Nocturnal bottleneck(en.wikipedia.org)
en.wikipedia.org
Nocturnal bottleneck
https://en.wikipedia.org/wiki/Nocturnal_bottleneck
13 comments
Yeah, adding photolyase to humans is high on my genetic engineering wishlist.
This would presumably only be useful if expressed in the skin?
I'm an absolutely incurable night owl. My theory is it must be an inherited trait, which is passed through the generations at random, and was first developed for a reason. For thousands of years, maybe longer, my forebears protected the rest of the tribe at night so everyone else could sleep peacefully and then go hunting or farming during the day. We were probably the ones that domesticated the wolf, I'd bet, as that makes sense. They'd be the ones coming around the campfires at night. And we'd say, hey buddy, want this juicy elk bone?
In return for saving civilization, we're now persecuted by people who think 8 a.m. is a good time to start school.
In return for saving civilization, we're now persecuted by people who think 8 a.m. is a good time to start school.
This exact theory has been put forward by scientists a few times - that variation in sleep-wake times helps guard a tribe or camp at night.
A 2017 study of an indigenous hunter-gatherer group found that there was virtually always at least one person awake in the group, around the clock. The longest contiguous time the whole group was asleep simultaneously was just 1 minute! Here's one article about it: https://www.discovermagazine.com/planet-earth/chronotypes-ev...
A 2017 study of an indigenous hunter-gatherer group found that there was virtually always at least one person awake in the group, around the clock. The longest contiguous time the whole group was asleep simultaneously was just 1 minute! Here's one article about it: https://www.discovermagazine.com/planet-earth/chronotypes-ev...
Oh no! There's absolutely zero way I just happened to come up with this exact idea independently. If it was someone else, I'd be calling BS. :-)
I don't have any memory of it, but I must have seen or heard that study mentioned somewhere. Thanks for pointing it out and saving me future embarrassment!
I don't have any memory of it, but I must have seen or heard that study mentioned somewhere. Thanks for pointing it out and saving me future embarrassment!
thank you for your service
I'm the exact same, and I've thought about the same theory, especially since I sleep way better during the day than at night.
That's what finally got me to come to terms with my extreme night owl shift. When I get up earlier than 9am (using light therapy etc), I get anxiety/panic attacks and have a hard time sleeping more than 6 hours. My natural schedule is sleeping around 5am - 1pm and I sleep like a baby and feel great.
Ha! That's just about my perfect schedule as well, though for practicality I try to make sure I'm winding down by 3:00 am so I can get up before noon. In college I'd regularly go get breakfast before heading to bed and marvel at the morning people around me.
My sleep shifts about an hour later every week, so that last week or so before it flips back is pretty tough, especially during the winter. Waking up at like 4 or 5 pm is definitely not good. I still need light!
My sleep shifts about an hour later every week, so that last week or so before it flips back is pretty tough, especially during the winter. Waking up at like 4 or 5 pm is definitely not good. I still need light!
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Which part is the "bottleneck"? Is it the idea that at one point nearly all mammals were nocturnal and that it became advantageous for some to transition to diurnal since there was less competition for resources during the day?
the bottleneck was a global ecosystem level of selection.
dinosaurs pressured the mammals to stay small, hide in burrows, and roam at night.
dinosaurs, and a lot of other things came to an abrupt end, the basal mammals survived in thier bunkers with hoards of seed, and were relieved of selective pressure, thus diversified in thier traits this is when mammalian diurnalism made a big comeback so they could now compete among fellow mammals radiate and expand niche into the estate of the late dinosaurs
dinosaurs pressured the mammals to stay small, hide in burrows, and roam at night.
dinosaurs, and a lot of other things came to an abrupt end, the basal mammals survived in thier bunkers with hoards of seed, and were relieved of selective pressure, thus diversified in thier traits this is when mammalian diurnalism made a big comeback so they could now compete among fellow mammals radiate and expand niche into the estate of the late dinosaurs
What a wild thought that our ancestor was a mousey thing that hid in a hole, terrified of the giant dinosaurs and falling asteroids, and survived only because it had the Jurassic mouse equivalent of a Costco habit while completely failing to suspect that its distant children will one day rule the planet.
