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Author Topic:   Birds and Reptiles
arachnophilia
Member (Idle past 1344 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 61 of 135 (598643)
01-01-2011 3:29 PM
Reply to: Message 58 by Buzsaw
01-01-2011 9:05 AM


picture time again
Buzsaw writes:
That one dino is considered bird
it's really substantially more than one dinosaur, buz. it's every bird that is considered a dinosaur. the same way that every primate is considered a mammal. and, on top of that, there are a whole host of non-avian dinosaurs with feathers. these are actually the ones we don't consider birds, proper. here are the ones we do.
doesn't mean birds are generally considered reptiles.
nope. as i posted above, "reptile" is a paraphyletic group, so this point is pretty moot. "reptile" is defined as the class of sauropsids (and basal amniotes) that excludes birds.
"reptilia" (from wikipedia)
that's the definition of the colloquial term, versus the cladistic tree. the colloquial definition means nothing, really, in terms of actual evolutionary origin. note that the diagram is missing "dinosauria", as it's really under debate whether or not dinosaurs should be considered reptiles, because they are so dissimilar from every other "reptile".
More objectively, from what I've read, the consensus is that they descended from dinos.
no, birds are dinosaurs. they are a highly specialized subgroup of dinosaurs, but they are dinosaurs.
My position that the Biblical record is correct would require many adjustments to the changed physique such as the flattened croc and gater heads, the rear claw in the foot for grasping smaller things, the leg structure, etc.
well, you can't argue with "it must have been a miracle" in the face of all the evidence that says exactly the opposite. crocodiles would have had to re-evolve several features, extremely convergently with other modern sauropsids. like, several digits.
Conclusion: there are not more similarities, by and large, of birds/dinos than reptiles/dinos. It's all assumed to accomodate evolution.
yeah, let's see that.

a. crocodile

b. coelophysis

c. compsognathus

d. archaeopteryx

e. velociraptor
so let's play, "one of these things is not like the other". keep in mind that one of these is a bird. another is a mostly-ectothermic "reptile". which one is the least similar? oh, and please note that, to be fair, i have included one of the most primitive dinosaurs, the mid-triassic coelophysis, so named for its bird-like hollow bones.
Edited by arachnophilia, : typo

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This message is a reply to:
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Buzsaw
Inactive Member


Message 62 of 135 (598687)
01-01-2011 8:21 PM


Re: Are Birds Dinosaurs?
Dinos and modern reptiles whereas birds are not. - Debatable
Dinos are reptiles , unlike birds - Debatable
Both cohabited whereas birds did not, Both had teeth and more similar bone structures unlike birds - Debatable
Overall appearance of lizards, crocks, iguanas, etc more resemble dinos than birds. By observation? Yes. Ask anybody on the street to look at lizards, iguanas, gators and crocks whether these by and large look more like dinos, both having swishy tails and similar looking heads than most birds and they will say that they do.
Digits of birds and theropod dinosaurs found to be non-homologous. What has been assumed for the last two decades by prominent paleontologists turns out to be questionable, as is so often the case in the conventional science arena.
Homologies of digits in the avian hand have been debated for 150 years. Cladistic analysis nests birds with theropod dinosaurs. Theropod hands retain only digits I-II-III, so digits of the modern bird hand are often identified as I-II-III. Study of the developing manus and pes in amniote embryos, including a variety of avian species, shows stereotyped patterns of cartilage condensations. A primary axis of cartilage condensation is visible in all species that runs through the humerus into digit IV. Comparison to serially homologous elements of the hindlimb indicates that the retained digits of the avian hand are II-III-IV.
Too often scientists see what they want to see
OSU research on avian biology and physiology has been raising questions on this issue since the 1990s, often in isolation. More scientists and other studies are now challenging the same premise, Ruben said. The old theories were popular, had public appeal and many people saw what they wanted to see instead of carefully interpreting the data, he said.
Pesky new fossils . . . sharply at odds with conventional wisdom never seem to cease popping up, Ruben wrote in his PNAS commentary. Given the vagaries of the fossil record, current notions of near resolution of many of the most basic questions about long-extinct forms should probably be regarded with caution.
--------------------------------------------------------------------------------

BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.
Time Relates To What Is Temperal. What Is Eternal Is Timeless.

