mutation and evolution

(This thread is a spin-off from Message 49 by Spofforth in the thread Teaching the Truth in Schools in the Education and Creation/Evolution forum. --Admin)

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In what population of organisms, except bacteria which I am guessing that you are not making the assumption that they can evolve immediate multicellular and complex capabilities, are there hundreds of billions of organisms?

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I think you misunderstand. How did you calculate the odds? Did you consider that there are astronomical numbers of experiments running simultaneously and that this has been occurring for a couple of billion years?

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If evolution can only happen at the population level, there still is not the grand scale number of organisms necessary fro mutation to be the driving factor.

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Attempting to cut the numbers by appealing to populations isn't relevant to the issue. Consider: Ten species with 100,000 individuals each. For simplicity, lets say they reproduce at the same rate and produce one offspring per generation. Each generation can be considered as 1 million genetic experiments-- ie, each generation produces 1 million individuals, each with a mutation or two. That these mutations do not cross species does not cut the total number of mutations. It does mean that the mutation is limited to the offspring of originating population. Perhaps nine of the ten species die out, but the tenth survives as it had the lucky mutation.

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Only the students that have demonstrated an understanding of biological systems and the scientific method should be allowed to investigate further.

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Funny, you want student to understand biological systems but do not wish to expose them to a key component of biology.

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What do you think a modification in the genetic code is doing? It is coding for a new amino acid which is coding in turn for a new protein.

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Ah... my mistake. Usually, creationists who make statements like "mutation can't create new proteins" mean "a completely new protein unrelated to any other." Or something very much like that. The reason creationists opt for this restricted definition is that mutation can and does modify existing protein and this happens quite a lot. So really, you've cut the rope from under yourself.But what is with the "coding for amino acid which is coding for a protein" part? Amino acids don't code for anything. They are components, like Lego.

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If the protein happens to fit with the other proteins that are present in the organism that organism might survive the mutation.

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Ta Da!!!!!! You are almost there. See, it isn't so hard to understand.

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Although the mutation is present it may not even get the chance to thrive in an environment and the organism may never pass it on to the next generation.

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Right-o. This would be natural selection.

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If we do not know the origination of the original genetic code we cannot teach that all organisms originated from the same lineage despite the fact that some evidence might point in that direction.

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What if all the evidence points in that direction?What you are basically arguing is that if we don't have all of the information we can't teach what we do know. We don't have all the information for any subject. Would you like to ban all knowledge, as it is all incomplete?

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If you want to be truly neutral in the science classroom no theories can be taught, just the scientific fundamentals that would allow the student to investigate further on his/her own.

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The idea of being 'truly neutral' sound pretty good until you realize that being neutral means presenting theories which have no evidence right along side theories that have great deals of evidence.No theories? We may as well call science class "nap time" then, because there won't be anthing to teach. Everything you learn is based upon something containing that dirty word-- theory.------------------
No webpage found at provided URL: www.hells-handmaiden.com[This message has been edited by Admin, 02-25-2003]

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I think you misunderstand. How did you calculate the odds? Did you consider that there are astronomical numbers of experiments running simultaneously and that this has been occurring for a couple of billion years?

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Attempting to cut the numbers by appealing to populations isn't relevant to the issue. Consider: Ten species with 100,000 individuals each. For simplicity, lets say they reproduce at the same rate and produce one offspring per generation. Each generation can be considered as 1 million genetic experiments-- ie, each generation produces 1 million individuals, each with a mutation or two. That these mutations do not cross species does not cut the total number of mutations. It does mean that the mutation is limited to the offspring of originating population. Perhaps nine of the ten species die out, but the tenth survives as it had the lucky mutation.

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The problem I see with that line of reasoning is that if you take into account that a new species can only arise from a previous species, according to evolutionary theory, then you can only take into account the mutations that occur within the parent species. That would lower the mutation rate significantly.If species A has a mutation, however it has no way to pass the mutation to species B that survives in the immediate area, the mutation would have no significance in population B. Therefore the populations that are affected and have the ability for mutation decrease significantly.quote:

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Funny, you want student to understand biological systems but do not wish to expose them to a key component of biology.

