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Author Topic:   Disabling Bacterial Resistance
RAZD
Member (Idle past 680 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 16 of 60 (216720)
06-13-2005 8:26 PM
Reply to: Message 1 by gnojek
05-24-2005 3:55 PM


Rate of Mutatability
One of the biggest problems I have with a lot of current genetic research is the fairly consistent assumption of constant (or relatively constant) rates of mutation as an environmental factor.

There are other experiments where the rate of mutation has been shown to encrease in response to stress, as if stress turns on a mutation switch.

We also know that some parts of the genome are much more susceptible to mutation than others -- that some mechanism is {protecting?} the sections with less mutations.

It could be something as simple as a coiling in the DNA that leaves some sections less {available/visible/exposed} than others, and stress causes an uncoiling.

We also know that environmental conditions have changed enough at different points in the past to have a significant effect on some of the environmental causes of mutation (production of 14C variation with climate is one {measure\example}).

It seems to me that the {rate of mutatability} has also evolved to ensure that not too much and not too little occurs in similar generations, that there is a {number of} mechanism{s} that can turn up or turn down susceptability to adapt -- after all, all the DNA that is around today is {highly?} evolved compared to ancestral DNA.

After all, a species that mutates too fast generates a lot of variation away from a known survivor and in it's extreme makes the creationist caricature hopeful monster with no siblings for mates, while a species that mutates too slowly doesn't adapt fast enough to survive.

Thus not only does Goldilocks find that the rate of mutation causing events is "just right" for adapting to changes over time, but the evolvability of Goldilocks has evolved to be "just right" for the current rate of mutation causing events.


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}


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bugeater
Inactive Member


Message 17 of 60 (216725)
06-13-2005 10:24 PM
Reply to: Message 13 by Trixie
06-13-2005 3:53 PM


Re: The SOS response
Thanks for that Trixie. It is as I expected. So in reality it is the antibiotic that is causing the damage, not the SOS response. Not surprising that an agent that leads to DNA damage would up the mutation rate :rolleyes:

So it is hardly a case of ID. After all, DNA damage response mechanisms are pretty important for all life and evolved very early. In mulitcellular organisms the seriously DNA damaged cell is likely to undergo programmed cell death (or you risk things like cancer), but in a single celled organism it is probably advantageous to turn off the error checking and have a go.


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Wounded King
Member (Idle past 3370 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 18 of 60 (216749)
06-14-2005 4:43 AM
Reply to: Message 16 by RAZD
06-13-2005 8:26 PM


Re: Rate of Mutatability
One of the biggest problems I have with a lot of current genetic research is the fairly consistent assumption of constant (or relatively constant) rates of mutation as an environmental factor.

I'm not sure why this is a problem. Certainly such an assumption is often made, but it is certainly not currently represented as based upon a weight of evidence. Rather it is an assumption for conveniences sake. There is plenty of current research on variable rates of mutation and variable 'molecular clocks' but to account for such variability in any long evolutionary time scale would be a pretty mammoth task.

It seems a reasonable approach in a small population scale genetic study to assume a relative constancy in mutation rates given a homogenous environment for that population.

TTFN,

WK


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mike the wiz
Member
Posts: 4721
From: u.k
Joined: 05-24-2003


Message 19 of 60 (216769)
06-14-2005 8:48 AM
Reply to: Message 14 by nator
06-13-2005 5:49 PM


Re: Mikey's catch 22
Shraff, the Iguana, how do you know it wasn't just an undiscovered species? Your link didn't work.

As for the bird and other one, that's just animals being clever like God made them. :)

A variation within a kind is possible don't forget. But big change into another kind of animal, like a cat to a fish, is highly unlikely. Or an ape into a man.

There isn't time. Please address catch 22. :)

Evolution is obsolete IMO. If you do survive, evolution hasn't had time to happen, if you don't, it still doesn't happen.

If you do or you don't, either way, evolution isn't fast enough to be useful, only small change under natural selection, just like AIG states.


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Brachinus
Inactive Member


Message 20 of 60 (216802)
06-14-2005 12:25 PM
Reply to: Message 19 by mike the wiz
06-14-2005 8:48 AM


Re: Mikey's catch 22
Mike, what makes you think "an ape into a man" would be a big change, rather than a small one?