Replies to this message:
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 Message 65 by arachnophilia, posted 01-01-2011 9:15 PM Buzsaw has replied
 Message 74 by PaulK, posted 01-02-2011 5:17 AM Buzsaw has replied

  
Panda
Member (Idle past 3713 days)
Posts: 2688
From: UK
Joined: 10-04-2010


(1)
Message 63 of 135 (598693)
01-01-2011 9:00 PM
Reply to: Message 62 by Buzsaw
01-01-2011 8:21 PM


Re: Are Birds Dinosaurs?
Buzsaw writes:
Ask anybody on the street to look at lizards, iguanas, gators and crocks whether these by and large look more like dinos, both having swishy tails and similar looking heads than most birds and they will say that they do.
This is the best way to do science.
I had an unusual looking mole on my arm, but rather than talk to an expert, I thought it best to ask people on the street.
Surprisingly, they thought I was stupid for asking people on the street.
They recommended that I talked to an expert.
Edited by Panda, : No reason given.
Edited by Panda, : No reason given.

This message is a reply to:
 Message 62 by Buzsaw, posted 01-01-2011 8:21 PM Buzsaw has not replied

  
arachnophilia
Member (Idle past 1344 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 64 of 135 (598694)
01-01-2011 9:07 PM
Reply to: Message 62 by Buzsaw
01-01-2011 8:21 PM


nonsense
Buzsaw writes:
Dinos and modern reptiles whereas birds are not. - Debatable
Dinos are reptiles , unlike birds - Debatable
Both cohabited whereas birds did not, Both had teeth and more similar bone structures unlike birds - Debatable
buz, this is nonsense. i don't mean that your ideas are ridiculous. i mean, nobody knows what the heck you're even talking about. can you rephrase these in ways that make sense? for instance, your first statement lacks a verb.
dinos and modern reptiles are what whereas birds are not?
and what the heck do you mean by cohabited?
Overall appearance of lizards, crocks, iguanas, etc more resemble dinos than birds. By observation? Yes. Ask anybody on the street to look at lizards, iguanas, gators and crocks whether these by and large look more like dinos, both having swishy tails and similar looking heads than most birds and they will say that they do.
most people are idiots. further, most people think dinosaurs look like this:

deinonychus antirrhopus, the "velociraptor" (paul 1988) as depicted in "jurassic park"
and not this:

