 All right, look, look at where we are. I'm going to take like this little zone and I'm going to rebuild this piece in a new place. Let's go somewhere else because I'm running out of room. So we're going to take all of our amniotes and what you're going to see is this. We're going to take our amphibians. Amniotic amphibians are going to be our out group and that is the frog, the salamander, those guys. All, everybody on this page is going to be a tetrapod, meaning it has four limbs. So you can imagine how that's going to be unique from the fish, which have fins. And then we said, okay, what is going to unite all the critters that are coming next and it's the amniotic egg. We've talked about the amniotic egg a little bit, but the amniotic egg is this amazing structure. Amphibians still have to have water to lay their eggs in. If they don't have water, their eggs will dry out and they cannot reproduce. So they're stuck, at least migrating to a water source to reproduce. If they don't have a water source, they're not going to reproduce. So someone along the line developed, mutated into an amniotic, to having an amniotic egg and I just need to show you a picture of this amniotic egg. It's a chicken egg, that's all. And what it is, you have a shell, you have a food source, you have your little critter in there and then you've got a series of membranes and various structures that ultimately function to provide oxygen. I mean, think about it. Like a chicken egg, sure you need to keep it warm, no doubt. You've got to keep it moist as well and you've got to allow gas exchange because that's a critter in there. So it needs to get rid of its carbon dioxide and it needs to get oxygen in. But other than that, like that is a little incubator and as long as you keep it warm and moist and allow it to do its gas exchange, it will grow from a tiny little thing into a baby chicken or a baby lizard or a baby turtle. I was about to say frog, but could it grow into a baby frog? That's a great question for an exam. No, because frogs, that's a great true falsi. Correct the falsi. Frogs have amniotic eggs. No, they don't. I don't remember what I was saying, but they don't have amniotic eggs so they cannot get one. I don't even know, but let's go over here. The first people to get the amniotic egg is the reptiles. So we could say reptiles are coming up, but watch what I'm going to do to our cladogram. This is going to make you mad because we like to think of ourselves as mammals of ever. I'm going to throw mammals here. Mammals are going to branch off of this tree and watch what happens to my reptile group. This is reptiles. In fact, the ancestor that had the amniotic egg was more similar to reptiles than mammals and we got various characteristics like hair, mammaries, warm-bloodedness, blah, blah, blah. In amniotic egg reptile land, there's a couple of things that happened. First of all, they all, in addition to having an amniotic egg, they have a special skull. And I want to show you a picture of this special skull because I think it just will help you visualize. Check out this hole right here. This is a diapsid skull and the reptiles have that in common. All of them have this diapsid skull. But then birds have a diapsid skull and non-avian reptiles share a common ancestor. So we'll call it an avian reptile and here's the crazy part. Back here, in fact, I want to make this into a branch that branches into the avian reptile and cross this one out in the middle and have it branch into a dead extinct branch of dinosaurs. What? True story, avian reptiles, birds, are basically the living ancestors of an ancestor that gave rise to dinosaurs and avian reptiles, seriously. And they share characteristics. They share skull characteristics and I have to show it to you. It's called the incredible ant orbital finestra, but of course. And when you take anatomy with me, seriously, are there more names to learn? Look, ant orbital finestra, there it is, it's a hole. And it's a hole that is found in dinosaur skulls and bird skulls. How's that even possible? Think about the word, ant orbital, ant anterior to the orbit, eye orbit. Ant orbital finestra is hole. There's a hole in front of the eye hole that is in birds and dinosaurs. That's how they know, that's one of the pieces of evidence that suggests that birds are nothing more, nothing more than living dinosaurs. Fantastic. So let's write that in here, ant orbital finestra, wow. In our non-avian reptiles, let's go back to our diversity sheet and look at all of our non-avian reptiles. Holy di-ver-se-t. Wow, there's a lot of those guys. And then we have to have a little smattering of avian reptiles, which, I mean, avian reptile watching, avian dinosaurs, that's not, those aren't reptiles, settle down. There is the end of my avian dinosaur reptile bird land. We used to think birds were their own thing, but they're not, they're reptiles. Okay, did you get that idea? I think so. Let's take a look at our mammals and we're going to call it good.