Like, I’m aware of there being exceptions like Penguins, Ostriches, and Bats. But in general, why is there such a distinct land/air split between mammals and birds? Why don’t mammals share the ground with ecosystems of plant- and meat-eating walking birds? Why didn’t we get birds that evolved to slither like snakes, or tunnel like rodents? Why isn’t it (land+sky) all just mammals, where we’d have parrot- and vulture-like bats that don’t lay eggs? If we started the simulation again, might things like this evolve?
I guess I’m forgetting that there were several different dinosaur periods spanning hundreds of millions of years. My mind defaults to the jurassic period being the only one.
Most of the more famous dinosaurs were actually from the cretaceous period. T. rex, stegosaurus, velociraptor (and the deinonychus and utahraptor that the movie Jurassic Park’s depiction of “velociraptor” was based on), triceratops, ankylosaurus. Pretty much all the non-avian dinosaurs the average person could name, other than sauropods like brachiosaurus, lived in the cretaceous. Some of those I named did admittedly first evolve in the jurassic, but most are most well-known in the cretaceous.
Though fwiw, birds did first evolve in the jurassic.