the phylogeographic challenge to creationism

There is another mechanism that may be in play with introduced species which doesn't necessarily apply to normal evolutionary processes.In the study of foraminifera by Arnold and Parker
Geology Dept article 3They had the opportunity to observe speciation explosions after the KT extinction event, and saw a proliferation of species diverging to fill the different foraminifera niches: It seems to me that some (by no means all) introduced species are different enough from the native {flora\fauna} that they are in a "partial vacuum" situation and thus can diversify in a similar manner.

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

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RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
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Unfortunately the fossils in the geologic column don't represent evolved creatures but simply what had been alive at the time of the Flood which wiped them all out at once from the bottom of the "column" to the top.

well, if that's true, we should expect to not see things that look like ancestral forms.

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אָרַח

Just for the record, what other mechanisms besides speciation are there by which genetic structure arises between populations? Meaning what exactly? Does "genetic variance" = "genetic diversity?" Or are you simply talking about the normal inherited changes from generation to generation or what? I don't think so. The reduction is slow and gradual until a certain extreme reduction in population is reached, but is nevertheless a reduction. I understand creationism to imply an initial genetic richness that even after the severe bottleneck of the Flood was still very rich by our standards now, so that many geographic dispersals would not cause a genetic problem for many many generations. I know current genetics doesn't recognize this, but creationists expect it to be shown eventually to be the case. Diversification in former times did not produce the drastic reductions we see now -- and still doesn't in all species for that matter -- but nevertheless the trend IS to reduction overall. Mutation is not a source, or at least not a major source of variation, according to creationism. I don't think that would be inconsistent with what I'm saying, but I'm not sure what you mean. Please explain. Do you mean INCREASE in genetic variability? Are you talking about the production of new phenotypes or what? And how is this measured? I really don't understand what you are saying. Is this "diversity" the same as the "variability" of the above paragraphs? Why should I be surprised at this if I understood what you are saying? That this diversity exists doesn't seem to have anything to do with the subject, or at least not be anything that challenges what I've been saying, but perhaps I'm just not understanding. But the very fact of BEING a migrant (sub)population means at "best" a shuffling of allelic frequencies, most likely in a larger population as you say, so that all alleles of the parent population are still present but probably in different proportions, and at "worst" the loss of some alleles altogether (left back in the ancestral population), which would be a reduction in genetic diversity, more likely in a smaller migrant population but nevertheless possible in a larger one. An INCREASE in genetic diversity doesn't occur in any case, whether phenotypically the migrant population changes slightly or dramatically. Increased DIVERSITY would mean an increase in kinds of alleles, and that doesn't happen unless something else adds them, such as mutation. How is "polymorphism" different from "more alleles and variable loci?"I can't see how migration or local adaptation could build up lost heterozygosity.

It isn't.TTFN,WK

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Interesting. So from that 85% variation present theoretically their descendants could approximate 85% of all the other human types present now? Could you get absolutely genetically disease-free offspring?

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It depends on what you would consider disease. I am not being evasive but if you have a slight sickle cell blood phenotype but are resistant to malaria infection, is the sickle cell a disease or an adaptation?
In any case, the 85% would only exist at the moment of the destruction of the rest of the world. From the first baby born after that event, the diversity would increase as each baby carries new mutations.

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I haven't mentioned my faith on this topic. Interesting how evolutionists can't leave it alone. I also haven't said mutations don't increase genetic diversity. I have reserved it for later discussion. If you insist on answering things I have not said I don't see any discussion left to continue.

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I brought up your faith because you have mentioned several times the "creationist" position which is a faith based position, contrary to the evidence which provides no testable or falsifiable hypothesis i.e. it is not science.

Ok, This will have to be one of my last posts for the next week. I have to deal with some students and am flying oversease to give a lecture. Mick, Wounded King and others can take over from me.

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You just won't acknowledge all the processes that subtract, obviously. You want to keep emphasizing increase. No discussion is possible then.

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No, this is exactly the opposite of the truth. I both acknowledge processes that lower genetic diversity and am much more familiar with them than you. YOU deny the processes that increase genetic diversity that act during every successful reproduction event which is why the discussion is hanging.

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This is how creationists think about "speciation." It's not some ad hoc invention. How can there be discussion if you refuse to treat it with respect.

