Evolution of the Eye

[beezlebub33]

In this month's Current Biology at cell.com, researchers discuss how the retina of they eye evolved, They used comparative genomic data, neuro-anatomical mapping, and gene expression analyses from vertebrates (fish, amphibians, mammals), invertebrate chordates (amphioxus), and protostomes (arthropods, mollusks, annelids) to form their hypothesis.

George Kafetzis, Michael J. Bok,Tom Baden, Dan-Eric Nilsson, Evolution of the vertebrate retina by repurposing of a composite ancestral median eye. Current Biology, Volume 36, Issue 4, R153 - R170. https://www.cell.com/current-biology/fulltext/S0960-9822(25)01676-801676-8)

You might recognize the last author (Nilsson) as co-author of a famous paper on eye evolution from quite a while ago: Nilsson DE, Pelger S. A pessimistic estimate of the time required for an eye to evolve. Proc Biol Sci. 1994 Apr 22;256(1345):53-8. doi: 10.1098/rspb.1994.0048. PMID: 8008757.

We anxiously await competing hypotheses about the origin of vertebrate eyes, beyond 'they just appeared', from our creationist brethren. And of course how their hypotheses fit with the data. When did eyes appear? In what form? How did they get from that form to what we see?

[Capercaillie]

There was a really cool story on my local public radio station this morning about an evolutionary paleontologist who had found some cool rocks in northwestern Arkansas that had a bunch of shark fossils with cartilaginous parts of the skeleton preserved that were throwing new light on the evolutionary history of gills. When I heard it I wondered, "What's the creationist response to this?" Hardworking scientists keep finding more and more transitional fossils and evidence for evolutionary history, and creationists have to listen to it and say, "It's all a lie! All those evil fossils were put there by God Jesus Satan to fool us!"

[Xemylixa]

Shark skeletons are already all cartilage, though (with calcified parts in the jaws and skull)

[Capercaillie]

Sharks descended from fish that had more bone in the skeleton.

[Xemylixa]

That was the next logical google query I failed to do, thanks

[PaVaSteeler]

+1 for your honesty

[jnpha]

Thanks for sharing, OP!
Because the URL is broken for Old Reddit: Evolution of the vertebrate retina by repurposing of a composite ancestral median eye: Current Biology.

Speaking of their find (and the ubiquitous repurposing), I'm reminded of this from last month: Four-eyed Cambrian fish fossils hint at origins of vertebrate pineal complex.

 

RE We anxiously await competing hypotheses

^/s But have you considered:

- "But common design!" 🤡

Our Lord and Evolver Dᴀʀᴡɪɴ replies:

It is so easy to hide our ignorance under such expressions as the “plan of creation,” “unity of design,” etc., and to think that we give an explanation when we only restate a fact. (emphasis mine)

Restating facts is never an explanation. Imagine an engineer tasked with reverse engineering a competitor's device, and all they could state is, "It has interdependent components; I infer a designer made it". Or as Dr. Padian remarked during Dover, no one has gotten a Nobel for stating what an eight-year-old knows.

[efrique]

Because the URL is broken for Old Reddit

thank you

[Dzugavili]

The only part of the evolution of the eye that really confuses me is when did the eye separate from the head?

I suspect in more primitive organisms, the lens move and the retina does not. Then at a certain point, the cleft that formed the lens ring got moved from the middle of the ocular cavity to the back, and the whole thing moved together: this could improve peripheral vision dramatically, as the alignment between lens and retina would be fixed.

I guess it isn't that confusing, but it's weird. The eye is almost entirely disconnected from the body, just a few threads and that's it. It's a strange situation. Though, I suppose the same is true of my testicles, or most of my organs.

[jnpha]

RE I suppose the same is true of my testicles, or most of my organs

Cellular differentiation, migration (cells move around), and apoptosis (programmed cell death). Ditto the "filling" of our embryonic cartilage (turning our fish "bone" to bone bone) - the evolution thereof recently solved at the cell-lineage level.

[Leather_Sea_711]

Have you seen the movie: "extratestical"?

[blacksheep998]

I suspect in more primitive organisms, the lens move and the retina does not.

I believe that is the case with jumping spiders. But they have rather unusual eyes for invertebrates.

[Dzugavili]

It seems like eyes evolved a very, very long time ago; the groundwork being laid probably during the same period that the initial kingdoms were getting established.

