So Stultis, educate me some more.
Which came first the dense-boned or hollow-boned dinosaurs? How exactly did that evolutionary process occur? Since some reptiles/dinosaurs are warm-blooded and some are cold-blooded (as you seem to indicate) what might have been the sequence of events?
Archaeopteryx supposedly proved that birds came from dinosaurs....except that was refuted by many bird experts (See Alan Feduccia)who have concluded that Archaeopteryx was 100% bird. The fact that birds were found later in lower strata than Archaeopteryx put to rest the conjecture that it was a transitional fossil.
Then came Archaeorapter, a hoax from China.... the big deal about this is not that it was a hoax. Fossil hunters know the big dollars that are out there if they can convince someone that they found a “transitional fossil”.
The big deal is that the major media wanted so much for it to be true that they threw “due diligence” out the window and just blindly accepted it.... kind of like the mainstream media does whenever some new “statistic” is put forth by NOW, GREENPEACE or any other left wing group with a cause they agree with.
National Geographic still has egg on their face over the huge spread they did on Archaeoraptor.
Having said all that....I’ll go to your links and read the information there. I’ll also do some due diligence and find out what others have concluded.
Have to wait for the weekend.
I'm not up to speed on that, but I'm fairly confident air-filled bones are only found among theropod dinosaurs (bipedal, primarily carnivorous, saurischians such as Tyrannosaurus, Deinonychus, etc). So the hollow bones came later.
Since some reptiles/dinosaurs are warm-blooded and some are cold-blooded (as you seem to indicate) what might have been the sequence of events?
Again, not up to speed. I read bits and pieces of the research, and many popular accounts, back in the 1980's, when the cold-blooded / warm-blooded debate started to heat up. But I haven't kept up to date much since.
Certainly, considering their diversity, vast differences in size, different eating habits, and etc, dinosaurs as a whole must have had many different thermoregulation strategies and regimes. We see the same in living creatures. There are several instances of living "cold-blooded" creatures where certain groups/species have the ability to elevate metabolic rates, even to the point of maintaining constant or near constant body temperatures. Off the top of my head I know that reptiles like sea turtles, and fish like tuna and some sharks, have this ability. OTOH, some mammals, namely the monotremes, have low metabolic rates and are often functionally close to being ectotherms (warmed by their environment rather than internally).
My best guess is that there were probably both full (or close to full) ectotherms and full (or close to full) endotherms among dinosaurs, and various in-between conditions. But understanding the details of thermoregulation has been difficult and taken many years to even partially sort out, even among living animals. So I'm not going to delve into this issue having not kept up with the latest controversies.
Although I will say that, AFAIK, it does remain a controversial area, with multiple competing hypotheses. I do get the impression, however, that most scientists think at least some dinosaurs were full endotherms or close to being.
Archaeopteryx supposedly proved that birds came from dinosaurs....except that was refuted by many bird experts (See Alan Feduccia)who have concluded that Archaeopteryx was 100% bird.
Yes. Archaeopteryx is 100% bird. That is, after scientists found a specimen with feathers, and then noticed faint feather impressions on older specimens. Before that it was 100% reptile.
Everything is 100% percent something. It is an artifact of the biological classification system that you have to put each individual species into one or another larger group, even if has characteristics of more than one group. In those cases you have to, often somewhat arbitrarily, pick one or a few characteristics you consider most characteristic to make the division.
Feathers used to be the deciding character for birds. If it had feathers, it was a bird. If it didn't, it wasn't. Of course this blew up when feathered dinosaurs were discovered.
Feduccia does indeed hold a minority position arguing that feathered dinosaurs (those with clear, pennaceous, as opposed to downy, feathers -- he thinks the downy feathers so-called are really something else) are actually misidentified birds and not dinosaurs at all. BUT THIS JUST ILLUSTRATES HOW CLOSE THE TWO GROUPS REALLY ARE!