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The key component I would want them to know before knowing any theory is the scientific method. I am not opposed to exposure of students to evolutionary theory, but I am opposed to teaching it as fact especially since so much depends on mutation rates in various populations.quote:

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But what is with the "coding for amino acid which is coding for a protein" part? Amino acids don't code for anything. They are components, like Lego.

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I'm sorry I mispoke, I meant to say build. I just meant that if the right amino acid was not in place then the protein would most likely be an irrelevant part of the organism.quote:

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The reason creationists opt for this restricted definition is that mutation can and does modify existing protein and this happens quite a lot. So really, you've cut the rope from under yourself.

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My contention would be that the existing protein is not modified all that frequently because the point mutations that would be most likely to survive often do not even change the protein. If you are looking at the codes for amino acids there can be several variations of bases that code for each one thus lowering the frequency of mutations that cause protein changes. I would certainly not argue against natural selection, I would however argue that it is acting on variation that is already present in the population. The gene frequency of a population may change. However, it is difficult to argue that an organism has changed without seeing the actual physical change in comparison to a genetic change. I would especially argue this point in complex organisms where one change might affect many systems.

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The problem I see with that line of reasoning is that if you take into account that a new species can only arise from a previous species, according to evolutionary theory, then you can only take into account the mutations that occur within the parent species.

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This is a repetition of the first objection you made, and I responded to it.

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The key component I would want them to know before knowing any theory is the scientific method.

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Why do you hold this up as so important, but dismiss the results it produces? Very few things have as much evidence behind them as does the ToE.

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I just meant that if the right amino acid was not in place then the protein would most likely be an irrelevant part of the organism.

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If an amino acid is not in the 'right' place then you have a mutant protein and I supppose the change is likely to be irrelevant, but sometimes it makes a difference.

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My contention would be that the existing protein is not modified all that frequently because the point mutations that would be most likely to survive often do not even change the protein.

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Have you bothered to look it up? I've found quite a few examples and posted a couple of them for you. Have you decided to look the other way?

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If you are looking at the codes for amino acids there can be several variations of bases that code for each one thus lowering the frequency of mutations that cause protein changes.

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Do you mean that several different stretches of DNA code for the same protein? Well, sure. And they code for a slightly different version of the protein. You are talking about mutation and the effects of mutation but claiming the opposite.

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I would certainly not argue against natural selection, I would however argue that it is acting on variation that is already present in the population.

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It does act on variation that is already present in the population, in a sense. When you get a copy error you automatically have a new variant in the population.------------------
No webpage found at provided URL: www.hells-handmaiden.com

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The problem I see with that line of reasoning is that if you take into account that a new species can only arise from
a previous species, according to evolutionary theory, then you can only take into account the mutations that occur
within the parent species. That would lower the mutation rate significantly.

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Evolution isn't just about mutation, or natural selection, or ...Evolution occurs as a system-level effect of the interaction
of a number of component forces. In particular it requires some
form of separation followed by isolation of a (sub-)population.As pointed out, it is suggested that mutation rates are much
higher than previously thought. It is also the case that (in
sexually reproducing organism anyway) that it is not one mutation
in the parent ... each (male) parent produces millions of gametes
each with the potential for copy errors.

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If species A has a mutation, however it has no way to pass the mutation to species B that survives in the
immediate area, the mutation would have no significance in population B.
Therefore the populations that are
affected and have the ability for mutation decrease significantly.

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Suppose species A has offspring Aa and Ab which differ slightly
in their genome. This new population splits into two populations
(maybe separated by a flash flood or avalanche or somesuch) A1 and A2.The separation leads each population into somewhat different
habitats. A1 is in a habitat which favours Aa individuals, while
A2 is located where Ab is the thing to be.The further mutations that occur in A1 and A2 are selected based
upon different environmental pressures, and the A1, A2 populations
could be further split in the future.Iterate around this for a few million years and I think you'll
see a marked difference in the extant populations.

