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Author | Topic: scientific end of evolution theory (2) | ||||||||||||||||||||||||
Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Not in complete agreement with the above, since random mutationand natural selection are the supposed mechanisms of evolution you could perhaps argue that even if they were not quite right, that evolution itself could still happen by some other mechanism. BUT, for now I would agree that falsifying either or both of thesewould cause a huge shake-up to the evolutionary camp (to say the least quote: Natural selection doesn't explain EVERY trait in an organism, almostby definition. The interpretation of the above example suggests that ALL traitsshould be generated via natural selection, but that is not the case. Traits which DO provide a survival advantage are selected for,but there are other genes on the same chromosome, and other chromosomes within the gamete which have to be carried forward because they are all part and parcel of the same organism/gamete. More importantly, natural selection cannot work at all withoutthis type of redundancy. For natural selection to work at all there needs to be variability within the population that, in the current situation/environment, provides no survival advantage but that might should conditions change. Many of the stated 'things the human mind are good at' are a by-product of higher 'intelligence', and I'm reasonably surethat that has given humans the survival edge that is denied them in purely physical prowess. quote: If pretty much all of the salamander can regenerate, then thatsurely suggests that regeneration is a general characteristic of salamander cells. The last point would tend to suggest that some types of cell, even in man, can regenerate too. The disappearance of 'advantageous' traits is NOT contrary tonatural selection. If by shedding that trait a trait of more immediate benefit is preserved, then so be it. Genes are not passed on one at a time ... they are linked togetherand thus the baby can get thrown out with the bath-water in some cases. quote: I don't know much about this plant, but plants in general survivebetter if they are not competing for resources with other plants don't they ? Wouldn't that suggest that there would be a survival advantage toa seed that fell further from the parent ? Is that story-telling ? :0)
quote: Natural selection, by definition, requires such redundancy. There must be variability within the population, which has NOnet survival impact in the current environment, but if the environment changes might. quote: The redundancy and 'knock-out' effects add support for ToE,and detract from a couple of the major arguments against it put forward by creationists. If you can modify the genes, without any noticeable phenotypedifferences then we no longer require transitional fossils, because you can have a genetic modification that isn't immediately expressed. It is even concievable that we might see a sudden and abrupt change in phenotype because of this phenomena. Equally it knocks-out the argument that mutations would bedetrimental and lethal. If we can add a stop-codon that has little or no discernable effect on the organism then we can have mutations. Perhaps these studies should be extended to generation by generationadd variations to see if a new species can be produced ? That would put more of a dent in evolution (if it couldn't) thananything you have described here. quote: The examples you have cited are examples of traits for which thereis no apparent selective pressure. That's OK as far as ToE is concerned. Not ALL traits in organismsare there because of selective pressure, but maybe they are on the same chromosome as one that was. The genetic redundancy you state is required by natural selection.
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Could you perhaps at least respond to the suggestion (and I'm not theonly one making it) that the genetic redundancies you are citing are actually both required and predicted by current evolutionary thinking ? I've put forward my reasons for this in previous posts.
quote: Not received anything.
quote: There are several
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I'm not sure I'd heard of much research into genetic
redundancy, but natural selection has always assumed that some parts of the genome would produce effects that are apparently not necessary for the organism's survival. If that were not the case, how could natural selection work at all ? Your suggestion that ALL genetic traits have to have emerged bynatural selection, is a little strange. Why is that the case ? Natural selection says that selective pressure is placed onthose traits which provide a net survival advantage. This implies that no survival advantage/disadvantage means no selection either way, which means distribution is just about genetic characteristics of the allele/gene, and on which chromosome it resides. You seem to have provided a lot of raw data on GR, so I acceptthat it exists. Could you elaborate your case for why this refutes natural selection. From your posts so far that doesn't seem very clear. And you are still not repsonding to suggestions that redundancyis necessary for and predicted by natural selection.
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Why should redundant genes change at a rate any different fromany other gene ? I don't see how the relationship (or lack of it) between GR andGD has any bearing on the issue at hand. The way I see it is this, for natural selection to occur in a waythat drives evolution, there must, at any one snap-shot of a species genome, be elements of the genome which apparently serve no survival purpose. These can be passed to a subsequent generation (regardless of fitness) because they are attached to genomes which have, elsewhere, aspects which DO provide a survival advantage. If the organism changes environment (or its environment changes) those 'redundancies' may contribute to survival ... in which case they become non-redundant. We may even say, that the existence of genes which have noeffect even when removed is consistent with a macro-evolutionary scenario. Genes do no operate in isolation (at all times) and often require another enzyme to activate them. Loose the enzyme and you loose the effect, but the section of genome is still there. This sort if change can cause the loss of teeth in birds, or the loss of appendages in crustaceans ... i.e structural modification. How ... in DETAIL ... is genetic redundancy incompatiblewith NDT ?
