Investigating the case of human nose shape and climate adaptation (2017)
71 comments
·January 30, 2025abricq
BurningFrog
Men will evolve to manage sperm banks and fertility clinics.
MrLeap
After the high profile grossness with those, you'd think every person using those services would do a paternity test just in case.
highcountess
To answer your question, it already has changed us in many ways. You are not the only one who does not realize this though. It is in fact the prevailing position.
We have diseases and genetic defects, among other impacts through modern behaviors and environments/toxins, which are also retained in the genetic mutational load. We even have a whole lot of energy and human activity working to counter evolutionary pressures and assure those accumulated mutational loads remain in the genetic code.
amanaplanacanal
Fitness depends on the specific environment the creature is in. Environmental fitness for the ancestral environment when all humans were hunter-gatherers is not necessarily the same as fitness for living in an industrial society. Evolutionary pressure still works just fine.
spacebanana7
Humans are beyond evolution. There's no meaningful selection pressure in our environment that kills people before reproductive age, so there's no reward for adaptations.
steve_adams_86
This simply isn't how evolution works. There's no way to be "beyond" it. It's an inevitable facet of populations of living organisms.
If a population used genetic engineering to collectively ensure their genetics didn't change, no mutations, no other populations involved, then... I guess? Otherwise, there is this staggering multitude of influences.
Living longer and reproducing longer is a huge weight on the scales of evolution. Why does anyone need to die early for it to work?
svara
Totally wrong, killing humans is not required for evolution.
Ignoring genetic drift and taking into account only natural selection, all that's needed is differences in fitness, i.e. differences in how much an individual contributes to the gene pool of future generations.
hammock
This. “Natural selection” refers to selection and survivability of traits, not of individuals. Evolution is how that selection process then manifests itself over time in a population.
red-iron-pine
no one is having babies mon ami. birth rates are declining.
it's not about killing people before reproductive age, it's about absolute numbers of offspring born. dying before reproducing ensures that number stays 0, but you can still hit sexual maturity and not reproduce.
plus there is a fertility window -- after 50 most humans, male or female, ain't having kids (a handful of rockstar types whelping babies at 80 notwithstanding).
there is a TON of meaningful pressure in our environment, like the inability to have a living wage reducing how many Gen Z's are marrying and having kids.
thaumasiotes
> it's not about killing people before reproductive age, it's about absolute numbers of offspring born.
Technically, it's about averaging offspring (weighted by your genetic contribution to them) across all of time. If you have 30 children, and all of them starve to death before reproducing, you've reproduced less than your neighbor with the one child and one grandchild.
But that's impossible to calculate, so mostly we just have to work with number of children. This detail, though, is something you might want to keep in mind when looking at reports of "effective population" in the past. Any actual population in the far past who end up being wiped out in the middle past are excluded from the "effective population" that we calculate.
ninetyninenine
There is incredibly high sexual selection. Birth control is effecting this.
Note that sexual selection selects for health, wealth and reputation. Women are doing most of the selection here.
SamBam
Evidence?
Take just the easiest to measure of those factors, wealth. Per your hypothesis, wealthier men should have more babies. Do you have any evidence that wealthier men have more babies?
In fact, it's quite the opposite. There is a strong inverse correlation between wealth and number of babies. Both globally [1] and in the US [2]. There is some data that you can seek out that will suggest the trend is reversed in some first-world countries in the past couple of years, but that's no where near enough time to draw conclusions.
Is there real evidence that men with greater "health" (besides the obvious, of, say, having a crippling disease) or "reputation" have more children?
I'm sorry, but this sounds like "women only chose alpha males" junk to me.
1. https://en.wikipedia.org/wiki/Income_and_fertility
2. https://www.statista.com/statistics/241530/birth-rate-by-fam...
toasterlovin
If there's a fertility gradient based on heritable traits then there is evolution happening.
dekhn
I believe we are currently measuring recent functional selection on humans and it's non-zero. That is, empirically you are incorrect.
washadjeffmad
Interesting. So how do you explain menopause and other population or age scale adaptations?
Humans aren't individuals, no matter how certain blips of modern culturalism pretend.
tpierce89
I would like to see if there is a correlation between Sleep Apnea cases and nose shape to determine if there is a link between humans living in an area they are not adapted to and how that affects their ability to breathe normally.
woolion
I suspect the impact would be extremely small compared to BMI, so it would be likely that there would be a link because of some dependent variables.
hammock
Ok, what about looking at nose shape of diaspora that have historically (multigenerationally) high BMI? Not an expert but might suggest Inuit, some Pacific Islanders, Māori, west Africans maybe. How are their noses shaped and anything that might help with apnea?
oremolten
I bet there is also a large correlation with computer/phone neck and posture
ninetyninenine
Sleep apnea usually comes from the back of the throat. It’s not a nose thing as much.
BurningFrog
People probably sleep in very similar conditions in all climates.
Sam6late
On a slightly related issue, I noticed that my nose gets bigger,in my photos, it turned out it was mostly irritation swelling due to pollution, while in a Nordic country with cleaner air quality, I noticed that is back to normal. And now I am always checking iqair.com- and it says:"PM2.5 concentration is currently 3.6 times the World Health Organization annual PM2.5 guideline value.
SamBam
If I'm reading this right, the hypothesis seems to be that in drier climates, humans need longer noses (simplifying) to increase the humidity of the air to an optimal level.
