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New Study Shows Tyrannosaurus Rex Evolved Advanced Bird-Like Binocular Vision
Science News Online ^ | June 26 2006 | Eric Jbaffe

Posted on 07/03/2006 12:32:51 PM PDT by Al Simmons

In the 1993 movie Jurassic Park, one human character tells another that a Tyrannosaurus rex can't see them if they don't move, even though the beast is right in front of them. Now, a scientist reports that T. rex had some of the best vision in animal history. This sensory prowess strengthens arguments for T. rex's role as predator instead of scavenger.

Scientists had some evidence from measurements of T. rex skulls that the animal could see well. Recently, Kent A. Stevens of the University of Oregon in Eugene went further.

He used facial models of seven types of dinosaurs to reconstruct their binocular range, the area viewed simultaneously by both eyes. The wider an animal's binocular range, the better its depth perception and capacity to distinguish objectseven those that are motionless or camouflaged.

T. rex had a binocular range of 55, which is wider than that of modern hawks, Stevens reports in the summer Journal of Vertebrate Paleontology. Moreover, over the millennia, T. rex evolved features that improved its vision: Its snout grew lower and narrower, cheek grooves cleared its sight lines, and its eyeballs enlarged. ...

Stevens also considered visual acuity and limiting far pointthe greatest distance at which objects remain distinct. For these vision tests, he took the known optics of reptiles and birds, ranging from the poor-sighted crocodile to the exceptional eagle, and adjusted them to see how they would perform inside an eye as large as that of T. rex. "With the size of its eyeballs, it couldn't help but have excellent vision," Stevens says.

He found that T. rex might have had visual acuity as much as 13 times that of people. By comparison, an eagle's acuity is 3.6 times that of a person.

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T. rex might also have had a limiting far point of 6 kilometers, compared with the human far point of 1.6 km. These are best-case estimates, Stevens says, but even toward the cautious end of the scale, T. rex still displays better vision than what's needed for scavenging.

The vision argument takes the scavenger-versus-predator debate in a new direction. The debate had focused on whether T. rex's legs and teeth made it better suited for either lifestyle.

Stevens notes that visual ranges in hunting birds and snapping turtles typically are 20 wider than those in grain-eating birds and herbivorous turtles.

In modern animals, predators have better binocular vision than scavengers do, agrees Thomas R. Holtz Jr. of the University of Maryland at College Park. Binocular vision "almost certainly was a predatory adaptation," he says.

But a scavenging T. rex could have inherited its vision from predatory ancestors, says Jack Horner, curator of paleontology at the Museum of the Rockies in Bozeman, Mont. "It isn't a characteristic that was likely to hinder the scavenging abilities of T. rex and therefore wasn't selected out of the population," Horner says.

Stevens says the unconvincing scene in Jurassic Park inspired him to examine T. rex's vision because, with its "very sophisticated visual apparatus," the dinosaur couldn't possibly miss people so close by. Sight aside, says Stevens, "if you're sweating in fear 1 inch from the nostrils of the T. rex, it would figure out you were there anyway."

Stevens, K.A. 2006. Binocular vision in theropod dinosaurs. Journal of Vertebrate Paleontology 26(June):321-330.


TOPICS: Religion; Science
KEYWORDS: atheismsucks; atheistdarwinists; bewareofluddites; creationism; crevolist; darwindroolbib; darwinwasaloser; dinosaurs; evolution; flyingbrickbats; godsgravesglyphs; guess; heroworship; ignoranceisstrength; junk; paleontology; patrickhenrycrap; pavlovian; pavlovianevos; shakyfaithchristians; trash; trex; tyrannosaurus; useyourimagination; yecluddites; youngearthcultists; youngearthidiocy
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To: Charles H. (The_r0nin)
"What?! No selection pressure in a zoo?"

See post #359.

361 posted on 07/03/2006 9:43:35 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Southack
Here you go: Labs and zoos can eliminate **natural** selection pressures.

Distinction without a difference.

