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Chance and evolution


eMTee
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First of all eMTee, this is the CHANCE AND EVOLUTION thread. If you want to discuss irrelevent youg earth creationist stuff, you should post in a different thread.

 

eMTee: you all probably heard of human footprints being found inside petrified dinasour footprints, ...

 

You mean the "human footprints" that even most Creationists have come to reject?

 

”For many years claims were made by strict creationists that human footprints or "giant man tracks" occur alongside dinosaur tracks in the limestone beds of the Paluxy River, near Glen Rose Texas. If true, such a finding would dramatically contradict the conventional geologic timetable, which holds that humans did not appear on earth until over 60 million years after the dinosaurs became extinct. However, the "man track" claims have not stood up to close scientific scrutiny, and have been abandoned even by most creationists. The supposed human tracks have involved a variety of phenomena, including forms of elongate (metatarsal) dinosaur tracks, erosional features, indistinct markings of uncertain origin, and some doctored and carved specimens (most of the latter on loose blocks of rock). This Web site provides a collection of articles reviewing the history of the controversy and evidence involved, articles on other alleged out-of-order fossils and artifacts, and information and links on dinosaur tracks in general. “ (http://www.talkorigins.org/faqs/paluxy.html)
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Biochemist: The mamalian eye requires concurrent development of extremely complex changes in three separate embryonic plates, any one of which would have been selected against millions of years previously.

 

Just to make sure everyone is on the same page, computer models have shown that intermediate stages in eye evolution are selectable.

 

”Their task was to set up computer models of evolving eyes to answer two questions. The first was: is there a smooth gradient of change, from flat skin to full camera eye, such that every intermediate is an improvement? …Second, how long would the necessary quantity of evolutionary change take?

 

 

They worked at the level of tissues: the level of stuff made of cells rather than the level of individual cells. Skin is a tissue, so is the lining of the intestine, so is muscle and liver. Tissues can change in various ways under the influence of random mutation. Sheets of tissue can become larger or smaller in area. They can become thicker or thinner. In the special case of transparent tissues like lens tissue, they can change the refractive index (the light-bending power) of local parts of the tissue.

 

The beauty of simulating an eye, as distinct from, say, the leg of a running cheetah, is that its efficiency can be easily mea-optics. The eye is represented as a two-dimensional cross-section, and the computer can easily calculate its visual acuity, or spatial resolution, as a single real number. It would be much harder to come up with an equivalent numerical expression for the efficacy of a cheetah's leg or backbone. Nilsson and Pelger began with a flat retina atop a flat pigment layer and surmounted by a flat, protective transparent layer. The transparent layer was allowed to undergo localised random mutations of its refractive index. They then let the model deform itself at random, constrained only by the requirement that any change must be small and must be an improvement on what went before.

 

The results were swift and decisive. A trajectory of steadily mounting acuity led unhesitatingly from the flat beginning through a shallow indentation to a steadily deepening cup, as the shape of the model eye deformed itself on the computer screen. The transparent layer thickened to fill the cup and smoothly bulged its outer surface in a curve. And then, almost like a conjuring trick, a portion of this transparent filling condensed into a local, spherical subregion of higher refractive index. Not uniformly higher, but a gradient of refractive index such that the spherical region functioned as an excellent graded- index lens.

 

Graded-index lenses are unfamiliar to human lens-makers, but they are common in living eyes. Humans make lenses by grinding glass to a particular shape. We make a compound lens. like the expensive violet- tinted lenses of modern cameras. by mounting several lenses together, but each one of those individual lenses is made of uniform glass through its whole thickness. A graded-index lens, by contrast, has a continuously varying refractive index with in its own substance. Typically, it has a high refractive index near the centre of the lens. Fish eyes have graded-index lenses. Now it has long been known that, for a graded-index lens, the most aberration-free results are obtained when you achieve a particular theoretical optimum value for the ratio between the focal length of the lens and the radius. This ratio is called Mattiessen's ratio. Nilsson and Pelger's computer model homed in unerringly on Mattiessen's ratio.

 

And so to the question of how long all this evolutionary change might have taken. In order to answer this, Nilsson and Pelger had to make some assumptions about genetics in natural populations. They needed to feed their model plausible values of quantities such as "heritability" . Heritability is a measure of how far variation is governed by heredity. The favoured way of measuring it is to see how much monozygotic (that is, "identical") twins resemble each other compared with ordinary twins. One study found the heritability of leg length in male humans to be 77 per cent. A heritability of too per cent would mean that you could measure one identical twin's leg to obtain perfect knowledge of the other twin's leg length, even if the twins were reared apart. A heritability of 0 per cent would mean that the legs of monozygotic twins are no more similar to each other than to the legs of random members of a specified population in a given environment. Some other heritabilities measured for humans are 95 per cent for head breadth, 85 per cent for sitting height. 80 percent for arm length and 79 per cent for stature.