Did the authors propose a counter-evolutionary pressure, to favor a shorter nose in more humid environments?
It's possible that the mechanism would be as simple as "it requires more resources to maintain a longer nose," but I'm also wondering if they suggested anything.
baxtr
From the author summary:
> We find that variation in both nares width and alar base width appear to have experienced accelerated divergence across human populations. We also find that the geospatial distribution of nares width is correlated with temperature, and absolute humidity, but not with relative humidity. Our results support the claim that local adaptation to climate may have had a role in the evolution of nose shape differences across human populations.
I really wonder how nose shape can affect evolution. What is the mechanism? How can better air lead to higher numbers of successful offspring or fatalities?
lm28469
> How can better air lead to higher numbers of successful offspring or fatalities?
Try running XX hours after an antelope and report back, most animals aren't optimised for long distance, humans are, you can hunt most things by following them and waiting for them to collapse, surely having better air intake helps. It might be something as dumb as more antelope meat = more social points = you get to bang more.
Why do 70%+ of the world population has brown eyes ? It offer marginal UV resistance but nobody becomes blind or sterile because they have blue eyes, certainly not before they can reproduce. Chances of reproduction can also be dictated by other things like attractiveness, and these are also very dependant on cultures and time periods.
DiscourseFan
Its more like if your tribe has access to more meat they can produce more offspring. I wouldn't think of this in terms of individual prowess.
BurningFrog
Pretty sure the best hunter gets the most kids on average.
euroderf
> Try running XX hours after an antelope and report back, most animals aren't optimised for long distance, humans are, you can hunt most things by following them and waiting for them to collapse
According to this theory, the rhythm was to walk a long long time and maybe hungry too, then a burst of activity, then stuff your face, then pass out for a while, then repeat. It seems logical & sensible & probable.
capitainenemo
Well, at least one selection pressure for blue exists - modestly better vision in low light levels.
DrScientist
Nose filters, and adjusts air temperature and humidity - it's not just a passive in/out hole.
Evaporation is a big factor in both controlling temperature and water retention/loss ( that's why dogs pant in hot weather ).
Remember the surface of your lungs are topologically on the outside - they are large and wet and are sensitive to both physical dust etc as well as potential infection.
The nose design has to find the best balance across all these factors ( as well as being important in the sense of smell ).
cyrillite
Respiratory efficiency is a pillar of health and performance, from sleep to hunting and fighting. I wouldn’t be surprised to find that marginal gains make a big difference and can be passed on.
SamBam
The article mentions an increase in upper respiratory tract infections in the air being breathed in is not humid enough. The hypothesis seems to be that in drier climates, humans need longer noses to increase the humidity of the air to an optimal level.
kseistrup
The parameters affect the temperature and humidity of the air that reaches the lungs. E.g., a long slender nose could perhaps moisten and warm up dry frosty air better than a shorter wider nose.
0xEF
Speaking as someone with a long slender nose, I have my doubts about it moistening dry frosty air. During the Winters, the only thing my nose seems to be good for is producing blood and dried mucus wafers like some cursed Triscuit factory.
kseistrup
It's not about your nose. It's about the relative differences of the air reaching the lungs when inhaled through different nose. You may not think that your nose does a very good job (or perhaps I picked a wrong example), but perhaps the job would get done much worse by a short wider nose.
Some environmental parameters are temperature and absolute humidity. But there are also significant differences in sex when a other parameters are equal. So perhaps the correlation is not so straight forward.
croisillon
Yay free proteins!
wiether
Silly suggestions related to snoring:
- harder to find mating partner before earplugs were inventend
- easier for your enemies/predators to catch you in your sleep
davidw
Going to use this as a comeback next time my wife makes a comment: "I'm just well-adapted to certain climates, so there!"
microtherion
Weirdly, I saw this paper mentioned just this morning, in the context of an r/AskHistorians post discounting the possibility of an African origin for Olmecs. Sounded interesting, and then I saw it linked here.
dagenleg
Same. Feels like we exist in a very small bubble doesn't it?
boxed
West African, but not East African? That seems like an enormous problem in itself.
InfiniteLoup
There is a rather distinct type of nose which I've only ever observed with people of Ukrainian ethnic descent.
Now I wonder if that is in fact some type of adaptation to local climate because the people of the surrounding areas don't seem to have that nose shape to the same extent.
indulona
so indeed jews are the spawn of satan since there must be quite dry in hell.
metalman
There are a large amount of enviromental adaptations in many human populations, a lot of them to do with enzimatic adaptations. Climate as a term in this context is only usefull if you include, everything, diet, the ability to pass certain contaminents, such as high arsinic concentrations in water, vs binding say calcium. The full list, is, well, everything!, horribly complex, the nose ,perhaps working as a proxy indicator for a number of less visible adaptations, as succes in more extream environments is absolutly dependent on multiple adaptations, none of which is optional over generational time spans, as extream conditions, in an already extream environment, are going to eliminate marginal indivduals.
justlikereddit
>This work was supported in part by the United States National Institute of Justice, the United States Department of Defense
nothrowaways
This is how our understanding about the world moves forward.
On a slightly related topic, I remember to have seen an exposition where an artist was asked to represents what a human who has naturally evolved to survive a car crash might look like. And it has a cool / terrifying website: http://www.meetgraham.com.au/view-graham
Quite fascinating topic to wonder about: how long will it take for the modern era to genetically change us ?