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Author Topic:   A Creationist's view of Natural Limitation to Evolutionary Processes (2/14/05)
crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 7 of 218 (185338)
02-14-2005 9:33 PM
Reply to: Message 6 by Faith
02-14-2005 9:28 PM


The answer is no, it is merely natural selection from pre-existing genetic possibilities,
But they design the experiment so that the population is decended, clonally, from one individual - what's called a "monoculture." Since bacteria are haploid, we know that one individual can have at most one allele for every gene.
So if genetic variants are being selected for or against in the mature population, we know that those variants arose through mutation. So we know that mutation is occuring. Selection among mutated variants is, of course, evolution. Your analysis is quite inaccurate.
Besides the pre-antibiotic variation that was established, the fact that four separate genes were ultimately affected in the acquisition of resistance to the antibiotic also suggests quite a bit of variability built into the original code.
Yes. And that variability is expressed through the occurance of mutations.

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 Message 6 by Faith, posted 02-14-2005 9:28 PM Faith has replied

Replies to this message:
 Message 10 by Faith, posted 02-14-2005 9:53 PM crashfrog has replied

crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 11 of 218 (185416)
02-15-2005 12:52 AM
Reply to: Message 10 by Faith
02-14-2005 9:53 PM


I get your point but it sounds awfully mystical that mutations simply show up out of the blue in order to provide resistance to the antibiotic.
No, they show up at random. The mutation is there before the antibiotic is introduced; it waxes and wanes in the population at random because there's no selection pressure on it yet. That's not the only mutation that is occuring, of course. All kinds of mutations are happening.
Absolutely nobody is proposing that the mutations show up on demand. That's Lamarkianism, not evolution.
How does resistance to the antibiotic develop in this population before something lethal to its existence develops given that mutations of all kinds are supposedly occurring apace?
At random, via mutation. Along with countless other traits.
Whatever it is that leads to resistance, or in fact to variation in the population at all from a single individual HAS to be pre-programmed
If it's random, how can it be pre-programmed? You can't program randomness, by definition. Even computers can't be programmed to be random - they have to look up numbers from a pre-generated random table.
The mutation for the antibiotic resistance is random; we know this because when we measure it in a population without antibiotic, the number of individuals with the gene increases and decreases at random. You can see this trend illustrated here:
Are Mutations Harmful?
The graph on this page is exactly what we would expect to see in a situation of random mutation.
Perhaps this situation has to do with the definition of "mutation" -- I've certainly discovered that that is one malleable term.
Not really. I think what's happening is that you see it applied to a number of different situations but you fail to understand how all the different situations are really the same. Mutation is simply when an organism has genetic sequences that it did not inheret from its parent(s).
the very processes that select the adaptive trait involve the reduction of genetic variability in the population, which is inconsistent with the overall theory of evolution.
It isn't inconsistent, though. But I like the way you're thinking about it. Evolution is like a dynamic balance between expanding variation via mutation and contracting variation via selection. The variation expands at random; the variation contracts in a way that is anything but random. The result are organisms adapted to their environment.
That is, no matter how the new strain of bacteria arrived, increasing variability temporarily, its selection involves a reduction in variability
Yes. But the reduction in variability is non-random; its a selection. The less fit variants are removed, and so the average fitness of the population increases. Variation expands from the center, but contracts from the bottom. That translates into an upward movement in regards to fitness.

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 24 of 218 (185519)
02-15-2005 10:58 AM
Reply to: Message 20 by Faith
02-15-2005 10:40 AM


I would really appreciate it if at least the fact that the processes I am talking about DO entail an inevitable reduction in genetic variability were acknowledged as this part is fundamental.
I don't think that anyone has denied that selective processes remove variants from the population. That's what "selection" is, after all - differential survival/reproduction among varying individuals.
most of them can be accounted for by the misnaming of pre-existing potentials as "mutations"
You've yet to show even one instance where this is the case; nor have you rebutted the evidence that proves that new variants in populations arise through mutation.
Of course the variants are already present when selection occurs; they have to be. The variants arise through random mutations. We call them "random" because they do not occur in response to environmental pressures, and because the outcome of a mutation is non-deterministic.
All the supposed processes of increasing variability would do is provide a larger roster of possibilities from which to select, but the selection process always produces reduced variability and theoretically at least always has an end point beyond which evolution/speciation simply cannot continue.
You're going to have to show the math on that one. You could just as easily claim that the variability caused by mutation will always outweigh the variability removed by selection, and that therefore variability will always increase. (Which appears to have been the case during the history of life on Earth.)
(they fail to note, however, that the change in question is always a reduction except in the case of mutation and immigration. This is my own observation).
Why on Earth do you feel that's an "observation" worth mentioning? It's like saying "except for the color blue, there are no blue colors."

