Evolution Opponents Lose Kansas Board Majority

[Bill]

Nope sorry I missed it. What about this one from the same webpage:

"An X-ray analysis of the Allosaurus fossil indicated that the Allosaurus ribs near the scapula (the shoulder bone) were cracked and had healed. The Allosaurus was capable of recovering after many severe forward tumbles that probably occurred while it was running. So the suggestion that perhaps the large short-armed theropods were not capable of running because they couldn't recover after a fall apparently wasn't so, at least for Allosaurus - this Allosaurus did recover many times after bad tumbles."

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LOL, nope right back at ya.

I would however submit that an animal the mass of Allosaurous falling at all(remember, allosaur was over 12 feet tall) would be very likely to cause a major trauma event, but one would have to accurately measure their bones in a variety of ways to determine if that's actually true.

It's also entirely possible(and quite possibly likely) that the Allosaurous in question fell some distance into a gulley or something, and was not running at all. A totally viable- and utterly disproveable- possibility.

It might've also been tail-whipped, or suffered some feeding related blunt trauma injury that caused that injury. There's simply no way to know, but it's obvious that a 2 legged creature falling has no means to break his fall...and that a two legged creature typically willl fall a greater distance(cause it's taller for a given body length), and thus suffer more damage than a like sized 4 legger would.

If horses fall they can suffer death too.
Yet they still run in the wild.

Often they do, however, being a four legged animal optomized for running, they have fantastic balance and stability, and as a result, horses very rarely fall at all.(i've got several years of riding under my belt to make that claim- western, of course...lol)

I don't see any reason to think T-Rex was a scavenger just because it had small arms.

One of the great archeologists of our time(who is still alive) is the champion of that belief, and he has plenty of followers apparently.

I honestly don't know enough to even have an informed opinion...but it seems entirely plausible.

If they were cariion animals then why would they need long arms? Doesn't that actually fly in the face of your theory that bigger arms were better?

That they are carrion animals is not my theory, but i did explain how longer arms would still be useful for holding a carcass while you tore at it(like a squirrel or other rodent does a nut).

Haven't you just refuted your own source above?

Nope, cause i offered a quite reasonable alternate source for allosaurous broken bones. And again, the "T-rex is a carrion" is not my theory, it is merely a competing theory about the species offered up by one of the top eggheads in the field.

If there is no compelling reason to think T-Rex has short arms then perhaps it didn't fall over?

T-rex did have short arms...at least the ones we found.

But some things are more likely that others. Short arms as seen in fossil evidence to date is far more likely to represent T-Rex than fossils we *might* find.

2 fossils dude. TWO. Only TWO t-rex fossils with arms intact have ever been found. TWO.

That's hardly a valid statistical database, agreed?

But there's no evidence for any such mechanism(that evolution is not random), even though it might be easier to assume.

Sure there is. The fact that so many animals are so well adapted to thier environment is a very real form of empirical evidence this may be the case.

Also our very existance has very little to do with DNA. If the extinction of the dinosaurs had not occured we would very likely not be around today.

Maybe. Of course, extinctions are a routine event on Earth when you look at things in a cosmological timescale.

Just as I imagine the mere notion of any intelligence in weather would get scientists up in arms. Even though I guess it's "easier to assume" that weather patterns are directed by some intelligent force.

There's no proof that there's not an intelligently designed system that governs weather. There's definitely a system(which we do not come even remotely close to understanding), natural, or otherwise.

[an4815]

That seems to be mutually exclusive to the currently prevailing theory of random unprovoked mutations that only take hold if they do not interfere in the species short term success.

Common descent leads to a tree shape of life, not a web shape. So species should be composed of features that developed on the branch it is on, not from other branches, which leads to a nested heirarchy pattern.

A duck should be fully capable of just randomly mutating venom

As an analogy if five people got round a table and rolled a dice each only one of them might get a 6. We could ask why other people didn't also get a 6 if they had an equal chance of rolling one.

An even better analogy would be the dices had different biases. The evolution of venom in say snakes may have been aided by two or more things in place in snakes at the time. Ducks may not have had any such advantage.

Or people. Why no major variations at all in people?

skin color, hair color, eye color, proportions. Lots of variation.

No feathers, no wings, no hollow bones, no retractable claws, no water breathers, no eagle-eyed night seers(i've got 20/10- which is practically as good as human sight gets, and even still an eagle would blow me away on the eye chart at the doctors office, lol).