deinonychus antirrhopus, as it would have really appeared
if you show them the far more accurate depiction above, they will invariably say "bird". the fact of the matter is that people thought of dinosaurs as glorified lizards for quite a long time, and frequently depicted them styled after lizards. the fact that when you say "dinosaur" most people think of something very lizard-like does not mean that dinosaurs actually were lizard-like. it just means that people have had inaccurate preconceptions drilled into their heads.
Digits of birds and theropod dinosaurs found to be non-homologous. What has been assumed for the last two decades by prominent paleontologists turns out to be questionable, as is so often the case in the conventional science arena.
alan feduccia is not a good person to discuss regarding avian evolution. he's basically the crank of the paleontological world -- him and his cronies larry martin and john ruben. not only are they wrong, but they frequently tout their research as proclaiming things it does not ("birds came first!"). on top of that, none of them are actually arguing for what you would like: they're arguing that birds (and, ahem, theropod dinosaurs) are not actually dinosaurs, but evolved separately and convergently from archosaurs. none of them question evolution, nevermind that birds are theropods. just that they're dinosaurs. which, frankly, is dumb.
as for the specific points, here's greg paul on the subject (he's the "paul" i mentioned above, under the jurassic park picture).
quote:
I have now read the Burke-Feduccia Science paper (Science vol. 278, pg. 666) on the alleged nonhomology of theropod and bird hands -- a subject I have worked upon (1984a) -- and the supporting viewpoint by Hinchliffe (Science vol. 278, pg. 596). As I suspected, it gives no reason to challenge the fact that birds are as much glorified dinosaurs. Instead, we are seeing the last gasps of a dying hypothesis.
To start with, the fossil evidence clearly shows that the outer digits are lost in theropods, leaving only I-II-III in avetheropods, with I always being a strong, big clawed thumb weapon (except when the arm is hyper-reduced). In herrerasaurs V is a wee splint and IV is just two small bones. There is no practical way to make IV into a strong finger with five bones including a large claw, while losing the big thumb, etc.
The anti-dinosaur group keeps stressing that digits are normally reduced symmetrically, and that this should be true of birds as well. Of course in the next breath they acknowledge that dinosaurs lost only the outer fingers, so there is no reason the other group of bipedal archosaurs, the birds, could not have done the same.
The basic problem is that even in the earliest bird embryos there are only four digits, the fifth is entirely lost. If there were five digits and we could watch which ones were lost there would be no problem. As it is there is currently no way to reliably number the digits in bird embryos. Doing so requires a number of untestable assumptions.
At the same time, we do not have any avetheropod embryos to examine. It is quite possible that they grew their fingers in exactly the same manner as baby birds, with the well developed digit opposite the ulna being III, rather than IV as is common in other tetrapods. After all, in adult avetheropods the digit opposite the ulna IS number III.
Why the avetheropod-bird clade would initially emphasize the development of III rather than IV is obvious. Loss of digit I in even the embryos would leave a big gap between the pisiform in the side of the wrist and metacarpal IV, unless the other digits shifted laterally. So IV would be were V was, and III would be were IV was. If the shift is not made from the get go, it is only going to have to occur at some point later. Also, IV will be entirely lost. To follow the usual tetrapod finger growth pattern would require IV to grow large in embryos, then be completely lost later on (Burke & Feduccia say that some lizards sharply reduce the size of IV, but it is not completely lost. Does anyone know what happens to digit IV in horse embryos?) This would be a waste of growth energy, and natural selection does not work to make finger buds convenient for embryologists to count, but to maximize efficiency of growth. The severe asymmetry of finger growth in theropods-birds should have forced them to reconfigure the growth pattern, so that III is initially emphasized rather than IV, and the latter is never more than a stub before it is eliminated.
The problem is that some embryologists expect digit IV to be large because it is so in animals with symmetrical finger reduction, and some want it to be IV, so they say it is, even though strong asymmetric finger growth could be expected to result in important changes in embryonic growth. As it is, there is no conclusive evidence that birds retain digits II-IV rather than I-III, there is no way to compare avian and dinosaur hand embryology, and so the problem is untestable.
Another thing the anti-dinosaur group does not have is a fossil record that in any way supports symmetrical reduction of fingers in protoavians. Of course this is because nondinosaurian ancestors of birds did not exist! There is a wonderful fossil trail of asymmetrical finger reduction in dinosaurs leading to the avian condition.
Science is always partly political, and it is important to understand the deep bias of some against birds being dinosaurs. For example, Feduccia (1996) claims that the hand of Archaeopteryx "does not closely resemble that of a theropod dinosaur." This when the [bird]'s long raptorial hand with a semi-lunate carpal block, and three gracile digits, is clearly a diminutive version of a dromaeosaur manus! Feduccia cannot point to any nondinosaur that has a hand anything at all like those of birds.
(source)
just to illustrate how truly dumb this is, let me again post pictures.

deinonychus

archaeopteryx

hoatzin chick (modern bird)

hoatzin adult (modern bird)
easy to see now? the digits are pretty clearly the same. this different numbering is an arbitrary thing that ornithologists have done because they assumed that birds lost their other digits symmetrically, where as paleontology shows that they did not.
Too often scientists see what they want to see
ruben? yeah, i saw a documentary which covered his incredibly ludicrous reconstruction of microraptor gui. i posted it on my blog a while back, and i will now re-post it here.

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This message is a reply to:
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Replies to this message:
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arachnophilia
Member (Idle past 1344 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 65 of 135 (598696)
01-01-2011 9:15 PM
Reply to: Message 62 by Buzsaw
01-01-2011 8:21 PM


the dinosaur with four wings
Too often scientists see what they want to see
so, since you brought up ruben and martin's just plain silly reconstruction of microraptor, i thought i would re-post this entry from my blog, originally posted sept 21. 2008, after viewing a documentary in which martin appeared.
please note that this is a blog entry, but it's full of useful links and pictures. please note martin's hilarious reaction to seeing the proper scientific reconstruction of microraptor, and how he very obviously only sees what he wants to.
quote:
the discovery channel aired a documentary the other night on microraptor called the four winged dinosaur, originally a production by NOVA for PBS. microraptor is a dinosaur that i find especially interesting, not so much because it further provides evidence for the dinosaurian evolution of birds, but because of the complications it presents to that theory. microraptor is also very curious in that it has four wings. as you can see in the above picture (the m. gui holotype specimen), it has rather long flight feathers protruding from its feet.
how exactly such an animal flew (or if it flew at all) is quite the puzzle, and i have never found either proposal quite satisfactory. i think we can discard the "default" positions, legs tucked up underneath the body like a bird, and legs extended downward like a theropod dinosaur, because neither position uses the flight feathers at all. there have been two major hypotheses regarding how microraptor used its hind wings.
flat

