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ainch 13 minutes ago [-]
I've only discovered Quanta this year but it's quickly become my favourite publication. The focus on quality articles across science, and especially pure maths, feels very unique. I don't know whether it's profitable or reliant on the Simons Foundation funding - but hopefully it's a sustainable business model that will stick around.
Terr_ 1 hours ago [-]
> (tumor cells often use anaerobic glycolysis to make energy)
More generally, human cancers cells often seem like they've rolled-back to an earlier, atavistic set of behaviors.
I wonder if that's a "direction" of random mutations which is less-likely to be attacked by the immune system, because it leads to things that are less-alien because they were normal at one point. (Or may still be normal in limited contexts.)
Ex:
> The hallmarks of cancer are not the acquisition of novel behaviors due to genomic mutation but rather the re-deployment of ancient, unicellular programs that support survival of the cell at the expense of the host and break the contract of cooperation required for multicellular life.
Soo evolution doesn't always optimize for biochemical efficiency in isolation. Sometimes it optimizes the whole system, and "wasteful" metabolism can be the right answer if it removes a bigger constraint.
VeninVidiaVicii 3 hours ago [-]
> Could this be an adaptation, or is it a coincidence of evolutionary history?
Ha! It’s the same thing.
HexPhantom 13 minutes ago [-]
Either way, the bird ends up with the same strange bargain: unobstructed vision paid for by an inefficient metabolic workaround
julienchastang 5 hours ago [-]
The photography of the bird eyes in the article is stunning especially the 3x3 grid.
HexPhantom 23 minutes ago [-]
And the photography almost steals the show
hombre_fatal 5 hours ago [-]
Yeah, they help remind me that eyes are strange biological sensors rather than the cartoonish familiar things I see daily.
Kind of like when you take acid and realize how weird you look. Or your cat’s basically a mouth with legs.
HexPhantom 18 minutes ago [-]
Once you look closely, theiliar animal face kind of disappears and you're just staring at alien biological hardware
Razengan 3 hours ago [-]
Wait till you see cephalopod eyes!
dhosek 3 hours ago [-]
Those bottom-row pictures were kind of freaky.
hanwenn 2 hours ago [-]
interesting article, but now I'm left wondering how the glucose gets to the retina. Why is this easier than supplying oxygen?
Aerroon 54 minutes ago [-]
My understanding is that glucose diffuses from the pecten oculi into the vitreous humor (it's the jelly-like thing that makes up most of the eyeball) and from there glucose diffuses into the inner retina.
I'm not sure why this is easier, but I'm guessing it has to do with how much oxygen you need for aerobic glycolysis. In blood, glucose just exists in the plasma by itself, oxygen has to be carried by red blood cells. Without blood vessels it's probably difficult to get enough oxygen through diffusion into the inner retina.
Fun fact: the human cornea also doesn't have blood vessels. Instead oxygen diffuses from the atmosphere into it and from the aqueous humor - a fluid? behind the cornea. The aqueous humor is also where the cornea (and the lens) get nutrients from.
Yep, your cornea basically breathes!
zapkyeskrill 1 hours ago [-]
Guess they don't need to wear baseball caps or sunglasses when flying looking directly at the sun
HexPhantom 30 minutes ago [-]
Apparently they skipped sunglasses and evolved a glucose-hungry retina instead. Seems like an expensive solution, but hard to argue with the results
jdthedisciple 2 hours ago [-]
Great article but I don't get their insistent on "inefficiency":
They start out saying oxygen vessels partially and subtly occludes vision.
So the bird's eye doesn't suffer from this disadvantage.
In other words: It uses 15x more energy but presumably also sees 15x sharper and more into the distance than our human eye.
Sounds proportional at most, but certainly not inefficient for the bird's purposes?
jibal 48 minutes ago [-]
Every mention of efficiency is about the chemical process, not about vision as such.
> anaerobic glycolysis that is significantly less efficient than oxygen-powered metabolism
> Oxygen molecules make energy production in cells extremely efficient.
> the presence of oxygen makes energy extraction from a single glucose molecule 15 times as efficient, and sometimes more.
> This energetic ability is powered by an inefficient metabolism.
> This suggested that the strange structure wasn’t bringing oxygen into the bird’s retina; rather, it was helping to pump glucose in, thereby enabling the less efficient anaerobic process.
sorokod 2 hours ago [-]
>the avian lineage had split from crocodiles
Aren't crocodiles and dinosaurs seperarte branches ?