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Science is not about respect. It is about testable falsifiable hypothesis and the gathering of data and observations that either support or refute those hypothesis. If you want "Kinds" to be taken seriously, please start a thread and provide a definition and the processes involved in their generation.

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What does this have to do with the processes of speciation that were the subject? Once you have two entirely different groups a lot has happened since the point of "speciation." Again you change the subject. There is no reason that there can't be two breeds of a Kind that differ drastically from each other and remain breeds of that Kind.

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It has everything to do with speciation. The processes that separate distinct genera such as Asian and African elephants, or chimps and humans are demonstrably the same as those that separate you from me. Calling them all the same kind is again useless since it is a completely non-descript term..it is like calling them all animals.

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No you have a reduction in the GENETIC possibilities, the number of alleles in the population, not the number of phenotypes.

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Nope that is wrong. My father has a different phenotype and genotype from me. We both exist in the population. Genetic and phenotypic diversity was increased the day I was born. It will again increase when I have kids since they will not be the same as me either...and I don't plan on dying the second my child is born. One genotype does not disappear when another arises.

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I am assuming no such thing. I've said the parent species changes too on the same principles if the removed part of the population was large enough to affect it. Again, it's not the number of phenotypes but the genetic diversity, the range of genetic possibilities that is decreased, and I've acknowledged many times that it is not ALWAYS decreased, but that this is an overall trend that is only fully exemplified at the extremes.

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But you are saying that. You say that each speciation event is a reduction event yet closely related species show great diversity with novel diversity appearing each generation...there is no trend towards decrease. The overall trend does not exist unless you can show the studies and observations in nature that support this I would suggest you drop this fallacy.

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Evolutionists DO assume genetic descent [from one Kind to another]partly because there has been no barrier demonstrated against genetic descent from one Kind to another.

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This is not my question. What is the evidence that you can provide that shows a genetic barrier? It would actually have to be multiple barriers that have arisen multiple times since EVERY SINGLE creature on earth uses the same kind of genetic inheritance mechanism differeing only by the nucleic acid they use (DNA or RNA). What evidence do you have for a barrier? Why have thousands of scientists over the last 150 years never found any such evidence?

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You have asserted it many times and not yet acknowledged it but it is not wrong. Mick acknowledged it and breeders know about it.

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No, you are saying you want to focus on events that reduce genetic diversity (emphasis on focus) and then claim that this is the only situation..reduction of genetic diversity. If that was the case, you would not have to FOCUS on it since it would be the only subject possible. You are misunderstanding Mick if you think he is agreeing with everything you say but I think you are overstating breeders concerns. Do you realize how hard it is for breeders, plant or animal, to keep their lines genetically homogeneous? Dog breeders have to maintain such rigid programs of breeding to fight against the unwanted diversity that creeps in and ultimately they fail. Diversity still creeps in even in so called pure bred lines. Why do you think cloning is so hot among breeders? It is one of the few ways one can get an identical genetic copy...though even "clones" have some differences since they to, have to replicate their genomes...you cannot escape mutation...it generates diversity all the time...breeders know this so it is a poor example for you to use to support your point.

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I simply want the SUBTRACTING PROCESSES clearly recognized. They are SEPARATE PROCESSES FROM MUTATION.

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Hate to disappoint you but you cannot get such a clear separation and you cannot even separate these proceses because of repair enyzmes and other mechanisms that work to increase or decrease the mutation rate. But again, this should be in a different thread. Science is not about fullfilling preconcieved notions..it is about dealing with the way nature is and trying your best to explain why. Not believing that something is simple and trying to fit nature to your simple model.

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What does that have to do with the subject? I have found dozens of online NONCREATIONIST discussions about the genetic situation of the cheetahs. I'm not making this up.

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It has everything to do with the subject. You are overstating the case of the cheetah. They are exceptional among Felidae in lack of genetic diversity. That is not the same as having no genetic diverstiy and not the same as losing genetic diversity. If anything they are gaining diversity because of both conservation programs based on maximizing the genetic diversity they have and its natural increase that you deny can occur.

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This needs tons of detailed explanation of what exactly you are referring to. It is meaningless as stated. But it is another topic for another thread.

