Aminotes

Hi. In this video, we'll be talking about AM notes, which are a group of tetrapods defined by their specialized amniotic egg. AM notes include reptiles, birds and mammals. Now let's turn our attention to that egg, which is a watertight egg that contains a Siris of membranes. I wanna talk about each of these membranes, so obviously on the outside here we have the shell. That's not one of these special membranes I want to talk about, but beneath that we have the Korean, which is the outermost membrane in one of those special membranes that I wanted to mention. We also have the AM neon, which is kind of the namesake for this whole thing. The AM Neon is the fluid filled cavity that, in cases the embryo. And of course, this little guy in here is our embryo. Now the yolk sac, characteristically yellow, provides food for the embryo, and you can see the blood vessels in here. These blue and red lines are connected to the gut of the embryo in pink. Right below that we have the Alon toys and the Alon Toys is basically the embryos toilet. It's maybe better characterized as it's, uh, septic tank. It's where all the waste products are excreted and you can also see that those air connected or that it's connected by blood vessels. Now, this solution that the embryo sits in, which I should point out these are the four membranes I wanted to talk Thio talk about. Obviously you don't want to talk to them. Then people will think I'm crazy. But the albumin, it's not one of those membranes, but it is important. This is what we call, uh, normally egg whites. Let me get my head out of here so you can see I'm just talking about this sort of darker blue region. The solution that cushions the embryo also provides nutrients, and it is very protein rich and again that that is what, uh, we eat when we are eating egg whites, that is the albumin. Basically, Now, reptiles are sort of the earliest, the earliest AM notes. Living relatives basically are these reptiles which are ect a thermic tetrapods, extra thermic, similar to amphibians, right. They get their heat source from ah, an extra mainly from an external source and they absorb it. They also have these scales that are made of carrot in carrot and you might remember is what's in our hail. It's a protein that's in our hair and our nails also in things like animal horns. For example, on this carrot in helps these guys prevent water loss. Remember, before reptiles, we had amphibians, and they have to constantly be kept moist. These guys have evolved these scales to adapt to life on land, Right? Uh, it helps them keep their ocean inside their bodies. Sort of how I like to think of it. So some characteristic organisms here we have a turtle. Um, that happens to be a sea turtle. There's also turtles that live on land. Uh, the rich tortoises, I should say a za Well, we have a snake here. This is a cobra. Uh, here we have a lizard, and over here we have a crocodile. So, uh, turtles, snakes, lizards, crocodiles, These air all reptiles. And it's important to note that fertilization in reptiles actually occurs internally. Prior thio eggshell secretion. That means that these guys need to mate. Mating is required for their sexual reproduction. And with that, let's turn the page

I want to briefly mention birds, which are endo thermic vertebrates that have feathers, beaks and lightweight skeletons. We often call hollow or hollow bones or bird bones. And the reason I want to bring these guys up is because they're actually part of the monofilament group dinosaurs. That is to say, birds are in fact, dinosaurs and dinosaurs are part of the monofilament group reptiles. So these guys, even though um, they look very different, they've evolved to have ah, very different morphology. They're part of that same monofilament group. So, uh, essentially birds are dinosaurs there, 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, uh, road runner from today And yes, that's a road runner, just like the bird from the cartoon. That's what they actually look like. And they don't go, Mimi. Also very quickly you can see a feathered dinosaur here on its way to adapting bird like flight, as we see over here Now, am newts come into basic flavors, right? There are these, uh, syrup seeds, which we just talked about. Those are reptiles and birds. And then there are these organisms called synapse IDs. And these were the group of AM notes that include mammals and they happen to be distinct from other AM notes or rather distinguished from other ami. It's do do certain features of the skull. Uh, 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 on trade I these guys, these the early forms of these creatures really do just look like reptiles, right? But hopefully you can see through these images I provided how they would transition from being more reptilian like you see here to something more akin thio mammals you're familiar with today, right? So the growing of hair is certainly 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, uh, kind of primitive, primitive early synapses and there going thio, you know. Eventually lead Thio later. Synapses like this guy who these These guys obviously like very reptilian looking. This guy is kind of weird on the way organism, right? Sort of has a reptilian look to It also has hair, you know, one of those weirder transition organisms. And then eventually we're going Thio, you know, get something more like this, which certainly looks like it's on its way to becoming a manual. Right has the for has the shape. But there's still something about it that looks, you know, hearkens back Thio. It's more ancestral form. And then, of course, ultimately we're going to get, uh, you know, rodent like mammals is the earliest, uh, you know, 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 air, what the earliest mammals look like. So hopefully these pictures can kind of give you an idea how these early synapses, which were very reptilian looking, would eventually become mammals. With that, let's flip the page

After all these strange organisms we've looked at, we finally arrive at mammals animals that look like us. These air endo, thermic AM notes, and they have mammary glands. That's what gives them their name. These air milk producing glands that feed the offspring mammals also characteristically have hair and three middle ear bones. This one seems kind of random. It's just one of the defining features. Don't you know? I wouldn't stress about it too much. It's, uh, the three bones used to convey sound in our ear. And, uh, the last feature of mammals is the neocortex. This one is important, right? This is what allowed for improved cognition and eventually for us to develop these big noodles that we have. So we said that mammary glands produce milk to feed the offspring most. That milk is coming from fat. It, or rather milk is mostly, uh, water and fat and sugar. So good nutrients. Thio bulk up a baby. Here, you can see a bunch of pups nursing on, uh, this mother aren't Corgi is the cutest. I love core G's. All right, so let's talk about mammals. Uh, first of all, monitoring IMS. These are kind of the weirdest mammals that there are these air, the strangest ones out there. They're egg laying mammals now. Generally, when we think of mammals, we think that mammals give live birth. These guys don't they actually lay eggs? Uh, that's why they, you know, are often looked at as sort of an early evolutionary offshoot from mammals. Right? Whereas later mammals would give birth to live offspring. These guys don't, uh there are very few monetary means in the world. There are plata pie. So here we have platypus spell that all wrong platypus. And then over here we have kidnap. And there are about four species of a kidney, if I'm correct. And on Lee, one of Plata Pie, so very few monetary means in the world. And they're all found in Australia with that, let's turn the page

marsupials are another one of those strange types of mammals. They actually birth underdeveloped offspring that have to remain in a pouch which contains the mammary gland nipple. So basically, these offspring come out and they're not fully developed Like, uh, the live birth offspring of most mammals that you're used to. They look almost like, uh, part way still like a fetus in many ways. And and that's why they have to remain in that protective pouch. You can see this little baby kangaroo poking its head out of the pouch there. Well, that is a much more developed kangaroo than what it looks like when they first come out. And just to give you some examples of marsupials, we have a koala bear here. It can grew here and possum here. Now, most marsupials are only found in Australia, like the Kuala bear in the kangaroo. A possums, on the other hand, made it to the Americas. Ah, so moving on, finally, we get to placental mammals. Thes are mammals like you are probably most used to. These mammals give birth to live developed offspring after a long gestation period, what we normally call pregnancy and the defining feature of these organisms is the placenta this Oregon pictured here that connects the developing fetus to the uterus wall and allows for the fetus. Thio, get nutrients from the mother to do gas exchange, as in breathe. This is, you know, this is how the fetus breathes essentially, and it also allows for waste disposal from the fetus. So here we have a new example of a developing fetus in the uterus with placenta pictured. And here is an example of a placental mammal, a three toed sloth by far the most regal, if not also one of the nicest placental mammals out there. That's all I have for this video. I'll see you guys next time.