this is the model that xu xing initially proposed when he first named microraptor. this model duplicates the way a flying squirrel would glide. but there a major problem with it, other than the fact that it looks just a little silly: dinosaurian hips are designed for forwards and backwards motion, not leg splaying motion. the documentary points out something along these lines, stating that dinosaurs evolved upright posture from their crocodilian ancestors who splayed their legs wide. you would have dislocate microraptor's hip joint for it to maintain that posture. even xu admits that this proposal is "probably wrong."
biplane

this is the more recent proposal, i believe first put forth by sankar chatterjee (somewhat known for his erroneous hybrid fossil reconstuctions). it was developed by trying to maintain a more bird-like posture, while still using the flight surfaces. this model is even more strange, and in my opinion, a good deal more silly. the flight feathers on the feet lack a strong leading edge, and would simply flutter in the wind too much to provide lift.
i've never found either idea particularly satisfactory. the program promised wind tunnel testing of a fully articulated and posable model of microraptor, so i was rather excited to see what conclusions they'd draw.
now, the dinosaurian origin of birds has been hypothesized since the very first discovery of a dinosaur. early paleontologists recognized right away that the hip structures of dinosaurs were very similar to birds, and that the three toed foot of the theropods was almost identical to a bird's foot. when archaeopteryx lithographica was discovered, a dinosaur with many bird-like features most prominently including flight feathers, it verified the link. the creationist objection at the time was that this was obviously a dinosaur that someone had carved feathers around. this was 1861. now they claim it's "just a bird" which is an even moe silly proposal. but archaeopteryx remained largely forgotten, as a curiosity and a footnote until the 1970's when john ostrom uncovered deinonychus antirrhopus. he noted many similarities between the two specimens, and the modern idea of the relationship between birds and dinosaurs began to take shape.
deinonychus also changed the way we think of dinosaurs. it's impossible to look at this animal and think "slow cold blooded lizard." until the 70's, this had been the preconception. but deinonychus just looks fast. and its tail is rigid; it can't be dragged on the ground. this was a warm-blooded, fully upright, counter-balanced, running predator. after the documentary covers the basic history of avian/dinosaur paleontology, it makes the obligatory jurassic park reference, showing pictures of their raptors. more on this later.
now, archaeopteryx and deinonychus and their high degree of similarity form pretty conclusive evidence that birds are dinosaurs, and other similar dinosaurs continue to back this up, even before microraptor is discovered. but we're continually discovering more and more dinosaurs with feathers, especially highly derived theropods. even tyrannosaurs seem to have been feathered at least in some regard. the only real debate regarding the origin of flight is whether flight evolved from ground up in running/flapping theropods, or from the trees down in aboreal gliding theropods. microraptor complicates the issue, because it is so closely related to running theropods, but must be arboreal due to the difficulty it would have walking with its enormous flight feathers on the hind limbs.
but cue the crackpots. perhaps my biggest problem with science journalism, even the better examples such as this, is the apparent need to be fair to all points of view. they give equal time to even the most ludicrous of viewpoints. including the non-dinosaur origin of flight. there is so much going against the idea (like, all the dinosaurs that are strongly homologous with birds, and all the dinosaurs with feathers), and the view is held by almost no one in the scientific community. you will likely find more flat-earth geologists than "birds are not dinosaurs" paleontologists. until the other night, i was only aware of one scientist against the dinosaurian origin of birds, alan feduccia. his name gets laughs in the paleontological world; he's not a paleontologist, he's an ornithologist. so he's easy to write off. his claim that paleontologists do not know much about birds is petty silly, too. because birds and crocodiles are the closest living relatives of dinosaurs (something even feduccia would concede), dinosaur paleontologists spend a lot of time studying our avian friends. it's feduccia that does not know much about dinosaurs.