362 posted on 07/03/2006 9:46:07 PM PDT by Charles H. (The_r0nin) (Hwæt! Lãr biþ mæst hord, soþlïce!)
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To: Southack
"Here you go: Labs and zoos can eliminate **natural** selection pressures.

Was that so hard?!"

You admitted an error. Good for you. It's a first.

"Must you continue to play dumb to make some nonsensical point?! You've known all along what I meant, yet played dumb anyway as if you didn't."

And then you blew it by changing the goalposts and taking back your admission...

Artificial selections are just as strong as natural ones. That being said, it's irrelevant, because we were talking about the evolution of crocodylia, which was not influenced by artificial selection pressures.

Mutation rates are FAR less important than selection pressure in determining the direction of evolution.
363 posted on 07/03/2006 9:46:32 PM PDT by CarolinaGuitarman (Gas up your tanks!!)
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To: Charles H. (The_r0nin)
"Now, at 200,000 mutations, which is more important? Draw your straight line through there! Cherry-picking data, huh?"

The same conclusion would be reached at 200,000 random mutations as for 0, 1, or 2...though the effort involved at illustrating said conclusion would be raised considerably (your goal, rather than having an honest debate).

I made my point by showing what happens at 0 mutations. Then I re-made my point by showing it again at 1 random mutation and then again at 2.

Your argument, in contrast, is so weak that you are left to merely raise the bar (e.g. to 200,000 random mutations). By that process, as soon as I showed the same result for 200,000 random mutations, you'd be so cheeky as to demand a result for 200 trillion random mutations.

Which is to say, you failed at 0, you failed at 1, you failed again at 2, and you'd likewise fail at 200,000 and 200 trillion...though you'd delay the inevitable with such inanities.

364 posted on 07/03/2006 9:48:21 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: CarolinaGuitarman

Time for bed. Night all!


365 posted on 07/03/2006 9:48:24 PM PDT by CarolinaGuitarman (Gas up your tanks!!)
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To: CarolinaGuitarman
"That being said, it's irrelevant, because we were talking about the evolution of crocodylia, which was not influenced by artificial selection pressures."

Oh yeah, right. As if you have proof of that!

Rolls eyes...

366 posted on 07/03/2006 9:49:54 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: CarolinaGuitarman
"Mutation rates are FAR less important than selection pressure in determining the direction of evolution."

That's not only incorrect, but already disproven in posts #322 and 332.

Don't play dumb. Making me repeat answers reflects poorly on your comprehension skills.

367 posted on 07/03/2006 9:52:11 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Southack
The alligators alive today would be seen by a time-traveler (e.g. modern paleontologist) 20 million years ago.

Link?

You did a deliberate word search on "alligator" on a web page ... Ridiculous.

Yes, silly of me. I should have searched for "Easter Bunny".

368 posted on 07/03/2006 9:54:43 PM PDT by OmahaFields ("What have been its fruits? ... superstition, bigotry and persecution.")
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To: Southack
Which is to say, you failed at 0, you failed at 1, you failed again at 2, and you'd likewise fail at 200,000...

No, I would succeed in my point, because at that rate of mutation, selection would play a greater role. Zero, one and two are all at the same basic scale, which is why you are using such laughably small numbers. If you were honest about it, you would admit the possibility that the graph would change at higher numbers, because it is far more logical. But, as I have found that you are untruthful, even to the point of asserting people said things that they never actually said (as you did in post #330), it is obvious that you will not even admit to the obvious. How can you trust a person's arguments when those arguments are built on lies?

369 posted on 07/03/2006 9:57:00 PM PDT by Charles H. (The_r0nin) (Hwæt! Lãr biþ mæst hord, soþlïce!)
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To: OmahaFields
"Yes, silly of me. I should have searched for "Easter Bunny"."

It would hardly have been less intelligent. Playing dumb won't score points.

370 posted on 07/03/2006 9:58:12 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Charles H. (The_r0nin)
"No, I would succeed in my point, because at that rate of mutation, selection would play a greater role."

Source? Link? Math? Example?

You've got bupkis. I proved my point for 0 mutations. I did it again for 1 mutation and again for 2 mutations.