Hi John,About this: I think Spofforth is making a conceptual math error from which he is not going to recover without assistance. Could you explain this again? Or perhaps use a simpler example using only a single population? Or maybe a progression of two examples, with the first being for a single population, and the 2nd for ten populations? I know its repetitive, but I think it might be worth it.------------------
--EvC Forum Administrator

Spofforth,Consider the human species. I did some quick math and worked out the following. If we assume the human population at an even 5 billion and assume the figure of 4 mutations per individual, as suggested in the article I cited, and further assume that 1 in 100,000 mutations are beneficial ( this article suggests that in fact the rate of beneficial mutation is 1 in 1000 ), you find that there should be 18,000 or so new beneficial mutations in the current generation of humans. That is quite a few. Consider that this process has been in place for billions of years, stretching through our line right back to the beginning. Nowhere along that line do we have to worry about 'trading' genes between species, as is a concern of yours. Every creature in our lineage can be considered the same population.As for the mutation rates being reduced due to populations being divided, pretend that you are a scientist running an experiment. You want to track mutations in 1000 bacteria. You don't want to watch all 1000 personally, so you divide up the population into ten sets of 100, each set to be watched by a student. The mutation rate is the same as if you hadn't divided the population. The total number of mutations is the unchanged. Imagine that you put your 1000 bacteria into a freezer in one lump. Ten bacteria have a mutation that allows them to survive and reproduce. The rest die. Now back up, and put those ten sets of 100 in the same freezer. The same ten that survived before, survive now. The rest die. The result is roughly the same. If these ten are in the same population then you'll have a flurry of life in one petri dish and 9 dull dishes and potentially one new species. If the ten are divided amonst the various dishes then you'll have several new species ( potentially ). But the total mutations and hence the total potential for adaptation remain the same.------------------
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The problem I see with that line of reasoning is that if you take into account that a new species can only arise from a previous species, according to evolutionary theory, then you can only take into account the mutations that occur within the parent species.
--------------------------------------------------------------------------------This is a repetition of the first objection you made, and I responded to it.

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You are right, I was viewing your statements as something completely out of context. I was viewing populations A,B,...F as completely separate populations and not as parts of the original. I apologize for the redundancy.

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Spofforth: The key component I would want them to know before knowing any theory is the scientific method.
--------------------------------------------------------------------------------John: Why do you hold this up as so important, but dismiss the results it produces? Very few things have as much evidence behind them as does the ToE.

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Yes there is evidence that tends to lead in the direction of evolution. I just find it hard to promote a theory as fact if the lineage of DNA cannot fully be traced from generation 1 to generation x. If the possible path is discussed and alternative theories are thrown in the student can draw his/her own conclusions based on the method or have an understanding of how to research it further if they choose.

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Have you bothered to look it up? I've found quite a few examples and posted a couple of them for you. Have you decided to look the other way?

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I have looked at them and they are discussing what I would consider microevolutionary changes. I believe that microevolutionary changes do occur because there is variation within every population. I believe that environmental changes can assist in microevolutionary changes. The thing that I cannot conceive, even given the possibility of billions of years, is that microevolutionary changes could lead to the wide scale variation in organisms today. The changes that are seen cause organisms to fit into specific niches and occur in response to environmental changes, ie. presence of nylon and not carbohydrate or pesticide resistance, however the populations tend to rebound as the stimulus is removed and the fitness of the "mutant" decreases in the population. If I am mistaken and there is evidence of current macroevolution, divergence of species, please point me in that direction.

Environmental changes cause a change in trait frequencies
over time ... so if the environmental pressures change
the dominate traits will change ... don't see the problem
there. If the environmental pressures don't go away, or
some of the population are isolated so that the two sub-populations
are subjected to different environmental pressures it's surely
reasonable to surmise that they would diverge. We know that such
divergence is possible (otherwise there would be fewer breeds
of dogs, cattle, cats, etc.).It's been brought up before (not sure where, sorry), but not
discussed in full (I think) ... but what about species which
can inter-breed, but produce infertile offspring?Doesn't that suggest that the species (horses&donkeys, lions&tigers,
various zebras) are diverging to a point where, should the
trend continue, they would be unable to interbreed?Is that still micro-evolution?Or is it the first step on the rung to more profound diversity?

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Yes there is evidence that tends to lead in the direction of evolution.

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That is a serious mistatement of fact. Since Darwin proposed his version of evolution 150 years ago, it has passed every test. Every bit of evidence that we've been able to scrape up has fallen into place in support of the ToE. Despite what creationists promulgate, there is no real challenge to the theory at the moment and there never really has been.