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It is not meaningless..if you were correct, that mutation could not add to diversity or that as a result of speciation genetic diversity worldwide would be reduced, 1) all life would have become extinct from the beginning 2) if you separated to populations they would just increase in numbers as clones with no increase in genetic diversityNiether 1 or 2 has been observed thus you thesis is disproven.

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What a Kind is cannot be determined because it was established 6000 years ago. Since then many branches of each have become extinct. Tracing it has become very difficult. Why this need to impute motivations to your opponents? (scared therefore inflate...)

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Sorry, but there is not a shred of evidence that species were established 6000 years ago. In fact, there is only evidence that most species are much much older, (genetic, morphological, and radiochronological)...in fact, the only species that are 6,000 that I can think of off the top of my head are a few cichlid species. So this is not only an assertion without evidence but one that contradicts reality.
In fact, if all species had originated 6,000 years ago, it should be extremely easy to sort them out genetically into distinct groups. But this is not the case.

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What processes are you talking about? Who said they didn't occur in the past?

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Because if you propose that different species cannot share common ancestry i.e. chimp and human then you have to propose a supportable reason why, when, and how genetic inheritence was suspended in the past.

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This is nonsense. Who ever said "genetics was suspended in the past?" This is the most bizarre straw man ever. You mean because we believe there was an original creation? Genetics has proceeded as usual since then, nobody denies it.

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No it is not nonesense and in fact the strawman you claim I am constructing you state as such in your fourth sentence. Special creation directly states that genetics had to have been suspended at each and every taxanomic level you wish to define as a kind. You are on the one hand agreeing to the relatedeness by descent for individuals among and within species, genera and further i.e. manatee and elephant but then turning around and claiming that the identity by descent is false because of special creation. Sorry, but you have to provide a compelling testable hypothesis that hereditary descent was suspended at some or multiple points in the past by "special creation". This is what is missing by creationists...a testable, falsifiable hypothesis of special creation that better explains the data than genetics and identity by descent. There is positive evidence for descent with modification including direct observation...creationists have never presented any other than to claim it is a part of their religious dogma.

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This is getting so ridiculous it's pathetic. EXCUSE me, I'm talking about MANY MANY GENERATIONS of breeding never producing anything but a variation on the original creature. Can't you fill in the details yourself or do you just have to think creationists are such idiots you don't bother?

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You have a lot of misundertandings about basic genetics...so it was not completely apparent to me that nobody would expect a dog to give birth to something else. Dog breeding is a lousy example the breeds are strenuously maintained.....put them all in the wild and see which dog breeds reproduce with one another. In any case, there are plenty of examples in plants, insects and in mammals with faster reproductive cycles like mice of novel species evolving..even radically different ones....and mick's chipmunk example is a good one. If speciation is a continuous process..at what point will you say that a dog is no longer a dog? Is a fox a dog? Is a wolf a dog? a coyote? Let me put it this way, if I wanted to, I could breed dogs for reproductive isolation from one another...but this is not the aesthetic that breeders have been shooting for.

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Because "at the levels we observe directly" all you can see is that kinds produce kinds -- and I guess I have to add that this is all you see even if you can produce thousands of generations. It is simply a terminological trick that defines variation as "speciation" implying "macro" evolution.

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No, kinds are a terminlogical trick. Species, genus, family, etc. are all well thought out terms to provide a way for people to determine a relative genetic/phenotypic difference between groups of organisms that have gene pools that interact to different measurable extents. No trick involved at all. Just one method of creating a terminology that is useful for scientists when they are studying nature and describing their results to one another.Kinds is a non-descript term that shifts by the preferences of the person using them. You have called all my examples just kinds...so genetically distinct gene pools such as Asian elephants, African elephants, manatees are a kind...this is lumping in completely different taxanomic units (most of which cannot even interbreed and are not morphologically very similar in some cases) to the point that nothing can be distinguished from anything else....which would also mean lemurs, baboons, chimps and humans are just a human kind...no real differences there..just variation within a "kind"..not at all useful. And to be honest, it is just a trick..creationists are so desparate to deny that evolution occurs you would probably include viruses in the same "kind" as humans if the definition would further your argument. Not to be mean but I have heard kind defined as low as hjman chimp all the way out to "carnivores"...might as well just call it the Earth gene pool.