And as for AIG, if they only believe in slow, small-scale evolution, does that mean they reject the notion that the millions of species alive today descended from only a few thousand "kinds" in less than 5,000 years?


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AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 21 of 60 (216821)
06-14-2005 2:44 PM
Reply to: Message 19 by mike the wiz
06-14-2005 8:48 AM


Not so subtle suggestion
This is one of the science forums, Mike.

Since you know what that means you will be, I'm sure, prepared to defend any statements you make.

AND NOTE TO EVERYONE:

We are starting to wander off topic. I will shut'er down if necessary.

This message has been edited by AdminNosy, 06-14-2005 02:46 PM


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PaulK
Member
Posts: 17171
Joined: 01-10-2003
Member Rating: 2.6


Message 22 of 60 (216834)
06-14-2005 3:34 PM
Reply to: Message 19 by mike the wiz
06-14-2005 8:48 AM


Re: Mikey's catch 22
There is no "Catch 22", just a false dilemma.

The underlying assumption is that either the species will die out in a relatively short time (no more than a few centuries) or it will be so well adapted that no evolutionary change is likely.

However this is not the case.

Even in a highly stable environment the fitness could be arbitrarily close to 1 . If it was a very little below 1 then the population would only decline very slowly, giving time for speciation.

But real environments often include short term variations like bad weather. A species that would otherwise hang on can be wiped out by a run of bad luck. If that required conditions that were expected to happen once in 2,000 years then on average the species wuld last 1,000 years - long enough to evolve into a new species which could better survive.

And we are not restricted to short-term variations. Environments can change over time. If the change is slow enough then a species which would otherwise die out can evolve to "track" the change. Examples include so-called "arms races" where predator and prey each drive the evolution of the other. As the predator improves it's ability to catch the prey, the prey is driven to evolve ways of better evading capture - and vice-versa.


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gnojek
Inactive Member


Message 23 of 60 (216865)
06-14-2005 4:53 PM
Reply to: Message 5 by randman
06-13-2005 12:01 PM


randman writes:

Additionally, I think it's an error to assume randomnness in the type of mutation. In other words, this shows the frequency of mutation is not random, but governed by cirumstance.


I don't see how to differentiate between "random" and "victim of circumstance."

It's the same thing.

The idea is that mutations are not random, but that there is an in-built code for activation and selection necessary to move the organism forward.

Forward toward what?

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gnojek
Inactive Member


Message 24 of 60 (216873)
06-14-2005 5:05 PM
Reply to: Message 17 by bugeater
06-13-2005 10:24 PM


Re: The SOS response
hanks for that Trixie. It is as I expected. So in reality it is the antibiotic that is causing the damage, not the SOS response

From what I understand, the class of antibiotics studied did not mutate DNA. They disrupted DNA gyrases and polymerases, which caused mutations in the DNA.

Anyway, I guess this is still a classic case of mutation and natural selection in action.

My bad.


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Hrun
Inactive Member


Message 25 of 60 (216875)
06-14-2005 5:10 PM
Reply to: Message 23 by gnojek
06-14-2005 4:53 PM


gnojek and randman, one thing that often gets confused is a 'random event' and 'events happening at the same frequency'.

Mutations are, as far as anybody can tell, random events. That does not mean that all mutations have to occur at the same frequency.

For example, imagine we each have a die, one with six numbers and one with twenty numbers. You roll the one with twenty numbers and I roll the one with six numbers. Now, it will be completely random whether we roll a 'one'. However, the frequence of me and you rolling a one will be completely different.

The same is true for mutation hotspots- different frequency, yet still ranom (i.e. not directed).


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gnojek
Inactive Member


Message 26 of 60 (216894)
06-14-2005 5:35 PM
Reply to: Message 4 by bugeater
06-13-2005 10:26 AM


For example, a bacterium I worked on many years ago (Klebsiella planticola) naturally carried a beta-lactamase enzyme, which sole purpose is to defend against penicillin. Presumably it was exposed to penicillin in the wild, not from human intervention.

This is very interesting.

A mold produces an antibiotic compound to battle off bacteria that may eat it or its food source.

But a species of bacteria developed a weapon against that.

It's like a bio-arms race.


