How do many-eyed animals see the world? With Dr Lauren Sumner-Rooney

and here we go the slides are up lauren take it away thank you very much and thank you very much to uh everybody joining me this evening uh to come take a look at some of these weird and wonderful creatures that i've spent the last few years looking at so what i wanted to do first of all was talk a little bit about about light and how animals sense light in general so light is one of the the most important and most ubiquitous uh cues in in the world for all kind of biological systems there are very few organisms on earth that can't sense light in in some way and it can provide cues for all sorts of really important behaviors and ecological aspects of an animal's life so we really need to kind of get to grips with a lot of these senses if we're going to understand how animals experience their world and what kind of guides them through it so light can provide information regarding all sorts of different aspects of their lives so it could be you know keeping their daily rhythms in check navigating finding a mate or finding a tasty snack all of these things are really important to their ecology their behavior and ultimately their evolution so really by kind of understanding how they experience their world we can then learn a lot more about all of these different aspects of their biology as well i wanted to start off by just talking about some of the properties of light so if we imagine um you know light is a simple wave there's three kind of major aspects that animals could pick up on that kind of bits of information embedded in that these things are wavelength polarization and intensity so if we think about wavelength to begin with we we interpret visible wavelengths as color so in this diagram you can see that a slightly longer wavelength so these more stretched out curves uh towards the kind of red end of the spectrum and ultimately into the infrared and eventually radio as things get shorter we get into greens blues ultraviolet and eventually x-rays intensity is really just about you know the the number of photons available so in a particularly bright system would be a large number of photons and a dim system will be relatively fewer polarizations may be a little bit less familiar so if you imagine we're looking at our wave uh kind of slightly um you know off angle you can see that it's oscillating along a particular plane so in most light and unpolarized lights that actually can happen around a number of different planes you have this kind of rotation around a single axis we as humans can't see polarization but we can you know know that it's there or you can notice is that if you put on a pair of polarized sunglasses um the world will get a little bit different and what's happening here is that all of that kind of off-angle light is being cut out by a linear filter and you're just then seeing one plane of polarization from them so how do animals actually sense all of these lights so most visual systems certainly most animal visual systems use a combination of an opsin protein and retina this kind of small molecule that's in the center here what basically happens is that when a photon hits this complex or several photons hit this complex the retinal changes shape and that then kind of induces a change in shape alongside the entire protein and this triggers a kind of signaling cascade inside the cell that may eventually then lead to a nerve impulse so that's the kind of nuts and bolts of how you might become light as an animal cell now these options are really ubiquitous again they're very widespread in the animal kingdom and they can be finely tuned to detect different wavelengths or different colours as we were talking about earlier so just by adjusting one or two pieces of this protein one or two amino acids we can tune it to you know detect uh shorter wavelengths so in this particular example you can see there's a short wavelength called blue sensitive mid wavelength or yellow sensitive and long wavelength or red sensitive sensitive oxide in the system so that would give color vision with three colors just like our own eyes as i said options are found in most animals and that means there's a huge array of different proteins across the animal kingdom they're adjusted to detect everything from kind of uv all the way through to the infrared there are lots of different types that fulfill lots of different tasks so they're an incredibly diverse but very conserved protein which can be very useful for us as we'll come to you later so what is vision position isn't just sensing light so if you imagine you have a single cell your cell contains a bunch of obsid it's going to be like sensitive but if that's all you have that cell can detect light coming in from any angle and that might be fine it depends what your task is if you just want to know whether it's day or night or whether you're you know hidden under a rock or exposed on the sea floor that's fine all you need to know is light and dark but if you want to start gathering spatial information for example about the world around you you can't just be able to detect light coming in from every which way so what most systems do in this case is start to screen their photoreceptors so in this example you can see there's a bunch of small gray dots which represent pigment granules or pigmented cells and this constrains the angle from which light can actually reach the photoreceptor meaning that it's only sampling a very specific part of the visual scene this in essence creates a pixel um you can sample a certain area of the scene in front of you and know exactly how light or dark it is in that area and once you start to kind of build up more of these cells and more of this screening tightening the screening you can have end up with multiple pixels and eventually start to kind of form an image and this is what we're really talking about when we talk about vision this spatial resolution of where light is and you know vision is a very ancient evolutionary innovation so those of you who are here for some of the first animals lecture series will recognize this picture it's a reconstruction of the cambrian of yunnan and china and you can see here that even 520 million years ago you have um organisms such as this oligodiction in the middle and the apex which both have either eye spots they're actually already quite complex compound eyes so this is a really ancient ability since then in the you know following half a billion years we've been seeing an enormous diversity of eye structures evolve across the animal kingdom we're pretty sure that eyes themselves have actually appeared more than 40 times across the entire animal tree and an enormous variety of shapes and forms some of which you can see here if we think about how vision works and the kind of parameters that define it it's a little bit more complicated than we just talked about the properties of light earlier but obviously some of those do kind of come into play so wavelengths are the color we've already spoken about but obviously if you have uh different cells that are set to different wavelengths you might then be able to have color vision polarization as we discussed different cells may be able to detect different angles of light different planes field of view is essentially just where that particular eye is looking so what part of the visual scene you're sampling and sorry and the resolution is essentially how um narrow or how wide each pixel is so again the kind of the narrowing or photoreceptor the finer your resolution the more detail you're going to be able to detect in your image and finally sensitivity so how many photons you really need to absorb before a response is triggered so if you're not very sensitive you'll enlighten your sight in the dark is going to be very poor you're going to miss out on more detail and more contrast most of these things we've actually learned from what we kind of think of as conventional visual systems so animals that have a pair of eyes like ourselves like this owl that you see here that doesn't actually reflect the kind of full diversity of visual systems and this is what i'm really excited about as a visual biologist is looking at all of these different animals that have kind of thrown out that blueprint and gone i want more more is more i'll have more eyes so all of these um examples that you can see here spread across the animal kingdom they have all sorts of different approaches to vision and some of them have tens or even hundreds of eyes sometimes spread across the entire body so just as a couple of examples to get started um this starfish for example has five compound eyes so um starfish actually all have a single eye at the end of each arm you can see here in there the central image at the top it's a kind of orangey uh tentacle tip you can see perhaps those little orange rings those are kind of created by the pigment that is then surrounding each of those each of those pixels in the eye now we know that although they're relatively simple starfish can use this not only to kind of work their way back to the safety of a reef if they're displaced but they can actually even if they're walking over an obstacle they stabilize their gaze as they're doing it so it's actually quite a sophisticated visual behavior even for something relatively simple um looking at scallops as well so it might be familiar to you as a you know delicious uh delicious dish and what we've actually got here is we can see that uh scallops have tens or even hundreds of these tiny but bright blue eyes kind of spread across the mantle so the kind of rim of the of the two shells here you can have a look at this cross section there's a quite an interesting thing about scallop eyes they've actually got two retinas so two layers of photoreceptive cells which are kind of highlighted here in blue so what the scallop eye does which is quite interesting is that it has a first retinal layer and then a second underneath there's then a kind of a