That was by design.
< wink >
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.
b
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.
If you had read the article I linked to, you would know that it demonstrated the accumulation of adaptive mutations -- by direct, detailed observation.
That was by design.
< wink >
And this can be proven how? Why on small changes? Is this because it is the only answer to evolution? I believe so. By making it happen over millions of years anything can be interjected into the program at any time and the populace is supposed to be in awe how learned people can reach such hypothesis.
If you had read the article I linked to, you would know that it demonstrated the accumulation of adaptive mutations -- by direct, detailed observation.
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.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.
Heh-heh. Once again mixing up two different things that have to be independently evaluated, eh? Apples and oranges?
Kinds like evolution vs. ID?
'Best' is totally relative in your comparison.
Predators have eyes facing forward (TRex, birds of prey). The binocular aspect thus gained helps them identify movement and judge distances. Generally their vision is pretty good, for the same reasons.
Herbivores like Triceratops, for example, often have eyes on the sides. What they lose in depth perception they gain in having a much wider field of vision, reducing the chance that a predator can ambush them from behind (obviously identifying movement is also important for the same reason).
So, in terms of which vision is 'best', it all depends on what you are looking for - distance and depth, or breadth. both have their advantages, depending on whether you are the 'chomper' or the 'chompee'...
Indeed.
I wonder when the little chompee decided he/she/it wasn't gonna take it any more and started to be the chomper?
|
|
|||
Gods |
Note: this topic is from July 30, 2006. |
||
|
· Discover · Nat Geographic · Texas AM Anthro News · Yahoo Anthro & Archaeo · Google · · The Archaeology Channel · Excerpt, or Link only? · cgk's list of ping lists · |
|||
[or Man is right and life on earth evolved over time and God had nothing to do with it.]
But I believe in evolution as designed by God, and I believe in good and evil. I don’t see the either or pronouncement as meaningful. God created things however he pleased, and then gave us minds to figure things out.
By the way, how do you explain the speed of light and the 13 billion year age of the universe?
Dinosaurs, the new Neanderthals : )
;’)
That's because you are ignoring the "wages of sin is death" paradox. If evolution is true then eons of death occurred before the fall. So if the Fall did not cause death to enter creation, then Christ lied and He died for nothing because death cannot be defeated because under your belief system God designed death as a part of evolution. You're also ignoring God's own account of how He made Creation. So to say that you believe in God, but not what He says He did, well, that's not belieft, that's lip service. It lets you control who God on your terms instead of believing in Him on His terms.
Genetics is one of the most elegant and beautiful of God’s creations.
Got it covered.
I didn’t look at the date of the article I was pinged to! Hahahahahaha. I just replied to a 3 year old post. Wow! Sorry, unreply...unreply...unreply.
Oh, Mr. Rex, what big eyes with a binocular range you have.
The better to see you, you scrumptious little morsel... er...my dear.
Take THAT Horner!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Not important at all.
We should burn all the mounted fossils, bulldoze the Museums and destroy all books and literature on Dinosaurs, while stopping all funding and support for paleontological research.
Happy now???
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.