Path dependence is neat!
I think it's a genetic trait diversity bottleneck? Mammals almost all went in the direction of nocturnal adaption and a lot of adaptions useful during the day were lost over time.
Like, mammals are very vulnerable to skin cancer. We lost some traits reptiles have that makes them cope better with UV.
Animals in the wild don't typically die of cancer, so that's probably not much of an adaptation evolutionarily. Even if they did die of cancer, it would likely be after they've reproduced, which means there's no selective pressure to develop the adaptation.
Wild animals do die of cancer and there are evolutionary pressures in regards to carcinogenesis.
https://onlinelibrary.wiley.com/doi/full/10.1111/eva.12025
https://onlinelibrary.wiley.com/doi/full/10.1111/eva.12025
> Animals in the wild don't typically die of cancer, so that's probably not much of an adaptation evolutionarily.
There's lots and lots of adaptations that repair damage to DNA and that deal with damaged cells. So there must have been lots of evolutionary pressure to keep them in place and keep them working.
Animals in the wild probably don't typically die of cancer, because those adaptations are in place.
But you are right, that even mammals active during the daytime have not (re)gained that specific photolyase DNA mechanism that their ancestors lost.
There's lots and lots of adaptations that repair damage to DNA and that deal with damaged cells. So there must have been lots of evolutionary pressure to keep them in place and keep them working.
Animals in the wild probably don't typically die of cancer, because those adaptations are in place.
But you are right, that even mammals active during the daytime have not (re)gained that specific photolyase DNA mechanism that their ancestors lost.
Imagine a cold-blooded reptile with sun allergy.
the environment limited some traits and allowed for others;
you (most likely) have three flavors of color cones in your eyes not four like birds(dinosaurs) and replies because the having more rods (B/W low light sensitive) was better suited to night survival. On the other hand our brains do not (usually) have a bone partition between the two halves because we did not need to sleep with one eye open underground.
Yes, apparently chickens (and other birds) really can sleep one half of their brain at a time. In chickens, the ones roosting on the edge of the flock keep their outside eye open and sleep the other side of the brain.
Dolphins and whales as well
https://www.scientificamerican.com/article/how-do-whales-and...
Global warming might well gradually force us back again to a semi-nocturnal/ underground existence too.
Bring on the night...
Extremely unlikely.
https://en.wikipedia.org/wiki/Economic_impacts_of_climate_ch... says that the best available studies foresee global GDP dropping between 0% - 20% from climate change (compared to no climate change).
Given that this happens against a backdrop of normal, regular economic growth, people in the future will still be richer than people today.
And approximately everyone today who can afford aircon (and needs it) gets aircon, rather than turning nocturnal.
https://en.wikipedia.org/wiki/Economic_impacts_of_climate_ch... says that the best available studies foresee global GDP dropping between 0% - 20% from climate change (compared to no climate change).
Given that this happens against a backdrop of normal, regular economic growth, people in the future will still be richer than people today.
And approximately everyone today who can afford aircon (and needs it) gets aircon, rather than turning nocturnal.
Given that this happens against a backdrop of most of human habitation being below sea level, I think GDP projections are probably an awful estimation of human impact.
Reading that link, those estimates are based upon us keeping temperature increases below 3 deg. In which case most human habitation will be fine.
It also means that analysis is not a good one to quote without qualifiers about 'controlled climate change'
It also means that analysis is not a good one to quote without qualifiers about 'controlled climate change'
What's that got to do with the possible need to adjust to changing climate by living underground or semi-nocturnally? I made no prediction of what level of technology we'd have. We may will simply find it provides a better mode of existence.
That analysis specifically states it only applies if we keep changes within 3 deg.
