Orthodox theory of evolution disproven by experimental results on adaptive mutation?

[mslxl]

I hope this hasn't been covered earlier in another thread.

If you look at the studies on adaptive mutation that have come out since the mid-eighties, they seem to consistently point in a direction that makes proponents of the orthodox theory of evolution more and more uncomfortable.

(If unfamiliar with the term, just google 'adaptive mutation' and poke around.)

One of the core tenets of the TOE is that the cause of variation is RANDOM mutation ONLY. Numerous, repeatable results obtained by altering the environment of bacteria populations consistently show those populations increasing their rates of mutation "in order to" adapt to the new environments.

Of course, biologists cannot say "in order to..." They would be guilty of vitalism, Lamarckism and other no-nos. The conclusions of their papers usually say "it looks as if...", "further study is needed" and other noncommittal statements. But the results unquestionably point in that direction.

Comments?

 

[Jimbo07]

One of the core tenets of the TOE is that the cause of variation is RANDOM mutation ONLY. Numerous, repeatable results obtained by altering the environment of bacteria populations consistently show those populations increasing their rates of mutation "in order to" adapt to the new environments.

I thought the modern idea of evolution was some combination of random mutation and natural selection in a complex feedback loop. Without either of us citing studies, and just from your words, that seems to be what you're suggesting.

Mutation, natural selection and feedback in both directions, suggesting a not-yet fully understood relationship between organism and environment?

That's hardly damning evidence against science, and some in favour...

What's your point?

 

[aggle-rithm]

One of the core tenets of the TOE is that the cause of variation is RANDOM mutation ONLY. Numerous, repeatable results obtained by altering the environment of bacteria populations consistently show those populations increasing their rates of mutation "in order to" adapt to the new environments.

In the short term, variation comes from both mutation and mixing of genes through sexual reproduction. In the long term, variation comes from these short-term changes being directed by natural selection.

I don't know of any serious scientist that believes that random mutation is the ONLY mechanism of change. They also don't believe that bacteria mutate "in order" to do anything. They mutate, particularly when their environment is stressed. The lucky ones mutate, by pure chance, into something that can survive the new environment. The vast majority don't. Fortunately for the bacteria, it only takes one survivor to pass on the new, improved genes.

 

[mslxl]

My point, again

I thought the modern idea of evolution was some combination of random mutation and natural selection in a complex feedback loop. Without either of us citing studies, and just from your words, that seems to be what you're suggesting.

Mutation, natural selection and feedback in both directions, suggesting a not-yet fully understood relationship between organism and environment?

That's hardly damning evidence against science, and some in favour...

What's your point?

I wrote:

One of the core tenets of the TOE is that the cause of variation is RANDOM mutation ONLY.

Once variation occurs, then the mechanism of natural selection acts upon it. The point of contention is the CAUSE of variation, not the whole theory. On the cause of variation, current theory is very clear: it is random mutation only.

 

[mslxl]

In the short term, variation comes from both mutation and mixing of genes through sexual reproduction. In the long term, variation comes from these short-term changes being directed by natural selection.

I do not think the genetic shuffling that occurs in sexual reproduction counts as variation that is eligible to enter the 'lottery' of natural selection. Since both organisms, if not mutated, are representatives of the CURRENT state of adaptation of the species, that kind of recombination of existing material would not provide the new input that could potentially lead to a new, superior adaptation.

[/QUOTE]I don't know of any serious scientist that believes that random mutation is the ONLY mechanism of change.[/QUOTE]

Again, I did not say that. I said it was the only CAUSE OF THE VARIATION upon which the process of natural selection acts. They do believe that, if they are in the mainstream.

[/QUOTE]They also don't believe that bacteria mutate "in order" to do anything. They mutate, particularly when their environment is stressed. The lucky ones mutate, by pure chance, into something that can survive the new environment. The vast majority don't. Fortunately for the bacteria, it only takes one survivor to pass on the new, improved genes.[/QUOTE]

My point, again, was that the adaptive mutation results strongly indicate that there is more than pure chance at work. They strongly indicate that the rate of mutation increases AS A RESPONSE to the changed environment.

You yourself wrote:

They mutate, particularly when their environment is stressed.

Why would they mutate PARTICULARLY when their environment is stressed if the only influence at work is pure chance?

 

[JamesDillon]

If I read the opening post right, the argument seems to be that the mutation rate itself increases when the bacteria are put into a new environment, which could suggest that some "intelligent" force is causing the organisms to mutate more frequently so as to speed their adaptive evolution along?