concave mirror at the very base of the eye which reflects light back up into the proximal retina so the bottom left here you can see that they actually see two different images at the same time finally is a kind of you know another quick example jellyfish so another thing that you may not necessarily have thought of is being a visual creature so box jellyfish actually have 24 eyes of four different types arranged in these kind of strange blobs called repalia around the edge so you can see here that the upper lens eyes at the very top here looks directly upwards of the animal and we now know that this is used for uh kind of helping the animal maintain its preferred habitat around the very fringes of mangrove swamps the lower lens eye looks kind of down into the water column and looks like it's probably going to be helping the animal to avoid obstacles while it's swimming so this is all well and good you know there's clearly a very widespread um and common evolutionary phenomenon but why go down this route why um you know to expand energy on having five eyes or eight eyes or a hundred eyes when you know we can certainly do everything we need with two and we're very visual creatures we have a lot of demands of needs and we can meet all of those with a single pair of eyes having two is great because it means you're protected against you know damage to one uh it means that you can you can benefit from things like depth perception uh you can set motion more easily but are there really kind of benefits beyond having two that um really promote a lot of these animals having more than that what's the real reason and if we look at the animal tree it's actually a really common solution so this is a phylogeny a tree of life of most major animal groups and just for a bit of orientation uh we're here in the chordates and a couple of uh familiar systems might then be in arthropods so insects and spiders animals so things like our scallops um squids and clams and if we actually have a look at where in the animal tree we see these um duplicated visual systems it's actually incredibly common so eight out of the ten largest animal groupings show some evidence or some instances of having these duplicated visual systems and we know that it's also quite an ancient solution because we see in particular burgess shale fossils such as this opamia that you do actually have very very ancient instances of having more than two eyes as well so it video famously has five um pusitive compound eyes but we don't know what they're using for so this all seems like a massive kind of blur of diversity and perhaps a little bit kind of confusing to begin with but the more we look at you know the animals that have these systems and these systems themselves uh a patent kind of starts to emerge and i think what the way i see it you can kind of sort these things into three kinds of name groups so first of all we have these animals that have uh large numbers of identical visual units so this is what we call multiplied visual systems so they'll have the same structure repeated over and over again possibly across the body we also have systems where there's more than one type of eye working so you might have one type of eye sensing something and one typifying sensing something else we also have what's uh kind of known as extraocular visual system now these are still pretty mysterious so we'll come soon at the end of the talk um but this is an instance in which we're not really sure whether they have one eye or several eyes or no eyes at all but that vision still seems to be um you know within the capacity of these animals so i'm going to do this evening it's just going to take you through an example of each of these and try and see if we can reach any kind of overarching conclusions that bring the three of them together so if we start off with multiplying visual systems for example we've already spoken about the scala and the starfish and there's all sorts of other examples as well so here you can see also um a fan worm a sabellaed worm and at the bottom of every kind of pink stripe that you can see on the the fan of the worm there is a small pair of very simple eyes you can also see a strep sector at the very top here which has lots of islets of miniature eyes in place of the compound eyes that we're familiar with a lot of other insects so if we think about our kind of five visual parameters and how these might help us kind of better understand multiplied visual systems because we know we have identical visual units we know that the sampling parameters and things like sensitivity and polarization should be identical across all of them so this means that if we really want to understand what's happening in these systems and how information across the eyes of being combined this field of view that's going to give us the kind of the most information to go on the best clue to how these animals are experiencing their world and why they're replicating the same eye over and over again and this is a kind of common misconception even in insect compound eyes is that you know you may be forming hundreds and hundreds of images that look in a very slightly different place but certainly in insect compound eyes even though this is you know what comes through lenses the animal then builds a single picture out of all of these tiny images so what is happening simply imagine for example that we have an animal with three eyes all three eyes do the same job and let's say that animal was looking at academy award-winning actor nicholas cage what does that animal see so if all three eyes are kind of sampling um you know overlapping fields of view they might all see very slightly different pictures of nicolas cage you know ranging from the top to the bottom and this could have all sorts of benefits it offers redundancy so if one of the eyes gets uh you know damaged or or pulled off then they can still see nick with the other two it could also mean that they're able to more easily detect things like motion and depth alternatively those three eyes could be looking at different parts of him so in this case you've got one looking at his forehead and one in his shirt and ultimately that could mean that they firstly cover a larger field of view in total and secondly that they could create a composite image covering him a bit more detail so the animals i'm going to use to kind of illustrate um some of this work is the chiton so chitins are mollusks you can probably find them in most rock pools in the uk if you go looking for them you can see in the top right this is the the underneath the ventral view of mollusk you can see a big muscular foot uh lots of gill pairs either side and a mouth at the top and at the bottom they've got some nice examples of how kind of colorful and beautiful and varied they can be you can see that they're covered by these eight kind of dorsal shells and they're really important to this so those shells in all mollusks are kind of filled with pores sensory pores that detect things like uh chemicals movement and potentially light but in some species um they've actually added what's this kind of small circular lens to the top of some modified pores and this is an entirely new instance of an eye that occurs in several species compartments now thanks to the work of dan spicer and some of his colleagues we know that each individual one of these eyes is able to detect uh sorry it's able to form an image of its own so the bottom right here you can see that a single eye would form a somewhat blurry image but certainly an image of a potentially frightening fish predator here um and we know that the entire animal is able to respond to this um because they the in the top left here what we're seeing is that animals respond to a circular target being prevented presented overhead by clamping down onto the substrate but you can see the bottom half of that diagram but they don't respond in the same way if you just turn the lights down a little bit so they are using image formation to guide their behavior and not just light and dark so really the question here is okay we know that we get one picture but what would a creighton see would a kite and see one picture of nicolas cage or would a kite see 300 tiny nicolas cages i believe there's a poll here so i'm curious to see what you all think of it let me know what you think is going to be uh more likely this uh lucky kitten so now that we know something about individual eyes and how they work you wanted to kind of like zoom out and look at the big picture how would all of these eyes then kind of fit together so using this particular species to each of the brunei we've started looking at a growth series and how animals add eyes throughout their lives so these two individuals you can see there's a an adult on the right hand side and a tiny little baby on the left hand side but you can see that they both have these um little dark dots which is where all the eyes are and as i said they add these eyes continuously throughout their lives kites kind of grow pretty much indeterminately throughout their life and they seem to steadily add numbers as they get longer so we wanted to look at first of all was whether this is a regular network so you can see that the eyes are quite beautifully arranged into these rays that kind of come out across the shells and we wanted to know whether or not those are equally spread out if they add more eyes as they grow older or if they're going to slow down we're going to detect this by trying to measure from the the center of every valve sequentially to each eye to see if we get this kind of nice curving pattern or a linear relationship that would indicate having a regular addition and what we find is that they they certainly don't slow down their addition of eyes it's kind of equivocal as to whether it's a regular edition or if they accelerate slightly but we do certainly see is they are adding our eyes pretty regularly and they're fairly evenly spaced across the shell you can also see that they're pretty