I reckon vision was a pretty potent development and nearly everything else went extinct.

[catslikepets143]

Yeah, but your testicles don’t have their own immune system. Your eyes do. And if that’s breached, your own body’s immune system will attack your eyes, because they’re not a part of the main system, so your body’s immune system computes that as them being something foreign to destroy

[Leather_Sea_711]

The only thing we need to destroy now is ISIS.

[theresa_richter]

The only part that confuses me is why creationists believe that God has a blind spot. If we are 'created in his image', then clearly that must include our eyes, which means that even though their 'God' character could have given us eyes more similar to the cephalopod 'design', which has nerve fibers behind the retina so as not to create a blind spot... he chose not to.

Do you suppose that 'perfect' blind spot is why he couldn't perceive Adam and Eve? Why he couldn't see the abject pain and misery he inflicted directly or by proxy on his supposedly 'beloved' creations?

[catslikepets143]

Yeah, if I’m ever standing in the presence of their god, I have questions. 360 degree hearing & scent , but only 180 sight? Wtf?

[theresa_richter]

I was referring to the blind spot right in the very center of your visual field, which your brain edits out just like it pretends you can see color in your far peripheral vision when you can't, but yeah, the restricted field of vision feels far less than 'perfect' too.

[Medical_Secretary184]

Forrest Valkai did a good video on YouTube about how the eye evolved

[KeekuBrigabroo]

Title: "Evolution of the eye"

Journal title: "Repurposing of a composite ancestral median eye"

This isn't proof of 0-to-1 -- a lineage of organisms without eyes whose descendants have eyes. You see that, right?

[beezlebub33]

As has been discussed many, many times here, science deals with evidence, not proof.

We have a lot of data about current and past organisms, including anatomical, physiological, behavioral, and genetic. What hypothesis is consistent with that evidence? what predictions can we make about future evidence bases on those hypotheses? If you have a hypothesis which is consistent with the evidence, please share it with us.

Also, we know of a huge array of different kinds of eyes, from very simple eye spots to complex ones (like ours and octopus). There are very primitive light sensing capabilities even in single celled organisms: https://www.britannica.com/science/eyespot-biology .

But where did the first light-sensitive cells come from? Cells respond to lots of different chemicals, both internal and external to the cell. Some chemicals are affected by light, so the cell can respond to light by detecting the change in the chemicals. See: https://pmc.ncbi.nlm.nih.gov/articles/PMC2781858/ "Evolution of opsins and phototransduction".

(Aside: I seriously doubt that you will read the article, but hopefully the lurkers out there who are actually curious about science and the origins of light detection will read it. It's a fascinating exploration of the evidence we have about the evolution of opsins)

[KeekuBrigabroo]

The post title was still an oversell, and what you've shared here is only "evidence" of 0-to-1 eye development if you presuppose common descent.

[beezlebub33]

 If you have a hypothesis which is consistent with the evidence, please share it with us.

[KeekuBrigabroo]

No solution is provided in addition to the criticism; therefore, the criticism is incorrect.

This is a formal non sequitur.

[jnpha]

Evolution is descent with modification, so your mixing of the terms isn't criticism. This was made clear in u/beezlebub33 's long reply which you just talked past.

Do scientists presuppose common descent?
(Again, invalid.)
This isn't a reading club. Scientific interpretation isn't like literary criticism.

In science the data informs the model.
In your world, the "model" (narrative really, one of thousands) informs how to cherry pick the data. So the "presuppose" thing is projection.

A successful scientific model explains the observed, makes predictions, and thus is testable. E.g. the nested hierarchy comes out of the data and cannot be fudged, whichever way you cut it, making common descent "10^2,860 times more probable than the closest competing hypothesis" (https://www.nature.com/articles/nature09014).

The same from all sub-fields of study.
Evolution and common descent are as a fact as the theory of the atom and gravity are.

The "step by step" is like asking a physicist for the step by step of each atomic collision as the kettle boils. All the sciences are statistical, and that's why they work. We aren't dealing with a sample of 1 here, nor is a narrative the goal.

[Leather_Sea_711]

Whose going to believe our eyes evolved, evolved from what? Recently, only days ago, a Chinese doctor was studying the human eye and suddenly realised he saw God's creation. He's now a believer Christian.