Under evolution there is no reason to expect such things to be present in people. Humans evolved in 6 million years. All available evidence suggests that feather evolution was a low probability event which only occured once in the history of life. Run the history of life again and there is no guarantee something that looked like feathers would evolve again.

There is exactly one species of people. Based on random mutation and the VAST array of closely related species all throughout the animal kingdom, why is there no cousin to the human being more like us than the chimp?(who while similar, is obviously not a humans peer.)

They all went extinct. We know of Neandertal which went extinct quite recently. Homo erectus, homo habilis are two other human species that went extinct. It's like how there are only two species of elephant left even though there were more around in the past (plus mammoths).

[Bill]

skin color, hair color, eye color, proportions. Lots of variation.

All very unremarkable differences compared to other related species differences throughout the animal kingdom.

Under evolution there is no reason to expect such things(widely diversified human variants with differing natural skills/features) to be present in people. Humans evolved in 6 million years. All available evidence suggests that feather evolution was a low probability event which only occured once in the history of life. Run the history of life again and there is no guarantee something that looked like feathers would evolve again.

No, i don't agree. If nature teaches anything it's that there are a gillion ways to do the same thing. Look at just how many different birds there are, or reptiles, or rodents. But only one kind of person.

This strikes me as peculiar.

They all went extinct. We know of Neandertal which went extinct quite recently. Homo erectus, homo habilis are two other human species that went extinct. It's like how there are only two species of elephant left even though there were more around in the past (plus mammoths).

Hmmm, i think a lot of people would tell you Homo Erectus and Homo Habilis were common ancestors of modern man rather than parallel species my friend. And the same could possibly be said about neanderthal too.

If humans randomly mutated- as is prevailing theory- from something else, then under that theory modern man might've mutated from neanderthals.

I personally don't buy that. I think that we were paralell species, and WE extincted them, lol.

Dey wuz punkazz biitchez.

[an4815]

It's also entirely possible(and quite possibly likely) that the Allosaurous in question fell some distance into a gulley or something, and was not running at all. A totally viable- and utterly disproveable- possibility.

Yes this whole area is just speculation, like the idea that T-Rex would have benefitted from longer arms.

One of the great archeologists of our time(who is still alive) is the champion of that belief, and he has plenty of followers apparently.

I've seen the otherside of that too, from here for example: http://www.pbs.org/wgbh/nova/science...09/02-ask.html

Your question is a common one these days. In the 1990s, paleontologist Jack Horner argued that T. rex was a scavenger, only eating animals that had already died, rather than actively hunting and killing them first. Because this claim contradicted the common notion that T. rex was a vicious predator, the media—from newspapers to radio to television—quickly picked up on the story, leading many people to think that science favored the "T. rex was a scavenger" theory.

However, of the paleontologists that I have met, it seems that only Jack subscribes to the theory. I, too, disagree with Horner; the arguments that I've seen him put forward for a scavenging T. rex are not strong. For example, he states that the short arms of T. rex were useless for hunting. True, but don't forget about the massive skull that's armed with a mouth full of teeth. The impact and bite from such jaws were no doubt quite effective in taking down prey, so who needs arms? Another argument that Horner commonly presents is that T. rex was not a fast runner, so it couldn't have successfully chased and captured its prey. Indeed, T. rex was probably no speed demon (see my answer to one of the previous questions), but neither were its potential prey items, the "duck-billed" hadrosaurs and horned ceratopsians, so T. rex did not need to be a fast runner—only fast enough.

...continues..

2 fossils dude. TWO. Only TWO t-rex fossils with arms intact have ever been found. TWO.

How many have been found with

That's hardly a valid statistical database, agreed?

It's enough for me. It means that we know that small armed T-Rex existed. We have absolutely no evidence that long armed ones existed anymore than evidence that small headed ones existed.

Sure there is. The fact that so many animals are so well adapted to thier environment is a very real form of empirical evidence this may be the case.

But there is no known mechanism in DNA that could explain that. For example put bacteria in antibiotic substances and they don't all develop antibiotic resistance as if that response is encoded in their DNA. Resistance to the antibiotics is down to chance mutation. If none of the bacteria have resitance then they will die. If one or two happen to have gained resitance to antibiotics before being put in the antibiotics then those will survive.

There's no proof that there's not an intelligently designed system that governs weather. There's definitely a system(which we do not come even remotely close to understanding), natural, or otherwise.

