Punctuated Equilibria theories

[bumab]

YOU MISSED THE WHOLE POINT!

 

No, I understand your point, I just don't agree with it at the moment.

 

Some people here are looking for a new, mysterious way that the RAW MUTATION RATE INCREASES sharply, and I am saying that's not needed: another way to increase the rate of evolution by increasing the genetic variation of a species is to have SELECTIVE PRESSURES REDUCED. Either way, the number of mutations accepted into the genome increases, but the second way is quite logical and straightforward, and requires no mysterious new process.

 

Very true. But can it increase it enough?

 

I suggest you read the recent news post about spurts in the evolutiononary history of humans. There's no mechanism suggested, but it does show evidence that mutations rates do not hold steady over time, regardless of selection pressure changes.

[paultrr]

YOU MISSED THE WHOLE POINT!

 

Some people here are looking for a new, mysterious way that the RAW MUTATION RATE INCREASES sharply, and I am saying that's not needed: another way to increase the rate of evolution by increasing the genetic variation of a species is to have SELECTIVE PRESSURES REDUCED. Either way, the number of mutations accepted into the genome increases, but the second way is quite logical and straightforward, and requires no mysterious new process.

 

PS: See my last post, where I posted a quote from my genetics text about the founder-flush theory.

 

Pressure reduction only accounts for certain cases and not all. If pressure reduction was really the full cause we could duplicate this very well in say large scale outdoor experiments. However, pressure reduction does not account for everything out there in the record. There are cases where there where pressure increases as far as human evolution goes and yet, we evolved in spite of those and more accurately because of the increased pressure.

[TeleMad]

paultrr: For all the posturing on both sides it is true that not only are most mutations at times fatal and that some mutational changes are not fatal. These two facts have always been a point of contention on both sides. Yet, what is missed is that both remain true.

 

But most mutations aren't fatal, they're deleterious. There's a difference between being dead and just being at a selective disadvantage.

 

Also, all of us discussing mutations should be careful not to focus on only deleterious and beneficial mutations: many mutations are neutral. Neutral mutations harmlessly expand the genetically coded information in the species' genome, which allows for a harmless search through sequence space. Some of the variation may turn out to be useful when the conditions changes.

[TeleMad]

bumab: I suggest you read the recent news post about spurts in the evolutiononary history of humans. There's no mechanism suggested, but it does show evidence that mutations rates do not hold steady over time, regardless of selection pressure changes.

 

Actually, it doesn't. It shows that the rate at which mutations were ACCEPTED fluctuated, not that the RAW rate at which mutations were produced did. This could in fact be an example of what I am currently discussing: the changes could be associated with a reduction in selective pressure, which allows mutations that would otherwise be rejected to be accepted.

 

Let me point out that I am not claiming that the rate of mutations is a constant for a species, just that there does not need to be some mysterious, new mechanism to explain rapid increases in the rate at which mutations are accepted. For example, I've also mentioned that mutations in regulatory genes could lead to rapid evolutionary change, as could genome duplications (which are rare in animals, but do occur).

[bumab]

Actually, it doesn't. It shows that the rate at which mutations were ACCEPTED fluctuated, not that the RAW rate at which mutations occurred did. This could in fact be an example of what I am currently discussing: the changes could be associated with a reduction in selective pressure, which allows mutations that would otherwise be rejected to be accepted.

 

Well, I'll give you that the info was inconclusive. Could be either/or.

 

Let me point out that I am not claiming that the rate of mutations is a constant for a species, just that there does not need to be some mysterious, new mechanism to explain rapid increases in the rate at which mutations are accepted.

 

I know. You are arguing the rate of phenotypic expression can vary, however central to your argument is the premise that the actual mutation rate is constant. Only when selective pressures are removed can that genotypic mutation rate really show it's teeth. It's pretty well proven that indeed happens, and often. But the jury is still out for many (obviously not all) as far as the extreme body changes seen on short PE timelines.

 

Nobodies trying to replace gradulism as a speciation method, more to suppliment it, to add on, to help with the incredible radiations we see at various times in the fossil record. Gould mentioned the "problem" several times.

[Biochemist]

But most mutations aren't fatal, they're deleterious...

Reference?

[Biochemist]

...many mutations are neutral. Neutral mutations harmlessly expand the genetically coded information in the species' genome, which allows for a harmless search through sequence space. ...

And the majority of these biochemical processes have specific receptor sites. The notion that these bahaviors are mutations is a postulate. It is a syllogism to assume that all genome changes are mutations, and then to note that some of the changes are positive/beneficial, and hence, advanced the species through mutation. We never proved they were mutations. We assumed it.

[Biochemist]

Nobodies trying to replace gradulism as a speciation method, more to suppliment it......

To be fair, I am. I think the evidence suggests that speciation MAY have occurred via mutation, but the general mechanism is not mutative. That is, the majority of higher taxa were not generated through mutation. If thie higher taxa were not, it would be probable that the majority of lower taxa were not either.

[TeleMad]

TeleMad: But most mutations aren't fatal, they're deleterious...

 

Biochemist: Reference?

 

...

 

"Since most mutations are deleterious, these statistics are anything but cheerful. Fortunately, most mutant genes are recessive and are not expressed in heterozygotes." (Integrated Principles of Zoology: 10th Edition, Hickman, Roberts, & Larson, McGraw Hill, 1996, p146)

[Biochemist]

Gentlemen-

 

(speaking as moderator)

 

This thread has become egregiously long, and it is unlikely that any new participant can acquire the background already posted in this thread to join in.

 

I suggest that we start new threads to continue the narrow points that have surfaced and remain open.