but the documentary introduced dr. larry martin (center), a paleontologist who says of microraptor "you have just shown me the death of the dinosaur origin of birds" (paraphrased from memory). he and his assistant are working on their own model, taken directly from casts of the holotype specimen of m. gui (shown at the top of this post). their model is a splayed-leg quadruped, which they claim is not even a dinosaur. they question the other model, produced for the AMNH under the direction of xu xing and mark norell, as an artistic and subjective interpretation. "if you call matching it to 1/1000th of a mm on sixteen different specimens 'subjective' that's up to you," (also paraphrased from memory) says the artist who made it. martin looks at the AMNH model, which physically cannot splay its legs, and immediately claims it was fudged to support the dinosaurian idea. the documentary rather quickly and a bit too civilly trashes this idea, showing that the martin holotype cast is rather flattened. and in an amazing close up it shows that the martin model doesn't even fit together because the hip bones are too flattened, and that even if it tried to splay its legs, the femoral ball would pop away from the socket joint. oops, who's fudging things now?
as they show the close up shot of the hips and the femur, the fully ridiculous nature of martin's argument strikes me, and for reasons other than the joint's ability to spread open.
  1. even if it could splay, there's no good reason that a dinosaur couldn't secondarily evolve such an ability. this idea would be far, far more elegant than a splayed-leg arboreal lizard convergently evolving hundreds of features exactly identical to dinosaurs, including the lower-branching dinosaur clades martin proposes that archaeopteryx and descendants like velociraptor are not related to.
  2. it's not built like a splayed-leg crocodilian archosaur, or even a semi-upright pseudosuchian. those animals are flattened vertically, so they can walk with their bellies close to the ground. microraptor's hips are very tall and flattened laterally, something that is completely incompatible with an animal that splays its legs. it's a bit like supposing sailboats that travel on land, with the base of their hulls at ground level. where does the keel go, exactly? a splayed microraptor would leave a trench cut out by its pubic bone wherever it went.
  3. dinosaurs (versus non-dinosaurs) are actually identified on a good deal more than their posture. the most obvious factor is, of course, the hip complex. it's the hips that indicate an animal must be upright, not just the joint. further, the hips actually indicate what kind of dinosaur an animal is.
even discarding the femur (the very similar a. lithographica pictured), i'd look at the pubis (blue), determine that it's not forked, and look at the shape of the ilium (pink), and classify the animal as a saurischian dinosaur. then i'd notice the knob on the end of the pubis, and determine it's a theropod. further, because the pubis is backturned, i'd immediately conclude that it was a dromaeosaurid dinosaur, probably a deinonychosaur. guess what the scientific consensus is? and i'm a layman. why can't you figure this out, mr. ph.d. paleontologist?
back to the legitimate ground-up/trees-down debate, and the wind tunnel testing, the AMNH team determined that microraptor did not generate enough lift to fly with just its fore-wings, and the biplane model was also a no-go. too much drag, not enough lift, and pitches upwards rather quickly, resulting in even less lift. after some head scratching, xu proposes his secret weapon of a hypothesis: that it would extend its legs all the way behind it, making the feathers meet around the base section of the tail. nobody thinks it will work, but it turns out to generate the most lift and the least drag by far. xu wins all the bets, but he's had the most time to think about it.
this idea makes the most sense for a number of reasons. if microraptor pushed off of trees, its legs would naturally end up in this position. the placement of the feathers roughly duplicates the placement of a modern bird's tail feathers, only inside out. microraptor would then be able to shift through the various biplane formations, causing a pitch upwards to meet the next tree feet-first. this feet-first dragging roughly duplicates the fishing behaviour of modern eagles, with a similar usage of their leg feathers to create drag (right). i now consider this problem solved to my satisfaction.
the problem regarding trees-down v. ground-up remains unsolved, but i suspect that flight evolved and was secondarily lost numerous times. so the answer might be "both." greg paul suggests in predatory dinosaurs of the world that animals like velociraptor (pictued right with protoceratops) maybe have evolved from flying ancestors of birds, and not vice-versa. microraptor helps demonstrate this fairly clearly. genetically, even in modern birds, scutes (foot scales) are secondary adaptations of existing feathers such as m. gui's. this creates another curious problem in that a. lithographica, an earlier banch in the tree, appears to only have flight feathers above the ankle. so whether m. gui's method of flight is representative of the initial development or simply a re-development is not currently known.
about jurassic park

