Clutch

Well, Jesus could wiggle his nose at it, of course. Now *that's* a satisfying explanation!

Godless Dave

As for the warm-blooded/cold-blooded question, the idea that all dinosaurs were cold-blooded went out of favor over a decade ago.

Thanatos

Where are the transitionals? Which type of reptile progressed to which mammal? Which fish into which amphibian? Where did sharks come from? Why haven't the tuatara, coelacanth fish, the horseshoe crab, and the native frogs of New Zealand changed for over 200 million years? Did bats and whales evolve from the same ancestor in a fairly short time on your timescale? Do the comparisons of the nucleotides of DNA or RNA sequences provide information that classify organisms with a higher degree of accuracy?

Thanatos

So which is it? Did cold-blooded reptiles evolve into warm-blooded dinosaurs, or did cold-blooded dinosaurs evolve into warm-blooded birds. Or were there cold-blooded and warm-blooded dinos?

Godless Dave

Thanatos, I'll try to find that information. But why are you asking me? Have you even consulted a basic biology textbook? Try your local public or university library.

MrDarwin

I don't have time to address the other stuff right now, but I found this question rather puzzling:

I'm curious to know what makes Thanatos think that the tuatara, and coelacanth, and the frogs of New Zealand haven't changed "for over 200 million years". Care to tell us where you got that info, Thanatos?

trunks2k

yes. Because it has features found in both reptiles and birds. Although it's classified as a perching bird, several pronounced features are very similar to features found in reptiles. It's classifiaction as a bird doesn't make it non-transitional.

Mageth

What we have here is not just a Tired Old Argument Barfer and a Quote Slinger, but a Question Sprayer as well.

Are you looking for one question that we can't answer so that you can feel smug and victorious? Some of the questions you ask are good ones, and some are not (as pointed out by MrDarwin).

Science has the advantage that it admits to questions, even difficult questions, and seeks to find answers. Science doesn't claim to have all the answers. Science revels in questions; it's what makes it interesting. Conversely, creationism assumes the questions are all answered with a big resounding "goddidit." It doesn't explain anything.

[ April 19, 2002: Message edited by: Mageth ]

[ April 19, 2002: Message edited by: Mageth ]</p>

MrDarwin

I don't believe evolutionary biologists try to avoid the issue. However, it cannot be easily answered based on what we have to go on: the fossil record. We don't know for a fact whether dinosaurs were warm- or cold-blooded, or whether the early birds were either (or even fossil mammals for that matter).

It's a logical assumption that somewhere in the lineage leading from early reptiles to modern birds, a warm-blooded metabolism had to evolve. But since we can study the metabolisms of extinct animals--that are known only from their fossilized skeletons--only by indirect inference, we are forced by necessity to look at other characters. And looking at the anatomical details, we have pretty good evidence that birds evolved from dinosaurs.

BTW I think that the ideas of Feduccia, Martin, et al. are red herrings to this discussion, and here's why: if they ever came around to the idea that birds did evolve from dinosaurs, would you change your mind also? Somehow I don't think so. (I would also note that Feduccia et al. believe that birds did evolve from reptiles, but not from dinosaurs; thus they don't seem to see any sticking point in the metabolisms of the respective creatures.)

Coragyps

The tuna and some related fish are, IIRC, sort of an "inbetween" as to warm or cold-bloodedness. If they ever let me go home from work today I'll try to dig up some details.