That's kind of my point. There's also no proof that there is an intelligently designed system that governs the evolution of life. Sure their might be, but then weather also might be controlled by some undetected intelligence.

[an4815]

All very unremarkable differences compared to other related species differences throughout the animal kingdom.

All humans are one species. We have the same amount of variation as most species out there I think. For example the variation in african elephants, or the variation in giraffes seems to be less than in humans to me (although im sure they would think the same about us if they could)

No, i don't agree. If nature teaches anything it's that there are a gillion ways to do the same thing. Look at just how many different birds there are, or reptiles, or rodents. But only one kind of person.

Well you you are comparing big animal groups with a single species. Birds are an animal class. Reptiles are an animal class. Rodents are an animal family. "Persons" are just one species. It's like saying 'Look how many different polish people there are, and how many different american people there are, but only one kind of me. It's peculiar'

Hmmm, i think a lot of people would tell you Homo Erectus and Homo Habilis were common ancestors of modern man rather than parallel species my friend. And the same could possibly be said about neanderthal too.

Even so I don't see why they wouldn't be an example of other hominid species like us.

[dalem]

First of all, i made a prediction which some egghead could easily test given the time and money. That prediction being:

-snip stuff about comparative features and abilities-

It's obvious.

A key point is that it may indeed be obvious (comparative advantage, that is) but it only truly becomes obvious after the fact, i.e. after the genes have rolled their dice and reproduced their mice.

I hate to rain on your parade, but not only is that not universally accepted even among scientists, there's simply no way whatsoever to prove it(so far). The question of random mutation vs environmentally driven enhancement is IMO, far from settled.

I will grant you that your view is the prevailing theory...but so far it is hardly cold hard fact.

Fair enough.

Well maybe that big rack was evolved to defend against some other top predator that for whatever reason vanished. In the absence of said predator the formerly helpful horns are now a huge disadvantadge, especially if said horns do not defend effectively against whatever other predator filled the vacuum.

OR....there was some local extinction event(virus, earthquake, whatever) that wiped them all out. Which is entirely possible.

Very true - we are saying the same thing with this one.

Bigger claws are an advantadge so obvious as to beyond debate as far as im concerned, but...

Look at every species of cat, every species of digging animal, and oh yeah, human females(they sure seem to think longer nails -our claws- aid in mating rituals and practices. And i think they're right, heheh). All have been highly succesful with large claws, and the bigger the better. And you can make a clear case that any of those animals would fail without those claws(except the human female, which is notorious for it's vanity and persistance....lololol)

Here I would disagree - bigger claws (or teeth, or liver, or lungs, or whatever) have the potential to be an advantage (and I would lean toward "almost always" as far as frequency there) but other factors may render them irrelevant or even disadvantageous, and therefore they may not be selected for.

This assumes that the genetics of the biological structures allow for their selection in the first place, but growth fields and dominance are more biology, and I come at Evolutionary Biology via Geology.

Please explain.

My training (truncated though it was) in evoultionary biology and paleontology was via the field and science of geology. My profs were very analytical (as am I) and didn't have a lot of interest in poorly-grounded speculations, as fun as they can be. So, say you find a "pure" dino fossil with feathers (as some Chinese paleontologists have claimed they have). You can stick with that discovery and talk about the sedimentation and other members of that Family or Genus and the like. You can also speculate on mating habits, uses of the feathers, and go down that road. The latter road is what I was taught to think of as "storytelling" - it's a less rigorous line of inquiry.

And btw, i now have proof that many scientists consider that longer armed t-rexes and allosaurs would've been better predators.

Check it out:

"There has been some discussion on whether or not the massive, short-armed theropods (like T. rex, Giganotosaurus, Albertosaurus, and Allosaurus) could run very fast because if they fell, their short arms would not break their fall and they would be badly injured (James Farlow, 1995). This meant that these large theropods were slow, lumbering animals."

http://www.enchantedlearning.com/sub...losaurus.shtml

And their long tails aren't balancing them? When Ostriches fall they can't get up or break their falls? What about 'roos? This claim seems very silly on its face.

Both of which appear to have been slow, lumbering beasts because their arms neither A) allowed for much counter-balancing(i read this several times in the last couple days, and B) they were too short to break a fall. And C), obviously they were too short to grab fleeing prey animals or be of any aid in hunting.

Ergo, longer arms are definitely better in several key ways.

