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Author | Topic: A test for claimed knowledge of how macroevolution occurs | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1694 days) Posts: 35298 From: Nevada, USA Joined: |
I don't think in terms of "advantage." That's a ToE concept that I don't think carries much weight. I think the lizards developed their larger heads and jaws AND the changed digestive tract without any regard whatever to the food available on the island. The changed digestive tract suggests a principle of parts working together that I have to suppose is built into the design of all creatures, yeah yeah yeah here comes God. I don't usually have to invoke God in these discussions but for something llke this it can't be avoided. ANYWAY, the genetic changes came first and then the lizards gravitated to the tougher kind of food they could now digest easily. Both the softer and the tougher foods had to have been available both before and after their isolation. No selection pressure, none of that. That's all ToE stuff and I've come to be convinced it plays no part in actual microevolutionary change.
They didn't NEED to change at all PK, to cope with the environment that is, they changed because of the gene frequencies possessed by the original ten founder lizards which brought out the new characteristics over generations. Yes this is *MY* krazy wakko model, it is definitely NOT the ToE which I think simply does not explain reality. Reality. REALITY. Some evidence of an indirect sort is that if natural selection by environmental pressure was the cause there simply wouldn't be time for them to develop the new characteristics. Mutations aren't going to arrive on schedule for that purpose, the genetic capacity has to have been there from the beginning. Certainly a whole new digestic tract isn't going to show up on demand. Edited by Faith, : No reason given. Edited by Faith, : No reason given.
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RAZD Member (Idle past 1655 days) Posts: 20714 From: the other end of the sidewalk Joined: |
You aren't going to see much of anything with one gene, ... The example has two genes, each with two alleles.
... it's the mixture of new frequencies of hundreds, thousands of genes, that brings out the new phenotypic picture. ... Why would this be any different? You still are using genes that exist in the parent gene pool, phenotypes that exist in the breeding population, and as the example in Message 580 shows you don't get a new phenotype that is not already in the breeding population -- when you ignore selection, mutation and ecological forces, and you are positing a "homogeneous" parent population (and I think you are misusing that word ... what you mean, I believe, is well mixed, all genes/alleles with virtually the same frequencies). Consider adding a third gene with two alleles to the above example, you would end up with three tables of possible combinations:
Now rather obviously each of these tables would go through the same process generation after generation as in the original example. You don't get a phenotype that is not in the parent population. You don't get a phenotype that cannot breed with the parent population or a similar sub-population.
OR we can add a third allele to one of the genes:
Now, if we consider that an event removes all individuals with the same allele -- say the a' allele -- then you end up with the original example, a breeding population with all phenotypes that exist in the parent population. Yes you have some genetic loss, but you don't have a new phenotype and you don't have a phenotype that cannot breed with the parent population or a similar sub-population -- you just can't get a phenotype that can't breed with the other phenotypes, because you have not created any barrier to breeding within the species/breeding population. It should also be readily apparent that adding a third gene with two or three alleles will not create anything new, just the mild gene frequency shift seen in the original example or variations on it. We can keep expanding the table, but the results will be similar: no new phenotype that never existed before, no new phenotype that is not capable of breeding with the parent population.
... Although you could get a new population with nothing but, say, changed striping, say in a raccoon population that split off from another population, ... The genes for variations in striping would exist in the parent population, and you have not shown that it would create a barrier to breeding.
... in large populations with lots of genetic diversity, like the wildebeests, more than one characteristic is going to change: blue hide, smaller stature, different antlers. The alleles for all those charcteristics are in the larger population but they don't get expressed until a new set of gene frequencies allows them to be expressed in the new population. But you have not shown that they don't or can't get expressed in the original population, (which you posit is "homogeneous"), so there is no reason for them not being expressed -- when you ignore selection, mutation and ecological forces, and you are positing a "homogeneous" parent population (and I still think you mean is well mixed). Throw in selection and ecological forces and you will see more shift the phenotypes, but you still will not get anything that could not exist in the parent population and breed with the parent population. You can achieve a different variety (different populations with different coloration, say) at best, but not a new species. We do see this happening, but not with a result of a new species without a barrier to reproduction. Perhaps the best example for you is the Greenish Warbler, where the original population splits and splits and splits again, with each breeding population being characterized by slightly different coloration and slightly different mating songs -- different varieties. They each have hybrid zones between one population and the next except at the close of the ring, where you have two varieties that do not readily mate (although there are occasional hybrids).
quote: The different genomes show mutations that added or modified alleles not in the original (or previous) breeding populations. That is where new phenotypes arise, and that is where breeding isolation develops. You really should think about this. Enjoy Edited by RAZD, : . Edited by RAZD, : .. Edited by RAZD, : clrtyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Faith  Suspended Member (Idle past 1694 days) Posts: 35298 From: Nevada, USA Joined: |
Yes of course the phenotype, all the phenotypes, are already in the breeding pool, but I'm going to have to come back to discuss this later.
