since anglagard brought it up in the gd, please read my previous response to you, on archaeopteryx and forgery. you don't have to respond to it here (continue your forgery discussion with anglagard in the gd), but at least look it over and try to understand why aig says this is an argument creationists should not use.
Archaeopteryx is back in the news again. Canadian Nick Longrich reports in the journal Paleobiology that the long feathers on the creature's hind legs were indeed flight feathers, making Archie a four-winged flyer like Microraptor gui.
Their dinosaurian hind legs could not be splayed for flight. This suggests that four-winged dino-birds held their feet close to their bodies and used their rear flight feathers as stabilizers in a configuration similar to that used by the Wright brothers in the first airplanes.
Microraptor in flight (LiveScience)
Links are all to LiveScience. Todd Marshall is the artist of the Archaeopteryx image that provided the detail I use for my avatar. The full-size image appears at LiveScience in the series 'Avian Ancestors.'
this is actually somewhat old news. archie's flight feathers on his leg do not extend all the way down his feet, like microraptor.
we've also had some discussion here before on how microraptor would have flown. the "splayed" model is anatomically impossible, but i suspect the "biplane" model is aerodynamicall untennable. i've heard some suggestion that the leg-wings which have been used as vertical surfaces, like rudders.
A graphic accompanies the article that shows the configuration of Archie's leg feathers. No, they are not exactly like Microraptor's. In fact, the graphic makes the difference obvious. The interesting thing is that the involvement of leg feathers in flight appears not to be the exception in the earliest birds, but the rule.
The news is the publication of a study confirming the function of the leg feathers in flight. There is a catalog of features one expects to find on flight feathers and these fill the bill. It represents a further filling in of the picture. It is not that Archie sported long feathers on its legs and body that might have served a flight function. That's where we were before.
Naturally, all of this becomes more fodder for the debate about whether avian flight evolved from the ground up or the trees down.
yes, it's a very complex picture, expecially since microraptor lived some 20 million years after archaeopteryx.
quote:Longrich speculates that the hindlimb feathers might have served other roles in addition to flight. Like modern pigeons, kittiwakes and vultures, Archaeopteryx's hindlimb feathers might have acted as airbrakes, or perhaps stabilizers, control surfaces or flaps, Longrich writes.
(from the article linked above)
i think that function is probably more likely, especially for archaeopteryx.
quote:Scientists don’t know when in their evolutionary history birds switched from a "four winged" design to a two-wing one, but it's thought that hindlimb wings were sacrificed in order to free up legs for other functions, such as running, swimming and catching prey.
there's an interesting idea that's looking more and more valid all the time -- that the idea of "fling birds" and "running dinosaurs" are a bit more convuluted than previously thought. meaning that early dinosaurs took to the air far sooner than previously thought, and subsequently lost flight capabalities, only to re-evolve them.
there are many things we are calling "birds" that have a good number of dinosaurian characteristics that archaeopteryx lacks, and vice-versa. as suggested earlier in this thread, it's quite possible that some of the especially avian maniraptorian dinosaurs might have actually evolved from something like archaeopteryx. so it might be right to call velociraptor a flightless bird, under the current thought. essentially meaning that our current colloquial usage of "bird" describes a polyphyletic group, composed of many groups that independently evolved from the dinosaurian line. it would certainly explain the "opposite birds."