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?
Birds already had a sky advantage and mammals had a land advantage when the dinosaurs went extinct. It takes millions of years to develop things like feathers, why compete with animals that are far more specialized than you for the task at hand.
So I think it all comes down to competition, evolution fills niches that are open, if it’s already crowded then naturally it’s more beneficial to expand in empty niches.
InvalidName2@lemmy.zip 1 day ago
The single, simple answer is the one that you don’t want to hear: There is no clean split. Bats are a large and diverse group of flying mammals just like birds are a large and diverse group of flying dinosaurs.
The simplest answer I can come up with (because it’s actually a very complicated and convoluted topic that I wouldn’t truly do just anyway) is: Most birds can fly because they are an offshoot of one group of dinosaurs (avian dinosaurs) that survived the last great extinction when their non-flying non-avian dinosaur relatives did not. Basically the ones that couldn’t fly mostly went extinct. And mammals mostly don’t fly, which is possibly because several groups of vertebrates beat them to it and essentially filled all the niches that would have been available to flying animals, kind of blocking that path for them.
Obviously that’s nowhere near the full story. There are lots of other factors at play, like some of the peculiarities of mammalian and dinosaur physiology that made one group better suited to flight than the other, ramifications of the great extinction that killed non-avian dinosaurs as well as most large animals in general and whole swaths of other species, and so on.
CmdrShepard49@sh.itjust.works 1 day ago
Is this accurate? I was always under the impression that birds evolved from “land dinosaurs”.
Makhno@lemmy.world 1 day ago
Well, yes, where else would the flying dinosaurs come from?
Zagorath@aussie.zone 1 day ago
The first flying dinosaur evolved from a non-flying dinosaur. The word for a “flying dinosaur” is “bird”. (Sort of. Bird isn’t a scientific term, arguably crown-group birds don’t include the first flying dinosaurs. But in that case the first bird evolved from a flying dinosaur which evolved from non-flying dinosaurs, so it still works.)
phantomwise@lemmy.ml 1 day ago
I guess that depends on your definition of what’s a bird is and where you place the transition between bird-like dinosaurs and birds. Like Archaeopteryx is one of the species in that weird kinda dinosaur kinda bird phase.