If true, that strikes me as interesting, but it certainly doesn't seem to be evidence against the truth of evolution. At most, it might be taken to suggest the existence of some intelligent being who uses evolution as a mechanism in biological creation. I hardly think that an increased rate of mutation in such circumstances is clear and convincing evidence of God, though.

Even if the mutation rate does increase as a response to a new environment, couldn't this also be a genetic adaptation? Aren't there genes that control the likelihood of a mutation in offspring? It certainly doesn't seem an implausible idea that such an adaptation could have developed.

 

[drkitten]

One of the core tenets of the TOE is that the cause of variation is RANDOM mutation ONLY.

Comments?

Yes. The statement quoted above is simply untrue, and almost certainly a creationist misrepresentation (whether you yourself are a creationist, or merely deceived byf creationists, is not clear).

 

[Arkan_Wolfshade]

Why DNA mutations occur:
http://gslc.genetics.utah.edu/units/disorders/sloozeworm/mutationbg.cfm

 

[ChristineR]

Mutations in humans can be caused by radiation, various poisons. There is certainly more than pure chance here, there are external forces causing genetic damage. Most of said damage is harmless, some is harmful, some may be beneficial.

The objection of non-random variations would be if it were claimed that radiation specifically caused mutations that are likely to make cells more able to deal with radiation. If such a mutation does take place, these organisms will have an advantage in this radioactive environment, hence you'll likely get more of them.

 

[mslxl]

If I read the opening post right, the argument seems to be that the mutation rate itself increases when the bacteria are put into a new environment, which could suggest that some "intelligent" force is causing the organisms to mutate more frequently so as to speed their adaptive evolution along?

Yes, correct.

If true, that strikes me as interesting, but it certainly doesn't seem to be evidence against the truth of evolution. At most, it might be taken to suggest the existence of some intelligent being who uses evolution as a mechanism in biological creation. I hardly think that an increased rate of mutation in such circumstances is clear and convincing evidence of God, though.

Whoah, slow down!

I did not say it is evidence of God's existence, clear or not, convincing or not.

I did not say it suggests "the existence of some intelligent being who uses evolution as a mechanism in biological creation."

I do not think disproving one of the central tenets of the TOE is equivalent to proving or suggesting any such metaphysical statements. Let's keep God and other intelligent beings out of this and stick to the topic.

I do think that the adaptive mutation results strongly suggest that the rate of mutation can, in some circumstances, be self-directed by a population or species. The biologists who did the research believe it too, and they don't know what to do about it.

 

[mslxl]

Yes. The statement quoted above is simply untrue, and almost certainly a creationist misrepresentation (whether you yourself are a creationist, or merely deceived byf creationists, is not clear).

All I can say, drkitten, is check it out. Get a Biology 101 textbook, or a reliable popularization book on evolution like Dawkins's books and look at it before you start to throw epithets around.

 

[Abbyas]

Actually, biologists have been commenting on the increase in the rate of mutation for quite some time.

Biologists correct me if I'm wrong here, but the situation is like this:

The rate of mutation is dependent on allelic variation affecting processes of DNA replication and repair. Some generational threads in the population have a high rate of mutation and greater allelic variation and others have a lower one.

Because mutation is not always benificial, those threads with a higher rate of mutation will die out in some proportion to those threads with lower rate of mutation. In a stressed environment, those threads with lower rates of mutation will die out faster than those who have higher rates of mutation.

Essentially we can think of it like this: a giraffe with a longer neck will pass that gene down and that generational line will beat out a shorter necked generational line.

The higher rate of mutation gene gets passed down more often in a stressed environment than a normal one.

Make sense?


Editted to summarize: biologists discussing evolution do not state that the rate of mutation is random. And it is not random for the above reasons.

 

[brodski]

All I can say, drkitten, is check it out. Get a Biology 101 textbook, or a reliable popularization book on evolution like Dawkins's books and look at it before you start to throw epithets around.

Big mistake.
DrKitten is very well versed in evolutionary theory, as are many, many posters here. If you want to prove her wrong, you are going to have to demonstrate that evolutionary theory stipulates that ALL mutations are random, you made the claim, you support it. If you are going to argue with DrKitten on evolution, you had better do your homework,because she will do hers.

 

[rudar]

I'm hardly an expert, but a completely non-intelligent (in the restricted sense of the word) possibility:

Mutations happen rather often.
There are complex mechanisms to repair mutations
These mechanisms are energetically costly
Stress physiology diverts energy from longterm projects (including DNA repair) to shortterm survival

Therefore, in stressful environments, mutations are less likely to be repaired, which increases the rate of unrepaired mutations.