symmetrical so there's very few instances of higher kind of 10 discrepancy between the left and right sides which might sound like a lot but if you have you know up to 600 eyes that's that's pretty good going if you're adding them throughout your life so we do see that you have this very kind of regular evenly spaced network that these kites are using across their whole body but what about the actual field of view so just because they're spread out regularly doesn't necessarily mean they're sampling the scene regularly so what we did next was uh take a bunch of these valves uh and essentially micro ct them so you could be able to generate these 3d models of what the valves look like so on this one you're going to see in pink here which is where every single eye is and what we did was then look a little bit closer at every eye you can see in the bottom right hand side here an x-ray section through that shell and you can see just about the shape kind of reflected from that diagram i showed you earlier there's a lens at the top and then a cavity that contains the retina the photoreceptors at the bottom and so the original authors of the previous article estimated that the the nodal point to the point at which the light kind of crosses over is probably in the center of the lower third of the lens there so what we can do is take that a hypothetical nodal point and then try and work out how much light could reach uh you know the entire retina by passing through that point and project outwards what field of view might be for that particular eye and if we do that for all of the eyes across half a valve this is what we get so every colored cone here is the visual field of a single eye so what we can see and i've given you some orientation at the bottom there the whole animal is a head facing to the left and if we have a look from the underneath again head to the left we can see that there's a gradual shift in what part of the visual scene those eyes are sampling so the oldest eyes are here in red and the youngest eyes are in purple so this kind of shift from looking backwards and outwards to looking forwards and more kind of towards the center as the animal grows older and if you start to look at both halves of the the shell together so you've now kind of rotated through 90 degrees and we're looking ahead on at the animal you can see there's actually quite a lot of overlap as well between the two halves of the vowel again with the uh oldest iron red and the youngest iron purple so this actually creates a pretty broad strip directly dorsal of the animal that's being sampled by almost every eye in the visual system and as we know that can be up to you know five six hundred eyes in some case which is an enormous amount of oversampling for such a supposedly simple system it might be that this is the most important area to sample of course um you know we think that the kite and visual system is there primarily to enact defensive responses against overhead predators such as this fish so how would a kite then probably see nicolas cage if nicolas cage was to you know wander over to it in a rock pool and try and pick it up we know that actually all of these eyes are probably massively over sampling here so i think what we what we expect to see is that we don't actually uh have one single image of nicolas cage forming it's probably going to be hundreds and hundreds of smaller ones and from what we know about the quite nervous system um this perhaps shouldn't come as too much of a surprise so if you were to expect these animals to kind of stitch together one larger uh image it would it would take quite a lot of kind of computational power quite a lot of processing here so if we uh if we actually piece together um all of those images it would take quite a lot of uh brain power and unfortunately that's not really something that these animals have so they do have a brain they have this kind of concentration and organization of neural tissue but they uh they probably don't have the smarts to piece together a 600 piece jigsaw puzzle so at least you know with with chitins in particular as our example of a multiplied visual system what we've kind of deduced is that they do have regular sampling they've got regularly spaced eyes they've got almost total coverage of the the global field of view but we see really high redundancy and that seems like quite a strange thing when you're pouring so much energy into having you know so many hundreds of eyes but actually given that we know that this response is really important if it's you know one of your only kind of defenses against approaching predators uh maybe it's really worthwhile investing that efforts in a reliable visual system so having a high redundancy can protect you from things like false alarms there could be a piece of detritus floating past your eyes protecting you from biofouling from damage to your eyes and of course improved sensitivity as well so just because they're not just because we don't think they're combining everything into one image doesn't necessarily mean that uh they uh they're not kind of relying on multiple eyes being triggered in order in order to trigger a response okay so let's kind of make things a little bit more complicated so that was having lots of replicates of the same kind of eye but what if we're thinking about parallel systems these kind of multiple eye types and all this might sound unusual it's actually again surprisingly common so even some things that you will have come across uh pretty regularly so things like insects have two parallel visual systems so as well as having those two compound eyes that are very familiar with on the side of the head most insects and certainly most lighted insects have an additional visual system these kind of three small dots that you can see in the center of the head here called the sli and these kind of provides uh everything from flight stabilization to horizon detection to polarization possibly as well so they can fill a wide range of roles but we do see this kind of same uh approach in a lot of different angles as well so unlike multiplied systems there's a whole lot more variables at play here so because we can have different functionalities we could have different color sensitivity different polarization sensitivity different resolution and field of view across all of these kind of different systems there's quite a lot happening that we need to get to grips with so this time it could be that one eye is seeing a beautifully well resolved fine detail picture of nick cage but it's all in black and white and it could be that our second visual system is actually seeing a pretty crummy picture but does all the kind of color recognition but this kind of seems strange to us because we can see nick cage perfectly fine in full color in full detail with just one pair of eyes so why why end up with two eyes doing the same job that one i could do and this is a question i'm going to use to use spiders to kind of address and this is this is your trigger warning for any irrational folks who are in the audience the cutest spider that i could find on the internet um but there are a couple of pretty gnarly ones coming up in a moment so look away spiders really are the kind of masters of having parallel visual systems and they have an enormous variety of eye distributions uh eye parameters uh size even number uh which makes them the kind of perfect system to then look at you know why you would uh use different structures to detect different keys as a kind of basic primer for spider eyes um there's uh you have four you know spiders have four pairs of eyes of two different types so you have the the principal eyes which you can see the bottom left here or the anterior median eyes these are essentially how you would design an eye the light sensitive part facing outwards but they also have up to three pairs of secondary eyes so this um has the photoreceptors inverted and then has a tepitab or a concave mirror just like the scallop does and just like uh cats do as well and there's an enormous amount of variation on this basic blueprint and spiders have done some really amazing stuff with this as well they have some real kind of visual olympians so a couple of examples here you can see that for the color coordination there's a lot of different uh configurations of the same structures over and over they use them for wildly different things so jumping spiders which you've already heard of uh have super high resolution vision in their anterior median eyes their principal eyes thanks to this kind of amazing telephoto style eye that they have this means they've got a great vision they can use it for very sophisticated tasks uh in this particular example you can see an extremely sexy dance from a male jumping spider who's causing a female they have a lot of visual communication which is pretty um pretty special and pretty unusual the second example we have this ogre face spider so spiders also hold the record for the most sensitive eyes that we know of in the animal kingdom so these guys have kind of uh you know issued hunting from a web and just waiting for free to come along uh and instead uh they'll spin this kind of gladiators net type web they'll hold between their two four legs and in pitch black they'll be able to capture frames they have incredibly sensitive posterior median or secondary eyes but not all spiders have amazing vision and that's fine obviously every visual system has to do the job that's necessary to the animal with that visual system so the two examples i've just given you they're both kind of very visual animals they have incredible eyes but most spiders you know don't necessarily need vision that much and that's why these guys are a perfect group to look at the evolution of parallel systems they have everything from uh web-based hunters who really don't have that much useful vision at all all the way through to these champions like dynapis and like the jumping spider what's really useful in this particular setting