And only goes to the end of the century. Climate change and its after-effects will be with us for many many centuries barring extraordinary levels of technological intervention (which is not out of the question, but even that is unlikely to bring back extinct species etc.).
Are those the models that assume that all indoor economic activity is unaffected by climate change?
This is ridiculous. People will just move towards the poles. Earth has been much warmer in the past and it was rainforests from pole to pole.
Antartica has average elevation of 2500 meters. AFAICT Antartica can offer very little habitable land after the ice melts.
Towards, not to.
Lots of land in Canada and Siberia is going to become a lot more habitable.
"average elevation" is a bit of a strange metric for a continent.
Several large American cities are above 1600m and just looking at a map of the land below the ice of Antartica, there is plenty of low-lying land.
And we need not exaggerate the actual expected warming. The beyond-worst-case doomers don't need that much attention.
People are going to move away from coasts because the sea will make a new coastline. Agricultural zones will move north and around because of changes to weather patterns.
Pretty cold places will become less cold and new cities will pop up further north. Canada will do pretty well and grow a lot.
Lots of land in Canada and Siberia is going to become a lot more habitable.
"average elevation" is a bit of a strange metric for a continent.
Several large American cities are above 1600m and just looking at a map of the land below the ice of Antartica, there is plenty of low-lying land.
And we need not exaggerate the actual expected warming. The beyond-worst-case doomers don't need that much attention.
People are going to move away from coasts because the sea will make a new coastline. Agricultural zones will move north and around because of changes to weather patterns.
Pretty cold places will become less cold and new cities will pop up further north. Canada will do pretty well and grow a lot.
> Canada will do pretty well and grow a lot.
Perhaps- but it's also warming at twice the rate of the rest of the world, which makes adaptation even more challenging.
Perhaps- but it's also warming at twice the rate of the rest of the world, which makes adaptation even more challenging.
I expect that will happen too, I don't see it's any more ridiculous than suggesting underground and more nocturnal living arrangements will become common too. Sea level rises will massively reduce the amount of arable land we'll have to occupy, and there'll be another 2 billion of us in 30-40 years, so we'll need every available option.
Both are a huge disruption from our current mode of existence. If you have kids under 20 now they'll very likely witness it in their lifetimes.
Source for “sea level rises will massively reduce the amount of arable land”? Seems like an exaggeration. My naive estimate would be that maybe 1% of arable land would be destroyed by sea level. I’m far more concerned about drought.
1% is massive if that 1% is where most people currently live (like in Australia).
And 1% is likely to be an underestimate - there are studies suggesting up to 600 million people being forced to relocate within the next century (based purely on rising sea levels - not sure what studies there are around forced relocation due to drought and extreme heat).
https://www.researchgate.net/figure/The-percentage-impacts-o... suggests it could be lot more than 1% too.
https://www.researchgate.net/figure/The-percentage-impacts-o... suggests it could be lot more than 1% too.
(Technically "arable" isn't the term I was looking for, I guess I mean "land suitable for large-scale human habitation")
Gotcha. “Arable” has a pretty specific meaning.
Agreed. And I think these changes will still develop slowly enough to adapt to. It would really surprise me if the Midwest and eastern US farmland doesn’t stay productive for a long, long time. But it would not surprise me if there are occasional bad harvests due to heat waves. Hopefully we can plan appropriately for that uncertainty.
Global warming is so 2010... It's climate change
IPCC still use both terms, at least, they were last year: https://www.ipcc.ch/2021/08/09/ar6-wg1-20210809-pr/#single-c...
I wrote "global heating" first but it still feels weird to me.
I wrote "global heating" first but it still feels weird to me.
I've always had a sneaking suspicion humans, like many other modern mammals, may be best thought of as variable among crepuscular, diurnal, matutinal, and vespertine.
Why not just call that, I dunno, nychthemeral?
That has among its meanings "lasting 24 hours" and also "a changing of day to night, back, or both". A single human is not likely to be equally active the whole 24 hours. Although I do know of some people who basically nap around the clock and don't sleep in an extended block, they seem to be a rare exception.
