I want to briefly mention birds, which are endothermic vertebrates that have feathers, beaks, and lightweight skeletons we often call hollow or bird bones. And the reason I want to bring these guys up is that they are actually part of the monophyletic group, dinosaurs. That is to say, birds are in fact dinosaurs, and dinosaurs are part of the monophyletic group of reptiles. So these guys, even though they look very different, they've evolved to have a very different morphology, are part of that same monophyletic group. So, essentially, birds are dinosaurs. They are the living embodiment of dinosaurs today. And hopefully, you can see that, to a degree with this picture of a feathered dinosaur on the way to becoming a bird next to this roadrunner from today. And yes, it's a roadrunner just like the bird from the cartoon. That's what they actually look like, and they don't go "me me". Also, very quickly, you can see a feathered dinosaur here on its way to adapting birdlike flight as we see over here. Now, amniotes come in 2 basic flavors. Right? There are these sauropsids, which we just talked about. Those are reptiles and birds. And then there are these organisms called synapsids. And these are the group of amniotes that include mammals, and they happen to be distinct from other amniotes, or rather distinguished from other amniotes due to certain features of the skull. You don't really need to worry about that. I am not going to get into it. All I really want to do here is convey how, in a qualitative way, get you to think about how these sort of reptilian looking creatures, these synapses, which, you know, to the untrained eye, these guys the early forms of these creatures really do just look like reptiles. Right? But, hopefully, you can see, through these images I've provided, how they would transition from being more reptilian, like you see here, to something more akin to mammals you're familiar with today. Right? So, the growing of hair is certainly one of those big changes. And also, just the change in, you know, face shape, losing that sort of reptilian look. So here again, we have some more, kind of primitive early synapsids, and they're going to, you know, eventually lead to later synapsids like this guy who, you know, these guys obviously look very reptilian. This guy is kind of a weird transition organism. Right? It sort of has a reptilian look to it, also has hair, one of those weirder transition organisms. And then eventually we're going to, you know, get something more like this which certainly looks like it's on its way to becoming a mammal. Right? Has the fur, has the shape, but there's still something about it that looks, you know, harks back to its more ancestral form. And then, of course, ultimately, we're going to get, you know, rodent-like mammals. These are the earliest mammals to hit the scene. And to be clear, I'm not saying that they are rodents. I'm saying they have a rodent-like appearance. Those are what the earliest mammals look like. So hopefully these pictures can give you an idea of how these early synapsids, which were very reptilian looking, would eventually become mammals.