Again, I refer you to other bipedal runners/movers. As far as grabbing prey, one could easily argue that T rex's gigantic head and jaw could serve as a very effective "grabber". Maybe its arms are so short BECAUSE it chiefly relied on its jaws in such a way. An early prof of mine used to paint a great picture of a T rex lurking in the bush by a riverbank for unsuspecting duckbills, SPRINGING via its tremendous legs onto a Hadrosaur, grabbing on with its massive jaws, leaning back on one leg and its mighty tail, and rabiit-kicking the sh!t out of its prey with a giant, viciously-taloned rear claw.

Great imagery, and maybe even some of it's true (although I think current extrapolations of muscle mass and arrangement preclude T rex from being thought of as even a marginal leaper), but storytelling aside, it does show how certain extremely specialized features of T rex might have been useful, and others not.

Was it intact? Did they actually find a feather growing out of it, or is this just some theory of some eggheads? Cause they can't even agree whether or not the Velociraptor had fur or not, nor can they even agree if the T-rex was a hunter or a scavenger.

So short of them finding a frozen 4-legged critter complete with feathers in place, i have to say....im highly skeptical(i will read up on it though).

Google it. Archaeopteryx is a small feathered dinosaur with teeth, and is widely accepted to be a precursor for birds.

-dale

[bandwagon]

Well maybe that big rack was evolved to defend against some other top predator that for whatever reason vanished. In the absence of said predator the formerly helpful horns are now a huge disadvantadge, especially if said horns do not defend effectively against whatever other predator filled the vacuum.

OR....there was some local extinction event(virus, earthquake, whatever) that wiped them all out. Which is entirely possible.

Very true - we are saying the same thing with this one.

Just nit picking in cos I think I know the answer to this one: The rack is more likely to be a consequence of sexual selection. Males compete for females. The larger antlers may help in combat, mainly by soaking up impact, but more importantly, they may serve to intimidate a rival, who is then more likely to give up before either get injured, which may help the species. In either case, the bigger the antlers the more likely they are to breed.

"...bigger claws...should allow for a slight increase in the % of succesful hunts, which should in turn lead to a slight decrease in the % of starvation among individuals of the species."

ONLY if small claws size is limiting its ability to catch enough food to feed its young. e.g. if its prey is evolving defences, or growing larger and stronger. But NOT if prey responds to predation by evolving more speed, or simply produces more and more young, in which case larger claw size is, if anything, a hinderance.

[Bill]

And their long tails aren't balancing them? When Ostriches fall they can't get up or break their falls? What about 'roos? This claim seems very silly on its face.

Again, I refer you to other bipedal runners/movers.

Let's look at it a bit more closely.

A T-rex is thought to have been as much as 20 feet tall and are said to have been capable of weighing in at as much as 14,000lbs.

A Red Kangaroo(the biggest) is 5 1/4 feet tall and 130lbs.

IOW, the T-rex is almost four times taller and about 108x more massive.

KE is mass x velocity squared.

There are no comparable bipeds in the modern world to compare these notional dinosaurs too. Remember, double mass and you double KE, and the T-rex is 108x more massive than the biggest Kangaroo! And because velocity squares KE, the T-rex falling from 4x the height is subject to utterly immense impact forces.

It would literally be like dropping a 7 ton utility truck off a 2nd story building.

Even steel axles or suspension components would get bent in such a fall.

As far as grabbing prey, one could easily argue that T rex's gigantic head and jaw could serve as a very effective "grabber".

Agreed, and a longer neck makes that a more effective tool, and compared to velociraptor(a dinosausr that actually had long arms and what was for a dinosaur a genius level IQ) it has a very short neck.

So there is fossil evidence of far more evolved and 'perfect' bi-pedal reptillian carnivore.

That suggests to me that given time T-rex probably would've evolved in a similar way.

"SPRINGING via its tremendous legs onto a Hadrosaur, grabbing on with its massive jaws, leaning back on one leg and its mighty tail, and rabiit-kicking the sh!t out of its prey with a giant, viciously-taloned rear claw. Great imagery, and maybe even some of it's true (although I think current extrapolations of muscle mass and arrangement preclude T rex from being thought of as even a marginal leaper), but storytelling aside, it does show how certain extremely specialized features of T rex might have been useful, and others not."

Sounds awesome. Sadly we'll never know just how they hunted. Ever.

Archaeopteryx is a small feathered dinosaur with teeth, and is widely accepted to be a precursor for birds.

A quadropod? (ps: will do)

[Bill]

"...bigger claws...should allow for a slight increase in the % of succesful hunts, which should in turn lead to a slight decrease in the % of starvation among individuals of the species."