It seems like a decent word to stretch a little into this use of the idea that members of a species may have different familial, social, or individual circadian activity. I hesitate to do that though, because I'm unaware of it being used that way to date and it seems it could be difficult in such a context to differentiate it from established meanings of the word.
It seems like a decent word to stretch a little into this use of the idea that members of a species may have different familial, social, or individual circadian activity. I hesitate to do that though, because I'm unaware of it being used that way to date and it seems it could be difficult in such a context to differentiate it from established meanings of the word.
Well, it won't become an established use until people start using it with this meaning: and you personally can help with that!
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This makes me speculate if intelligence was enabled by the slop available from nocturnal animals becoming diurnal. As in, perhaps intelligence would be much harder to achieve in a step by step fashion, but the adaptations to night living left some things on the table that enabled a random walk to intelligence: richer sensory input, and more energy available for processing that input. And perhaps faster and more flexible outputs. If intelligence hadn't come about, presumably evolution would have pushed things back towards faster / extreme sized (smaller or bigger) / more streamlined, basically repopulating the non-mammalian design points.
(Note that by "intelligence" I'm not referring to human intelligence, just the basic form of using mental processing power to facilitate survival. Which is not specific to mammals, nor necessarily strong in all mammals.)
(Note that by "intelligence" I'm not referring to human intelligence, just the basic form of using mental processing power to facilitate survival. Which is not specific to mammals, nor necessarily strong in all mammals.)
Octopuses and corvids are plenty smart, more than comparable to most mammals.
Not sure they had a nocturnal bottleneck in their evolution? So that is probably not required.
Looking at plenty of relatively dumb mammals, I don't think the nocturnal bottleneck is sufficient either.
Of course, it might be a more complicated correlation than just sufficiency / necessity.
Not sure they had a nocturnal bottleneck in their evolution? So that is probably not required.
Looking at plenty of relatively dumb mammals, I don't think the nocturnal bottleneck is sufficient either.
Of course, it might be a more complicated correlation than just sufficiency / necessity.
I like the theory. If true, it's another example of the virtue of leaving some slop in your systems.
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>placental mammals were mainly or even exclusively nocturnal through most of their evolutionary story, starting with their origin 225 million years ago, and only ending with the demise of the non-avian dinosaurs 66 million years ago.
i guess we're lucky that dinosaurs didn't evolve IR vision (not that it wasn't impossible given that snakes did get IR sense).
i guess we're lucky that dinosaurs didn't evolve IR vision (not that it wasn't impossible given that snakes did get IR sense).
IR does not work for warm-blooded creatures. You will be jamming your own IR vision with heat coming from your body. That, or having eyes on beanstalks.
And archosaurs were at least partly warm blooded.
And archosaurs were at least partly warm blooded.
Even 'cold blooded' creatures warm up when they move around a lot, or when they bask in the sun.
More details in this paper, “The nocturnal bottleneck and the evolution of activity patterns in mammals” (OA): https://oa.mg/work/10.1098/rspb.2013.0508
But how many social mammals are nocturnal? Seems to me that when mammals began moving and living in social groups they could watch out for each other like those cute meerkats.
First social nocturnal species of mammals that come to my mind are hyenas and beavers. But it does seem that most social mammals are diurnal.
Were some of these adaptations a major factor in mammals largely surviving K-T?
I don't think mammals largely survived K-T? What's the evidence for that?
(Some mammals survived, definitely, the evidence for that is that we are here.)
(Some mammals survived, definitely, the evidence for that is that we are here.)
its more like K-T was a bottleneck and those adaptations carried through the selection regime
How certain can we be that that's the case? Seems like thermo-regulation and burrowing in particular could have been helpful traits in the immediate and long-term aftermath of the asteroid impact
the mammalian traits you speak of were the default mamalian due to pressure from the dinosaurs existence, they could not compete so survied in a compressed niche.
when the dinosaurs failed to survive the bottleneck at the KT boundry, the mammals were in a position to weather it out and expand niche into a landscape devoid of most large dinosaur lineages, this was followed up with mammalian diversification founded on the small cynodont plan.
this is all a tale of the fossil record and the principle of superposition
this is all a tale of the fossil record and the principle of superposition
This explains a lot.
