the bushes to eat us. Exactly. The one thing questions like this overlook is that even in extremely rapid cases, evolution tends to take place over thousands of years, and is typically on even longer scales in the millions of years. There’s likely to very little that we can conclusively identify as evolutionary changes over recorded history, much less over the time scale when technological improvements have lessened infant mortality. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [November 7, 2016, 6:44pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/31 "2016-11-07T18:44:36Z")
> [@Pleonast](#): > > If I recall, infant mortality used to be predominantly due to infectious disease. Those deaths are now greatly reduced. The remaining infant mortality rate would seem to be due to genetic conditions. That imply that reduced infant mortality has increased selective pressure, and presumably the correlation between genetics and reproductive success. I’ll counter your WAG with one of my own. Selective pressure is going down since 1) dying due to infectious diseases _is still_ A selection pressure for particular genes. For what reason would it be not true scotsman selection? 2) Infant mortality is very, very low in the developed world. That’s because we haven’t just largely eliminated deaths due to infectious diseases, but numerous other causes too. also of course 3) In the majority of cases, the kind of things that are killing young children today would also have killed them in a pre-civilization society. It’s not like there was _only_ infectious disease previously. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 7, 2016, 7:21pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/32 "2016-11-07T19:21:51Z")
> [@Mijin](#): > > I’ll counter your WAG with one of my own. > > Selective pressure is going down since 1) dying due to infectious diseases _is still_ A selection pressure for particular genes. For what reason would it be not true scotsman selection? > 2) Infant mortality is very, very low in the developed world. That’s because we haven’t just largely eliminated deaths due to infectious diseases, but numerous other causes too. > also of course > 3) In the majority of cases, the kind of things that are killing young children today would also have killed them in a pre-civilization society. It’s not like there was _only_ infectious disease previously. Sure, it could go either way; I’d like to see evidence on how correlation between infant mortality and genetics has changed. My point is that merely the reduction of infant mortality doesn’t tell us anything, because the deaths we’ve reduced might be less dependent on genetics than the remaining deaths (and thus increase the importance of genetics has on that measure of fitness). We need evidence that the correlation between our genes and our reproductive success is less (or more) than it used to be to claim that evolution has slowed (or quickened). Simply looking at death or fertility rates doesn’t give us that evidence. ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [November 7, 2016, 10:30pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/33 "2016-11-07T22:30:35Z")
It seems to me that this whole question is being strongly influenced here by the Religion of Evolution and the Myth of Progress. “Evolution” means “development”, not “improvement”. ---
**Author:** ![Kimera757](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kimera757/32/3765_2.png) [@Kimera757](https://boards.straightdope.com/u/Kimera757)\ **Post date:** [November 8, 2016, 12:36am UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/34 "2016-11-08T00:36:04Z")
> [@Pleonast](#): > > I’m not sure how falling infant mortality affects the correlation between genetics and evolutionary fitness. > > If I recall, infant mortality used to be predominantly due to infectious disease. Those deaths are now greatly reduced. The remaining infant mortality rate would seem to be due to genetic conditions. That imply that reduced infant mortality has increased selective pressure, and presumably the correlation between genetics and reproductive success. I think a lot of people today are surviving to adulthood due to medical advances, who would not have survived a few generations ago. I wonder what happened to people 200 years ago who suffered from celiac disease or PKU. The latter is genetic. With advances in medical testing, you can identity someone who suffers from PKU and change their diet fast enough to avoid brain damage. Fatal allergic reactions might be more common now than a few hundred years ago, but if you were fatally allergic to beestings, and you got stung by a bee a few hundred years ago, you died, possibly before having any children. These days a person with this allergy carries an epipen. I once worked in a bee lab with a scientist who was allergic to bee venom. Perhaps not fatally, but that would have been recklessly dangerous a century ago. I worked with someone seriously allergic to orange peels, and we had signs warning about that. On occasion someone would forget, but the person with an allergy had access to medical technology that would keep them alive. (How do you even identity such an allergy?) A variety of noninfectious diseases are not killing people in the first world anymore, and probably killing a lot fewer people in poorer nations. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [November 8, 2016, 2:25am UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/35 "2016-11-08T02:25:49Z")
> [@Pleonast](#): > > My point is that merely the reduction of infant mortality doesn’t tell us anything, because the deaths we’ve reduced might be less dependent on genetics than the remaining deaths (and thus increase the importance of genetics has on that measure of fitness). Well when infant mortality has dropped as low as it has it strongly implies that the selection pressure has decreased, all else being equal. I’m not going to argue on this point though since it’s a side issue to me. So OK; I take back the claim that selection is slowing. But regardless, I maintain it’s an irrelevance compared to the rate of human technological and social change. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 8, 2016, 7:18pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/36 "2016-11-08T19:18:33Z")
