|
Register | Sign In |
|
QuickSearch
EvC Forum active members: 64 (9164 total) |
| |
ChatGPT | |
Total: 916,838 Year: 4,095/9,624 Month: 966/974 Week: 293/286 Day: 14/40 Hour: 3/2 |
Thread ▼ Details |
|
Thread Info
|
|
|
Author | Topic: What drove bird evolution? | |||||||||||||||||||||||
arachnophilia Member (Idle past 1371 days) Posts: 9069 From: god's waiting room Joined: |
I was trying to be polite the first time. If you're going to stick with this sort of ignorant bullshit, there's no real need for politeness hey mods?
There is no animal with more than one heart and no reason to believe there ever would have been. That would require that dinosaurs had been a totally separate creation from all other animals, which NOBODY believes, evolutionists, creationists, or anybody else other possibly than the people who write the Marvel comic books. what kind of animal is a dinosaur? is it a reptile? nope. they actually have their own class. dinosaurs had about 160 million years of evolution, longer than any other classification of animal alive today. we find very, very weird things in dinosaurs.
Moreover, a number of totally competent scientists have flatly stated that a sauropod dinosaur could not hold his head high due to the problems of the blood pressure which would be required to do so (in our present gravity). on, uhh, bear-fabric-dot-com? i'm sorry, i read alot on paleontology as a child, and that statement is simply wrong. and aside from that, most sauropods held their heads straight out from their bodies. brachiosaurus MAY have held his at a bit higher of an angle.
Christopher McGowan (DINOSAURS, SPITFIRES, & SEA DRAGONS) goes into this in detail (pages 101 - 120). He mentions the fact that a giraffe's blood pressure, at 200 - 300 mm Hg, far higher than that of any other animal, would probably rupture the vascular system of any other animal, and is maintained by thick arterial walls and by a very tight skin which apparently acts like a jet pilot's pressure suit. A giraffe's head might reach to 20'. How a sauropod might have gotten blood to its brain at 50' or 60' is the real question. you're figures are wrong, first of all. most sauropods didn't get big enough to put their heads that high. second, a giraffe's blood pressure varies depending on where you take it. at it's head, it's significantly less than at the heart. and it wouldn't rupure a turkey's vascular system. turkeys have 100mm hg higher blood pressure than the highest reading on a giraffe. ...and guess what sort of animals turkeys evolved from?
"...in a Barosaurus with its head held high, the heart had to work against a gravitational pressure of about 590 mm of mercury (Hg). In order for the heart to eject blood into the arteries of the neck, its pressure must exceed that of the blood pushing against the opposite side of the outflow valve. Moreover, some additional pressure would have been needed to overcome the resistance of smaller vessels within the head for blood flow to meet the requirements for brain and facial tissues. Therefore, hearts of Barosaurus must have generated pressures at least six times greater than those of humans and three to four times greater than those of giraffes." ah, yes, barosaurus. that was the one i was thinking of before. i've read that article. you have to quote in context, you know. the rest of the study goes on to talk about the cardiovascular system of barosaurs, and i do believe that was the article that introduced the 8-heart idea. in fact, i dunno if you have the original magazine, but the pictures are quite interesting. it had a very nice painting of a barosaurus rearing up to defend its young from an allosaurus, mimicing the display in the american museum of natural history. i'm pretty sure it also had diagrams, and suggested that such behavior was abnormal for this dinosaur.
"Brachiosaurus was built like a giraffe and may have fed like one. But most sauropods were built quite differently. At the base of the neck, a sauropod's vertebral spines unlike those of a giraffe, were weak and low and did not provide leverage for the muscles required to elevate the head in a high position. Furthermore, the blood pressure required to pump blood up to the brain, thirty or more feet in the air, would have placed extraordinary demands on the heart (see opposite page) [Lillywhite's article] and would seemingly have placed the animal at severe risk of a stroke, an aneurysm, or some other circulatory disaster. If sauropods fed with the neck extended just a little above heart level, say from ground level up to fifteen feet, the blood pressure required would have been far more reasonable." i do believe i said something to that effect, that most sauropods kept their heads about level with the rest of their body. sauropods, btw, have a few other ridiculous consequences of their size. for instance, you can tell from just the bones if a female has ever mated, because if she has, vertbrae and ribs are cracked. This message has been edited by Arachnophilia, 07-18-2004 05:23 PM
|
|||||||||||||||||||||||
arachnophilia Member (Idle past 1371 days) Posts: 9069 From: god's waiting room Joined: |
The crane is irrelevant because it is supported by cables anchored at a point substantially higher than the body of the crane itself, and no animal has a neck which is built like that. i'd like to add this picture, which is the aforementioned barosaurus/allosaurus display at the american museum of natural history.
i'd like to point out that not only does this dinosaur hold the current record for longest neck, but this particular skeleton also holds the record for tallest free-standing dinosaur skeleton. that's right, no cables.
|
|||||||||||||||||||||||
AdminAsgara Administrator (Idle past 2330 days) Posts: 2073 From: The Universe Joined: |
Ok, can we take the discussion of dinosaur hearts, high blood pressure and decreased gravity to http://EvC Forum: Dinosaurs and the reduced felt effect of gravity ??
