[sopooneo]

Does this mean that distinct, non-flying species of dinosaur independently evolved to be able to fly? Or does it mean that one species of dinosaur evolved to have the ability to fly, and then further branched into all know species of birds?

[loosescrews]

According the the Wikipedia page on animal flight, dinosaurs and birds are believed to have evolved flight independently.

https://en.wikipedia.org/wiki/Flying_and_gliding_animals

[tsimionescu]

Actually, according to that article pterosaurs, that are explicitly not dinosaurs, evolved flight separately from the dinosaurs/birds (with two other separate times flight evolved mentioned, in insects and in bats).

[ajuc]

Another time it evolved independently was in homo sapiens.

[gnulinux]

I think you meant to say pterosaurs and dinosaurs (in particular, avian dinosaurs, including birds) evolved flight independently.