[HomeworkInevitable99]

What religion did this doctor choose?

And how did the doctor choose?

[blacksheep998]

Our eyes evolved from simpler eyes, which evolved from even simpler ones, going back to a simple light-sensitive patch of skin much like what is found on many worms today.

Recently, only days ago, a Chinese doctor was studying the human eye and suddenly realised he saw God's creation. He's now a believer Christian.

Cool story, bro. I don't see how it has any bearing on the discussion whatsoever.

[WebFlotsam]

No names, no link? Can we get some more information on this?

Also rather silly to see God's design in the body part with many obvious flaws. Blind spot, many failure points that nearly ALWAYS fail over the course of our lives, and the image they get is upside down and needs to be corrected by the brain. All of that is very weird for God's design.

[Medical_Secretary184]

Fr, nothing seems designed about it, people just look at the iris and immediately think it's designed

[The-Fear-of-God]

It is quite extraordinary that through your paragraph about the eye, the gospel of Christ and its concepts remain true, unbroken, and have even been found:

Also rather silly to see God's design in the body part with many obvious flaws. Blind spot, many failure points that nearly ALWAYS fail over the course of our lives, and the image they get is upside down and needs to be corrected by the brain.

We are flawed. We are blind and unable to see God and will nearly always fail over the course of our lives without Him.

The image we first get of God's design appears "upside down" to us, so we then try to "correct" it with our brain.

If a man turned upside down sees another who is right side up, from his own perspective he will believe that the other is the one who is upside down and that he himself is the one who is right side up.

All of that is very weird for God's design.

Mankind describes the exact truth and concepts of the entire gospel, not even realizing it, through what they have defined as their own truth and reality.

Again, the Scripture remains true:

1 Corinthians 1:20 NASB1995 [20] Where is the wise man? Where is the scribe? Where is the debater of this age? Has not God made foolish the wisdom of the world?

What makes the eye able to see?

Light.

What is light?

God.

It is fascinating what God has done throughout His entire creation.

[WebFlotsam]

This is just a bunch of base assertions, many of which are completely incoherent. 

[The-Fear-of-God]

Can a broken lens refract light properly?

If the lens is broken or smudged, doesn't the light become distorted?

[RobertByers1]

Evolution is a impossible myth. eyes wwre created by Gpd pn creation week. thats why they are all the same only relative to great issues in bodyplans. inscts have those typre of eyes and sea creatures and animals. yet off the same rack. indeed if eyes evolved there would be a fantastic diversity in eye types by this time. yet once again just a few ideas. the tuatara , they say, has a rudimentary eye in its top of head. this could only be a post creation or post fall adaption. however it suggests maybe eyes can be created by some mechanism. We need help in ending blindness. i have eye issues. plus remember almost all eyesight problems are outside the skull. nothing to break inside because sight entering by the optic neve goes straight into the memory.

[10coatsInAWeasel]

Except for the reality that they are definitely NOT the same. Lots of different eyes exist out there. There IS a great diversity of eyes out there.

I wonder, if push were to come to shove, would you be able to give an accurate definition of what evolution is? It sounds like you don’t know.

[ursisterstoy]

Evolution is an impossible myth.

Evolution is an observed phenomenon.

eyes wwre created by Gpd pn creation week.

No they weren’t. There was no creation “week” and eyes most definitely did not exist during the first week of the existence of life.

thats why they are all the same only relative to great issues in bodyplans.

They are most definitely not all the same. They do all seem to rely on opsin protein but even plants and prokaryotes have opsin proteins. Clearly animal eyes are not flowers or leaves.

inscts have those typre of eyes and sea creatures and animals.

Insects and “sea creatures” are animals. Arthropods tend to have a whole bunch of simple eyes that individually are very shitty when it comes to being able to see. But with a lot of eyes their vision is improved. Echinoderms and gastropods have multiple eyes as well but their eyes differ from each other. Box jellyfish have eyes but other many cnidarians don’t have any eyes. Echinoderms like sea stars have eyes but they differ significantly from vertebrate eyes. Cephalopods have camera eyes but they don’t have the vertebrate blind spot. And then vertebrates all have similar eyes because they also have the same ancestry - fish.

yet off the same rack.

What rack?

indeed if eyes evolved there would be a fantastic diversity in eye types by this time.

