Global Climate Change Is and Always Has Been a Population Problem

[myccrider]

18. Birds definitely existed before the asteroid hit,

with the same basic features that we recognize as ‘birds’ today, eg feathers, beaks instead of teeth, loss of tails, wishbones, powered flight, loss of ‘fingers’ on the end of wings, etc. There’s vigorous debate among paleontologists and evolutionary biologists about exactly where to draw the (artificial) line between flying/gliding dinosaurs and fully avian dinosaurs. All extant pre-asteroid. The only branch that survived the strike and its aftermath were the neothornithes (iirc), who already were pretty much what we call birds today, just different species. (wish there were an "I’m being pedantic" smilie, maybe the ‘teacher’ covers that. )

I’m not trying to be quibbly, this is just an area of interest to me. And, yes, there have been further evolutionary changes (penguins! hummingbirds! maybe flightless birds, raptors?).

Here’s an overview paper, if you’re interested. https://www.sciencedirect.com/science/article/pii/S0960982215009458