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 41 of 218 (185854)
02-16-2005 11:50 AM
Reply to: Message 30 by Faith
02-16-2005 6:36 AM


Or perhaps I should ask: Is there any room any more for the idea of normal allelic variation or is everything mutation?
I'm not sure what you mean by "normal allelic variation", but I thought I would point out that sexual reproduction creates new phenotypic variation, but not actually new allelic variation. I thought that might be germaine to the discussion.

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 49 of 218 (185932)
02-16-2005 4:12 PM
Reply to: Message 48 by Faith
02-16-2005 3:36 PM


Re: evolution does not proceed solely by drastic events
How do you know that this is a mutation rather than a normally occurring allelic variation, however rare in the guinea pig population?
I would presume, though I'm not an expert, that we know its a mutation because none of the organism's ancestors possess the trait. Since it didn't inherit the trait, but its decendants have inherited the trait, we know that it arose through mutation.
but that being the case a mutation just sounds like another shuffling of chemicals, the question being whether it is a mistake or a normal possibility given whatever laws govern the whole process
I don't percieve a difference between those two alternatives. Genetic sequences mutate because its impossible to completely prevent mutation, because of the laws of physics. Does that mean that DNA is "meant" to mutate? That's not really a question science can answer.
I mean, DNA can't break the laws of physics. Anything that happens to a genetic sequence has to occur according to the laws of physics, including mutation.
The probabilities of anything nonlethal occurring through random "accidents" just "seem" astronomical to my untutored mind.
Why? Protein structures are often malleable to some degree. An inert polypeptide has no effect on cellular chemistry, beyond tying up some amino residues that could be better employed elsewhere. It seems to me that there's considerable room to play around with cellular protein chemistry. The really crucial stuff is often backed up by the very evolutionary precursors that allowed it to evolve. (For instance your cells have two separate metabolic pathways; the original anaerobic pathways that first evolved those billions of years ago, and the more modern, much more effective aerobic pathways that evolved subsequently. Which is not to say that you can survive without oxygen, but many of your cells can, at least for a little bit; that's why you get muscle cramps, for instance.)
and again the question for the sake of the theory of evolution is whether life-enhancing or at least nonthreatening mutations outstrip these effects or not.
According to observation, this must clearly be the case. If you like, you could easily perform an experiment on bacteria in a chemostat; you could raise a monoculture to maturity and assess how quickly variation expands in a population experiencing as little selection as you could devise. In fact I should think this experiment has probably already been done.

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 61 of 218 (186021)
02-16-2005 10:23 PM
Reply to: Message 59 by NosyNed
02-16-2005 9:14 PM


thinks that might be called "computational evolution". (I'm makin g that up.).
Isn't that the field known more commonly as "bioinformatics"?

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 66 of 218 (186038)
02-16-2005 11:34 PM
Reply to: Message 64 by Faith
02-16-2005 11:17 PM


Re: selection & mutation - which is faster?
I don't think this fact is even noticed generally.
I think it's noticed by everyone; you're the only one that seems to find it significant. It's like you're saying "except for everything that is up, everything is down."
I mean if you specifically ignore the process that increases genotypic variation, then there's no surprise to find you're only looking at the processes that decrease variation. What about that is significant?
Selection isn't evolution; mutation isn't evolution. Mutation and selection, together, are evolution. This has been repeated but it never seems to sink in. Why is that?

This message is a reply to:
 Message 64 by Faith, posted 02-16-2005 11:17 PM Faith has replied

Replies to this message:
 Message 75 by Faith, posted 02-17-2005 1:30 AM crashfrog has replied

crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 67 of 218 (186040)
02-16-2005 11:40 PM
Reply to: Message 65 by Faith
02-16-2005 11:31 PM


I tend to think all such traits are what somebody here called "hidden" traits if I understood his use of the term, that is, they are latent in the population until a selective event kills off or reduces the alleles with greater frequencies and allows it to come to the fore.
We've already addressed this. In a clonal population of haploids, there is only one allele (per gene.) There aren't any "latent" traits; it's impossible for there to be any.
In a monocultural population of haploids, if there's any more than one allele per gene, then those additional alleles can only have come about through mutation. There's no way that they could have been latent in the population.
There's the assumption I keep finding in most of you here, this notion that mutation is the ONLY way new traits are created.
It's not an assumption; it's the only possible explanation. There are no other possibilites in a monoculture of haploids; there are no latent traits or less frequent alleles short of those that arise through mutation.
You describe the same process but assume that the origin of the allele was mutation. I don't assume that any allele is produced by mutation, but is "already present in the population" as a normal variant, given in the Species at its origin. Perhaps this is because I am a creationist and you an evolutionist
No, it's because you're ignoring evidence (or not understanding it), and we're not.
but you can't trump mine by simply assuming mutation because it fits your model.
We don't assume it; we conclude it, because it's the only possible explanation for alternate alleles in a monoculture of haploid individuals.