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I just find it hard to promote a theory as fact if the lineage of DNA cannot fully be traced from generation 1 to generation x.

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Really? Can you trace your lineage back even 2000 years? How about all the way to the beginning 6000 years ago? Seems this would be an easier task but can you do it? Nope. Guess we can write off decent from Adam then. Did you read the Jet's Challenge thread? EvC Forum: How does evolution explain the gaps? The same issue came up there.

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I have looked at them and they are discussing what I would consider microevolutionary changes.

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All evolution is micro in the short term. That is, a horse does not suddenly give birth ocean adapted offspring. The change is slow and takes much longer than the lifespan of a human. We only get to see a few seconds of the ball-game. There is nothing anyone can do about this. Relationships of long duration we have to infer from the evidence we have at our disposal.

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I believe that microevolutionary changes do occur because there is variation within every population.

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Yes, indeed. Evolution does occur because there is variation within a population. Your mistake is in assuming that, or insisting that, this variation is stable. It isn't. Mutation is rampant. And it does produce variant individuals. Hence there is no hard micro/macro barrier. The distinction, as creationists use it, is just a smoke screen.

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The thing that I cannot conceive, even given the possibility of billions of years, is that microevolutionary changes could lead to the wide scale variation in organisms today.

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Yet you believe in... what.... ? Magic? A creator unlike anything you experience who poofed everything into existence? That doesn't make sense. Evolution has reams of evidence and more comes to light every day. The alternative has zero evidence-- not one shred. Yet you are incredulous about evolution? It simply does not make sense.

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The changes that are seen cause organisms to fit into specific niches and occur in response to environmental changes, ie. presence of nylon and not carbohydrate or pesticide resistance, however the populations tend to rebound as the stimulus is removed and the fitness of the "mutant" decreases in the population.

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Changes don't 'cause' organisms to fit into niches. It isn't teleological.Fifty or a hundred years ago there would have been no nylon for the nylon-bacteria to digest. Why would it have code in its genome for this ability? In other words, if you wish to describe all adaptation as variation within existing DNA, you have to explain why the bacteria would have the ability to eat nylon prior to nylon having been invented. Why would its genes code for the ability to eat something that was yet to exist for it to eat?We have plenty of examples of speciation-- ie. examples of populations splitting into variant groups THAT CANNOT INTERBREED. That pretty much kills the idea that populations 'bounce back' in all cases. Once the split occurs, there is no going back.------------------
No webpage found at provided URL: www.hells-handmaiden.com

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quote: If the environmental pressures don't go away, or
some of the population are isolated so that the two sub-populations
are subjected to different environmental pressures it's surely
reasonable to surmise that they would diverge. We know that such
divergence is possible (otherwise there would be fewer breeds
of dogs, cattle, cats, etc.).

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However if the environmental pressure were removed would the populations not tend to rebound toward their predivergent state? Which would tend to eradicate the mutation from the population or store it in a dormant state within the population. If this is the case is it not possible that genetic information has always had messages in dormant states waiting to be turned on when environmental conditions were right and off when they were not? Yes, selective breeding has led to a vast diversity of domesticated animals. If left to nature would they not reach a state of equilibrium in their genetic material?

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quote: It's been brought up before (not sure where, sorry), but not
discussed in full (I think) ... but what about species which
can inter-breed, but produce infertile offspring?Doesn't that suggest that the species (horses&donkeys, lions&tigers,
various zebras) are diverging to a point where, should the
trend continue, they would be unable to interbreed?Is that still micro-evolution?Or is it the first step on the rung to more profound diversity?

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I would venture to guess that this would still be micro-evolution. However, would the interbreeding variants within the population again be able to reproduce freely and produce a population that reaches some state of equilibrium?

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quote: That is a serious mistatement of fact. Since Darwin proposed his version of evolution 150 years ago, it has passed every test. Every bit of evidence that we've been able to scrape up has fallen into place in support of the ToE. Despite what creationists promulgate, there is no real challenge to the theory at the moment and there never really has been.

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Puntuated equilibrium to explain gaps in the fossil record, modern synthesis to correct for Darwin's nonrandom mutation?