is that a lot of a lot of what we know about eyes means that we can learn or infer a lot about their function just by looking at their structure and partly this is thanks to decades and decades of studies um by other biologists and partly thanks to some laws of physics as well so for example we uh imagine you have a simple camera eye like this it's looking at a black and white grating and we can basically deduce from the spacing of the photoreceptors in the retina and their distance from this nodal point in the lens we can then calculate what's called the interior receptor angle so the angle that one particular pixel will occupy in an image and from this we can work out what the maximum resolution of that particular eye is so what is the finest detail that it could really pick out and in this case that would be the distance between this black and this white part of the grating here all of these kind of functional relationships that we know about eyes is really helpful from the kind of the study of uh visual evolution because it means that we can actually learn a lot about uh things like sensitivity polarization sensitivity and resolution just from looking at structure so one of the things that we've been doing is then uh you know taking spiders from our own museum collections and from several other collections around the world are trying to look at compare all of their eye structures across large uh large large distances in terms of their relatedness so here you can see uh we've taken the spider collections and the bottom right here uh you can see in a tube with a pink arrow there is one tiny spider head inside this enormous machine uh which is based at the sigtron which is uh essentially a particle accelerator which we visited once in oxfordshire at diamond light source and once in switzerland at the swiss light source so i mentioned ct scanning earlier this kind of ability to you know use x-rays to get three-dimensional images the cyclotron is basically a really really super tough ct scanner so that kind of ring-shaped uh building is a particle accelerator and uh there'll be a kind of a beam line that comes off that that produces really uh high-energy and specific energy x-rays so what we can see um well that will have a i believe we'll have a video there we go and what we can see here is an example of one of the scans that's produced by the synchrotron so this is us passing through the head of spider you can see the two things in the middle two eyes appearing and then two more pairs of eyes at the very bottom there and if we zoom in a little bit more we can actually see that we get really gorgeous detail um out of these scans which only take a few minutes to take so here you can see we've got the the lens the vitreous body and this kind of black and white stripey u-shape at the bottom here which is the retina so you can see that this is kind of uh there's a pale layer with all these dark dots every one of those dark dots is an individual photoreceptor cell the kind of pale layer surrounding it with the screening pigment that we're talking about so from these scans we can extract a lot of data we can deduce things like inter-receptor angle which we talked about earlier we can look at things like uh rounds and lengths and ramped up diameter so again both things that influence how sensitive a particular photoreceptor is we can look at the potential focusing optics of the lens so looking at the radius of curvature the aperture diameter so how much light can actually enter the eye and of course the diameter of the thickness of the lens itself and once we've got all this uh these image stacks we can actually not just be restricted to keep them in 2d as we might do by um dissections or uh histology but actually look at the eye in its full three-dimensional context you know what direction is it looking in how does uh how do all of these parameters change across the rest for example which is a really invaluable tool so i'm not going to dwell too much on kind of individual adaptations here but i just really wanted to demonstrate how much variation we see across all of these different structures so this is uh principal eyes taken from eight completely different families of spiders you can see that we've got an enormous kind of range of morphology both in terms of shape and size the position of the retina and again it looks like we have very different different resolutions as well with different spacings this isn't just the case of the principal eyes even in these posterior laterals which are one of the secondary eye pairs again we see enormous diversity um between all of these different families uh needless to say we've kind of come across a few interesting tidbits while we've been like surveying all of these uh you know many many dozens and even hundreds of scans and just to give you a kind of a little flavor of some of the things that we've found a couple of examples here so in the top right we have a gyrometer aquatica which is the only fully aquatic spider spends the majority of its life underwater uh it spins basically a little a little silk sac that surrounds the abdomen here you can see there's a kind of air bubble trapped within that so spider lungs are located in the abdomen so this allows it to breathe while it's doing its business underwater and what we found in this particular spider is uh unlike its close relatives which all have pretty relatively shoddy vision and quite flat uh not particularly curved lenses that we can see in the uh the left image here i'm sorry the bottom left of that blue panel we've got these kind of almost spherical lenses in the principal eyes here which are very different from the other eyes as you can see at the top so this is something that we see very commonly in in other aquatic systems so things like fish have released variable lenses ultrasound very sorry for lenses as well so actually it's probably an adaptation to being underwater so the the focusing power of the lens is massively reduced if you're under water because the refractive index of the water and the lens is very very similar whereas fast the refractive index of uh air and elements is much higher so we don't need them to be quite as thick or as rounded in the bottom left the kind of orange panel here is a different example this is zadarian which is an ant hunting spider they have this fabulous lifestyle where they build themselves a tiny igloo out of stones and they venture out of their igloo they go hunting for ants and then they work their way back to their igloos at the at the end of their hunt and they do seem to be able to navigate their way back without too much trouble which is kind of a curious thing so one of the things that we noticed while we were looking at the the eyes of reconstructing the eyes of this particular animal is that you'll see under this red lens we have two layers of retina here so you may be able to see that the kind of uh you know green and yellow layer is at a right angle ish to the teal and blue layer underneath and this is really typical of something that we see in animals that have polarization sensitivity so just by turning the receptors through 90 degrees you can then kind of differentiate between different plates of polarization which is a really neat trick for these animals it might be really useful at getting back to their igloos at the end of the end of their hunt so we actually have a natural pattern of polarization cast by uh the sun and the moon across the sky which several other animals are known to use to navigate so it could be that you know that's how these spiders are getting back to their igloos when they're done feeding but i eventually want to talk about evolution so if we start to look at you know some of these characteristics that we've surveyed across spiders and then start to uh you know try and compare those across different uh related families what do we see so this is another phylogeny another kind of family tree of all of these different spiders you can see on the right hand side like a little graphic of their kind of eye arrangement and what they look like simply to take a couple of basic uh examples here um one of the things that we're really interested in is resolution right so the finer the resolution the more detail you can see so the colored vertical bars here indicate points in evolution where statistically it looks like spiders have crossed that threshold they've reached a certain resolution if you want to think about how uh you know three degrees of resolution looks if you uh take your little finger and you hold your armor arms length the width of your little fingernail is about one degree so if you imagine three degrees is actually pretty close resolution still but good for a spider so we'll take that as you can see the instances where this evolves seem to coincide uh relatively neatly with the estimated origin of webless hunting so animals leaving the web going to either you know wanted to find their prey or actually visually hunting them so maybe this isn't you know a huge surprise you need vision you get better vision you see the same thing with polarization sensitivity so again this possible way of navigating which might suddenly become much more useful once you're leaving your web and going hunting elsewhere but it's not just a case of uh you know spiders that need better vision have better vision across the board that's not necessarily true so one of the things that we did next was compare a fairly simple metric so looking at lens diameter the size of the eye as kind of a proxy for the investment they made in that ipad and you can see here that the the three families i've picked out which are all quite visual hunters uh not only do they have you know maybe higher investment overall they actually have much more variable investments so if you compare for example the far left the salticids you've got dramatically different eyesizes compared to for example the rna is in the middle layer which are kind of classic orb weavers which you know in