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mike the wiz
Member
Posts: 4721
From: u.k
Joined: 05-24-2003


Message 27 of 60 (216944)
06-14-2005 8:20 PM
Reply to: Message 22 by PaulK
06-14-2005 3:34 PM


Re: Mikey's catch 22
If a species lasts one thousand years then it has survived without evolution. Why would it then speciate if it survived? Also, speciating isn't really the morphological change I'm talking about, because the fish still becomes a fish, or a monkey a monkey.

If a monkey species lasts long out of it's niche and survives a few hundred years, then it has survived without evolution. If you can survive without evolution then why would something then evolve?

I mean, animals are supposed to evolve because they need to in order to survive. I can't see that an ape needs to become a man because of niche change. It wouldn't even need any extra brain power. It seems that if it did need extra brain power, yet it survived in another niche without the extra brain power?

Hmmmmm. I doubt it. It sounds more like a naturalistic answer for man's God given intelligence. It seems more logical that the bible is correct, to me.


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Hrun
Inactive Member


Message 28 of 60 (216949)
06-14-2005 8:45 PM
Reply to: Message 27 by mike the wiz
06-14-2005 8:20 PM


Re: Mikey's catch 22
mike the wiz writes:

If a species lasts one thousand years then it has survived without evolution.

This is false. Evolution (as understood here) is the change of genetic material over time in a population of organisms due to processes like natural selection. So, only if you find NO genetic changes in the population can you say that a species survived without evolution.

mike the wiz writes:

Why would it then speciate if it survived?

What is this why you are asking about here. Are you looking for a underlying reason? Are you looking for causes? Speciation happens. We can observe it in numerous examples.

mike the wiz writes:

Also, speciating isn't really the morphological change I'm talking about, because the fish still becomes a fish, or a monkey a monkey.

Well, then you should state what you are talking about. I have the feeling there is this fuzzy definition of 'kinds' coming up, right? Fish stays fish kind? Monkey stays monkey kind? But how do you determine what is a fish and what is a monkey? And, are you suggesting that (micro)-evolution explain how guppies and sharks had a common ancestor? Is a whale fish kind or mammal kind? How about a penguin?

mike the wiz writes:

If a monkey species lasts long out of it's niche and survives a few hundred years, then it has survived without evolution.

Again, if genetic change occured due to processes like natural selection then they survived with evolution, not without.

mike the wiz writes:

If you can survive without evolution then why would something then evolve?

You have yet to show an example of anything 'surviving' without evolution. Sexual reproduction (and even asexual reproduction) leads to changes in the genetic material. If these changes have any effect on the organism, then evolution is inevitable.

mike the wiz writes:

I mean, animals are supposed to evolve because they need to in order to survive.

False. Animals are not supposed to evolve for any reason, they just do.

mike the wiz writes:

I can't see that an ape needs to become a man because of niche change.

In this case it is not necessary to become man due to the niche change. However, looking at our population numbers it certainly seems to be a temporary advantage to do so. If it was not advantageous, then non-human apes could have spread out of Africa and colonized earth... but they didn't.

mike the wiz writes:

It wouldn't even need any extra brain power. It seems that if it did need extra brain power, yet it survived in another niche without the extra brain power?

Again, you may not think it was necessary, but it certainly didn't seem to hurt. In fact, when you look at the competition over habitat within all ape species, then it certainly seems like those large brains kick some mighty butt. Just look at those strong mountain gorillars sitting in their rain forest, only surviving because some humans like watching them.

mike the wiz writes:

Hmmmmm. I doubt it. It sounds more like a naturalistic answer for man's God given intelligence.

Hmm, sounds to me like a deistic answer for a normal biological process.

mike the wiz writes:

It seems more logical that the bible is correct, to me.

So, to you it seems logical that a book written a few thousand years ago that postulates the universe was created in six days is a correct source for understanding nature. Well, so be it.


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mike the wiz
Member
Posts: 4721
From: u.k
Joined: 05-24-2003


Message 29 of 60 (216956)
06-14-2005 9:01 PM
Reply to: Message 28 by Hrun
06-14-2005 8:45 PM


Re: Mikey's catch 22
False. Animals are not supposed to evolve for any reason, they just do.

Not false. Mutations are supposed to be random, and natural selection apparently selects the fittest trait. The faster runner will survive for example, because running fast helps him get away from a beast, so he evolves for that reason.

