So the confusion with how "if birds are reptiles, why are there still other reptiles"

First. Nothing can evolve out of a clade or group if lifeforms.

For example. If an animal has a spine it is a vertebrate. But what if an animal doesn't have a spine, but its ancestors did? Well then it's still a vertebrae but it'll be in a new subcategory.

Now in a very simplified version. "Reptiles" as we colloquially know them (birds, crocs, snakes, lizards, turtles) all come from a group of ancestors that all shared certain features.

Deep in the past the group that became turtles started becoming different enough they became their own group.
So what was once 1 group splits into 2. The turtle group goes one way and becomes turtles. The rest continue.

Now fast forward and another split will happen.
Lizards and archosaurs will split. Archosaurs are the group crocs, dinosaurs, and pterosaurs belong to.

Fast forward even more and now theropod dinosaurs specifically will split off into avian dinosaurs also known as birds. But all of the reptiles that came before that didnt go extinct are still there.

During this lizards will also split. Becoming snakes, mosasaurs, and all modern lizards.

Evolution is really weird. And clades can be hard to understand.

If you'd like to learn more about it. I highly recommend checking out forest valkai's BioLogic and Light of evolution series. Or Clint's Reptiles' "you are the hagfish of reptile"

The reason the branch happened is because the avian dinosaurs were the ones to survive most of the cataclysms, they evolved to be smaller and lighter which allowed them to adapt to different environments quicker. It's similar to why mammals survived, most of them were tiny and reproduced quickly to survive on minimal resources and spread out across a vast area.

It was still adaptation for survival, just in different ways for different circumstances.

3:45  To answer your question, it depends on what traits got passed on in a species. If a group of  people had four arms, but they died before they had any children, no one else would have those. But also, DNA can randomly mutate, and if those get past on,it might change the species. It's the same reason we aren't incredibly hairy like gorillas, even though we're both apes.

There's not millions of bugs. There's trillions, maybe even more.

As an upcoming paleontologist myself, I’d be happy to answer any questions to anyone curious about stuff.

3:33 theres birds because they were small dinosaurs and lived by flying away, lizards exist because they were smaller than dinosaurs and hid, pretty much

Dinosaurs are both, brilliant and confusing animals that walked the earth

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10:52 there’s a massive crater in Yucatán, Mexico called the “Chicxulub crater” about 110 miles wide, which was where the asteroid hit

10:05 Welp now we know about the badger's ancestors

Yup. They were basically birds and not giant reptiles. I went down a rabbit hole years ago to find that out

I think the reasons why Jurassic Park's infamous "the T-Rex can't see what moves" line is a thing is because back when that movie was created, we didn't have a full understanding of how the T-Rex really worked compared to the research we hsve currently, and that because it was a mostly accurate replica that didn't have all the correct dinosaur trait we now know they have, their eyesight was affected because of their head shape being partially inaccurate with their snouts blocking their central vision and their eyes facing slightly outward

7:00 he should have mentioned that we have a smaller species of Quetzalcoatlus called Q. lawsoni that is much more complete. On top of that we also have other azhdarchids that give us a more complete picture of these pterosaurs. In general its important to note that not all species we have are super fragmentary. We have cases like Amargasaurus or Carnotaurus where we have a single specimen thats extremly well preserved, or cases like psittacosaurus where we have literally hundreds of specimens. So that point that he made is a little missinforming so its deffinetly not all guesswork. Most fragmentary species we have are at least parts of clades where we can make educated guesses and know its not to far off, its only when we have certain groups with poor fossil record that it becomes a problem, like megaraptorids or spinosaurus specifically for example.

12:27 MIKEY PLZZ DO MORE DINOSAUR VIDEOS I NEED TO NERD OUT TO YOU GUYS BECAUSE THIS IS MY LIFE DINOSAURS ARE MY LIFE PLLEEEAAASE AARON DO SOMETHING

6:14  I know a single, small playlist from Lindsay Nicole that can let you know about the entirety of all life on earth. Honestly real simple.

7:32 for the speculation thing, is done in a quite simple process(in theory) let's take Quetzalcoatlus for exemple, we get the arm bones, then we compare it the the arm bones of anothe, more complete pterosau we have, the closer they are from each other the better, after comparing, we scale them based on what the other more complete fossils look like

Exemple:"oh this one is like 3ft tall, and thir arm ar 1ft long, which means that, by scaling it up this 3ft long arm must be from a 9ft tall member of a similar species l"(this is a very simplified description of the process, but i think you got the idea) this process also works in other branches of science, but also there are other types of speculation methods, it depends on what you're looking for

Birds are technically a dinosaur

The only reason why the T-Rex’s arms aren’t really being used is because it has a giant head and whatever it sees food what’s the point of arms when you could just bite down on your prey and eat

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