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Let me put it another way, from forensics, I can show that I am the direct descendant of my mother and father genetically. I have no idea who my great great great great grandfather was. There are no records of him. No name. No physical evidence. Should I assume that he did not exist and that he did not contribute to the lineage leading to me? Why or why not?

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Straw man.

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No, it is not a strawman...it is your, and all creationists, argument against evolution. You claim that the process I described in forensically associating myself with my unknown grandfather ancestor is not applicable to higher taxanomic levels...you state this by claiming special creation..or some creationists claim individual special creation events. Yet ironically, you do not claim that I am the result of a special creation event that dates back to the point where I can no longer positively identify my ancestors from a direct record. Why? Your position is completely inconsistent. The data without fail supports a standard genetic model of identity by descent. But that does not explain how a creationist can reconcile the belief that they are related to their unobserved great great great grandparents genetically but not to chimpanzees, etc.(after all chimps and humans are no more distant from each other than African and Asian elephants). You either should believe you are always poof banged into existence with no relation to anybody or accept that genetics is valid. You can't have it both ways.

this is a non-sequitur to my post faith.denial is not evidence either.

Only addressing part of this post for now: Just for the record, from a creationist point of view, nothing would ever have become extinct if it hadn't been for the Fall which brought death into the world. The point of the cheetah example is that it represents an extreme of "evolution" through the Evolutionary Processes (founder effect, natural selection, bottleneck, etc). All of them split populations, all of them produce new phenotypes in the process, all of them reduce genetic diversity in the separate populations as part of the process of producing the new phenotypes.Mutation is the only "evolutionary process" that doesn't. Or epigenetics as Modulous suggests. For later discussion.The familiar definition of Evolution: Evolution by this definition ought to be falsified by the fact that most changes in the frequency of alleles in a population do correspond to a reduction in genetic diversity (ignoring mutation's effect for the moment), which is hardly what would be expected if an evolutionary direction were in fact occurring via these processes.At the very least the processes are misnamed, and evolution on the basis of them misconceived. t appears more and more that evolution has ONLY mutation to rely on, and the definition really ought to be changed to reflect this fact as the current definition doesn't describe Evolution but Devolution, to less and less genetic diversity with each change in the phenotypic picture of a population all the way out to drastic genetic depletion and the threat or actuality of extinction. This is the TREND of all these processes that change the frequency of alleles. Yes, there are stable populations, and recombinations that do increase the number and frequency of alleles, but OVERALL, as a TREND, no, the direction is to reduced numbers of alleles, and reduced diversity, therefore reduced possibility of further change, reduced adaptability, the opposite of evolution.Again, ONLY mutation counters this overall trend it seems to me, and if everyone will recognize that this trend of reduction in diveristy exists, THEN we can talk about whether mutation actually has what it takes to counter it to the degree necessary to produce evolution out of devolution. In other words evolution really really NEEDS mutation, doesn't it? All the processes called evolutionary aren't and that pretty much leaves mutation. Yes, I understand the basics here. Although this is for a later discussion about mutation, I'd like to know how you are so sure that this "thick fur" gene (or any gene) originated by a random process. Do you merely ASSUME it or do you think you KNOW it? Has the acquisition of such a useful allele been OBSERVED? If it has been observed, how would you know if it had or hadn't appeared many times in the population already? Yes, I'm very sure that without mutation evolution has no hope. But on this thread I'd really really really like to isolate the OTHER processes, the subtracting processes, the selecting processes, the populating diverging and reducing processes, etc., so that their inevitable overall trend to genetic reduction is acknowledged, by the very processes that are defined as "evolutionary." You are right, I see it now."How the alleles got there" does seem to be exclusively understood by evolutionism to be explained by mutation. Not necessarily "low" genetic diversity but simply LOWER as reduction is the trend. All I'm saying is that I want the processes that select and subtract clearly acknowledged as such, and THEN we can discuss the effect of mutation and epigenetics, because otherwise evolutionists merely blur the two together and it is impossible to see that all these subtractive processes are called evolutionary processes though they couldn't possibly lead to evolution. I quoted the concerns of wildlife managers in my post to DBlevins. I also have tried to avoid saying EVERY new phenotype, as some are formed by recombination of alleles when previously split-apart populations merge. But all the examples given by Mick in the OP of new chipmunk types were created by the fact that they split off from the parent population with a reduced number of alleles. I think if one removes mutation from the picture just for the purpose of thinking this through it becomes obvious that all the other processes either merely shuffle or reduce alleles, but don't add anything.