Aerolfos 1 hours ago [-]
They have common ancestors, but it really should be "the crocodiles had split from the avian lineage", with avians including dinosaurs at that moment in time
jibal 32 minutes ago [-]
A split is a split. Archosaurs split into a crocodile line and a dinosaur/bird line--"the avian lineage" (birds being a kind of dinosaur, and the only ones still living) ... that's what "the avian lineage had split from crocodiles" means -- it is not saying that birds are an offshoot from crocodiles, it's saying that the two lines (both kinds of archosaur) split from each other. Likewise, crocodiles are not an offshoot of dinosaurs.
jibal 40 minutes ago [-]
Note the word "lineage". That would include the dinosaurs that were ancestors of birds. Birds are dinosaurs, so reword the statement as
> the dinosaurs had split from crocodiles
Birds and crocodiles are both archosaurs (which includes all dinosaurs as well as crocodiles) and are each others' closest living relatives.
dnnddidiej 2 hours ago [-]
Would be great for modern humans as plenty of calories available for an inefficient but better vision eye.
ordu 7 hours ago [-]
> The retina is one of the body’s most energetically expensive tissues.
I never knew, but it explains why when you close to fainting you lose your vision. Or when you are working at high heart rate close to your maximum. It works as a kind of a warning sign, than you are probably shouldn't try it that hard.
> The lack of blood vessels could also offer birds the advantage of better vision.
Now they are ready to reintroduce blood vessels back, but this time behind the retina.
yieldcrv 5 hours ago [-]
How does it explain either of those things?
ordu 4 hours ago [-]
When you have not enough oxygen it breaks. And parts using a lot of it fail first. Vision fails first, not memory, or thinking. Thinking is impaired but still works.
I'm not sure how fainting works, but fainting looks to me like an energy crisis, so kinda not surprising the results are the same.
kreelman 6 hours ago [-]
Interesting title. These thoughts are before reading the article, use grains of salt as required.
I believe that birds brains are kind of uniquely advanced too. Lightweight (in terms of mass) structured differently to mammalian brains... I've heard a definition of sight as "a bit of the brain popping out for a look". I wonder if the same brain density tricks bird brains use are used in some parts of their vision system. This is all as my memory serves. Feel free to correct any mistakes in my understanding.
There's some very interesting work happening to understand their calls too. If (my) memory serves, there able to identify particular call types quite well now.
If someone calls you a "bird brain", perhaps that could be taken as a complement! Trying to do more with less!
Fascinating to also think that birds are of course evolved dinosaurs. Raptors of the sky. It would be fascinating to link whats being looked at here with any kind of data that can be pulled from fossil evidence (though there might not be much...). I wonder which unique bird genetic traits were useful or super enhanced dinosaur traits.
...I think the strong but light bone structure was something inherited from the dinosaurs too? Fascinating creatures.
On the face of it, seems sensible that avian evolution has spent many genetic GPU cycles to generate advanced vision needed to fly and hunt from the air.... One wonders which "subroutines" have been reused from dino-days, as mentioned.
nkoren 5 hours ago [-]
I had an an interesting experience with a bird brain today.
There's a robin who often sits in the fig tree in my back yard, giving friendly little chirps whenever I'm near. (I have no way of knowing whether it's the same robin from day to day, but if it's different robins then they all seem to be on the same wavelength.)
Anyhow, today a neighborhood cat came to the back door, and was aggressively friendly when I opened it. Clearly offering affection in exchange for... what? I've never given this cat anything before, apart from a friendly pat. Meanwhile the robin was overhead in the fig tree, giving totally different chirps than I'm used to. Clearly "warning!" "danger!" chirps. It was amazing how unambiguous they were.
I was puzzled who the robin's audience for this was, however. I'd never noticed it freaking out about cats before. Was it trying to warn me for some reason? Trying to warn other nearby birds? I couldn't see any. I thought that maybe it was just shouting at the cat out of general pique.
Then the cat led me to the answer. Turns out it had trapped an (uninjured) baby squirrel behind a planter box near my door. It couldn't reach the squirrel, and the squirrel couldn't escape. The cat seemed to be under the impression that since we were now friends, I could move the planter box and help it to get the baby squirrel. Sadly I had to disappoint it, and after unexpectedly acrobatic shenanigans, I facilitated the squirrel's escape instead.
The robin, meanwhile, ceased its warning chirps the moment it saw that I was aware of the baby squirrel. Then it watched the ensuing affair unfold, from the safety of the fig tree. Once the squirrel was safe and the cat had left disappointed, the robin looked at me, gave a few of its usual happy chirps, and flew away.
m463 4 hours ago [-]
crows warn about stuff.
If I go outside and the crows are going crazy, something interesting is happening.
Mostly it is hawks, and the crows will chase and dive bomb them.