 

Heritabilities are frequently more than 50 percent, and Nilsson and Pelger therefore felt safe in plugging a heritability of 50 per cent into their eye model. This was a conservative, or "pessimistic", assumption. Compared with a more realistic assumption of, say, 70 per cent, a pessimistic assumption tends to increase their final estimate of the time taken for the eye to evolve. They wanted to err on the side of overestimation because we are intuitively skeptical of short estimates of the time taken to evolve something as complicated as an eye.

 

For the same reason, they chose pessimistic values for the coefficient of variation (that is, for how much variation there typically is in the population) and the intensity of selection (the amount of survival advantage improved eyesight confers). They even went so far as to assume that any new generation differed in only one part of the eye at a time: simultaneous changes in different parts of the eye, which would have greatly speeded up evolution, were outlawed. But even with these conservative assumptions, the time taken to evolve a fish eye from fiat skin was minuscule: fewer than 400,000 generations. For the kinds of small animals we are talking about, we can assume one generation per year, so it seems that it would take less than half a million years to evolve a good camera eye.

(http://www.simonyi.ox.ac.uk/dawkins/WorldOfDawkins-archive/Dawkins/Work/Articles/1995-06-16peepers.shtml)

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Do you have any thing against the eye witness claims of seeing dinasours in remote areas?

 

Claims from some eye witnesses in remote areas is about as bad of evidence as one can have. Not until the baseless claims are supported with actual science do they carry any weight.

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Just to make sure everyone is on the same page, computer models have shown that intermediate stages in eye evolution are selectable.
I am pretty sure you are proving my point here. The computer model is ludicrously simple, and (of course) bypasses the core conundrum of concurrent changes in separate embryonic plates.

 

Your tendency to automatically accept this study as "proof" underlines my point that your faith position on this skews your objectivity. Even this simplistic model ignores that fact that there are probably hundreds of thousands of favorable alterations reguired to get from a "flat tissue" to a 3-embryonic-plate eye (if you look at the biochemical differences between say, planaria and elephants). 500,000 generations would not come close to elucidating the number of biochemical changes, even if they were to occur favorably in every generation.

 

This is good computer modeling work, but "proves" nothing except your bias. It would be useful to the audience if you would admit that there are interesting unsolved problems here.

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TeleMad: Just to make sure everyone is on the same page, computer models have shown that intermediate stages in eye evolution are selectable.

 

Biochemist: I am pretty sure you are proving my point here.

 

I am pretty sure I am not. I am pretty sure that what I am doing is sucessfully countering your earlier claims.

 

Biochemist: Your tendency to automatically accept this study as "proof" underlines my point that your faith position on this skews your objectivity.

 

You are equivocating. The "faith" scientists have in science is of a entirely different sort than the blind faith religious people have in their God. You've been comparing apples and oranges.

 

Biochemist: Even this simplistic model ignores that fact that there are probably hundreds of thousands of favorable alterations reguired to get from a "flat tissue" to a 3-embryonic-plate eye (if you look at the biochemical differences between say, planaria and elephants). 500,000 generations would not come close to elucidating the number of biochemical changes, even if they were to occur favorably in every generation.

 

And your support for your claims? Where's your calculation of how many generations it would take, and what variables does your model use, and what values do you assign to them?

 

You aren't talking science, you're talking anti-science.

 

Biochemist: This is good computer modeling work, but "proves" nothing except your bias. It would be useful to the audience if you would admit that there are interesting unsolved problems here.

 

It would be useful to the audience for you to admit that I whooped your butt again!

 

You said that "incrementalizing" a process wouldn't change the probability much, remember?

 

Biochemist: The math is not substantially improved by suggesting that the steps can be incremental, or that most steps fail.

 

I convincingly showed you were wrong.

 

Oh, and you are wrong about the second part of you assertion too. Natural selection tends to filter out the detrimental, leaving behind 'only' the advantageous. Natural selection allows most mutations to fail while still allowing progress.

 

 

Buffy was right and you were wrong.

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You are equivocating. The "faith" scientists have in science is of a entirely different sort than the blind faith religious people have in their God. You've been comparing apples and oranges.
As near as I can tell, TM, your definition of faith is anything that someone else believes is true.
You aren't talking science, you're talking anti-science....You said that "incrementalizing" a process wouldn't change the probability much, remember?
What I suggested (that you apparently cannot understand) was that the 747 metaphor above still characterizes a problem that you continue to sidestep, and that incrementalism does not satisfactorily address. Unless your science is highly faith-based, like yours.
Natural selection tends to filter out the detrimental, leaving behind 'only' the advantageous.
Do you lay awake at night chanting "natural selection, natural selection..."? It is not clear why you refuse to acknowledge the long list of difficulties with gradualism. The less you admit that the core thesis is problematic, the sillier your position looks.

 

Almost all higher life forms have biochemical pathways that destroy foreign substances, particularly proteins, that are not a part of the existing cell machinery. In more advanced phyla, this function is usually concentrated in the lysosomes, although they are not the only scavenger systems. The more advanced the life form, the less likely that any incremental protein structure would survive a generation (for the cell, much less for the organism). For those cell structures that require several multiple-enzyzme enzyme systems (most of them), there are only extremely rare cases where anyone can demonstrate incremental value for the constituent pieces. Ergo, the vast majority of proteins that were mutations (even the miniscule fraction that were actually functional enzymes) would have been eradicated by design before even a second enzyme (out of 6 to 10 in a typical sequence) would show up by another mutation. These numbers make the 747 metaphor look conservative, even though that analysis is overly simplistic.