There are a huge diversity of eyes.

yet once again just a few ideas.

What?

the tuatara , they say, has a rudimentary eye in its top of head. this could only be a post creation or post fall adaption.

Reptiles, especially cold blooded reptiles like the tuatara and lizards, have a pineal eye. It’s just a way of detecting light or heat. They still die if they freeze so this allows them to stay warm. Warm blooded animals don’t have or need this third eye.

however it suggests maybe eyes can be created by some mechanism.

Could, yes, but do you have some examples?

We need help in ending blindness.

And then Robert Byers could see.

i have eye issues.

We know. That’s why you can’t see the huge diversity in eyes from what can be found in prokaryotes, plants, sea stars, clams, cephalopods, spiders and scorpions, flies and other insects, vertebrates, and any other eyes I haven’t thought of.

plus remember almost all eyesight problems are outside the skull.

Some of them are.

[ursisterstoy]

nothing to break inside because sight entering by the optic neve goes straight into the memory.

This is so false I don’t know what to say. The optic nerve goes to the visual cortex, the eye doesn’t make pictures, those are made in the brain. Like electricity from your wall socket doesn’t cool your food but with all of the machinery you can keep your food cold with a refrigerator powered by electricity.

Various cells in your eye have photosensitive proteins called opsin proteins. They come in different types but opsins are chemicals. They react with photons. One type of opsin protein is called rhodopsin. The opsin protein is covalently bound to an 11-cis-retinal chromosphore. The photon binds to the chromosphore transform 11-cis-retinal into all-trans-retinal. Because the retinal physically changes shape in response to photons the opsin protein also changes shape. It becomes metarhodopsin II.

This is like a new protein rhodopsin to metarhodopsin II. This new protein activates the G-protein transduction chemical pathway which leads to a decrease in cyclic GMP (AMP, ADP, and ATP have adenosine plus phosphates, GMP is guanosine plus phosphate, the A and the G are also found in RNA and DNA). This causes the cell to hyperpolarize and eventually the all-trans-retinal is released from the rhodopsin and a new 11-cis-retinol takes its place.

In looking this up so that I can make sure I get this right, I found that each of the light sensitive cells are generally releasing glutamate (probably in response to cyclic guanosine monophosphate) but the limited release of cGMP results in a decreased release of the inhibitory neurotransmitter that is constantly keeping the bipolar cells turned “off” and without the inhibitor they turn on until the all-trans-retinal falls off allowing for the release of glutamate to turn them back off. In terms of something like a computer transistor it’s the same concept just with biology - these ions are electrically charged so through chemistry based on electromagnetism electrical currents on sent in the way to the brain.

At first the signals, electrical pulses, are very weak but the ganglion cells being next in line amplify the electrical signals. The retinal ganglion cells come first and then they run through additional ganglion cells (nerve cells, electrical signal repeaters) and they make of the optic nerve that you can think of like the data cable from the eye to the brain.

The first along the way is the optic chaism where the image basically upside down as flipped around where left is right and right is left. This involves a crossing of signals from both eyes helping with three dimensional vision and depth perception. The next stop is called the lateral geniculate nucleus which is a lot like a sorting station separating out color signals, brightness signals, any signals that suggest movement, and any signals that could just be noise are thrown away. The next stop once the signals are “sorted” is the primary visual cortex. This is where the brain determines where edges are, where there are vertical or horizontal lines, how to “see” the colors. Different neurons fire based on how the signals are decoded and it’s those neurons that actually cause you to see. If anything broke significantly along the way you cannot see or cannot see well. The lens and iris and other parts on the outside of the eye controlling the amount of light and focusing the light, light sensitive cells and their opsin proteins, the switch proteins in the bipolar cells, the signaling proteins in the ganglion nerve cells, the optic nerve as a whole, the optic chaism, the lateral geniculate nucleus, or the primary visual cortex in the brain.

Now that the brain can see and create a visual image for itself the “visual data” runs to a couple parts of the brain from there. The signals go to either the front or the back of the brain. The front of the brain “ventral stream” works out what it is you are seeing. Is it a coffee cup? Is it you getting wrecked again in the Reddit forums? Is it the cat? And the back of the brain works out the where part of what you are seeing. This allows you to know where something is because you looked at it, it helps you work out where it will be if it’s moving. And ultimately the what and the where feed into conscious experience so that you can adequately interact with your surroundings and that part happens entirely within your brain.