Once I came outside and the crows were going nuts, but not flying. And right in the middle of the driveway was a bobcat. no wonder.
retrac 5 hours ago [-]
when pigeons are navigating their brainwaves oscillate around 150 - 200 Hz
a 60 fps computer display for pigeon vision is like a sequential slideshow it's much too slow to blur into what they would perceive as motion
many species of birds when they switch posture the motion is so fast it is imperceptible to the human eye it's like switching from one still frame to another
humans have perhaps 1/10th the temporal granularity that pigeons have
this leads me to the conclusion that if birds have a subjective experience it has a very different tempo than for humans or indeed most mammals
soupspaces 5 hours ago [-]
> different tempo
Cats also seem to have faster reactions that might be overlooked by our perceptive frame rate (imo, tested after recording interactions and reinterpreting them). Beyond eyesight, I suspect human breathing can be too noisy for their ears (consistent hissing).
dhosek 3 hours ago [-]
The thing I find fascinating about birds is that they’ve independently evolved warm-bloodedness in a completely different lineage from mammalian warm-bloodedness.
vkou 3 hours ago [-]
There are a lot of metabolic advantages to warmbloodedness, it makes some sense that it could evolve independently multiple times.
ETH_start 6 hours ago [-]
It is plausible that the original non-avian theropod dinosaurs which gave rise to avian theropod dinosaurs like modern birds were more vision-oriented predators than mammalian predators.
That would have favored eyes built for sharper vision at the expense of higher metabolic demands.
The different evolutionary track may come from the fact that theropods stood upright on two legs, so they could scan farther across the landscape. Also, they were active during the day. Early mammals, by contrast, were mostly nocturnal, so hearing and smell mattered more than sharp vision.
Interestingly, humans have some of the best vision in the animal kingdom and humans are both upright standing and diurnal, i.e. active in the daytime.
dhosek 3 hours ago [-]
Which means the Jurassic Park tyrannosaur that could only see things that moved was probably seriously inaccurate (also in reality it probably had feathers).¹
⸻
1. While checking Wikipedia to confirm my belief about feathers, I found that the consensus among paleontologists was that tyrannosaurs had superb vision, better than humans, in fact.
deafpolygon 2 hours ago [-]
It is theorized that they had vision like eagles or possibly exceeded that of eagles that enabled them to see prey at great distances. Then using their legs optimized for locomotion, they would chase them down.
It feels like most people mix the two things up: excellent vision and predatory response. An eagle can absolutely see a mouse hiding in the bushes, not moving. But a moving prey is what triggers their predatory response. Plausibly… they probably don’t attack a non-moving mouse because it could be a dead mouse.
Human vision evolved for different things. Our ancestors were tree-dwelling and optimized for depth perception, social cues and color acuity. So it’s just a different strategy.
awesome_dude 3 hours ago [-]
It really hit me moving to Australia, most of the mammals are nocturnal (Kangaroos were the ones that caught me most by surprise) - most (if not all) of the reptiles are diurnal - got to have that sweet sweet sun to warm the blood.
More generally, human cancers cells often seem like they've rolled-back to an earlier, atavistic set of behaviors.
I wonder if that's a "direction" of random mutations which is less-likely to be attacked by the immune system, because it leads to things that are less-alien because they were normal at one point. (Or may still be normal in limited contexts.)
Ex:
> The hallmarks of cancer are not the acquisition of novel behaviors due to genomic mutation but rather the re-deployment of ancient, unicellular programs that support survival of the cell at the expense of the host and break the contract of cooperation required for multicellular life.
https://www.sciencedirect.com/science/article/abs/pii/S00796...
Ha! It’s the same thing.
I'm not sure why this is easier, but I'm guessing it has to do with how much oxygen you need for aerobic glycolysis. In blood, glucose just exists in the plasma by itself, oxygen has to be carried by red blood cells. Without blood vessels it's probably difficult to get enough oxygen through diffusion into the inner retina.
Fun fact: the human cornea also doesn't have blood vessels. Instead oxygen diffuses from the atmosphere into it and from the aqueous humor - a fluid? behind the cornea. The aqueous humor is also where the cornea (and the lens) get nutrients from.
Yep, your cornea basically breathes!
They start out saying oxygen vessels partially and subtly occludes vision.
So the bird's eye doesn't suffer from this disadvantage.
In other words: It uses 15x more energy but presumably also sees 15x sharper and more into the distance than our human eye.
Sounds proportional at most, but certainly not inefficient for the bird's purposes?
> anaerobic glycolysis that is significantly less efficient than oxygen-powered metabolism
> Oxygen molecules make energy production in cells extremely efficient.
> the presence of oxygen makes energy extraction from a single glucose molecule 15 times as efficient, and sometimes more.
> This energetic ability is powered by an inefficient metabolism.
> This suggested that the strange structure wasn’t bringing oxygen into the bird’s retina; rather, it was helping to pump glucose in, thereby enabling the less efficient anaerobic process.
Aren't crocodiles and dinosaurs seperarte branches ?
> the dinosaurs had split from crocodiles
Birds and crocodiles are both archosaurs (which includes all dinosaurs as well as crocodiles) and are each others' closest living relatives.