And lets keep this discussion civil. There is no need for the mudslinging. AdminAsgara Queen of the Universe http://asgarasworld.bravepages.com http://perditionsgate.bravepages.com |
|||||||||||||||||||||||
Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.3 |
as i believe someone pointed out, there is no such dinosaur. the brontosaurus was an apatasaurus who's head somehow got changed with that of a camarasaurus. An incidental point of fact, but: this is actually a mashing of the truth. There was a reconstruction of an Apatosaur with the wrong head, however that is not what the difference between a Brontosaurus and an Apatosaurus. The actual difference is: nothing. They're different names for the same dinosaur - the international committee that decides these things chose Apatosaurus as the official name. (See Stephen J. Gould's Bully for Brontosaurus for further details)
|
|||||||||||||||||||||||
arachnophilia Member (Idle past 1371 days) Posts: 9069 From: god's waiting room Joined: |
i suppose i heard wrong years ago, then.
but the point was that it dates the argument, and makes it sound a little paleontologically ignorant.
|
|||||||||||||||||||||||
interrobanging Inactive Member |
So you're still a bit off in your Brontosaurus story.
Brontosaurus and Apatosaurus are not the same animal. In fact, Brontosaurus never was an animal. It is correct that what was originally called 'Brontosaurus' was an Apatosaurus skeleton with a Camarasaurus skull (clearly the wrong type of skull, even). When a correct 'Brontosaurus' skull was placed upon the model to correct the error, it was shortly thereafter discovered that the animal in question had been named 'Apatosaurus' in the scientific literature a scant few years before it was named 'Brontosaurus'. The latter name was simply published in a more prominent journal and, as is often the case, it was overlooked for years that the same genus was being described. Law of primacy of naming within the scientific community gave prevalence to 'Apatosaurus' at that point, in the late 80's, I believe. Sometimes the law of primacy isn't, in fact, followed. In this case it was. It doesn't seem as much like a law as an arbitrary decision. A case in point is that of the red imported fire ant, which, being the most intensely studied insect in the field of entomology, has thus far continued to keep its incorrect, though more popular, name.
|
|||||||||||||||||||||||
Cthulhu Member (Idle past 5879 days) Posts: 273 From: Roe Dyelin Joined: |
You'd have to do a volumetric study to get a realistic weight estimate for the seismosaur's neck but, visually, you can line up three to five 10,000 lb elephants alongside the guy's neck and figure 40K lbs and you're probably ballpark.
Considering that elephant are a bit thicker and bigger that the neck of of a Seismosaurus, I'd say that your estimate is far, far, far higher than the actual weight. Proudly attempting to Google-Bomb Kent "The Idiot" Hovind's website Idiot
|
|||||||||||||||||||||||
interrobanging Inactive Member |
So I just read your June 21 response to the initial question of the Topic 'What drove bird evolution?'
The only response to it that I can fathom is: "Why are you such a pompous asshole who feels the need to belittle, line by line, an earnest question from someone seeking education and/or information?" or possibly: "What is wrong with you that you feel the need to be cruel to a request for understanding?" or then again: "You certainly did a damned good job of explaining things. I know that I, as well as, I assume, many others, have a far greater understanding of the concept of evolution now that you've given absolutely no information. It's really great to not be educated by someone who likes to make fun of others' lack of information while simultaneously not providing any information his/herself, therefore superficially justifying his/her attack simply because it is an attack, without substantiating the potential that he/she has any actual information." but most likely: "Huh. Even if this person isn't totally ignorant of the subject he/she is making pretenses of knowing so well, his/her absolute ignorance in the ways of socialized human behavior lead me to believe he/she to be little more than a chimp in a chair pounding the keys." Grow up a bit before you post your ignorance to a public forum.
|
|||||||||||||||||||||||
happy_atheist Member (Idle past 4941 days) Posts: 326 Joined: |
At last we have a post that is almost back on topic! As nice as hypothesising about a way to increase the gravitational field strength on the surface of the earth without killing pretty much all life is, the topic of this thread is meant to be bird evolution!
Anyway interrobanging, I think that post that you refer to has already been discussed by the OP and the poster, so hopefully any differences they had have been ironed out. I'll try and very briefly summarise the positions so far in the thread. Creationists: Bird morphology is irreducibly complex. If any of a number of features weren't there then it would be impossible for a modern bird to fly. Evolutionists: Modern birds didn't arrive overnight. Primitive birds could NOT fly as well as modern birds, and all of the features in a bird can concievably be reached by modifying pre-existing structures that aren't used for flying. Intermediate forms exist in the fossil recod. Sorry if i've oversimplified too much, but it's just meant as a brief summary to get back on track. Anyone care to dispute the Evo position?
|
|||||||||||||||||||||||
Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.3 |
That the committee chose to pick Apatosaurus as the official name does not stop Brontosaurus being another name for the exact same dinosaur.
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024