total probably have about the same total diameter of eyes but it's much more evenly spread and if we look at sampling parameters some of the things that we talked about earlier in terms of uh you know retinal morphology we see a very similar pattern so if we compare random length which influences sensitivity with intervals of angle which influences resolution you can see that we have this kind of unit downwards uh correlation here at these two factors and if we look at how these different animals hunt we can see quite an interesting pattern once again so if we look at the web hunters so our rnas and our forces you can see that they fall two quite quite tight clusters of points here you'll also notice that in both cases there are three points that are much closer together than the fourth and these three are the secondary eye pairs and the fourth one is the the primary ipad we look at ground hunters we suddenly see kind of a much kind of wider distribution particularly the dictators and they're going to stretch out along a lower part of the graph here we look at our visual hunters actually we have the opposites we have a big shift towards the left-hand side but again quite a big expansion of all these different uh combinations of parameters they encapture so again we see quite a lot more variation it's not just it's not just better vision it's more varied between the eye pairs despite the fact that these animals are more visually reliant so let's come to field of view we've kind of talked about some of these sampling parameters now and how they vary between visual and non-visual species so if your video is something that's quite difficult to uh to analyze i suppose but we have all of these you know beautiful models spider visual systems and you can see that quite aside from what every wrestler is looking at you can also see that the eyes themselves are spread out and sized very differently between these different groups so we've used a technique called uh geometric warfare metrics to try and get a a grasp on how those things are spread out and whether or not you know more visual species have different eye arrangements than less visual species so the way this works is that from our 3d models we can place landmarks that will then analyze in a mathematical way so you can see from these two species we've placed landmarks um you know at the two two centers and around the edges of the eye and you can see that they actually represent reasonably the shape and distribution and also the orientation of the four eye pairs of these two species now when we place these landmarks they're done in uh so the landmarks has to have to correspond basically between species so when we put this analysis um you know we're aware that the two blue landmarks are absolutely comparable both of those would be the center of the principal eyes in whichever species we look at and both of the pink landmarks are again the center of the posterior leather eyes no matter what species you're looking at so what the analysis does basically is take all of that variation in three dimensions uh and related to each other and tries to collapse that into a couple of uh two-dimensional uh parameters that we call principal components so what you're seeing is a complex multi-dimensional mathematical problem kind of squashed into 2d and what happens if we do that is that we what we can see is we actually have our three hunting groups fall out into quite different spaces so in pink we have a selection of visual hunters there's i think a bunch of different families in there and you can see that they kind of like form a cluster at the top of the graph here surrounded by that pink circle what we see in our web hunters is actually there's not that much overlap between these two so they're kind of occupying quite different parts of this uh theoretical shape space our ground hunters kind of sit somewhere in between and they're clearly kind of encompassing a bit of both of them as well but we can see quite a clear distinction between at least our visual and our web hunting spiders and this is clear if we look at the models themselves as well so you can see in the bottom left that um while our web hunters have quite widely dispersed and uh differently oriented eyes in our visual hunters we seem to have much more uh you know concentration towards the front of the head as well as seeing this kind of dramatic difference in eyesight that we discussed earlier so what might be happening here is that with our web hunters you know we've got actually very distributed fields of view and our two different types of eyes aren't necessarily looking in the same direction and that's fine they can be functionally different and looking in different places if that's what's useful to them so for example here um you know our principal eyes our pink eyes might be interested in looking at nick's facial expression and see how he's feeling but the blue eyes might only be interested in the color of his shirt the fact they don't overlap doesn't mean they're not doing a good job they're just you know completely fulfilling different tasks here by contrast a jumping spider might be really interested in how nicholas cage is feeling so you know in this example they're getting both high definition for the principal pair of eyes and color vision from the secondary pair of eyes both of which in this case are facing forward and sampling the same part visual space but this brings us back to the problem we had at the start if you're using two pairs of eyes to simultaneously sample the same space why not just collapse it and have a single pair of eyes do the same job and this is kind of an issue that seems strange to us as humans because we have amazing eyesight really kind of among animals above the best part of this is a size issue so if you compare the size of even a human eye that has a human head to the size of these amazing jumping spider eyes they're absolutely enormous and because uh eyes are constrained by both kind of biological constraints and by optimal constraints this really matters so we can obviously have an enormous number of uh photoreceptors giving us very fine resolution but you can't make those photoreceptors infinitely smaller and give you infinitely better resolution if you have a very small eye you also have a shorter focusing distance and this kind of you know if your total body size is less you can't grow an eye bigger than your so from the spiders what it seems to be is that the greater your reliance on vision the greater divergence you're going to have between these parallel systems but at the same time having greater functional divergence you're likely to have greater spatial concentration so you kind of have these two different forces at play here which is what seems to have produced things like jumping spiders and wool spiders that have multiple forward forward-facing pairs eyes doing very different jobs we think that the reason behind this is probably actually a functional constraint purely on size so finally i just want to talk to you uh relatively briefly about these extra ocular systems there's a slightly mysterious about the beginning but they remain mysterious as you'll see in a minute so these are kind of systems where animals don't appear to have eyes they don't appear to have discrete organs or focusing optics or any of these things that we would associate with you know an eye in any other animal and broadly speaking this has only really been kind of looked up in any depth in sea urchins and brittle stars so these are both relatives of sea stars and starfish that we talked about the beginning but they don't have the same compound eyes that the starfish have so in particular i want to talk about uh this one species called gymnastics so this kind of became the the poster child of looking for extra ocular vision because it's it's very light sensitive it does this gorgeous kind of color changing tricks this is the same individual uh photographed during the day at the top with this kind of dark uh brown coloration and during the night at the bottom so it's got this like really a pale beige look they really hate being exposed to light and they'll kind of crawl away into any crevice uh at the first opportunity so these were kind of the uh the the first place to go looking for vision and animal with our eyes but of course if you don't have eyes we find it very difficult to know what we're looking for so you know first of all we need to work out you know where and how light is detected before you can even start thinking about you know what the function might be and how vision might work so going back to the beginning we remember we spoke about absence being this kind of fairly ubiquitous way of detecting light and visual systems this is now massively helpful to us because it means that we have a basic building block that we know that we're looking for so what we did was uh you know take a couple of arm snips from these animals and sequence the rna so uh this means that we can detect which genes are actually being expressed from which genes are actually just available in the genome so you can tell what a particular tissue type is doing and what we found is that actually they do have a large number of options so this is again a phylogeny but only of the genes we can do this to look at how different genes are related to each other the important thing here is i wanted you to look at the top so these two groups of options c and r are used for vision in the vast majority of animal systems and what we found was that there are three different r options uh available in this opioid sticks are uh it's actually the this kind of option that most invertebrates use for their vision so we're like cool excellent like this is a pretty promising lead let's go looking for some robsons so what we use next was a a technique called immunohistochemistry so this basically means if you if you know you're looking for a particular protein what you can do is design an antibody that will bind to that protein