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Kimura: "Of course, Darwinian change is necessary to explain change at the phenotypic level -fish becoming man- but in terms of molecules, the vast majority of them are not like that."
http://www.tulane.edu/~eeob/Courses/Heins/Evolution/lecture14.html#INTRODUCTION The above link is about Nuetralist Theory. Basically it does notrefute natural selection as the mechanism behind adaptation, it simply says that natural selection is not the whole story. I.e. it says that not all genes are fixed in populations by naturalselection ... which is more or less what natural selection already implies since it focusses on the passing on of those traits which DO have a survival impact. http://www.xrefer.com/entry/462336has the following (my emphasis in bold):: "Its [neutral theory's] proponents,while recognizing the importance of selection in determining functionally significant traits,hold that the great majority of the differences in macromolecular structures observed between individuals in a population are of no adaptive significance and have no impact on the reproductive success of the individual in which they arise. Hence, frequencies of the corresponding mutant alleles are governed by purely random events. This contrasts with the orthodox neo-Darwinian view that nearly all evolutionary changes have adaptive value for the organism and arise through natural selection" I think a perceptual problem has arisen in re-defining Darwin'schanges in traits over time to changes in allele frequency over time. The link between allele frequency and traits seems to be the stumblingblock ... it's kind of a 'systems' problem. Applying functionalist reductionism to the problem doesn't appear approriate because of emergent properties. Non-the-less, not even Motoo Kimura was suggesting that naturalselection didn't happen ... only that it wasn't the whole story. Hmm ... perhaps Syamsu's 'General Theory of Reproduction' wouldhave some benefits after all quote: Doesn't that just mean that we do not yet know the completestory about how genes are formed (which I thought was common knowledge) ? Not knowing something bears little on any topic, surely ?
quote: If they are carried on the same chromosome as a survival trait,they would be subject to selective pressure by default. You don't inherit one gene off of a chromosome, you inherit the entire chromosome. Likewise, survival doesn't depend on one gene, it depends on thesum of all the genes and how that relates to the phenotype. Natural selection operates on the expression of genes (i.e. traits). And isn't this issue what Kimura et al talked about anyhow ?
quote: I think it is directly relevent. You are interpreting geneticredundancy as a refutation of ToE, I am supplying an alternative interpretation that is, if acceptable, in keeping with ToE. quote: Hmm ... tricky one that. Is it a LOSS of teeth, or the GAIN of abeak ? [This message has been edited by Peter, 07-16-2002]
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Why should these 'redundancies' (and you have yourself
stated that they are more likely to be 'of unknown function' in any case) have a different mutation rate than any other section of DNA ? (I've asked this before and you haven't given an answer). DNA is subject to copy errors, and any part can be mis-copied. Trying to claim that gene selection happens at the individualgene is a little ridiculous isn't it? Aren't large numbers of genes present on each chromosome? Wouldn't that mean (and I'm not talking about duplication) thata gene that exists on the same chromosome as a gene that produces a phenotypic effect of use would be preserved with the trait in question? If we didn't have sections of genetic make-up (with currentlyunknown function and apparently no survival benefit to the organism) we couldn't have natural selection at all, could we? (This has been asked before and you have not answered). You have in no way refuted random mutation. You have said thatsome DNA sites have a higher tendancy to be copied wrong. That does not make the mutation non-random. Giraffes don't generate mutations to neck lenght control mechanisms becuase they need longer necks. Peppered moths (and they MUST rest somewhere during in the dayeven if it is not near a biologist's trap ... most moths I have seen during the day are sitting high on the wall of my house, or on a high window) show a natural variation, and the distribution of that variation can be affected by environmental conditions. That IS natural selection isn't it? That we haven't found the exact molecular level explanation doesnot refute the theory ... it just means there are pieces of the puzzle missing ... we already know that. Redundancy doesn't refute ToE, it is an expected feature. Mutation enables evolution, and mutation happens. you have not shownthat there are any non-random mutations in the sense that 'random mutation' is used in ToE, only that some sites are more prone to copy errors. This is good for ToE, it means that there is an observed mechanism that can explain away the 'you can't get enough mutations for that' arguments. Read some 'Information Science' literature (or cite thatwhich you have read) before agruing from Information Theory.
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: I have read some articles by Kimura, and he doesn't himselfseem to doubt natural selection as acting, just not on ALL traits. I'll look up some more though.
quote: I understand what you are saying (I think), but it seemsbackward logical to me. If there are parts of the genome which are neutral in terms ofsurvival at the level of the organism now, then something changes that makes that very feature important ... then that's exactly what we need for ToE to work. You have said that we do have sections of the genome which haveno selective pressure associated at the point in time when the genome was investigated. For mutations to drive evolution, we would require areas of thegenome which, if changed, would not outright kill the carrier, but on subsequent changes might promote new function. You said we do find that ... or at least apparently functionlessjunk sections. quote: I'll re-read to check.
quote: Reasonable point ... it's an assumption on my part.
quote: Why? If it supports natural selection as a process, how is that badfor NDT? quote: It doesn't seek to ... so that's a given (hey we agree on something!)
quote: We are in disagreement over 3), so stating your conclusion isnot marking a hole in the theory. Many of us are of the opposite opinion, and thus the discussion.
