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→And if they flew, they would be birds, surely?: Exanding definitions
:::: I was referring to the "definition" of birds as egg-laying feathered warm-blooded animals, all of which may or may not have been characteristics of some species commonly or scientifically referred to as "dinosaurs." This is why whether or not pterodactyls being warm-blooded or not may be relevant, since it is still not completely determined whether dinosaurs were cold-blooded like reptiles or warm-blooded like birds. As for your first statement, if pterodactyls were neither birds nor dinosaurs, where do you think they fall? Palaeontology textbooks (which admittedly always take the evolutionist side) classify them in Dinosauria (though some books list Aves as a subset of Dinosauria). [[User:CherryS|CherryS]] 13:08 13 June 2008
:::: I was referring to the "definition" of birds as egg-laying feathered warm-blooded animals, all of which may or may not have been characteristics of some species commonly or scientifically referred to as "dinosaurs." This is why whether or not pterodactyls being warm-blooded or not may be relevant, since it is still not completely determined whether dinosaurs were cold-blooded like reptiles or warm-blooded like birds. As for your first statement, if pterodactyls were neither birds nor dinosaurs, where do you think they fall? Palaeontology textbooks (which admittedly always take the evolutionist side) classify them in Dinosauria (though some books list Aves as a subset of Dinosauria). [[User:CherryS|CherryS]] 13:08 13 June 2008
:::: Correction, old paleontology textbooks think pterosaurs are dinosaurs, but most believe them now to be true reptiles that could fly. You learn something new every day! :) [[User:CherryS|CherryS]] 13:13 13 June 2008
:::: Correction, old paleontology textbooks think pterosaurs are dinosaurs, but most believe them now to be true reptiles that could fly. You learn something new every day! :) [[User:CherryS|CherryS]] 13:13 13 June 2008
::::: I think your discovery about pterodactyls removes most of your argument, but there's still a valid question hidden in there. That is, if the sequence is cold-blooded dinosaur --> add feathers --> add ability to fly --> add warm-bloodedness, then at what point are they considered "birds". And perhaps you are correct. Perhaps until they reach that last stage, they are not considered "birds". (Keep in mind that such definitions are man-made and somewhat arbitrary [[classification system]].<-- read that.) But a hundred or so years ago, you had the following definitions (loosely stated): Dinosaur = "large cold-blooded reptile". Bird = "warm-blooded feathered flying creature". That is, there was no provision for "warm-blooded reptile", "cold- or warm-blooded reptile with feathers", and "cold-blooded feathered flying creature". When scientists realised that some dinosaurs may have been warm-blooded, they didn't invent a new category, but expanded the definition of "dinosaur" to included warm-bloodedness. And when they started to imagine that dinosaurs evolved into birds, they expanded the definition again to include feathers. But why keep expanding the definition of "dinosaur"? Why not expand the definition of "bird"? Including "cold-bloodedness" in "bird" seems more reasonable (especially given that the precedent with dinosaurs is that blood temperature is not really a critical determining factor). So in the sequence above, they became "birds" not at the last step of acquiring warm-bloodedness, but at the second last step of gaining the ability to fly.
::::: Of course that's all based on that particular sequence. If (some?) dinosaurs were warm-blooded before acquiring feathers, it would seem that the sequence is wrong, and I suspect that there's likely biological reasons why it's better for flying creatures to be warm-blooded anyway.
::::: [[User:Philip J. Rayment|Philip J. Rayment]] 19:45, 13 June 2008 (EDT)