I never knew, but it explains why when you close to fainting you lose your vision. Or when you are working at high heart rate close to your maximum. It works as a kind of a warning sign, than you are probably shouldn't try it that hard.
> The lack of blood vessels could also offer birds the advantage of better vision.
Now they are ready to reintroduce blood vessels back, but this time behind the retina.
I'm not sure how fainting works, but fainting looks to me like an energy crisis, so kinda not surprising the results are the same.
I believe that birds brains are kind of uniquely advanced too. Lightweight (in terms of mass) structured differently to mammalian brains... I've heard a definition of sight as "a bit of the brain popping out for a look". I wonder if the same brain density tricks bird brains use are used in some parts of their vision system. This is all as my memory serves. Feel free to correct any mistakes in my understanding.
There's some very interesting work happening to understand their calls too. If (my) memory serves, there able to identify particular call types quite well now.
If someone calls you a "bird brain", perhaps that could be taken as a complement! Trying to do more with less!
Fascinating to also think that birds are of course evolved dinosaurs. Raptors of the sky. It would be fascinating to link whats being looked at here with any kind of data that can be pulled from fossil evidence (though there might not be much...). I wonder which unique bird genetic traits were useful or super enhanced dinosaur traits.
...I think the strong but light bone structure was something inherited from the dinosaurs too? Fascinating creatures.
On the face of it, seems sensible that avian evolution has spent many genetic GPU cycles to generate advanced vision needed to fly and hunt from the air.... One wonders which "subroutines" have been reused from dino-days, as mentioned.
There's a robin who often sits in the fig tree in my back yard, giving friendly little chirps whenever I'm near. (I have no way of knowing whether it's the same robin from day to day, but if it's different robins then they all seem to be on the same wavelength.)
Anyhow, today a neighborhood cat came to the back door, and was aggressively friendly when I opened it. Clearly offering affection in exchange for... what? I've never given this cat anything before, apart from a friendly pat. Meanwhile the robin was overhead in the fig tree, giving totally different chirps than I'm used to. Clearly "warning!" "danger!" chirps. It was amazing how unambiguous they were.
I was puzzled who the robin's audience for this was, however. I'd never noticed it freaking out about cats before. Was it trying to warn me for some reason? Trying to warn other nearby birds? I couldn't see any. I thought that maybe it was just shouting at the cat out of general pique.
Then the cat led me to the answer. Turns out it had trapped an (uninjured) baby squirrel behind a planter box near my door. It couldn't reach the squirrel, and the squirrel couldn't escape. The cat seemed to be under the impression that since we were now friends, I could move the planter box and help it to get the baby squirrel. Sadly I had to disappoint it, and after unexpectedly acrobatic shenanigans, I facilitated the squirrel's escape instead.
The robin, meanwhile, ceased its warning chirps the moment it saw that I was aware of the baby squirrel. Then it watched the ensuing affair unfold, from the safety of the fig tree. Once the squirrel was safe and the cat had left disappointed, the robin looked at me, gave a few of its usual happy chirps, and flew away.
If I go outside and the crows are going crazy, something interesting is happening.
Mostly it is hawks, and the crows will chase and dive bomb them.
Once I came outside and the crows were going nuts, but not flying. And right in the middle of the driveway was a bobcat. no wonder.
a 60 fps computer display for pigeon vision is like a sequential slideshow it's much too slow to blur into what they would perceive as motion
many species of birds when they switch posture the motion is so fast it is imperceptible to the human eye it's like switching from one still frame to another
humans have perhaps 1/10th the temporal granularity that pigeons have
this leads me to the conclusion that if birds have a subjective experience it has a very different tempo than for humans or indeed most mammals
Cats also seem to have faster reactions that might be overlooked by our perceptive frame rate (imo, tested after recording interactions and reinterpreting them). Beyond eyesight, I suspect human breathing can be too noisy for their ears (consistent hissing).
That would have favored eyes built for sharper vision at the expense of higher metabolic demands.
The different evolutionary track may come from the fact that theropods stood upright on two legs, so they could scan farther across the landscape. Also, they were active during the day. Early mammals, by contrast, were mostly nocturnal, so hearing and smell mattered more than sharp vision.
Interestingly, humans have some of the best vision in the animal kingdom and humans are both upright standing and diurnal, i.e. active in the daytime.
⸻
1. While checking Wikipedia to confirm my belief about feathers, I found that the consensus among paleontologists was that tyrannosaurs had superb vision, better than humans, in fact.
It feels like most people mix the two things up: excellent vision and predatory response. An eagle can absolutely see a mouse hiding in the bushes, not moving. But a moving prey is what triggers their predatory response. Plausibly… they probably don’t attack a non-moving mouse because it could be a dead mouse.
Human vision evolved for different things. Our ancestors were tree-dwelling and optimized for depth perception, social cues and color acuity. So it’s just a different strategy.