/sci/ - Science & Math

The answer to this question is in optics and how different geometric shapes interact with light. I am too much of a brainlet to tell you the specifics.

>>9846107 everything would be too blurry. It's far more advantageous for a nomadic tribe to be able to scan it's surroundings more clearly. It's not like we slept all day after a big meal. We walked all day in hopes for one instead.

>>9846107
What is the evolutionary process by which the eye was developed from a microscopic point of view?

Vertical slits are good for stalking animals that rely on the first precise strike, while horizontal pupils prioritize field of view over anything. Round pupils are a compromise that aren't especially deficient anywhere.

>>9846128
Tell which berries/food are poisonous or not.

what the hell is the advantage of the W pupil

>>9846128
photo-sensitivity is a useful adaption, cellular clusters specializing in it are more efficient.

>>9846107
Vertical slit pupils can help an animal more easily judge distance, as well as allowing them to quickly adapt to different light levels in an instant.

Horizontal rectangle pupils are usually combined with eyes on the sides of the head instead of the front, allowing an extremely wide field of view. Additionally, it's parallel with the ground, preventing the sunlight above from blinding the animal. Some animals with horizontal pupils can have almost a 360 degree FOV.

The weird W shaped pupils are used to see both forwards and backwards simultaneously with two seperate images using only one organ.

← evolution of the eye
"In the Blink of an Eye", Andrew Parker

>>9846130
>>9846421
this

>>9846107
Molluscs see color by diffracting different colors of light like a prism across their retina, and then reconstructing the colored image in their more developed brains, rather than having different types of photoreceptors with specialized pigments for seeing different colors.

>all these garbage ass eyes
Best eyes incoming

>>9846130
but kitty's eyes get big before the pounce

what i want to know is what a cat sees when its eyes go from slits to circles in half a second

>>9846763
>what a cat sees when its eyes go from slits to circles in half a second
When their eyes slit up it makes their peripheral vision go fuzzy and they get a very shallow focus that heps them zone in on their prey.

>>9846387
Don't know -- but it looks like it might be good for a wide field of view (at least motion detection) n a situation where you might also be trying to cut out glare, particularly from above. Sort of like squinting without eyelids...

>>9846596
>event
Implying eyes didn't develop independently multiple times.

>>9846717
You got to see them in motion for the full effect.

>>9846662
Sauce, that's cool as shit.

from what i remember, horizontal slits are good at focusing landscape viewing, to check predators, that's why you find it on prey, and vertical is best to focus on escaping prey, since you follow them or something like that, so its for predators. Round is best for accuracy, to target points, like us with our hands.

>>9846828
Those aren't actually pupils though.

>>9846906
https://phys.org/news/2016-07-explanation-cephalopods-black-white-vision.html

>>9846940
they are technically pseudopupils. the shimp (and praying mantis as another example) have compound eyes that focus light onto light-sensitive patches akin similar to a retina. The optics of the eye allow you to see this patch from more angles than you would otherwise expect, and it seems to follow you around no matter how you look at it (however, that just means you're within the animal's field of view, not that the animal is tracking you).

>>9846971
Yeah I know that's why I said they weren't pupils.

Large hunters that chase prey seem to all have round pupils, as well as most birds who need to spot prey from a high altitude. I’m sure there’s some basis on how circular pupils confer more accuracy and detail to an animals vision, but I don’t know the science behind it.

>>9846391
And how do you develop a photo-sensitive spot from mutation or chance from the skin that would have been there before?

Life freaks me out

what the fuck is going on

>>9847158
Random mutation
Even having a small number of light sensitive cells puts them at a statistical advantage against those who don't, meaning as generations pass this advantage will become more pronounced and eventually take over completely

>>9847169
Yes, but my point or issue is in "randomly developing photosensitivity" by chance. What individual aspects are required for photosensitivity from a microscopic standpoint? It seems to me to have irreducible complexity.

>>9847180
>irreducible complexity
t. bible class

>>9847180
Mutations can be naturally random.

>>9847210
Yes, mutations are random. It just seems like you would require too large of a step to get photosensitivity and taking smaller steps wouldn't themselves be advantageous. If you had a single photosensitive cell that could replenish the compounds required, yes, I agree natural selection would spread that.