since i mentioned it above, it's worth saying a few more words about. when jurassic park came out 15 years ago, it was the most scientifically accurate dinosaur movie ever. today, it doesn't hold up so well. watching it somewhat recently, i was actually surprised at just how many errors there were. the documentary glosses over one by correctly discussing deinonychus while showing clips of jurassic park's "velociraptors." they mention that the only noticeable issue is that they should have had feathers. we now know that v. mongoliensis (and presumably d. antirrhopus) had flight feathers on its wings, like many other similar theropods. well, even in just the clips they showed, i was able to spot a few more errors.
  • that they don't have feathers is actually a much more complex point. michael crichton evidently read greg paul's aforementioned "predatory dinosaurs" book, as it's paul who proposes that "velociraptor" is a synonym of "deinonychus" and refers to d. antirrhopus as "velociraptor antirrhopus." this is the dinosaur that crichton intends for his book, as it matches the size and geographic locations. all species of velociraptor are dog-sized asian theropods. d. antirrhopus is a man-size north american theropod. however, he apparently only took cues from paul selectively, as every single depiction of either dinosaur in paul's book has feathers. this is, in fact, part of the main argument of the book.
  • the "raptors" of the movie are consistently depicted with bent wrists, palms facing downward and backward (as above). while maniraptors have incredibly flexible wrists (for dinosaurs) due to their semi-lunate carpals, they would still have to physically break their arms to hold them this way. the proper position is palms inward. think of bird wings, not human arms.
  • not shown in the clips, the movie makes mention of deinonychosaurids gutting their prey with their sickle-shaped claws on their second toe. we now know that they simply couldn't have done so because they lack the necessary muscle and bone strength, and the slashing edge on the claw. they probably went for the throat (jugular, coratid, or trachea) in a much more precision fashion, as shown in the "fighting dinosaurs" above.
i mention this last part because it probably provides a good use for their diminutive flight feathers, and possibly an answer to the trees-down vs ground-up dilemma. as raptors generally could flap, at least in part, the wings could be used as both lifting aids, and a distraction to get a surprised ceratopsian prey to turn its head and show its weak spot, while the raptor jumps in feet-first like a landing microraptor. after the rather terrifying displaying of flapping, it could grab on to a frill with its hands, effectively blinding its victim with the wings, and go for a precise puncture kill. then it could flap off, get away to safe distance, and wait for the prey to bleed out. it'd be sort of like a big scary cock fight. and powered flight in modern birds might have evolved from this behaviour in terrestrial dinosaurs, partially derived from the behaviour of gliding dinosaurs like m. gui.

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This message is a reply to:
 Message 62 by Buzsaw, posted 01-01-2011 8:21 PM Buzsaw has replied

Replies to this message:
 Message 66 by Buzsaw, posted 01-01-2011 10:25 PM arachnophilia has replied

  
Buzsaw
Inactive Member


Message 66 of 135 (598702)
01-01-2011 10:25 PM
Reply to: Message 65 by arachnophilia
01-01-2011 9:15 PM


Re: the dinosaur with four wings
arach... writes:
it's impossible to look at this animal and think "slow cold blooded lizard."
In the Wyoming Rocky Mtn region where I grew up and on the desert I've seen some really fast little miniature somewhat dino looking lizzards which dart around likity split.
Assuming the accuracy of the Biblical record, the dino reptiles pre-flood would have likely been very lively, given the perfect warm climate that is implicated before the flood changed things.
Perhaps I missed it but what about the study which I cited about the non-homogeneous digits of dino & bird?

BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.
Time Relates To What Is Temperal. What Is Eternal Is Timeless.

This message is a reply to:
 Message 65 by arachnophilia, posted 01-01-2011 9:15 PM arachnophilia has replied

Replies to this message:
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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


(1)
Message 67 of 135 (598704)
01-01-2011 10:33 PM
Reply to: Message 66 by Buzsaw
01-01-2011 10:25 PM


Asserting absolute nonsense is not evidence Buz
Assuming the accuracy of the Biblical record, the dino reptiles pre-flood would have likely been very lively, given the perfect warm climate that is implicated before the flood changed things.
Buz, the Biblical Flood has been totally refuted and the climate before the date of the flood was just about like now.
See Message 28 and also Message 1.
Trying to introduce such nonsense, particularly in a science forum is just plan silly. You know it ain't gonna fly.
Why do you keep trying to introduce your fantasy and fable in a science forum?

