 Oh, that works amazingly. Sometimes it works. Right, so thank you Tom for this wonderful introduction to Mike's work and what he's done through his life. I'm going to talk more about vision, but very much in the spirit of Mike. So Mike looked at all sorts of animals across the animal kingdom, as Tom has just shown us, and we're actually not nearly, but in every case where he looked at a new animal in new place, he tried to measure the performance of the eyes and the visual system to see what it would do. And he did that because he wondered about what is the, what are these eyes useful? You can always ask what was the purpose of the eyes? What kind of functions did they serve? And in that kind of spirit, you can kind of ask, in general, what are eyes actually useful? The obvious answer is seeing, yes. But you can actually divide vision into a number of different major domains. And from that pulls out that there is one domain that is extremely essential to us and to basically all animals that have eyes, but it's unexplored. So you all have an unexplored domain of vision in your system. I'm going to tell you about that towards the end. Let's have a short look at the diversity of the visual systems, which Mike was one of the people that actually told us about. There are of course all sorts of eyes on the head, called cephalic eyes, the sitting head. There's a left eye and the right eye. There are lots and lots of different animal groups that have these paired cephalic eyes. Some have eyes like us who cannot have eyes, others have compound eyes. Some have higher resolution eyes, others have lower resolution eyes like little slugs and all sorts of worms have a pair of cephalic eyes. You would think that that is eyes. If you think about eyes, that's what you think of normally. But there are lots of other real eyes. There are median eyes. Many animals have median eyes right in the midline of the head. Often together with lateral eyes. They actually have something like that as well. That is, for instance, a vertebrate, that's a lizard which has a parietal eye. We have something similar. We've got a pineal organ. We are mammals and mammals have lost their light sensitivity in the pineal organ, otherwise, pineal organs are light sensitive, medium, little light sensitive organs. So we have it. Lots of other animals have similar things like that. And lots of animals have eyes on other parts, especially animals that have reduced the loss of never had a proper head. They've got eyes in various other parts and might work on many of them, like the scale of eyes and other things like bandworms. They have been there a bit more later on and the starfish and jellyfish they would have rather amazing eyes, but not on the head because they don't really have a head. Then there are actually animals that have vision, but no eyes at all. They've got light sensitive cells sprinkled with their body and they display visually guided behaviors. They can move towards particular structures that they like, but they don't have any proper eyes. So vision is more than eyes, actually. From this enormous diversity, we actually ask, then what do these things do is can we actually, is there a hundred different types of purposes for these eyes? Well, you could say that, but many of those tasks are kind of similar so we can start to kind of divide vision into different types of tasks. And one obvious thing is if vision is based on discriminating objects or not, because as humans we are extremely biased towards objects. Everything we see, that's a human, they're a human, there's a chair, there's a computer there. We categorize things and call them things and we have different behaviors in relation to different things. We don't do the same things together with chairs as we do together with humans or computers. Same thing with animals. Animals that have object vision, they do different things. They have different behaviors towards different types of objects. That is a really powerful thing. All animals don't do that. Many of those animals that have small, low resolution eyes, they can't do, they can't discriminate objects because you actually need a reasonable acuity to do that. So all the smaller animals that don't have fantastic large eyes, but they still have eyes, they still have vision and they do non-object based vision, which we actually do too. When I walk, take a walk, I see that I'm moving, that has nothing to do with objects. I'm moving my own speed, I know how fast I'm moving and I can see the direction I'm moving. I can see the distance to things. I don't need to see objects for that. And that is used to orientation, which is really important. That came, obviously, about much earlier than the object vision. You can find animals that have small eyes that need no orientation throughout the animal. It's actually only three major groups of animals. It's the vertebrates, it's the arthropods, all the insects and crustaceans and spiders. And it's the cephalopods, which is the catfish and the octopuses wing. So those are the three groups that have evolved object vision. So now we've divided visual system into two types, non-object based, that's kind of a mouthful. So let's call non-object based vision something simpler. Let's call it ancient vision, it wasn't started with ancient vision. We still have ancient vision. And then object vision evolved. So there are two different types, ancient vision and object vision. All animals do that have object vision. So when object vision evolved, it didn't mean that ancient vision was discarded and superfluous, still as important as it ever was. So now we've got two major domains, but you can also divide vision into action vision. Mike actually studied very much with our movements and things like that, how how animals use and humans as well use