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 81 of 218 (186143)
02-17-2005 10:13 AM
Reply to: Message 75 by Faith
02-17-2005 1:30 AM


Re: selection & mutation - which is faster?
The lists of processes of evolution present them all separately-and-equally as separate processes.
Because they are. Mutation is not selection; selection is not mutation. They're two different processes.
But together they are evolution. (It sounds like I'm describing the Wonder Twins.)
I'm the one who said it sounds like the definition should be changed from Evolution = change in the frequency of alleles to Evolution = Mutation PLUS the selection processes that reduce diversity.
I don't see the difference. If you have a process that expands diversity randomly, combined with a process that contracts diversity non-randomly, the result is going to be a directed change in allele frequencies. Obviously.
If this is now the going definition of evolution, acknowledging all these elements in the process, fine.
Again I don't see how the elements you've mentioned aren't directly implied by the definition of evolution as a change in allele frequencies. Nonetheless, though, I think you've actually added something to the discussion - the idea of the processes of evolution being counterposing forces that expand or contract diversity - and for that your clear thinking should be commended.
This message has been edited by crashfrog, 02-17-2005 10:14 AM

This message is a reply to:
 Message 75 by Faith, posted 02-17-2005 1:30 AM Faith has replied

Replies to this message:
 Message 87 by Faith, posted 02-17-2005 11:15 AM crashfrog has replied

crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 82 of 218 (186146)
02-17-2005 10:25 AM
Reply to: Message 79 by Faith
02-17-2005 4:10 AM


Re: Time for a Reality Check
No rain, no wind, no flooding, no erosion, no earthquakes, no disturbances?
What makes you think that there are no disturbances, or that these processes didn't leave marks in the strata that we can detect? I mean its news to me that the geologic strata contains no evidence of all of these processes occuring. Wherever did you get such an idea?

This message is a reply to:
 Message 79 by Faith, posted 02-17-2005 4:10 AM Faith has replied

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 88 of 218 (186176)
02-17-2005 11:33 AM
Reply to: Message 87 by Faith
02-17-2005 11:15 AM


Re: selection & mutation - which is faster?
My point was that mutation is apparently considered to be going on in all populations, even in the most extremely fixated.
Not "considered", known. It's known to be going on in all populations, in every individual.
Also, I was the one who had to point out to somebody earlier on that they are two different processes.
I don't think there's anyone here but creationists who don't understand that selection and mutation are two different processes, with unique effects on a population's genetics. That's why we always formulate evolution as natural selection and random mutation; and why creationists point out that mutations aren't selective and that selection isn't creative and think that they've refuted evolution.
If you don't make it clear that you assume mutation to be ongoing in ALL populations then it appears that selection could occur without it
Of course selection could occur without it. But it never does, because it's impossible according to the laws of physics to avoid mutation. It has to happen, and we observe that it always does.

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 Message 87 by Faith, posted 02-17-2005 11:15 AM Faith has replied

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 89 of 218 (186182)
02-17-2005 11:40 AM
Reply to: Message 85 by Faith
02-17-2005 11:00 AM


Re: Time for a Reality Check
Faith, I hope you'll join us in a discussion of your objections here.

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 Message 85 by Faith, posted 02-17-2005 11:00 AM Faith has replied

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 109 of 218 (186282)
02-17-2005 3:57 PM
Reply to: Message 108 by Faith
02-17-2005 3:38 PM


Re: Considering rapid rate of mutation
I'm talking about decreased VARIABILITY, not variation.
Well, that's news to me, at least. Shifting the goalposts, are we?
New variations through selection processes decrease variability.
No, they don't. Why would it? Mutation happens; the only thing that can restrict that are specific traits that confer resistance to mutation. Expanding variation itself does nothing to restrict mutation rates; mutation rates are density-independant.
Selection does not reduce the likelyhood of mutations, contrary to your assertion.

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 110 of 218 (186286)
02-17-2005 4:00 PM
Reply to: Message 98 by Faith
02-17-2005 1:38 PM


Re: evolution does not proceed solely by drastic events
As I've asked before, is there simply no more idea in anyone's mind at all of a BUILT-IN set of genetic variables that combine in sexual selection and define a species, and upon which all the selective processes work?
No, because there's no mechanism for it. Diploid organisms have at most two alleles per gene; haploid organisms have only one allele per gene. There's simply not enough room in the genome for the sort of restricted recombination that you're proposing.
Flood theory assumes an enormous pre-existing built-in set of genetic variables
For which there's no room in an organism's genetics. So right there we can falsify flood "theory".