quote: I mention it again because you are still hanging on to duplications,which I said I wasn't talking about, and not responding to the suggestion that some 'by default' selection goes on because many genes are physically linked on one chromosome. If I have three books each containing three stories, but I onlywant to keep one story ... by default I have to keep the other two in the same book (assuming I don't rip it out of course). I have 'selected' two stories indirectly because I had no choice.
quote: How do you know that ?
quote: It's already in ... has been since people knew about genetics. It says that mutations + selection drive evolution. Anything relating to the mechanisms behind mutation (barring aserial number on a genome) is OK. I'll re-read some of the examples you give, but if you can showme a mutation that couldn't have happened by chance I'll go 'Hmmm .... er .... ' and start making stuff up quote: My current opinion is that nothing that you have put forwardFALSIFY's ToE, that's true. Provide me with some more compelling analysis of data and Iwill change my mind on that. [This message has been edited by Peter, 07-31-2002]
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: But have consistently failed to answer the criticism that youuse two different interpretations of random to do so. Evolution requires mutation + selection. Mutation is consideredrandom in the sense that it is not a response to an environmental stimulus per-se ... and that the time and site of the mutation cannot be predicted in advance. Not even sure whether 'randomness' is 'required by' or 'assumed by'evolutionary theory ... and that would be important. What ToE does suggest is that mutation is a naturalistic process,and it has long been assumed to be accidental. There is an article in New Scientist or Scientific American (I'lltry to dig it out for a proper reference) which suggests that DNA in brain cells is deliberately re-arranged ... perhaps as a quantum memory store ... which suggests a mechanism for deliberately changing cell DNA sequence. Does that refute NDT? Mutation + Selection = NDT, does itreally make any difference if there is some unknown natural process that aids mutation ... or does that help ToE? quote: I have read the thread ... maybe you could answer your critics?
quote: Perhaps you could be less condescending and more informative ...what do YOU mean by falsification? quote: You have NOT falsified natural selection. You have suggested that not all traits in the genome are subjectto selective pressure ... NDT doesn't say they are either ... does it? Perhaps you could cite the NDT references where this is stated. Even Kimura says that some ARE subject to selective pressure. You have still not expressed an opinion on gene selection due tolocation on the same chromosome as a gene subject to selective pressure as in the book+story analogy I suggested previously.
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
If I understand it correctly PeterB is saying that the
existence of regions which have a higher probability of undergoing mutation makes mutations non-random. If my interpretation is correct, then I think the logic isskewed to say the least. Because a region is more likely to be subject to a copying errordoes not make any actual instance of a copy error non-random.
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Have you heard of a gorilla named (and I'm not sure
of the spelling) Koko ? She was taught sign language, and can use a keypad thatspeaks the words of the picture on it (like 'banana' or whatever). There seems to be a bias in thinking that this cannot belanguage use because she's only a gorilla ... but I think you are right that this bias is from the religous viewpoint of man as the pinnacle of creation. Perhaps this is why there is such a strong feeling against evolution,after all, if ToE is correct we are just animals like every other creature on the planet ... nothing any more special than a gorilla, chimp, okapi, frog, ant, etc. etc. etc.
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
[This appears to have been put in twice]
[This message has been edited by Peter, 09-10-2002]
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I'll ask again :-
Isn't 'neutral evolution' just a side effect of theway genetic material (i.e. chromosomes) are passed from one generation to the next ? My analogy previously was in having three books each containingthree stories. I only actually want one story from each, but in order tokeep them (nicely bound) I have to keep all nine stories. I haven't 'selected' the seven I'm not interested in, theyjust came along with the bits that I did select.
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Apologies ... this was a comment in message 137, somehow
I must have got mixed up ... thought I had posted twice by mistake and deleted-by-edit one. Sorry. [This message has been edited by Peter, 09-10-2002]
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
But if you get a mutation of that type, and it is
preserved due to linkage doesn't that cover what you are saying refutes NDT? Or am I missing something here?
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Peter Member (Idle past 1499 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: It's not communication unless it's two-way (the recipient hasto understand the transmission surely). Also Koko was asked about past experience, and described the huntin which she was captured as juvenile (she refers to people as 'feet' incidently, which implies languistic capability since she chose that word to describe people out of the set of words that she is capable of using). quote: Already apologised for this error ... wrong post. I don't suggest anything in linguistic capability that isconcerned with common descent ... we can also communicate with dogs and cats and probably pretty much anything else provided we know its method of communication. quote: Eh?
quote: Glad to hear it ... so long as you are sure.
quote: Are you sure about that? Motivations for belief can be convolutedat best, and the sources of bias within our own thinking need to be constantly addressed. quote: At the level of the genome all that we require is mutations,and we have those. Do we fully understand what the entire genome is for, or howit relates to phenotypes? If we don't then the leap you have made is based upon incompleteinformation, and therefore unfounded (presently). quote: I don't usually respond to personal comments, but I find thislast point somewhat patronising ... is that a debating ploy to undermine credibility?
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