vision to directly guide movement, directly guide actions with a feedback. So as soon as something happens in the visual world that is fed back to the brain which corrects and changes the actions towards the goal. So this active vision is of course one thing, but you also have perception, you also take in what there is around you, which will affect what you will do maybe in a couple of seconds or in a couple of minutes or in hours, in days, in years. So you pick up information that is not immediately guiding or correcting your movements or your actions. And so we can simply call this perception or assessment vision you assess your environment, all animals with eyes have to assess them around. If you don't assess your environment, how would you know where to go. You need to work out, you want to go in that particular direction that is an assessment and then you actually do it. So you've got action vision and perception. So now we've got two completely different ways of dividing visual systems or vision. We can combine them now, which of course then ends up in four quadrants. And if you combine ancient vision with action vision, you get orientation. If you combine object vision with action vision, you get interaction with objects. If you combine object vision with perception or assessment, you get what most people would call perception. All these things are well studied for more than 100 years. Neurobiologists and psychologists have particularly looked at that third quarter, but no one has really looked at this fourth quadrant. So we have an action vision, not object based stuff with perception. But animals of course must have done that and we do it too. And we do that, all animals do that in order to work out where they are, to be able to select where to be, the kind of environment you're in. But not just that. Let's take a closer look at that fairly soon, but let's just see what kind of information there is in these different patterns for orientation you of course pick out the borders and contrasts in the image and how they move. So it's the what is called the optic flow for interaction with objects you have a separate objects from the background. Often using cues from exactly the same you will say it's actually used here used to select objects. Then in order to interact with objects you need to, you need a tension so you need to be able to focus on particular objects. For the third part, which is basically the same as the, the second is just that you have to take in more things you get an assessment of the situation you see those things are there and they're moving in those direction that tells you about the situation. The second is then more about reading the conditions it takes very much the same information as from here but actually also does something else, which is rather different the distributed distribution of light in the environment. So that's not concerned with single scenes. If you're in one place and look like that you see all the things over there you turn around, you see something completely different but you're in the same environment. Of course, doing that is actually important animals have to select their habits. They need to know where they want to be on that they need to know if they're in the right place or if they should relocate to another place. But they also need to work out what to do, because they shouldn't do the same thing all the time, and will have a large behavior repertoire, and they have to pick the right behavior at the right time. So that depends on where they are and what the conditions are or time of day it is what the weather conditions are lots of things like that will have to be taken into determine what to do. Animals of course have to forage, find food and escape from predators which were that poor fish that has miserably failed on. I think the bird of prey, the eagle had actually a better vision of the fish than I've performed the fish there. And animals have to interact socially they have been engaged in reproduction will take care of nests and young and things like that, another different types of behaviors that animals have to do, and also need to recover and rest and sleep. These are also behaviors, so that you can make a long list of different types of behaviors which animals constantly have to choose the right kinds of behaviors for. And that's really important. Vision has a very important role in determining where to be, what to do. If you end up in one of these two environments you'll probably, if you had a choice you possibly some of you would pick that environment, and I guess if you would pick the other environment, but wherever you end up you would not just randomly choose activities. You pick something. A few activities from seeing natural under those conditions in there, and other activities from seeing natural in the other place there but how can we assess animals and humans assess the environment. Because as I just said before, if you look at different scenes like that. It's kind of irrelevant if you want to assess the environment that there is a tree over there and a tree over there you don't really need to know anything about trees. You can assess this environment. So if we just add many of these scenes on top of each other. You have a really slow part of your visual system, which will accumulate over a little while that will accumulate information about the general distribution of light, and the general is the distribution of structure. That's why there's an animal of course quantified in the in a simple way you have this diet, everything that is straight down here that is straight up. And you've got intensity in various ways on these scales here. So in in an environment, the intensity varies from straight down to straight up so there isn't a vertical gradient of intensity. There is