so in the same way as uh you know you might develop antibodies to a particular pathogen you can design antibody to attack essentially a protein of your choice and then you can attach a fluorescent protein to that antibody and then when you put it under a reverse microscope you'll basically have it light up exactly where that protein is located so what we're looking at here is the the arm plate of opioid elastics and what we can see in red is where there's opsin is being expressed so just for orientation on the kind of top right here you can see a kind of a microscope image of the surface of that plate so we've got lots of calcite bumps with these little pores surrounding them and from the fluorescent image it looks like what we're seeing is the oxygen is located within those pores and if you look at the scale at the top right here so that's that scale bar is 10 microns so 10 1000 one thousandths of a millimeter this means that these animals have tens of thousands potentially if these oxygen expressing essentially light sensitive cells spread all across the body uh they work just on the kind of upside the top side of the arms you found them on the sides underneath all over so there really are thousands and thousands of these things working and other animal systems where we have tens of thousands of photoreceptors they're usually pretty great uh so things like dragonflies for example have incredibly fast high resolution very colorful vision uh you know they have extremely complicated flight behavior they need to coordinate so you know arbitrary stars aren't really doing any of that stuff so it seems a bit suspicious that they have quite so many photoreceptors so what are they doing we spoke at the beginning about uh you know what vision is and why vision has to be different from just detecting light so it's ability to kind of resolve spatially where light is coming from so we wanted to you know just make sure that first of all this british star is actually able to do that so what we did is uh this kind of behavioral setup which we'll uh talk about a couple of variations on essentially what happens that you have a circular arena filled with seawater and the animal is placed in the center but one side of that arena you present a stimulus a visual stimulus of some kind in this case you can see that it's a black bar centered on a white bar vertically the rest of the arena is grey so what this essentially means is that the the light reflected by the stimulus which is black and white so very light and very dark on average is about the same as it's reflected by the gray so if you can't spatially resolve if you're only detecting kind of you know directional it's darker this way it's lighter this way you shouldn't be able to detect that stimulus and you should just orient randomly because we know that these animals do kind of seek shelter uh during the day or when they're exposed to light we hypothesize that they will want to move towards the stimulus if they can't detect it what we tried was a couple of different variants on this as well as you'll see at the top there are these three different stimuli that we kind of tried to feed the animal to see whether it would go towards a dark stripe on a white background this kind of a black and white stripe on a gray background and then more kind of gradual gradient stimulus so the results of these experiments i'm going to show you plots that look a little bit like this they're circular plots so this imagine if you're looking uh you're looking top down at the arena which is this gray circle and essentially every pink dot that you can see is one animal and where it ended up at the side the arrow at the center shows you the kind of uh lean direction that they moved in and the length of the arrow shows you kind of how strong that response is the kind of arc around the outside is just a confidence interval for that area so this is a control there was no stimulus present in this particular experiment and as you can see the animals didn't really move in any particular direction they're fairly uh spread out around the edge you've got a very short arrow but if we present them with any of our visual stimuli you can see that there's a slightly different picture so here again they're actually much more kind of moving towards uh the stimuli that are being presented at the top here this is cool this is one of the first times that we've ever demonstrated that an animal doesn't have eyes is able to do this kind of spatial resolution of uh different parts of the visual scene and it isn't just moving to like an overall darker or an overall lighter space which is very exciting so we thought we'd play around with this a little bit more and try and work out exactly what it is that's the limit of this visual system so we repeated this experiment uh with the black and white bars making them kind of smaller and larger in terms of their angular size so their angular width as viewed from the center of the arena in this particular graph i'm actually percentage of success so how many animals actually made it to that stimulus successfully as you can see here we basically see that animals are very happy and very successfully oriented to stimuli that have occupied 50 degrees of their horizon and above so you can see in our kind of blue and orange lines uh random charts so just like the chance that they would randomly wander into the stimulus without seeing anything and the actual observed success rate so you can see that there's quite a clear difference between a 40 degree stimulus which they seem to be unable to locate a 50 degree stimulus which they're very kind of geared towards which is really cool however 40 degrees if you remember that you know your little finger is one degree seems really big and not particularly useful so again this is kind of a lesson in uh a visual system is good if it is fulfilling its purpose it doesn't have to be as good as ours so if we try and uh imagine what that animal could be seeing this is an image that was taken from the site where you collect the brittle stars so you can see these kind of like big coral heads that you know might provide shelter perhaps if we then transform that image so that we uh kind of simulate a 40 degree resolution and a 50 degree resolution when looking at it you can see that we lose almost all of the detail uh but certainly with a 40 degree image if you kind of squint you can see that there are two very very coarse darker blobs where these two coral heads should be so it could be that even if it is really coarse resolution it's sufficient to enable them to find them a shelter so even if it seems again like a massive energetic investment it could be they're gearing towards something very useful so in terms of how they're doing this how the vision is facilitated we turn to look at a closely related species called opiate canela so this is an interesting one because uh oji canelo appears to have all the same options it has the same option expressing cells it has these photoreceptors but it doesn't respond to our visual stimuli and it also doesn't like being exposed to light what it doesn't do is that it doesn't have this fancy color changing trick that atmastix does which kind of gave us a clue so like cool maybe this color changing is something to do with the pigment and the screening that we said earlier is really necessary for the vision of the spatial resolution so we thought we'd go back and use our opioid sticks but at night time when it's in this kind of like pale uh beige form and sure enough it doesn't seem to be able to locate the stimuli anymore so we thought well okay that seems maybe silly because we're trying it at night time there's not enough light available to it maybe it just can't see you because it's too dark so we tried a couple of different treatments uh firstly giving it artificial lights at night and secondly kind of keeping it keeping it a dark box so that it would uh adapt to the darkness and then running experiment during the day and neither of these rescue the orientation behavior so if there is something that the pigment is doing we need to be able to demonstrate that it's actually starting to you know restrict the passage of light to those photoreceptors so we had all of our kind of fluorescent microscopy images we had x-ray data and we had histology so what we did was then build these composite models of what the photoreceptor system actually looks like in these three instances so we have our light-adapted opioid sticks here with pigment granules surrounding the photoreceptors on the left uh ophelia canelo with no pigments and our ophio mastics at night for the pigment right-hand side what we did was then kind of take uh digital sections through each of those photoreceptors and rotate through 360 degrees measuring the angles at which light could possibly you know reach it at incident without being uh interrupted by an obstacle and if you plot those angles onto the field of view so here imagine that a single photoreceptor is at the middle of that sphere what you can see is that indeed when you do have pigment that's a massively constricted area that light can reach that photoreceptor from so our opioid canal and our dark adapted atmospheric so you can see that there's you know light can reach that photoreceptor from almost 120 degrees which is an enormous amount of visual field so what it looks like happening here is that we actually have a kind of visual system that's controlled by the movement of this pigment between the surface and the inside of the arm between day and night which is which is really neat it looks likely that the photoreceptors themselves so that the light sensing cells are probably fairly common so you can see that they're in ophea canelo they may well be in other brittle stars and it's only the addition of the pigment that really kind of confers this ability to start to discriminate a little bit more this might seem like you know this is one species we looked at one species we've maybe worked