All you've done is make a grand claim that somehow the "Easter Bunny" (reference to a different poster playing dumb above) would magically change your results if tried a bunch more times (e.g. 200,000).

You can't come close to showing such a result. Can't happen.

You lose.

371 posted on 07/03/2006 10:00:40 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Southack

Defend your lie in #330.


372 posted on 07/03/2006 10:02:13 PM PDT by Charles H. (The_r0nin) (Hwæt! Lãr biþ mæst hord, soþlïce!)
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To: Charles H. (The_r0nin)

You're changing the subject. It must have dawned on you that you couldn't back up your wild-eyed "200,000" claim.

Too bad. You lose.

373 posted on 07/03/2006 10:04:19 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Southack
No, you lost by having to resort to deceit, distortion, and ridiculous argument. And everyone who ever reads this thread will know the truth. They'll see it with their own two eyes.

At least you could apologize for your falsehood, so that those who read this in the future might think better of you in your defeat...

374 posted on 07/03/2006 10:07:47 PM PDT by Charles H. (The_r0nin) (Hwæt! Lãr biþ mæst hord, soþlïce!)
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To: tomzz
That's meat, pure and simple.

You can tell more from a photo that the experts with all there sophisticated techniques?

375 posted on 07/03/2006 10:12:26 PM PDT by OmahaFields ("What have been its fruits? ... superstition, bigotry and persecution.")
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To: Charles H. (The_r0nin)
"And everyone who ever reads this thread will know the truth. They'll see it with their own two eyes."

Anyone who reads this thread **objectively** will see that I made a claim (mutations more important than selection) that I later proved holding true for cases of selection when there were 0, 1, and 2 random mutations.

Such a person would further see that you made the opposite claim, that selection is more important than mutations if there are 200,000 random mutations...as well as that you were unable to prove your claim.

Moreover, they'll see that you are stuck on yourself (re: some perceived lie or personal slight) rather than on the intellectual debate itself.

And there can only be one conclusion from such observations: you lost.

376 posted on 07/03/2006 10:13:35 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Southack
I've already supported my claims up-thread with far more than you have. And they'll see this part of the thread as an attempt to shift the discussion away from how your argument was based on distortion and inventing statements and arguments of your opponents. A house built on sand...

At least clear your conscience by admitting you made up the charge in your second sentence in #330. It's the Christian thing to do...

377 posted on 07/03/2006 10:23:13 PM PDT by Charles H. (The_r0nin) (Hwæt! Lãr biþ mæst hord, soþlïce!)
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To: Al Simmons; All
Sorry, I had to come out of vacation in Alaska for this--Calvin and Hobbes had the definitive last word on the controversy (sorry I can't find the strip to cut-n-paste):

"T Rex was definitely a predator because it would be so LAME if it were just a scavenger."

Calvin said it. I believe it. That settles it.

Cheers!

378 posted on 07/03/2006 10:23:25 PM PDT by grey_whiskers (The opinions are solely those of the author and are subject to change without notice.)
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To: Charles H. (The_r0nin)
"I've already supported my claims up-thread with far more than you have."

That's incorrect. I supported my "mutations more important than selection" claim in post #322, among others.

You've supported your "selection more important than mutation" claim...mmm...nowhere. Just some wild-eyed "200,000" mutations would make it so.

That won't cut it. Support your claim or forever be seen as losing this debate.

379 posted on 07/03/2006 10:27:55 PM PDT by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: 6SJ7
Forty years ago, scientists thought dinosaurs were slow, stupid, cold-blooded and lived in swamps. Now they think they were smart, fast, and had sophisticated hunting skills. Next they'll be telling us that dinosaurs had a vocabulary of over 1,000 words and could drive cars, if cars existed in the Jurassic period.

You really need to find a used copy (now out of print, you see) of Science Made Stupid. Hilarious satire, Hugo award winner for sci-fi, and it includes just this point.

The picture of a T-rex smoking a pipe as it contemplates a chessboard is itself worth the price of the book.

Cheers!

380 posted on 07/03/2006 10:32:43 PM PDT by grey_whiskers (The opinions are solely those of the author and are subject to change without notice.)
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