Why reptiles are not considered dinosaurs but the birds are?

Question

The reptiles to me look exactly like dinosaurs, their skeleton resemble fossils and they are cold-blooded.

In: 1

Answer 1

It depends on how exactly you define these groups. If you group species based on their features, then it’s because birds share a lot of features with dinosaurs that other reptiles don’t like being warm-blooded, certain parts of their skeletons, feathers, etc. More often though, species are grouped based on their evolutionary relationships to each other, in which case it’s because birds evolved from dinosaurs and other reptiles didn’t.