I really don't see anything in this that would invalidate any tenets of TOE, central or otherwise. If in fact any serious evolutionary theory would have as a central tenet that mutations are RANDOM, there are probably some qualifications on what they mean by RANDOM in that context. It probably does not mean that no aspect whatsoever of anything remotely to do with mutations is in no way whatsoever ever affected in the slightest by any environmental factors.

 

[Arkan_Wolfshade]

Initial searching seems to indicate the phrase "orthodox theory of evolution" is only being used by anti-evolution websites. My gut tells me this is an intential mischaracterization of the scientific theory of evolution in an attempt to make it look dogmatic and immutable, so as to be able to refute it without addressing what the current scientific paradigm on evolution is.

 

[Abbyas]

One of the core tenets of the TOE is that the cause of variation is RANDOM mutation ONLY. Numerous, repeatable results obtained by altering the environment of bacteria populations consistently show those populations increasing their rates of mutation "in order to" adapt to the new environments.

Of course, biologists cannot say "in order to..."

I think you're problem is in the wording.

Let's look at it this way.

Giraffes have long necks.

It would be misleading to say that populations of giraffes grew long necks "in order" to adapt to their environment. This implies that the giraffes individually grew long necks instead each generation having a greater and greater proportion of long necked giraffes due to shorter ones dying out. Populations do adapt, individuals do not.

It's the same thing with the rate of mutation. Individual bacteria do not change their rate of mutation. The population as a whole does.

Does that make things clearer?

 

[drkitten]

All I can say, drkitten, is check it out. Get a Biology 101 textbook, or a reliable popularization book on evolution like Dawkins's books and look at it before you start to throw epithets around.

Alternatively, I might suggest that you get a better sources than a Biology 101 textbook.

Lots of things are known to affect mutations. Look up the word "mutagen."

 

[Nick Bogaerts]

If in fact any serious evolutionary theory would have as a central tenet that mutations are RANDOM, there are probably some qualifications on what they mean by RANDOM in that context. It probably does not mean that no aspect whatsoever of anything remotely to do with mutations is in no way whatsoever ever affected in the slightest by any environmental factors.

Not mere qualifications, but precisions need to be brought. Random is too a vague term; I don't believe anyone would argue were I to call mutation a stochastic process.

 

[drkitten]

Mutations happen rather often.
There are complex mechanisms to repair mutations
These mechanisms are energetically costly
Stress physiology diverts energy from longterm projects (including DNA repair) to shortterm survival

All of these are individually known to be true statements.

Case in point: free radicals are known to cause a certain amount of "oxidative DNA damage," which is chemically reparable up to a certain point. Since the total amount of damage depends upon the chemical environment, low concentrations of mutagens like peroxides will cause low (and therefore largely reparable) damage; higher concentrations will cause greater damage, above the abiilty of the cells to repair. The net effect, of course, will be that cells in a chemically stressful environment will experience a greater rate of mutation, and probably evolve faster....

As a related example, look up the "radiation hormesis" debate, which is essentially a medical procedures that relies on the ability to environmentally manipulate the body's ability to repair genetic damage caused by radiation. The idea is that below a certain level of damage, the cells don't really "realize" (I apologize for the anthropomorphism) they're damaged and therefore don't bother to make repairs. Paradoxically, by stimulating additional damage, you can (at least under these theories) raise the total amount of damage to just enough to trigger the repair mechanism and result in a lower overall mutation rate.

You're also simply making a category error. There's a difference between mutations being random in effect and being uniform in frequency. But even the idea that mutations have to be random in effect isn't required by the theory. Some DNA may well have better self-repair capabilities than others. For example, it could be stored redundantly so if one copy is mutated, there will still be a 'good' copy to use as a repair template. (There's also, of course, the mathematical point that "random" doesn't mean "uniformly random," but that's a minor side issue.)

I'm afraid I stand by my statement. Your original statement about what the TOE requires is a creationist misrepresentation.

 

[hgc]

Initial searching seems to indicate the phrase "orthodox theory of evolution" is only being used by anti-evolution websites. My gut tells me this is an intential mischaracterization of the scientific theory of evolution in an attempt to make it look dogmatic and immutable, so as to be able to refute it without addressing what the current scientific paradigm on evolution is.

mslxl,

What is orthodox theory of evolution? How is it distinguished from other theories of evolution or other variations on the theory of evolution? What other qualifying adjectives can be used for the theory of evolution?

If your answer contains the word "Darwinism," then I will still want to know how that is distinguished from other variations on evolution.