ONLY if small claws size is limiting its ability to catch enough food to feed its young. e.g. if its prey is evolving defences, or growing larger and stronger. But NOT if prey responds to predation by evolving more speed, or simply produces more and more young, in which case larger claw size is, if anything, a hinderance.

Well, i would submit that a cat(just an example) with newer bigger claws(say a wild domestic cat whose claws mutate from 3/8" to 1/2") can suddenly hunt slightly bigger, slightly better armored, slightly faster prey- thereby opening up a larger potential food source, which when you combine it all should translate into a slightly better survival rate species wide, which would then suggest a slightly larger number of animals mating, and then spawning young.

It's like going into a knife fight. Obviously a 4" blade is in all ways a wee bit preferrable to one that's 3.5".

Now, i will agree that if the cat lives in an area with no slightly larger prey animal that'd be of no use(though imo also no detriment), but i'd also submit that there is usually such a game animal.

IOW, that 1/8" could be the difference between succesfully hunting rats(easy for any domestic cat) and racoons(a real stretch for the vast majority of domestic cats- but doable for big Tomcats). Racoons are obviously a much better payoff for your investment in time and energy...and with the bigger claws, our improved cat can now bag them.

Hell, some cats DO have longer claws than others, and those ones typically are also bigger, and yep- i'd say that you could definitively say they're better than the average domestic cat. IOW, if the average shifts up to the old upper limit, IMO in this case, the cats would be the better off for it.

[bandwagon]

Well, i would submit that a cat(just an example) with newer bigger claws(say a wild domestic cat whose claws mutate from 3/8" to 1/2") can suddenly hunt slightly bigger, slightly better armored, slightly faster prey- thereby opening up a larger potential food source, which when you combine it all should translate into a slightly better survival rate species wide, which would then suggest a slightly larger number of animals mating, and then spawning young.

Sure. In that situation, claw size is a performance limiting feature. But look what happened: change in phenotype, change in niche, that is speciation, evolution in action. And this new cat would live along side the domestic cat who would continue to catch mice and birds with its little claws, efficiently.

[Bill]

Sure. In that situation, claw size is a performance limiting feature. But look what happened: change in phenotype, change in niche, that is speciation, evolution in action. And this new cat would live along side the domestic cat who would continue to catch mice and birds with its little claws, efficiently.

Well we've yet to see that that species born in captivity(as the vast majority of domestic cats are). If it's random, the domestic cats should also be subject to the same mutation as if it were pressure driven.

If a demonstrably bigger more powerful species(that goes beyond just being a big tomcat) is born in the joneses laundry room(or rather a lot of laundry rooms) i suspect we'll hear about it before too long on the evening news...and then you'll have your definitive proof.

[dalem]

Let's look at it a bit more closely.

A T-rex is thought to have been as much as 20 feet tall and are said to have been capable of weighing in at as much as 14,000lbs.

A Red Kangaroo(the biggest) is 5 1/4 feet tall and 130lbs.

IOW, the T-rex is almost four times taller and about 108x more massive.

KE is mass x velocity squared.

There are no comparable bipeds in the modern world to compare these notional dinosaurs too. Remember, double mass and you double KE, and the T-rex is 108x more massive than the biggest Kangaroo! And because velocity squares KE, the T-rex falling from 4x the height is subject to utterly immense impact forces.

It would literally be like dropping a 7 ton utility truck off a 2nd story building.

Even steel axles or suspension components would get bent in such a fall.

What are you even trying to get at here? That every T rex that fell down died?

Agreed, and a longer neck makes that a more effective tool, and compared to velociraptor(a dinosausr that actually had long arms and what was for a dinosaur a genius level IQ) it has a very short neck.

So there is fossil evidence of far more evolved and 'perfect' bi-pedal reptillian carnivore.

That suggests to me that given time T-rex probably would've evolved in a similar way.

Only because you don't understand evolutionary biology. Maybe a beefier-armed Tyrannosaur would have emerged, maybe not (and if it did, it would be called speciation ).

But if it was getting along fine without using its arms much already, then I would place my money on them being lost completely, and we'd have a truly odd duck - a true two-legged dinosaur.

A quadropod? (ps: will do)

Yep, four limbs, forearms complete with hands and claws.

-dale

[Bill]

What are you even trying to get at here? That every T rex that fell down died?