also a vertical gradient of contrast which is how much visual structure there is up in the sky there's not much visual structure, and that depends on the environment how these first look. There may also be, or there is a vertical gradient of spectral distribution of different colors, different wavelengths of light. And if you combine all these things and look at different environments it turns out that you can characterize with very little data. The difference between different types of environments. You can have a forest. But even if you look at different types of forest you can tell different types of forests apart and say that that is that type of forest where I want to be. That's another type of forest where I don't want to be even different parts of the forest, the same forest you can pick that out from these pairs. And the same thing is true for the underwater world, different underwater worlds have different personal life periods. The same environment under different conditions this is exactly the same environment under different weather conditions that they are really reliable cues from these vertical light gradient that tells you what the conditions are. You can also tell the time of day from this vertical light gradients and you can tell the season if you're in a place where there are seasons. So all these things you can work out, you can work out the type of environment where the condition time of day season, and if you live in water you can even work out the depth. You can do those things independently so you get separate information about these things which is incredibly powerful to work out where to be and what to do. So what part of the ice does this. Well, in insects, for example, you might think it's the large compound most but I would actually say yes it's these median ice that does it. At least in many insects. Some insects may actually be partly the compound ice. Let's take a look at the vertebrate system. We've got, as we know, the ice. And from the brain there are light sensitive parts to pineal and then some some work that's actually have a pair of pineal as well and some summer it's have evolved a parietal eye. But these systems actually look very, very similar. We look at that shortly at the neural circuitry there it turns out because there are two different types of light sensitive cells in the animal kingdom. They're called ciliary and rabbimeric photoreceptors in the, the eye in our eye in vertebrate eyes that are primary photoreceptors are ciliary photoreceptors for they connect to the new ones or a subset of the neurons that feed into the brain are on the other time, which is called the rabbimeric time. If you look at the pineal organ, it turns out that those also subset, they have the primary photoreceptors are ciliary, but the subset of the neurons that feed into the brain are actually rabbimeric photoreceptors on the other time. And this looks awfully similar so there is, there are extreme similarities between our medium photoreceptors, but not ours, because we haven't gotten mammals across and the ice, and that doesn't look like any other part of the animal kingdom. Because in general, the lateral eyes are of the rabbimeric type it's the median eyes that sometimes rabbimeric sometimes ciliary and in some cases even both. There's a group of the vertebrates, the Lancelot or antioxidants, they still exist today, they have no lateral eyes, they only have median eyes where they, and there are, there are American ciliary photoreceptors, just in the middle. The vertebrates have this combination, both in the midline and as lateral eyes, so that kind of gives me indication that vertebrates early on actually lost their rabbimeric natural eyes. We may actually have lost our original natural eyes and made new ones from that. Well, if you imagine the cross section of the brain, the roof of the brain, there are these photoreceptors. Which may actually have evolved lateral cups to pick up the vertical like gradients, because that gives you much better information about where you are so you can decide what to do. If those natural cups then moved out and formed new lateral eyes, that would explain exactly why vertebrates have such odd eyes why they don't look at all like the lateral eyes of other animals. So, and that sounds weird, but actually we wouldn't then have lateral eyes which has to have median eyes, weird kind of median eyes. It's not completely unheard of, Mike has actually worked on many of these groups that have done that. Popepods, a small group of crustaceans, they've lost their lateral eyes, but some have actually evolved or made new lateral eyes from the median eyes. And these spiders have done exactly the same thing, their answers. They had median eyes, which actually put them into those large lateral eyes spiders. So, these glasses may not actually be as stupid as they may seem, but I'm sure that Mike Land would have had really funny jokes about this. Some beautiful. Thank you. So, how can you test that? Yeah, that's not actually very easy. Actually much of the data is already there. Much of the evidence that this is the way it happened is already there. It's actually hard to get much more than developmental biology. The problem is that all vertebrates have this system, and then there is a huge gap between vertebrates and these glanzolates that they have the oxys. There's nothing in between. We've got some sea squirt larvae that are even more like the other invertebrates and then we've got all the other invertebrates, which are not 100% consistent either. There are exceptions, whatever you look at. It's, if you could time travel, you could do this. Are there any vestiges of compound eyes in arachnids at all? Not in arachnids, no. But you have it in lingualis, of course. Yeah, yeah. And median eyes. So next is