This hypothesis is my new go-to to explain my night owl habits.
It sure does.
Not that scientific but maybe a little on topic, I'm just reading a book about the memoirs of past Soviets leaders, and at some point Khrushchev is complaining how Stalin had an almost all nocturnal life, how for him 2AM was still "an early hour". Afaik Churchill was also a very nocturnal man. I'm wondering what other past leaders were in the same category as Stalin and Churchill when it comes to their night life.
Not that scientific but maybe a little on topic, I'm just reading a book about the memoirs of past Soviets leaders, and at some point Khrushchev is complaining how Stalin had an almost all nocturnal life, how for him 2AM was still "an early hour". Afaik Churchill was also a very nocturnal man. I'm wondering what other past leaders were in the same category as Stalin and Churchill when it comes to their night life.
It was probably the only time they could get anything done without constant interruption.
In a past life where I was a lead of a larger team, I would have a fair chunk of my work day devoted to mentoring and meetings, and spent a few hours late in the evening doing actual programming work.
In a past life where I was a lead of a larger team, I would have a fair chunk of my work day devoted to mentoring and meetings, and spent a few hours late in the evening doing actual programming work.
This is me, too. I start work relatively late, because it gives me a few hours of uninterrupted, productive work past "EOB" when everyone else fades out and the meetings are over.
Did they pay you to both program and lead the team? I realized that I didn't have any time left to program one week after I was given the lead of a small team. Meeting customers and the sales team to get requirements, design, explain to the team, check for progresses, etc. I could have been writing code at night but it was clear that my company didn't expect me or anybody else in my position to do that. I was writing code at night anyway, but on my own projects.
The company did have a "production bonus" if you worked a certain number of hours or more (couldn't call it overtime for legal reasons, as we were salaried).
A major reason for the number of hours worked is that it was a consultancy / agency type company. The types of contacts we worked varied, but we were building for clients. I couldn't bring myself to let our clients get sub-par work just because I didn't feel like taking the time to mentor juniors or rushed my own output.
I eventually left for a variety of reasons, only in part because we were paid below market, the company was terrified of raising rates, and struggled to be profitable. It is a shame, as the variety of work- everything from quick two month marketing sites to years long projects for three-letter government agencies- was fantastic, and there was no better place to get rapid exposure to many types of problems and solutions.
I still find myself working some evenings, but that's because I'm at a company with a small team that is fine with very flexible working hours. Being able to pop out to the store in the middle of the day or taking an extra long lunch without anyone caring is a perk I no longer want to do without.
A major reason for the number of hours worked is that it was a consultancy / agency type company. The types of contacts we worked varied, but we were building for clients. I couldn't bring myself to let our clients get sub-par work just because I didn't feel like taking the time to mentor juniors or rushed my own output.
I eventually left for a variety of reasons, only in part because we were paid below market, the company was terrified of raising rates, and struggled to be profitable. It is a shame, as the variety of work- everything from quick two month marketing sites to years long projects for three-letter government agencies- was fantastic, and there was no better place to get rapid exposure to many types of problems and solutions.
I still find myself working some evenings, but that's because I'm at a company with a small team that is fine with very flexible working hours. Being able to pop out to the store in the middle of the day or taking an extra long lunch without anyone caring is a perk I no longer want to do without.
I'm actually seriously worried my current role is going to end up like that. The annoying thing is that the meetings are actually quite important and useful too (undoubtedly some of them could be shorter). But I know it's not inevitable as I did manage to avoid it in previous roles as a principal engineer, just not sure how now!
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[1] https://en.wikipedia.org/wiki/Photolyase