 

Don't tell me about natural selection again, or pull out the tired example of reuseable flagellum proteins, OK? There would have to be millions, probably billions of examples of lysosome failures for gradualism argument to make sense. Do the math on a billion lysosome failures, assuming that they are, say 99% effective. And I suspect they are far more effective than 99%.

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So you all deny that any of the clames are facts?

 

I deny that the alleged "human footprints" show that humans and dinosaurs coexisted.

 

I deny that the eyewitness testimony of some people in remote areas, claiming they've seen dinosaurs, means that dinosaurs are still living is a fact.

 

I deny that the geological record supports the Biblical flood story: geology actually contradicts it.

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Biochemist: Almost all higher life forms have biochemical pathways that destroy foreign substances, particularly proteins, that are not a part of the existing cell machinery. In more advanced phyla, this function is usually concentrated in the lysosomes, although they are not the only scavenger systems. The more advanced the life form, the less likely that any incremental protein structure would survive a generation (for the cell, much less for the organism). For those cell structures that require several multiple-enzyzme enzyme systems (most of them), there are only extremely rare cases where anyone can demonstrate incremental value for the constituent pieces. Ergo, the vast majority of proteins that were mutations (even the miniscule fraction that were actually functional enzymes) would have been eradicated by design before even a second enzyme (out of 6 to 10 in a typical sequence) would show up by another mutation. These numbers make the 747 metaphor look conservative, even though that analysis is overly simplistic.

 

So your "biochemical" view of a cell has a vast army of lysosomes partolling the grounds, continuously roaming through every sector, nook, and cranny, checking every single protein's passport and if it's not valid, the protein is consumed and degraded?

 

Gee, that's not at all the picture one gets from reading molecular cell biology texts. But hey, you never were big on science, were you.

 

Biochemist: Don't tell me about natural selection again ...

 

Okay. But did you know that natural selection tends to eliminate the detrimental mutations while preserving the beneficials ones. This allows 'progress' to be made even though most mutations are deleterious.

 

Biochemist: Don't ... pull out the tired example of reuseable flagellum proteins, OK?

 

Okay. But did you know that many of the proteins in the supposedly irreducibly complex bacterial flagellum exist in a different cellular machine - the type III secretory system - which performs a different function? Yes, a subset of the bacterial flagellum's proteins are functionally selectable outside of the flagellum.

 

And did you know that many of the proteins associated with vision are also found in non-visual cells? Yes, a subset of the visual system's proteins are functionally selectable outside of the visual system itself.

 

Nature employs cooption a lot.

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I don't believe that chance has anything to do with evolution, of course I am a supporter of determinism and chance sounds too much like a random act to me.

 

I think a better word would be chaotic. Chaotic systems can and do generate order. But their not fully predictable on everything either even if an underlining order exists there. Evolution does not rely upon chance as much as some people tend to think it does.

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Do you have any thing against the eye witness claims of seeing dinasours in remote areas?

 

As near as I can tell, TM, your definition of faith is anything that someone else believes is true.

 

of course not. it's a lie, we didn't exist back then, and they don't exist now.

Is it a lie for real?

 

Claims from some eye witnesses in remote areas is about as bad of evidence as one can have. Not until the baseless claims are supported with actual science do they carry any weight.

 

I agree with Biochemist.

You cannot exclude "data" that doesn't work, it has to be included.

It can not be simple thrown out....

 

I deny that the alleged "human footprints" show that humans and dinosaurs coexisted.

 

I deny that the eyewitness testimony of some people in remote areas, claiming they've seen dinosaurs, means that dinosaurs are still living is a fact.

 

I deny that the geological record supports the Biblical flood story: geology actually contradicts it.

 

What geological evidence contradicts the Bible’s claim of a world wide flood?

Many ancient civilizations on every continent all around the world believed it to be true.

 

Who says that there is no evidence to these claims people make? Where you there..did you search?

My grandma claimed that she saw a dinosaur, she was solid on that..she would even point out which one it looked like. Imagine this, you are driving threw the jungles of Africa in the middle of nowhere, and all the sudden this most odd thing pops out and runs across the road. These things happen at the least expected times..and you stand shocked and stunned.

 

I say this…there is no evidence with the theory of one thing turning into another thing…we never run into any animal that are two or more different animals put together ..you have never found any links of anything turning into something else at any time in history…you find bones..big deal…you can make bones into anything you want them to be, you can make a skeleton of a horse into a beast..and it would even look good. So you can interbreed a loin and tiger…what does that prove? Has anyone tried to breed a rat and a blue jay? It wont work..and it will never work. You find a lot of deformed this and deformed that…but they are still fully thatever their parents are…and they will still produce only fully whatever they are…they have never changed..and they will never change. So the theory, I can say is a lie in and of itself.

 

What better evidence is out there than an eyewitness? And who is to say they are all lying?

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