Thank you, that's what I thought.

Not a non sequitur. When it comes to the fossils there is no evidence possible RAZD, it's all a matter of interpretation, so I gave you mine. If we're talking genetics we have to stick to living things.This message has been edited by Faith, 12-05-2005 01:31 PM

Mammathus, I really think you need to get your priorities right

This will have to be a short post as I have a final paper draft due toady and class, so here it goes. I wonder if you actually read through the complete articles or picked and choosed what you wanted to paste. I also wonder if there is not some cognitive dissonance working here (IE you read it but unconsciously picked and chose what portions to paste without attempting to understand the article.)The article you quoted goes on to say that you should be careful to distinguish how you measure genetic diversity.

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Finally, Avise (1994) notes that the level of genetic diversity in one marker class (e.g. allozymes) may not reflect genome-wide diversity. It is important to distinguish among measures of genetic diversity. For example, inbreeding (here connoting mating between relatives) within a population will reduce observed heterozygosity but does not alter overall allele frequencies. In other words, all else being equal (and ignoring possible purging of deleterious alleles), such inbreeding reduces one measure of genetic variability (observed heterozygosity) while the other (allelic diversity) remains the same.
  —Canadian Wildlife service

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(my bold.)And as far as Evolution is concerned, you are correct in stating that it is change in frequency of alleles over time. This is also something you conveniently seemed to gloss over in your use of the link you provided. Namely:

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Genetic drift: The genetic make-up of a population may change over time because of chance differences in the survival or reproduction of individuals with different genotypes and sampling errors of gametes from one generation to the next ” this process is known as random genetic drift or simply genetic drift...

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Changes in allele frequencies via genetic drift are entirely at random; thus, different populations within a species may follow independent evolutionary trajectories. In other words, genetic drift alone can result in evolution (a change in allele frequencies), although only natural selection produces adaptive evolutionary change...

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While genetic drift leads to a decrease in genetic diversity over time, it is still also an evolutionary constructive process. Which addresses your point below: In short, evolution, described as the process of the change in allelic frequency over time, still occurs without mutation via genetic drift. The caveat being that without mutation and natural selection you don't adapt to environmental changes and eventually go extinct.

My post was about the explosion of species when there is a vacuum to fill, the fossils are irrelevant to the argument really, but substantiation for those of us who like it.The topic involved was the observed increase in diversity in introduced species (to areas outside their natural occured area)They too could experience a similar {vacuum\fill} response if they are different enough from the native {flora\fauna} of the area introduced into, such that they could 'explode' into the introduced area. examples: rabbits in australia, starlings in america.(Both of these species (and others) btw demonstrate the mechanims of punk eek whereby a new species can suddenly appear in a short time, where the founding population is small and where the formation of the new species has not been recorded.)If they are not confined to as small a niche as they were previously then they can respond with greater diversity before natural selection pulls in the reins.

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

​

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

Hi Faith, Speciation is not a mechanism, it is an event. It is a grade of genetic structure. All of the articles I cited were based on analysis of the frequency of heterozygotes. They were measured as F statistics as explained in a previous post. If you argue that the structuring of populations results in subpopulations that have less heterozygosity than their ancestral gene pool, then the observation of high heterozygosity within human races is WHOLLY inconsistent with your argument. And the observation of migrant populations which are more heterozygous than ancestral populations in various plants and insects is also WHOLLY inconsistent with your argument. Well you could provide some evidence for that assertion. Well, of course, mutation does inded provide new alleles. If a gene mutates, then it is either identical to an allele that already exists in the population, or it's a new allele. When local adaptation occurs, this often results in strengthened barriers to hybridization (i.e. this article). AS for the idea that being a migrant population means "at best a shuffling of alleles" and not the origin of new ones; all you have to do is imagine a mutation occuring in one gene of one member of one migrant population. I just don't see why this is supposed to be impossible. This is PRECISELY what appears to have happened in the myelitus example linked a few lines previously.What mechanism are you proposing for the salinity adaptation of these myelitus species other than mutation?MickThis message has been edited by mick, 12-05-2005 05:21 PMThis message has been edited by mick, 12-05-2005 05:23 PM