out a little bit more about how this works but does this really contribute much more to the big picture and at the beginning i said that it's only really brittle stars and sea urchins have really been investigated for extraocular vision in this way and one of the nice things that uh we realized uh after completing some of this study is that actually the only species of sea urchin which uh you know they've been shown to been shown to respond to the same sort of stimuli is this species which is called diadema africana again it's a it's a tropical species and even more importantly it changes color in response to light and dark so it could be that we've kind of stumbled upon an accidental visual system again that we know that there are photoreceptors in a lot of different urchins but vision itself has only been demonstrated in this one dark color changing species so that's kind of a bit of a whistle-stop tour of three examples of these kind of strange distributed systems but have we learned anything that could be kind of used to unify these three seemingly very different approaches to vision mean importantly we've seen that you know all of these fundamental things that we know about conventional visual systems absolutely have to hold up if you're looking at something less conventional so things like you know logically using these five parameters to learn a bit more about how the visual system works uh these kind of fundamental functional and morphological uh relationships that we see in eye structure have to hold up uh and things like you know requiring pigment in order to actually screen your photoreceptors and produce resolution absolutely holds up in these systems as well something i think is really interesting that's kind of emerged from working on a bunch of these different systems as well as and some of the ones that we've seen tonight is that we actually also see a very broad general trend between spatial distribution and functional uh kind of complexity and diversity so uh our opiomatics for example top left of this has super dispersed photoreceptors across the entire body but functionally it's very coarse resolution uh we don't really know how it works it's quite simplistic in its function and at the other end of the spectrum if you pass through our kind of multiply systems you then have really uh kind of uh functionally uh diverse and complex systems like those in the spiders and we even saw this you know just looking at the spiders themselves we saw this very clear relationship between uh very distributed eyes and all weavers through to very concentrated eyes and visual hunters so this works at several different scales as well and whether or not this is you know purely because of uh you know the different types of visual system isn't necessarily clear so there could be a whole bunch of different ecological uh developmental evolutionary uh constraints at work here as well so for example uh one of under spectrum we have you know much more kind of sessile maybe sedentary animals that don't need very active lifestyles might be more likely to have uh simple but very dispersed visual systems whereas at the other end of the spectrum we could have these very active hunters flighted insects etc that have parallel visual systems and lots of different functional types but more spatial concentration it could also be an ecological thing so we could be looking at you know things that are more likely to be prey species and need to be kind of you know looking out for threats approaching for all sides versus things that are predators and are pursuing something they want to keep in front of them and it could just be uh you know in terms of body plans in general so again these distributed systems uh rely much more on these kind of unconventional body plans either kind of radial symmetry or the lack of the head or the covering of the head the shells uh versus this conventional kind of biomaterial body plan that we see in these bottom right so i hope that you know some things are kind of becoming clearer in looking at some of these distributing systems and i hope that i've been able to give you a small flavor of some of the kind of amazing diversity that there is out there um hopefully you know as the as research goes on we'll learn more and more about them and some of these kind of general patterns will all come into a bit more focus but uh for now i hope i'll be able to kind of give you a a bit of a tour of what we what we do know what we still have to find out with that i just want to say thank you very much to there's been an enormous number of people involved in this work uh collaborators uh people who willingly and unwillingly helped me at the synchrotron uh hit everybody who's learnt specimens uh and of course uh to all of uh all those bodies that have funded this work as well so thank you very much hello hello lauren thank you so much for a wonderful wonderful tour that has taken us round all sorts of weird and wonderful beasties with many eyes and as you can see we have changed our position because we've gone we've gone to look for some some beasties that also have many eyes and in the in the collection here is a a scale worm that was collected from the from the southern ocean in 1926 and some of these have multiple uh pair survives and we're also going to use another example to segue into a reminder here's some other lovely specimens we have in the museum you can see some some types of organisms that have many eyes the the scorpion as well but you can see there are many insects in here as well and that's just another nudge towards a reminder that if you would like to hear what of insects ever done for us we look forward to seeing you in two weeks time for dr george mcgavin who will be talking on that topic and the link for that is up in the chat at the moment as i try and put that down without it breaking excellent excellent do keep your questions coming in on the chat we've had lots of questions we're going to start off with one from uh had a lot of love for nicholas cage and all sorts of questions back what does it feature in that talks i feel like whether whether people should uh have more eyes so that they can uh see nicolas cage better we we should also at this point give some uh some feedback from the poll um the the question was um which would be better um you know what how would the kite on see nicholas cage uh with 78 of the vote was one big nicholas cage and and with 21 of the vote was 300 tiny nicholas cages do you want to comment on the outcome of this uh democratic event lauren well i'm very glad that everybody has such faith in the nervous system of titans to kind of you know put together this amazing jigsaw puzzle but my personal opinion is they probably would see 300 tiny nicholas cages there you have it there you have it and at that point we're going to ask a question about the the synchrotron these high-energy x-rays for looking inside these wonderful beasties and both mark and jethro wanted to know what kind of preservation do you need for these uh these organisms to to gets to get the resolution that you need from the synchrotron so maybe how are these specimens preserved i know myself because we spent many days um carefully putting them into the synchro but tell us how these specimens are preserved before they go into the synchrotron beam so because we were working with museum collections a lot of the specimens that we were both using were preserved in ethanol so this isn't usually the the optimal way of preserving structure so often we use nastier chemicals like glutaraldehyde and then potentially staining agents to increase the contrast as well but uh because i've been trusted with loads of specimens from both our museum and elsewhere we're not allowed to do that so that would be counted as destructive um so ours are actually just preserved in ethanol often it's thought that that kind of disrupts the structure a little bit but um as you saw from some of the scans that we showed we do actually have a surprising amount of preservation even from some really old testament so the video that i showed was actually from a spider collected in 1890 so preserved exceptionally well uh well for a biologist not a paleontologist because exceptionally well over more 100 years wonderful wonderful and shout while we're on uh on uh eyes and sharon wants to know does a spherical lens give a huge field of view is there some advantage to having a spherical lens does it give you a better field of view good question so it depends what surrounds that lens so if uh for example your variable lens was sitting at its kind of widest point at the eye aperture then you may well get a very large field of view a lot of these things it sits a little bit further back so it really depends on the the angle between the that nodal point at the center and then the aperture itself where the retina is so the main benefit of the spherical lens i think is for the focusing power and then we have a question from the netherlands which is if some creatures don't use their eyes or don't need them then why take the energy to make them why have eyes if you're not going to use them oh excellent question and so this is something that we see in the most extreme cases in for example animals that lives in caves or that live in the deep sea and those generally speaking do tend to kind of lose their eyes over millions of years the animals that i was talking about in terms of being less visual so these spiders that have very similar eye stretches they're still using them in some way so even if they're not using them to capture prey or communicate with one another they may well still use them to detect you know very grainy shadows or just kind of light and dark so in a lot of these cases the eyes are still doing something it may not be a very sophisticated task because we think about it but they're often still fulfilling a job if the eyes are completely useless as they would be in a very dark environment for example then a lot of animals absolutely