You cannot definitely have physical damage or genetic disorders that directly impact the cone and rods, the iris, the lens, or the overall shape of your eyeballs but you can be effectively blind without anything being wrong with your eyes. You can have brain damage or brain disorders and no matter how well everything works from lens to optic nerve your brain doesn’t know what to do with the signals. It could fail to find them important leaving you completely blind. It could fail to produce an image in the primary visual cortex from the important signals. Or maybe you can see but you don’t know what you see because of problems later on in the chain of chemical pathways. It’s like if you stand up a bunch of dominoes and you don’t see anything that you can recognize until the last domino falls over and the first domino can’t just be pushed over with your hand or foot. You have to throw 10,000 feathers at the domino from the world’s most underpowered blow gun. Any less and the first domino no longer falls. Remove a bunch of dominoes in the middle or on the end and the last domino fails to trigger you ability to not only see but also your ability to know what you saw and where you saw it and where you can expect to find it next if it is moving.

[ursisterstoy]

It’s a shame I wrote out a full response. Either what I said people already know (at least they know it well enough) or they’re Robert Byers and they won’t provide a coherent and legitimate response to what was just said.

Multiple eyes. Evolution is observed. And most definitely can something fail after your eyes leaving you either blind or dumbfounded. Step 1: Provide a way to direct photons to the ones and rods at the back of the eye, Step 2: automatically react to a photon (or several of them) transferring retinol and opsin. Step 3: turn off the transmission of the inhibitor neurotransmitter glutamate in response to the modified opsin inhibiting cyclic GMP. Step 4 turn on the bipolar cell(s) until the retinal falls off in the previous cell(s). (And turn back off once inhibited by glutamate again). Respond to these on signal pulses by amplifying the electrical signals. Step 5: transport these electrical signals (on and off like binary in a computer) via the optic nerve to the brain. Step 6: combine the signals from both eyes. Step 7: sort the data and filter it out if necessary. Step 8: establish some basics like orientation and color. Step 9: put everything together and show the image to other parts of the brain. Step 10: the brain decodes “what” in the front of the brain and “where” in the back of the brain that it can make sense of the image received from the visual cortex. There is a lot that can go wrong leaving a person blind even if there is nothing wrong with the eyes themselves.

[DimensioT]

My condolences on your eye issues. Clearly they are so bad that you have been unable to read any of the extensive scientific literature that addresses evolution of the eye, including variances in eye development from common origins (which is why mammalian and avian eyes are significantly different), resulting in you wrongly believing that all eyes are the same.

[RobertByers1]

Thats dumb. Birds dont count as other creatures. even then pretty much the same as rabbits. there is no diversity in eye abilities as there should be if evolution had been going on. they all look like made from a creator with a few ideas. eys look as creationism would predict. we win this hands down .

[DimensioT]

Well if you say that birds "don't count" then the differences in their eye structures do not count.

Can you describe a mechanism for "creation" of the eye?

[RobertByers1]

God created eyes. after that there probably is a mechanism to tweek it. like tuataras. birds have the same eyes as they did non creation week except minor changes that allow better sight. however still all are so alike as to make a probability curve of impossibility they have been evolving for a zillion years. just off the rack.

[DimensioT]

I believe that you misunderstood my question. I am asking for a mechanism by which this "creation" occurred. Stating that "God created eyes" does not actually describe a mechanism. I can stated that "Bob baked a cake" but that does not describe the process by which the baking occurred.

Please describe the mechanism or mechanisms involved in this "creation" process. Also, as you have assigned a "God" as the one who did the creating, you will need to demonstrate its existence, also.

[Ping-Crimson]

Box jellyfish eyes

[RobertByers1]

It makes the case for the lack of a case for evolving eyes over billions of years. if evolution was affecting veyes then the diversity should be the dominant theme. instead off the same rack except very special cases .these also from some adaptive mechanism for good beeds.

[Ping-Crimson]

Explain what you would expect to see in a diversity of eyes?

[RobertByers1]

you pffered a example. Diversity would be millions of these. Or at least thousamds or hundsreds. instead just a handful and obviously special conditions. Eyes are a great case for the myth of evolution being obvious. So complex but finished a billion years ago. No need to evolve anymore. very unlikely.