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We only get to see a few seconds of the ball-game.There is nothing anyone can do about this. Relationships of long duration we have to infer from the evidence we have at our disposal.

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So from where would the evidence for the evolutionary process as an absolute come? This sounds a lot like my were you there argument. If you cannot see the entire game how do you know what occured in the first thirty seconds? Sure you can make inferences from the evidence, but that does not make a theory fact.

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Quote: Yes, indeed. Evolution does occur because there is variation within a population. Your mistake is in assuming that, or insisting that, this variation is stable.Quote: In other words, if you wish to describe all adaptation as variation within existing DNA, you have to explain why the bacteria would have the ability to eat nylon prior to nylon having been invented. Why would its genes code for the ability to eat something that was yet to exist for it to eat?

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Gene turned off (dormant) inversion, Gene turned on (active)point mutation followed by deletion. Perhaps chromosomes were designed with the ability to alter genetic material in response to environmental change. Intelligent designer: synthetic material will arise someday as a result of human intelligence designed by me, there may someday be a need for natural means of disposal, Poof --> nylon eating bacteria?

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Intelligent designer: synthetic material will arise someday as a result of human intelligence designed by me, there may someday be a need for natural means of disposal, Poof --> nylon eating bacteria?

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And you think we're too credulous??? And where even, does a bacterium store this DNA in its single copy of a minimal genome?

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However if the environmental pressure were removed would the populations not tend to rebound toward their predivergent state?
Which would tend to eradicate the mutation from the population or store it in a dormant state within the population.

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Yes. The environment has changed (albeit back) so the result
would be for the trait frequencies to re-align. Unless of course
the environmental change lasted for a number of generations, during
which time some or all of the original traits were lost from the
genome ... then there is no going back.Accepting that trait frequencies fluctuate with changing environmental
pressures is something we appear to agree on though.

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If this is the case is it not possible that genetic information has always had messages in dormant states waiting to be turned on when
environmental conditions were right and off when they were not?

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Unlikely when you view the effects of selective breeding.
Traits are picked by the breeder and bred for, resulting in
a huge diversity in, say, dogs. If left to their own devices
(as in Portugal for example, where dog packs roam the streets
reasonably freely and have done so for some time), there is still
wide diversity ... even after much inter-breeding.This suggests that traits are not 'switched off' or 'made dormant'
but are irrevocably changed (although there is some emerging evidence
for re-evolution in insects I believe).

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Yes, selective breeding has led to a vast diversity of
domesticated animals. If left to nature would they not reach a state of equilibrium in their genetic material?

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See above for why I find this unlikely, feral cats in the UK are
another example that springs to mind. They still show the
domestic breed varieties (in various mixtures), but have in some
areas been left to 'nature' for many generations.Selective breeding indicates that changes can be 'selected'
into the genome in a manner that does not allow for an easy
route back to the start point.Of course no new species have been created via selective breeding
(that I am aware of) so that still remains another issue.The implicaiton of mules and ligers, though, is divegence to
the point where biologists would classify the critters as
separate species ... but that's just my opinion.

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Yes there is evidence that tends to lead in the direction of evolution. I just find it hard to promote a theory as fact if the lineage of DNA cannot fully be traced from generation 1 to generation x.

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So, you disbelive all of the implied evidence we have which points to evolution, which is quite strong, because our knowledge is not perfect?We don't have a very good understanding of gravity. There isn't even a single, widely agreed upon Theory of Gravity. We have much, much, much more evidence for and understanding of evolution than gravity. Do you suggest that we not promote the idea that gravity is real?If you have positive evidence for any other scientific theory, please bring it forth.

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If the possible path is discussed and alternative theories are thrown in the student can draw his/her own conclusions based on the method or have an understanding of how to research it further if they choose.

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What alternative scientific theories (with as much or more confirming evidence which agrees across as many branches of science as the ToE) for the origin of species are there?For example, I was taught about Lamarkism (inheritance of acquired characteristics) in Biology as a scientific alternative to the ToE, but even though it is scientific, it does not explain the evidence as well as the ToE.Oh, and here is some evidence for macroevolution:29+ Evidences for Macroevolution: The Scientific Case for Common Descent[This message has been edited by schrafinator, 02-28-2003]