do want to conserve that energy and you know cut their losses and get rid of the eyes sorry at that point i'm just going to remind everyone that um oxford university museum of natural history is a charity and as well as putting on public engagements events like this we also look after a collection of over seven million objects we also support research and many other things so if you are able to please please uh consider donating i am about to put a link up in the chat and with that we will carry on with a few more questions joe botting a friend to many of the paleontologists in the audience asks a question do plants use opsins to detect light direction or something else and we should say opsins are a protein that is light sensitive so what do you think about that lauren uh no see like uh plants don't use obstacles options are an animal thing really um i remember my plant biology plants use a lot of oxins rather than options to detect light but that's kind of pushing my knowledge a little bit there you go splitting your opsins from your oxins very important hannah asks why does some animals see particular wavelengths better than others oh good question so i mean for us because we have very good colour vision um it's kind of difficult to imagine what your life would be like if you couldn't see quite so much or of course if you could see more so for example i guess part of it depends on um you know how again how big your eyes are how many different kind of types of cell you can maintain how many option sequences you happen to have down to chance in the evolutionary sense but also it depends how important it is to you so one of the kind of fundamental ideas behind why humans can see red and primates can see red which is quite an uncommon thing is um this idea that it was possibly used for foraging and finding um ripe fruits among trees uh similarly um if you look for matches between for example flower coloring and flower patterns you often see corresponding sensitivity to those wavelengths in their pollinators so often it's you know a particular task which is really really important you will then eventually you'll be selected to be very sensitive to that particular wavelength which is important to you excellent excellent and stephen wants to know do you find eye development changing drastically within families for example do you have particular development of eyes within families that are doing particular things i think we're mixing together a question from stephen and a question from thomas there brilliant very good questions this is actually something that i've just started working on um in the spiders so as of the 1st of september we are looking at differential eye development between different families of spiders and so my postdoctorish is currently doing a whole bunch of sequencing and institutes to look at how gene expression creates these different eye patterns within families so that's something i'll come back to in a year or so but we are really interested in looking at exactly how development uh directs um you know the adult morphology and i think that also answers ivo's question which was what were you planning to investigate in the future well there you are either you've got your answer it's the very question we just asked there thorsten asks what about temporal resolution so what about how quickly the the whatever is viewing the world can see changes is there a direct relation between temporal resolution and the structure of the eye so the structure i'm not entirely sure you'd be able to tell but for temporal resolution often you can um you know it often you can kind of anticipate what it might be like by a lot of the behavior of the animal itself so often if you have very heightened temporal resolution of a receptor you could be really fast moving uh you might be really active or have a very high metabolism so we can have other predictors that might help us anticipate what the temporal resolution might be like so for example i think recently there was a paper looking at um snapping shrimp and found that they have among the highest and poor resolution of any eye and they have this kind of you know um very rapid uh prey capture behavior so make sense they have very high resolution whereas something like um the starfish for example have been shown to have very slow uh turnover of their photoreceptors and you know they're also moving very slowly so that makes sense it depends what they're using their vision for as well so if for example using it to avoid an obstacle that obstacle is not moving you're doing moving so again you can kind of get away with having a slightly lower resolution but if you're tracking something else and both of you are moving you might have to have kind of finer time spacing between your samples a few f more final questions now we go to jethro who would like to know and this is a brilliant question what animal do you think has the most under appreciated vision he asks what animal surprises people when you tell them about their visual capabilities oh that's a great question um so i think there are some definitely some unsung heroes of animal vision for sure um i think actually those those box jellyfish are among them for me i think jellyfish are really one of those things that people don't think about as being visual and they're having 24 eyes and four types that are able to do all these different things like i think that's amazing i think they're super cool wonderful wonderful wonderful and we always love the box jellyfish perhaps we could have another poll sometime on whether we love box jellyfish more or less than nicolas cage um i am going to go to steven bennett who asks humans can have blue green brown eyes so we're talking about the color of the the pigment in the eyes what what we see when we look into other people's eyes humans can have blue green brown eyes why and do other animals have different colored eyes oh wow that's a that's a good question i'm not sure i can tell you about other animals having different colored eyes um but certainly from from what i know about human eyes it's a particular protein structures of the muscle of the eye itself so when you can see your kind of you know your pupil and expanding contracting the part of the eye that you see the color in is actually those muscles so i think it's just slightly different proteins that are expressed in there i couldn't tell you about other animal eyes i have to admit sorry there you go ladies and gentlemen next time you're gazing deeply into the eyes of another think about the proteins that are making up the colors of their eye and at that point i think we're going to go to the final question which this week i'm going to give to duncan murdoch who asks if you had which is a modification on our usual last question if you had to choose one group which would it be kytons brittle stars or spiders and i'm gonna add why oh that's uh that's pretty brutal see quite kittens are my my research home they were where i was you know born and raised in a scientific context so i kind of always come home to them um but my loyalty probably lies with the spiders now which i know is not what duncan will want to hear as a professor acnophobe there you go ladies and gentlemen moving from the kytons over to the spiders and they have persuaded her to stick with it now there you go and perhaps um we will hear more about spiders in the future as your wonderful research continues thanks once more to dr lauren sumner rooney for joining us this week for a wonderful talk that's taken us given us a new view on the way people way things see the world a final reminder that we look forward to seeing you again in two weeks time when george mcgavin will be speaking on the topic of what have insects ever done for us you can sign up on the link in the chat and if you've enjoyed tonight why not share your thoughts on social media media using visions of nature and you can see this and all the other talks again on our youtube channel oumnh videos so at that point thanks once more to lauren we've loved bringing you into the museum and inadvertently taking you on a bit of a tour to some of the different rooms who know we made who knows we may do this again next week but at that point thank you for joining us this evening and we very much look forward to seeing you again in two weeks time good evening everyone

Channel: Oxford University Museum of Natural History

Views: 2,691

Rating: 4.7619047 out of 5

Keywords: museum, science, animals, vision, sight, eyes, oxford, evolution, visions of nature, oxford university, oxford university museum of natural history, nature, lecture, natural history, natural history museum, OUMNH, animal evolution, dr lauren sumney-rooney, event, live lecture, online lecture

Id: 5WsoJyXsnHQ

Length: 72min 54sec (4374 seconds)

Published: Fri Oct 23 2020

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The evolution of vision revolutionised animal biology, and eyes have evolved in a stunning array of diverse forms over the past half a billion years. Among these are curious duplicated visual systems, where eyes can be spread across the body and specialised for different tasks. Although it sounds radical, duplicated vision is found in most major groups across the animal kingdom, but remains poorly understood. We will explore how and why animals collect information about their environment in this unusual way, looking at examples from tropical forests to the sea floor, and from ancient arthropods to living jellyfish. Have we been short-changed with just two eyes? Dr Lauren Sumner-Rooney is a Research Fellow at the OUMNH studying the function and evolution of animal visual systems. Lauren completed her undergraduate degree at Oxford in 2012, and her PhD at Queen’s University Belfast in 2015. She worked as a research technician and science communicator at the Royal Veterinary College (2015-2016) and held a postdoctoral research fellowship at the Museum für Naturkunde, Berlin (2016-2017) before arriving at the Museum in 2017.