>>9847233

I don't think we can just intuitively rationalize evolution in our brains, it requires a crazy amount of time

there are lots of other species with much simpler eyes or photoreceptors that exist today that could give more insight, maybe the leap from photosensitive cell cluster to "eye" is extraordinary but after that it is an arms race for who sees the best

>>9847158
One spot just happens to be more receptive to the warmth. It tingles or some shit. Then it keeps going ...

>>9847243
Sure, but the way I see it, a photosensitive spot is a basic eye that cannot blink or focus, still incredibly useful. I just don't know well enough how to make a photosensitive spot, not knowing the chemistry myself. What would be the first step in going from a cluster of whatever non-photo-sensitive cells to photo-sensitive? If the answer is it just becomes photosensitive, then I doubt there is enough time in the universe to do that randomly through mutation, requiring multiple mutations to work together.

>>9847245
Is nobody here a chemist? Maybe I'll ask another night with a different group of people.

>>9847180
light-sensitive proteins can mutate into existence, they just need to be able to be excited by light which is pretty common for molecules
imagine if there's some ion channel that deals with sensation, then if that channel protein mutates to trigger on light you suddenly feel light as a sensation
I think it's actually the same mechanism in photosynthesis, except the energy is used for signaling instead of synthesis

>>9847149
Round pupils means you can focus all incoming light onto one nice neat resolved point. Think of a camera aperture and the reason it is roundish.
The verticle slit is a very useful adaptation for low light because it lets the pupil dilate to a larger opening, which collects more light. It has downsides, like bad peripheral focus, but you can still see better in a situation where other critters can't see at all.
Rectangular pupils like goats are found on herbivores who don't need to resolve fine detail so much as they just need to detect motion of predators first.

>>9847835
Is there a reason why slit pupils seem exclusive to only ambush hunters and small animals?

>>9846107
>evolutionary

please

>>9846107
Implying we aren't already born with slit eyes and we have them surgically removed because round pupils are incapable of seeing electromagnetic light

BOIIII, I AM WOKE

>>9846387
so all the bokeh looks like (＾ω＾)

>>9846421
>can have almost a 360 degree FOV.
Holy shit, you are right

>>9846130
So why not have a cross shaped pupil?

>>9847180
G-protein coupled receptors. Opsins, the proteins that are sensitive to light and cause intracellular reaction cascades that alter cellular behavior and gene expression, are derived from G-protein coupled receptors that sit in the membrane.

These proteins existed before they became sensitive to light, already having the function of being sensors of changes in the extracellular environment (related proteins are also involved in pain and the sense of touch). It was a rather trivial change that caused them to become sensitive to light.

http://genomewiki.ucsc.edu/index.php/Opsin_evolution:_orgins_of_opsins

>>9849403
Just speculation but many of those animals are nocturnal or crepuscular, which means they deal with more change in light levels as a matter of course.
A lot of times they're also pretty low to the ground, so maybe it's also the opposite of the horizontal pupils and gives them a more vertical fov (but I'm just making that up).
It's got to have a practical advantage because, for example, not all cats have vertical pupils, but there are canids that do.
Venemous snakes have vertical slits, but nonvenemous ones dont.

>>9847161
i feel the same way

normies are so calm. we jumped out of a plane without a parachute at birth and everyone thinks itll be ok when we land

>>9850304
>everyone thinks itll be ok when we land
The fuck else are you going to do about it? It's always been too late to save yourself.

>>9846824
>implying evolution is a finite process

So we can see everything through a fisheye lens and never see the earth is flat

>>9846387
Causes light to diffract differently into the eye, allowing the scuttlefish to see contrast better.

They're colourblind btw. Pretty silly for an animal that can change its colours. But that's nature for you.

>>9846763

>>9846111
That's not brainlet, that's just low WIS stat. Nice trips btw.

>>9846156
My God the IQ of this board is almost as bad as places like /v/

>>9846387
This I have no clue about and am curious as well. Although cephalopods are extremely visual creatures, so much so that they actually match not just the coloration and patterns but in many species also the very texture of their skin to the surrounding environment, so I am sure it has something to do with that. I would also surmise that it probably has something to do with the way light works under the waves of the ocean, but in truth I have no idea.

>>9846391
This is the correct answer

>>9847158
Time, mutation, and the impact of heat and light on cells. Plants for example don't have anything even resembling animal eyes and yet they "see" light in that they grow towards it. Not hard to imagine beings becoming increasingly sensitive to this form of energy.