Anyone so limited that they can only spell a word one way is severely handicapped!

This message is a reply to:
 Message 66 by Buzsaw, posted 01-01-2011 10:25 PM Buzsaw has not replied

  
arachnophilia
Member (Idle past 1344 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 68 of 135 (598717)
01-01-2011 11:34 PM
Reply to: Message 66 by Buzsaw
01-01-2011 10:25 PM


running, and digits
Buzsaw writes:
In the Wyoming Rocky Mtn region where I grew up and on the desert I've seen some really fast little miniature somewhat dino looking lizzards which dart around likity split.
for very, very short bursts of speed, yes. no "reptile" is an endurance runner. they simply aren't built for it. iirc, the side-to-side running motion actually impairs respiration in reptiles. (perhaps a herpetologist can comment?) but this is definitely not the case in a dinosaur -- their respiration is actually aided by their running. this is the primary advantage that allowed them to become the dominant lifeforms in the mesozoic. the could out-endure any of their prey.
look at how a crocodile hunts, vs how an ostrich avoids being eaten. the crocodile is an ambush predator. if it doesn't catch you in the first snap, it simply gives up. they don't give chase. the ostrich will keep running, and running, until it's safe.
Assuming the accuracy of the Biblical record, the dino reptiles pre-flood would have likely been very lively, given the perfect warm climate that is implicated before the flood changed things.
so, this is a science forum, buz. we can't just assume things like the accuracy of the bible, or even that genesis is a record of anything. plus, dinosaurs lived in cold climates, too.
Perhaps I missed it but what about the study which I cited about the non-homogeneous digits of dino & bird?
it's nonsense, from "birds came first" ornithologists and crackpots. they assume that birds would have lost their digits symmetrically, and thus they cannot be homologous to the theropod hand, which is non-symmetric. this is obviously a bad assumption for a number of reasons:
  1. the theropod hand is homologous to the avian carpometacarprus
  2. hoatzin ontogeny recapitulates this particular development, and hoatzin are born with hands that have freely moving digits, claws, and are nearly exactly identical to a maniraptoran hand, except for some extra wrist bone fusing
  3. there is a very strong and convincing history of the evolution of the carpometacarpus, with all kinds of transitional forms, that shows precisely which digit is which, all the way from herrerasaurs (with five digits) to theropods (generally with three) to birds (with essentially one).
there is an excellent rebuttal by greg paul, above, in post #64. it goes back this far because, remember, these "birds came first" crackpots deny that theropod are dinosaurs, not that birds are theropods.

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Blue Jay
Member (Idle past 2697 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(1)
Message 69 of 135 (598720)
01-02-2011 12:43 AM
Reply to: Message 55 by arachnophilia
01-01-2011 12:29 AM


Re: Comparing Similarities And Differences
Hi, arachnophilia.
arachnophilia writes:
i was less than technical with buz. but i'll point here that the word you're looking for is "sauropsid".
This is actually a term I had forgotten: thanks for the refresher course. I was tempted to talk about diapsids, but... meh, you've got to pick your battles.
I tend to avoid the sciencespeak entirely with Buzsaw.
-----
arachnophilia writes:
Bluejay writes:
Also, there are dinosaurs that have beaks!
well, ornithischian ones, anyways.
Actually, I was picturing oviraptorids when I wrote that. Now that I think about it, it is kind of a disingenuous comment, given the homology implications. I probably should have avoided that.

-Bluejay (a.k.a. Mantis, Thylacosmilus)
Darwin loves you.

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arachnophilia
Member (Idle past 1344 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 70 of 135 (598721)
01-02-2011 1:04 AM
Reply to: Message 69 by Blue Jay
01-02-2011 12:43 AM


Re: Comparing Similarities And Differences
Bluejay writes:
Actually, I was picturing oviraptorids when I wrote that. Now that I think about it, it is kind of a disingenuous comment, given the homology implications. I probably should have avoided that.
oh, yes, right. oviraptors. heh, i knew i was forgetting something obvious. oviraptors are closely related to the origin of birds, though the beak is still somewhat convergent, as birds come from the non-beaked theropods. so, that's not nearly as disingenuous as the psittacosaurus picture i almost posted.
so, uh, carry on. don't mind me.
I tend to avoid the sciencespeak entirely with Buzsaw.
i know what you mean. but it's important to note (and i've pointed it out directly to him as well) as he keeps throwing around this "reptile" term, when "reptile" is really just an a completely arbitrary term that excludes birds and possibly dinosaurs by definition, and has no real relationship to any particular clade.