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crashfrog
Member (Idle past 1578 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 170 of 218 (341410)
08-19-2006 2:27 PM
Reply to: Message 168 by Faith
08-19-2006 1:42 PM


Are all genetic diseases a matter of the combining of two of the same defective genes?
It depends on what the disease is. Imagine inheriting your belt from your mother and your suspenders from your father. You could safely inherit a faulty belt from your mother and suffer no ill effects because the suspenders will hold your pants up; you could instead get faulty suspenders from your father and still suffer no effects because the belt still works.
But if you inherit both a faulty belt and faulty suspenders, you're going to have a disease called "ankle-pants." And you're definately going to pass on something faulty to your children, either the belt or the suspenders; whether or not your children can't hold their pants up is going to depend on whether or not they get faulty belts or suspenders from their father.
Those diseases are chromosomal recessive, they're the disorders you're thinking of when you describe them, incorrectly, as "combining two genes." It's not that Gene A mixes with Gene B to form Disease C; it's that being sexual, diploid organisms means that we have two copies of every gene. If one copy is broken the other can do the job, often. But if both copies are broken you're going to suffer whatever malady is going to result from your body not manufacturing that gene product.
Not all diseases are like this. Some disorders are chromosomal dominant, where simply having inherited one copy of the gene is enough to cause the disease. These disorders are caused by the presence of a gene product that shouldn't be there, rather than the absence of one that should. All it takes is one gene of that kind for the body to start producing something that it shouldn't.
Color blindness is predominantly passed on through males, but I inherited a very mild case of it -- undetectable except on very refined tests -- apparently from my father who had severe red-green color blindness (he distinguished the red signal light from the green one by degree of brightness and position above or below on the pole). I have trouble distinguishing a light pastel shade of yellow-green from the same light shade of orange or peach.
Some diseases are sex-linked. We specified earlier that you have two copies of each gene, and this is because you have two copies of each chromosome. Well, you do, being a female. You have 46 chromosomes, that's 23 pairs, including a pair of chromosomes called "X".
As a male, I don't. I have 46 chromsomes, 22 pairs of similar ("homologous") chromosomes, plus 1 X and 1 Y. So any gene that lives on the X chromosome, I only have one of. To get back to the first analogy - it's like I inherited a belt from my mother - but no suspenders at all from my father. So if the belt I inherited doesn't work, my pants fall down. There's no suspenders of any kind to hold them up.
Color-blindness is like this. The gene for color-reception (actually, the gene makes proteins your eye cells need to see certain colors) is on the X chromosome. Your father's mother had 2 X chromosomes, and if she wasn't color-blind, we know that she had one "good" gene, and one "broken" gene. Your father got the X chromosome from his mother with the bad gene. From his father, we know he got a Y chromosome - because your father is male - which has no color vision genes at all. So the only gene for that trait he got was the broken one. Hence, he was color-blind.
In your case? How did you get the "weak" version of it? It's a long story. Try to bear with me. We know that you are female, which means you got your father's X chromosome instead of his Y chromosome. And you obviously recieved a normal X from your mother - women only pass on X chromosomes because they don't have Y's. So you're a carrier of the same kind of color-blindness that your father had on one of your chromosomes. Half of you male children can be expected to be color blind. None of your female children will be unless your mate is also color-blind in the same way.
But what about you? How come you have a weakened form of it? Because a human cell only needs one X chromosome to work. It can only allow one chromosome to work. So, when you were a developing zygote, your cells each picked one of the X chromosomes in your cells to "deactivate". They were basically rolled up into balls and tucked away. Not destroyed, so that they could be passed on to your children, but also not a part of that cell's regular genetic activity.
The thing was, each cell at that stage picked at random. Not every cell picked the same X chromosome to mothball. And when each of those cells divided, those "daughter" cells were committed to their parents choice.
The result? Your body is made out of two different kinds of cells - cells that turned off the "bad" X, and cells that turned off the "good" X. They're all mixed up throughout your body, in patches. In your eye, probably what happened is that some of your retina cells - "cones" are normal, and some are color-blind. The reason you only see the effect in low-light or low-saturation conditions is that normally, with bright colors, enough of your normal cones can pick up the slack for your color-blind cones. But when there's not much color in the first place, the deficiency becomes a lot more apparent.
Edited by crashfrog, : No reason given.

This message is a reply to:
 Message 168 by Faith, posted 08-19-2006 1:42 PM Faith has replied

Replies to this message:
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