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.
What ever you do, don't bring up the speed of gravity.
from my understanding of evolutionary theory, the belief is that random mutations and natural selection operate together in producing new species. (so both processes need to be focused on; not one or the other.)
however, the fact that these mutations are random in a naturalistic sense does not say anything about whether or not God planned them.
it seems to me that God, being all powerful, could plan out random mutations.
Maybe later I will have time to introduce the rest of the rules and how they apply to the ID'rs here. Meanwhile, enjoy.
Rule 8: Whenever possible, make gravity the Coyote's greatest enemy. Another Chuck Jones' classic, Scrambled Aches, has Wile E. watering a rock in order to grow it to boulder-size so he can crush Road Runner flat in his tracks. In true Wile E. style, the rock expands just as the tottering coyote lifts it over his head, letting gravity take its course. It's the law, you know.
I would consider it entertaining to create a universe of foward moving rules and see where it lead to.
Just look how popular SimCity and other such games are.
I wasn't offended. Insulted perhaps, but not offended.
I remember Robert Bakker expounding on this theory nearly twenty years ago. My favorite dinosaur, Stenonychosaurus (I don't like the name Troodon, it sounds like the name of a Luxembourg death metal band) also had binocular vision.
Alberto, Alberto, where ya been so long ...
It sure is quiet here. I didn't realize my singing would scare everyone off ...
BWAAAAAAAAAAAAAAAAHAHAHAHAHA!
There were no late Cretaceous sauropods in North America until the very end of the dinosaur age, when some titanosaurids moved north across the land bridge from South America...evidence indicates that Hadrosaurs and Ceratopians were the primary large herbivores in TRex's environment....to my knowledge no group burial of TRexes has yet been found that would provide evidence they lived in family groups (unlike the Giganotosaurs of South America, for which 2 mass burials have been unearthed, most likely courtesy of flash floods that drowned them)....
Definition:
Insulted = To give offense; offend
You still won't answer the question?
Someone, and I cannot remember who, a week or a few weeks ago, gave me that link....It was so funny...guess I was just holding onto it, until the right time came along, to bring it out, and see if I could get someone to bite, and actually believe that the article was a real field report...
You would think I would remember who first gave me that link, because its just such a great find...perhaps someone, somewhere on FR, will read this, and remember that they gave me that link...and let me thank them again for that link...
The sad, sad thing is, people will actually believe what they are reading, little realizing that they have played into the hands of whoever wrote the article..I would say, at that point, the writers of the article, have accomplished their mission...
When I posted that link to that article about the dinosaur saddle, I posted it, believing that everyone would of course recognize that it was a joke...
Because just the names are a hint that this is not a serious article but satire...Dr. Booble?...Claptrappe, Oklahoma?...Holy Patriot Bible University and Correspondence College?...come on now, just those names alone should have been a clue...
Dinosaur saddles?..Dinosaur corrals?...Ride em, Dino-boys...
:-)
Oh, puhleeze. Quit acting like a child and own up to your beliefs.
I have my beliefs.
Then why the secrecy? What's so hard about stating your beliefs? Do you believe in God or not?
Another freeper posted tonight that God never designed anything that kills children. Yet dozens of Freepers have posted to me that God designed the bacterial flagellum.
What do you think?
No secrecy. I just don't like to get into conversations with those that ping me and others as atheists.
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