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Blue Jay
Member (Idle past 2697 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 71 of 135 (598722)
01-02-2011 1:09 AM
Reply to: Message 58 by Buzsaw
01-01-2011 9:05 AM


Re: Comparing Similarities And Differences
Hi, Buz.
Buzsaw writes:
I maintain that my points are valid.
I agree that you are entitled to your opinion, but it's a very poor debate strategy to just maintain that your points are valid
If you don't want to debate, that's fine: just tell me and I'll back off.
But, if your intention is not to debate your opinions, but to simply maintain them, then why are you posting them on a debate forum?

-Bluejay (a.k.a. Mantis, Thylacosmilus)
Darwin loves you.

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 Message 58 by Buzsaw, posted 01-01-2011 9:05 AM Buzsaw has not replied

  
Nuggin
Member (Idle past 2492 days)
Posts: 2965
From: Los Angeles, CA USA
Joined: 08-09-2005


Message 72 of 135 (598723)
01-02-2011 1:38 AM
Reply to: Message 66 by Buzsaw
01-01-2011 10:25 PM


Re: the dinosaur with four wings
Assuming the accuracy of the Biblical record...
And right there is where your thinking runs right off the rails.
This is no more a valid statement than "Assuming the accuracy of Harry Potter" or "Assuming the accuracy of Ovid's Metamorphosis"
Assuming in and of itself is a failure. Applying it to a document which is demonstrably inaccurate is twice as bad.

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arachnophilia
Member (Idle past 1344 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 73 of 135 (598725)
01-02-2011 1:53 AM
Reply to: Message 72 by Nuggin
01-02-2011 1:38 AM


demonstrably inaccurate
Nuggin writes:
This is no more a valid statement than "Assuming the accuracy of Harry Potter"
you are clearly out of the loop, as we are continually finding more evidence that demonstrates the accuracy of harry potter.

(source)

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PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 74 of 135 (598769)
01-02-2011 5:17 AM
Reply to: Message 62 by Buzsaw
01-01-2011 8:21 PM


Re: Are Birds Dinosaurs?
quote:
Dinos and modern reptiles whereas birds are not. - Debatable
Dinos are reptiles , unlike birds - Debatable
More like irrelevant. As I have already pointed out this classification was made without the benefit of the evidence we have today. It was a mistake. If we must defer to expert opinion we would do better to use modern experts who ARE fully aware of the evidence - and THEY generally classify birds as dinosaurs.
quote:
Both cohabited whereas birds did not, Both had teeth and more similar bone structures unlike birds - Debatable
There's plenty of reason to think that both birds and snakes cohabited with dinosaurs (and without your ad hoc additions to the Bible your hypothesis would rule out snakes and dinosaurs cohabiting). Early birds had teeth and chickens still retain parts of the capability to grow teeth. And as has been pointed out the bone structures of some dinosaurs were closer to those of birds than snakes or lizards or crocodiles - even to the point of being hollow.
The issue of digits has been dealt with - so I won't repeat it here, because the argument and the answer get quite technical.
As to the other article all I will point out is that the basic argument is flawed. It assumes that the "ground up" hypothesis is the only way for birds to have evolved from dinosaurs. But that is false. The rival "trees down" hypothesis is still valid and supported by the microraptor fossil. And you will note that the article admits that there are fossils, currently classified as dinosaurs that are very bird-like. I guess that those fossils aren't just assumptions after all !

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arachnophilia
Member (Idle past 1344 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 75 of 135 (598771)
01-02-2011 5:34 AM
Reply to: Message 74 by PaulK
01-02-2011 5:17 AM


Re: Are Birds Dinosaurs?
PaulK writes:
Early birds had teeth and chickens still retain parts of the capability to grow teeth.
and tails! i don't know if the experiment was ever peer-reviewed, but hans larsson apparently managed to make chickens grow very dinosaurian tails.
The issue of digits has been dealt with - so I won't repeat it here, because the argument and the answer get quite technical.
it basically comes down to "ornithologists can't count", which isn't really all that technical.
Edited by arachnophilia, : typo

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