> [@Mijin](#): > > Well when infant mortality has dropped as low as it has it strongly implies that the selection pressure has decreased, all else being equal. > > I’m not going to argue on this point though since it’s a side issue to me. So OK; I take back the claim that selection is slowing. But regardless, I maintain it’s an irrelevance compared to the rate of human technological and social change. I agree. It’s the “all else being equal” that I’m skeptical of. And no doubt that evolution of the human species is becoming less natural selection and more self selection. ---
**Author:** ![Kimera757](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kimera757/32/3765_2.png) [@Kimera757](https://boards.straightdope.com/u/Kimera757)\ **Post date:** [December 6, 2016, 11:16pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/37 "2016-12-06T23:16:22Z")
I read this interesting news story: [Caesarean births 'affecting human evolution' - BBC News](http://www.bbc.com/news/science-environment-38210837) > [@](#): > > More mothers now need surgery to deliver a baby due to their narrow pelvis size, according to a study. > > Researchers estimate cases where the baby cannot fit down the birth canal have increased from 30 in 1,000 in the 1960s to 36 in 1,000 births today. > > Historically, these genes would not have been passed from mother to child as both would have died in labour. I see this as humans modifying their own evolution in a form of artificial selection. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [December 6, 2016, 11:34pm UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/38 "2016-12-06T23:34:46Z")
> [@Kimera757](#): > > I read this interesting news story: [Caesarean births 'affecting human evolution' - BBC News](http://www.bbc.com/news/science-environment-38210837) > > I see this as humans modifying their own evolution in a form of artificial selection. Cool example. The rate of death in childbirth used to be extremely high, so it’s quite plausible that the dramatic elimination of that natural selection could lead to a rapid change in a few generations. Still, it’s an empirical question whether there really has a been a population genetic change. An environmental factor like better nutrition could mean bigger babies, right? ---
**Author:** ![Kimera757](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kimera757/32/3765_2.png) [@Kimera757](https://boards.straightdope.com/u/Kimera757)\ **Post date:** [December 7, 2016, 1:14am UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/39 "2016-12-07T01:14:06Z")
> [@Riemann](#): > > Cool example. The rate of death in childbirth used to be extremely high, so it’s quite plausible that the dramatic elimination of that natural selection could lead to a rapid change in a few generations. > > Still, it’s an empirical question whether there really has a been a population genetic change. An environmental factor like better nutrition could mean bigger babies, right? Could be better nutrition. Could be **worse** nutrition too 😃 Baby size (and canal size) aren’t based solely on genetics, but it might be possible to determine the heritability of one or both traits. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [December 7, 2016, 1:24am UTC](https://boards.straightdope.com/t/has-human-evolution-stopped/770732/40 "2016-12-07T01:24:31Z")
> [@Kimera757](#): > > I wonder what happened to people 200 years ago who suffered from celiac disease or PKU. The latter is genetic. With advances in medical testing, you can identity someone who suffers from PKU and change their diet fast enough to avoid brain damage. 200 years ago someone with PKU likely wouldn’t survive to adulthood, and even if they did, they’d be severely damaged. In a hunter-gatherer environment they’d die early. On the other hand, in a hunter-gatherer environment it likely wouldn’t matter if someone had celiac - wheat, rye, and anything else containing gluten would be either a rare or non-existent part of the diet. It would be irrelevant. It’s only when gluten-containing grain becomes a feature of the diet that it matters. > [@](#): > > Fatal allergic reactions might be more common now than a few hundred years ago, but if you were fatally allergic to beestings, and you got stung by a bee a few hundred years ago, you died, possibly before having any children. True, but allergies were much less common overall 200 years ago, and extremely rare in ancient times. Every now and then someone would die from such a reaction but it would probably be even less common than being struck by lightning. > [@Kimera757](#): > > I read this interesting news story: [Caesarean births 'affecting human evolution' - BBC News](http://www.bbc.com/news/science-environment-38210837) > > > [@](#): > > > > More mothers now need surgery to deliver a baby due to their narrow pelvis size, according to a study. > > > > Researchers estimate cases where the baby cannot fit down the birth canal have increased from 30 in 1,000 in the 1960s to 36 in 1,000 births today. > > > > Historically, these genes would not have been passed from mother to child as both would have died in labour. > > I see this as humans modifying their own evolution in a form of artificial selection. Alright, but keep in mind that in the past NONE of those women would have had multiple pregnancies and births. They _might_ have had one child, delivered by a knife after their death, but no subsequent children. These days, such women can have three, four, or even more children so _of course_ the number of such instances has risen. But that doesn’t mean there are more individual women with such a problem, just that they aren’t dying in their first labor. > [@Riemann](#): > > Cool example. The rate of death in childbirth used to be extremely high, so it’s quite plausible that the dramatic elimination of that natural selection could lead to a rapid change in a few generations. Doubt it. > [@](#): > > Still, it’s an empirical question whether there really has a been a population genetic change. An environmental factor like better nutrition could mean bigger babies, right? It can also mean a narrower pelvis, if malnutrition is involved. But yes, excess food can mean excessively large babies. That is also a feature of pregnancy-induced diabetes, an extra-large child. Could be in the past some of those diabetic women either couldn’t successfully carry a child to term, or, in the case of women who have diabetes prior to pregnancy, they died before they could become pregnant. [Previous page](https://boards.straightdope.com/t/has-human-evolution-stopped/770732.md?page=1) [Next page](https://boards.straightdope.com/t/has-human-evolution-stopped/770732.md?page=3)