In this case it is not necessary to become man due to the niche change. However, looking at our population numbers it certainly seems to be a temporary advantage to do so. If it was not advantageous, then non-human apes could have spread out of Africa and colonized earth... but they didn't.

This isn't really an explanation. You might aswell have just said, "oh we just are brainy". If ape-men did survive, then they done so for a long time, without major change. It seems that the human brain is inexplicable, as there is no cause for it, and it wouldn't come about through one mutation, but apparently a number of them. Hmm, that doesn't figure, the design is better explained as being a created organ rather than a willy nilly half-baked mutation experiment.

So, to you it seems logical that a book written a few thousand years ago that postulates the universe was created in six days is a correct source for understanding nature. Well, so be it.

It explains the brain, and gives better reasons for such an overwhelming brain. It seems all the other species survive without such a brain. I fail to see how such a brain could come about over time, as a complete package, without being needed, don't forget, NS only chooses what it needs.

This is false. Evolution (as understood here) is the change of genetic material over time in a population of organisms due to processes like natural selection. So, only if you find NO genetic changes in the population can you say that a species survived without evolution.

Again, even a small change doesn't account for big ones, if you get small you still don't require big. A human brain was never needed, and wouldn't happen, as the species survived without it for cast periods. But small change hasn't happened anyway. If it does it's so tiny that it in no way constitutes evolution, just variation within kind.

You have yet to show an example of anything 'surviving' without evolution

Ever seen a dragon fly fossil?

And that's after millions of years. But evolution takes very long periods. A species wouldn't survive long enough to evolve. If it needed a human brain, there's no way it would ever get one in time. If it didn't need a human brain, why would it develop one?

This message has been edited by mike the wiz, 06-14-2005 09:08 PM


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nator
Member (Idle past 1445 days)
Posts: 12961
From: Ann Arbor
Joined: 12-09-2001


Message 30 of 60 (216958)
06-14-2005 9:08 PM
Reply to: Message 19 by mike the wiz
06-14-2005 8:48 AM


Goodbye, mike
quote:
Shraff, the Iguana, how do you know it wasn't just an undiscovered species? Your link didn't work.

It might have been, but so what?

What you asked for was a species which was found outside of it's usual environmental niche and some morphological adaptations reflective of that niche.

Other species of iguanas do not have webbed feet and do not dive to eat algae in the ocean.

quote:
As for the bird and other one, that's just animals being clever like God made them.

So, the poorly-designed crossover air and food tubes in our throats is evidence of God making a lousy choice?

[quote]A variation within a kind is possible don't forget.[/quoote]

What is your precise definition of "kind"?

What criterion do I use to determine one "kind" from another?

Are all primates a single "kind", including humans?

What is the barrier to many small variations adding up over time to produce big changes?

quote:
But big change into another kind of animal, like a cat to a fish, is highly unlikely.

What is your precise definition of "kind"?

What criterion do I use to determine one "kind" from another?

quote:
Or an ape into a man.

"Man" is an ape.

quote:
There isn't time. Please address catch 22.

What is your evidence that there isn't time?

quote:
Evolution is obsolete IMO. If you do survive, evolution hasn't had time to happen, if you don't, it still doesn't happen.

What is your evidence that there isn't time?

quote:
If you do or you don't, either way, evolution isn't fast enough to be useful,

Really?

Then why do we have to get a different flu shot every year?

Mutation seems to work pretty well for viruses.

quote:
only small change under natural selection, just like AIG states.

Mike, this is my last post to you.

I have lost all respect for you, I am sad to say. You are not worth my time anymore, because I have answered all of these questions for you at least a dozen times. You clearly DO NOT WANT to understand anything.

You are smarter, much smarter than this, but you have chosen willful ignorance over enlightenment.

I am really very sad.

Goodbye, and have a nice life wrapped up in your ignorance.

This message has been edited by schrafinator, 06-14-2005 09:10 PM


"History I believe furnishes no example of a priest-ridden people maintaining a free civil government. This marks the lowest grade of ignorance, of which their political as well as religious leaders will always avail themselves for their own purpose."--Thomas Jefferson

There is no greater threat to civil liberties than an efficient government. -jar


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