I'm getting at the fact that for a T-rex to fall even while stationary likely resulted in things breaking. Probably things that were attatched.
All you gotta do is look at the forces involved. So what i'm saying is that T-rex was taking his life into his hands if he ran at any appreciable speed at all, especially with no arms to break his fall.

Simple math:

At a running pace of 20mph a 7 ton T-rex(excluding any velocity increase from the vertical fall) would have to absorb 186,000 foot-lbs of impact energy upon hitting the ground.

IOW, it's the same energy release as a truck hitting a wall at 20mph.

So CLEARLY shock absorbers(ie long arms that could absorb energy over time)would hugely benefit a t-rex, especially a running t-rex.

Only because you don't understand evolutionary biology.

Again, there is no definitive proof that evolution is caused by random mutation vs environmentally driven need. It's prevailing thought, yes, but to say i don't understand is wrong. I simply don't agree.

Maybe a beefier-armed Tyrannosaur would have emerged, maybe not (and if it did, it would be called speciation ).

It may very well have emerged. And yeah, if it could be proven to be a direct relative of T-rex via genetic matching, yep....that'd be speciation by any definition of the word.

But if it was getting along fine without using its arms much already, then I would place my money on them being lost completely, and we'd have a truly odd duck - a true two-legged dinosaur.

We really don't know that T-rex was 'getting along fine' with the two little arms because we've only found two examples that were intact enough to definitively say, "Yup, critter had short stubby arms". For all we know THOSE TWO are of the failed ancestry line, and we've simply yet to find an improved variant. As far as i know we've found less than 10 t-rex remains sites at all.

Two examples is IMO just far too small a sample to make any concrete final statements about that particular dinosaur. I do agree it was a predator though...not a scavenger.

[dalem]

I'm getting at the fact that for a T-rex to fall even while stationary likely resulted in things breaking. Probably things that were attatched.

-snip-

So CLEARLY shock absorbers(ie long arms that could absorb energy over time)would hugely benefit a t-rex, especially a running t-rex.

Again, there is no definitive proof that evolution is caused by random mutation vs environmentally driven need. It's prevailing thought, yes, but to say i don't understand is wrong. I simply don't agree.

No, you simply don't understand. The vast majority of evidence and agreement is as I (and others on this thread) have described previously - random mutations (within acceptable body plan frameworks) occur, and the environment can then act as a determinant of the utility of those mutations.

It may very well have emerged. And yeah, if it could be proven to be a direct relative of T-rex via genetic matching, yep....that'd be speciation by any definition of the word.

But... haven't you already denied the evidence of genetic mapping as evidence for a common ancestor of modern chimps and humans?

We really don't know that T-rex was 'getting along fine' with the two little arms because we've only found two examples that were intact enough to definitively say, "Yup, critter had short stubby arms". For all we know THOSE TWO are of the failed ancestry line, and we've simply yet to find an improved variant. As far as i know we've found less than 10 t-rex remains sitesat all.

Two examples is IMO just far too small a sample to make any concrete final statements about that particular dinosaur. I do agree it was a predator though...not a scavenger.

T rex was around for 15 million years - that's a decent time for a species line to "prove" itself as viable. And full skeletons are rarely encountered for anything anywhere in the fossil record, so harping on "only 2 full skeletons" is a poor criticism. Most examples are partial, and there's no reason T rex should be any exception.

-dale

[Bill]

No, you simply don't understand. The vast majority of evidence and agreement is as I (and others on this thread) have described previously - random mutations (within acceptable body plan frameworks) occur, and the environment can then act as a determinant of the utility of those mutations.

I don't care about 'vast majority' of evidence cause the evidence is still not set. All scientists do not agree that evolution is caused by random mutation.

But... haven't you already denied the evidence of genetic mapping as evidence for a common ancestor of modern chimps and humans?

I do not believe there was a single common ancester, nope.

T rex was around for 15 million years - that's a decent time for a species line to "prove" itself as viable. And full skeletons are rarely encountered for anything anywhere in the fossil record, so harping on "only 2 full skeletons" is a poor criticism. Most examples are partial, and there's no reason T rex should be any exception.

Dude, there have been less than ten t-rex finds in total. Less than ten. ( i think it's seven, but i dont remember for sure).

And seriously....you have no proof that the two armed variant existed for 15 million years. It is merely thought(not proven- thought) that the species lived for about that long.

The MOMENT we find the next T-rex EVERYTHING we believe about them could change....it's happened before with other finds.