What species did birds come from?

Originally posted by aardvarkhome
reptile have lungs or are you being deliberately stupid?

The type of lungs, my friend.

In order to pursue this topic a little further with honesty, I will suggest something which strengthens the creationist hypothesis a little bit.

As I understand it, the creationist hypothesis claims the first birds came into being fully formed, as opposed to evolving from another life form. From that point on, evolution took place, but it was only "horizontal" or "downward" evolution which never resulted in "an increase in information". Now this last sentence is a major point of weakness in the creationist position, but I have addressed that elsewhere and am willing to do so again elsewhere - it's not what I want to talk about here.

Possibly the reason that Archaeopteryx did not have full bird lungs is that it lost them in a "loss of information" evolutionary event. Now, assuming that's the case, again, how does a scientist know if a particular species is a descendent of the bird "kind" and not some other "kind"? What are the "kinds"? Can someone provide a list?