[TeleMad]

Biochemist: The notion that these bahaviors are mutations is a postulate. It is a syllogism to assume that all genome changes are mutations, and then to note that some of the changes are positive/beneficial, and hence, advanced the species through mutation. We never proved they were mutations. We assumed it.

 

So you're saying "God did it"? Or maybe magical space aliens?

 

Or are you using your own personal, non-scientific definition of the term "mutation"? In case you need a refresher... http://en.wikipedia.org/wiki/Mutation#Types_of_mutations

 

 

 

 

Oh, and as to what I said about neutral mutations, here's an interesting statement from Wikipedia ...

 

”Neutral mutations do not affect the organism's chances of survival in its natural environment and can accumulate over time, which might result in what is known as punctuated equilibrium, the modern interpretation of classic evolutionary theory. “ (http://en.wikipedia.org/wiki/Mutation)

[bumab]

Oh, and as to what I said about neutral mutations, here's an interesting statement from Wikipedia ...

 

”Neutral mutations do not affect the organism's chances of survival in its natural environment and can accumulate over time, which might result in what is known as punctuated equilibrium, the modern interpretation of classic evolutionary theory. “ (http://en.wikipedia.org/wiki/Mutation)

 

Key word being "might." The problem is all those mutations have not been selected for, so the VAST majority will be deleterious, as you said. All at once doesn't help if they are all bad...

[TeleMad]

bumab: Nobodies trying to replace gradulism as a speciation method ...

 

Biochemist: To be fair, I am. I think the evidence suggests that speciation MAY have occurred via mutation, but the general mechanism is not mutative. That is, the majority of higher taxa were not generated through mutation.

 

Reference?

[Biochemist]

These reference are all just standard recitations of standard dogma. They are not proving anything except that most folks believe in mutation. There is minimal evidence that "most" mutations are "deleterious" (versus "all") because these references all presume mutation-driven speciation. These are still circuitous arguments, not evidentiary support.

[TeleMad]

bumab: Key word being "might." The problem is all those mutations have not been selected for, so the VAST majority will be deleterious, as you said. All at once doesn't help if they are all bad...

 

What? You're very confused about what I said. Please reread what I actually said about neutral mutations, this time paying attention.

[TeleMad]

These reference are all just standard recitations of standard dogma. They are not proving anything except that most folks believe in mutation. There is minimal evidence that "most" mutations are "deleterious" (versus "all") because these references all presume mutation-driven speciation. These are still circuitous arguments, not evidentiary support.

 

... said the anti-scientific Creationist ...

[TeleMad]

Biochemist: These reference are all just standard recitations of standard dogma. They are not proving anything except that most folks believe in mutation. There is minimal evidence that "most" mutations are "deleterious" (versus "all") because these references all presume mutation-driven speciation. These are still circuitous arguments, not evidentiary support.

 

 

TeleMad: ... said the anti-scientific Creationist ...

 

Some support for his anti-scientific statements being Creationist and religious (emphases added)...

 

”Creationists often say that all mutations are harmful and deleterious, and degrade the genome. They say that mutations can only scramble the information that's there, and that mutations cannot produce new "information."

(http://www.nmsr.org/nylon.htm)

 

 

”Although creationists sometimes assert that all mutations are harmful, this is not so.” (http://www.stephenjaygould.org/ctrl/news/file021.html)

 

And from a religous site that tells believers how to respond the atheists...

 

”Answers for Atheists [a religious site]

...

 

But what about evolution? Doesn't that contradict the Bible?

 

...

 

Asked once what were the probabilities that life could have been formed by chance, Dr. Wickramasinghe said they were about as plausible as "a tornado blowing through a junkyard and assembling a Boeing 747" [a position Biochemist defended ... for evolution, not abiogenesis, none the less!] ‑a modern jet airliner. ...

 

Evolution also says that changes in living things brought about by mutation are often beneficial, while in fact no beneficial mutation has ever been observed, either in nature or in laboratories. Yet evolutionists tell us that mutations provided the changes necessary‑the changes upward in order of complexity‑for macro‑evolution to occur. So far as science has ever observed, all mutations are harmful, not helpful, to living organisms. But because some people believe in macro evolution, they have hypothesized that some beneficial mutations must occur. for without them, macro evolution cannot have occurred. This means they are allowing their faith in macro evolution to determine what they think about nature.”

(http://www.greatcom.org/resources/answers_for_atheists/ch_14/default.htm)

 

 

And here, after the statements that clearly show this is a Creationist site, we have a snippet from a Creationist’s version of a hypothetical dialog between a “stupid” (i.e., mainstream) biology professor and an amazingly “brilliant” (i.e., Creationist) student.

 

”Evolutionary theory is a myth. God created everything; the evidence clearly points to it. This is science vs. evolution—a Creation-Evolution Encyclopedia, brought to you by Creation Science Facts.

 

…

 

Student: But prof, there is no evidence supporting evolution by mutations. In contrast, there is clear-cut evidence against it.

 

...

 

Student: But prof, all mutations are harmful! Most are weakening or damaging, and many are outright lethal!

 

…

 

Student: But prof, not once has a beneficial mutation ever been recorded. They always only harm, damage, weaken, or kill outright.

 

...

 

Student: But prof, it has been found that mutations, which are always harmful, have widespread damaging effects on genes.

 

...

 

Student: But prof, this mass of knowledge has only confirmed that mutations are always harmful and are totally incapable of changing one species into another.

…”

(http://www.pathlights.com/ce_encyclopedia/10mut17.htm)

 

Does the Creationist student remind you of anyone? Oh, perhaps Biochemist?

 

 

Any of these Creationist/religious beliefs ring a bell? Oh, perhaps in Biochemist's "scientific" arguments?