TED talks are pretty blasé but this one's pretty interesting.
Basically there a lot of "different" dinosaurs because the rush and "clout chasing" of early paleontologists wanting to discover new different kind of dinosaurs.
This guy cut open a lot of samples of dinosaur bones he had and found a lot of things, like the Allosaurus was really just a younger Tyrannosaurus and etc. because one day he started to wonder where the hell the baby dinosaurs were.
Conflicting sage cause shit thread but I like dinosaurs.