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PaulK Member Posts: 17909 Joined: Member Rating: 7.2 |
quote: I don’t think that rejecting natural selection is really going to help your case. It destroys any analogy to your pigeons which were the result of strong selection. And if you want to insist that it was just drift then you make your story even more implausible.
quote: How did it spread through the population when it offered no advantage, and when it is based on recessive traits as well ?
quote: It’s all an amazing coincidence ? I’m not ready to buy that when the information isn’t in.
quote: As I have said before I don’t think it is either.
quote: If there wasn’t time for the characteristics to spread through selection, then there certainly wasn’t time for them to spread by drift. Drift is slower than selection (as should be obvious). But then, I don’t think that selection is the answer - it’s just a better answer than drift.
quote: I don’t see anyone arguing that they did. I don’t believe it.
quote: A caecal valve seems to be a pretty minor modification, not a ”whole new digestive tract”. You would do better to argue that the changes to the head and the digestive system are independent. Two mutations arriving at just the right time is a lot less likely than one. Except that also undermines your idea that it was drift, and not selection.
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herebedragons Member (Idle past 1107 days) Posts: 1517 From: Michigan Joined:
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- but I'm sure they have very high genetic diversity And your evidence of this is.... that you want or need it to be true to support your argument? But then you go on to say...
again all I can do is point out that to get any kind of domestic breed REQUIRES losing the genetic stuff for all other breeds. So they have low genetic diversity compared to the original population. We have all agreed that this is generally true. What is not true is that changing allele frequencies alone is sufficient to explain the origin of new species. And it simply does not match what is observed.
I honestly do not know what you think you are observing, but I am very very sure it is not what you think it is, or what you think *I* think it is or whatever I actually work with real genetic data from real organisms and do real projects that involve molecular (read genetic) ecology. So yea, we are definitely talking about different things.
You are wrong that I'm ever talking from the genomic perspective So you're not talking about genotypes and you're not talking about phenotypes? You're only talking about allele frequencies that cause populations to look different but this is neither a genetic or phenotypic issue? If there is any confusion of terms, it's you that's confused.
And please do NOT give your genomic perspective... and no I don't want to try to cope with your illustration of changing allele frequencies. In other words... You don't really want a fact based discussion; you just want to continue making baseless assertions and disparage members who don't agree with you. Well... I can post what I want. If you want to ignore it and avoid actual evidence... thats your choice. HBDWhoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for... I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca "Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem. Ignorance is a most formidable opponent rivaled only by arrogance; but when the two join forces, one is all but invincible.
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Percy Member Posts: 22933 From: New Hampshire Joined: Member Rating: 7.1 |
Faith writes: You are wrong that I'm ever talking from the genomic perspective... This isn't true. You frequently include genetics in your posts. Recent examples:
quote: Your posts are peppered with terms like allele, gene and genome. You're constantly making claims from a "genomic perspective." --Percy
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Faith  Suspended Member (Idle past 1694 days) Posts: 35298 From: Nevada, USA Joined: |
So what? You define it all to suit yourself.
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Faith  Suspended Member (Idle past 1694 days) Posts: 35298 From: Nevada, USA Joined: |
I'm guessing about the high genetic diversity of the wildebeests but my evidence is that they rarely form new populations, they remain an enormous homogeneous population, but when they do form a new population, such as the bluish ones, they are distinctively different, showing plenty of genetic stuff to work with.
Oh yes changing gene/allele frequencies is quite sufficient. I'm getting into a bad mood. Time to exit for a while.
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Pressie Member (Idle past 225 days) Posts: 2103 From: Pretoria, SA Joined: |
Faith writes: Actually, there's not a lot of them left in Africa. And they have a very small range left. ...they remain an enormous homogeneous population... Edited by Pressie, : No reason given.
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Taq Member Posts: 10296 Joined: Member Rating: 7.4 |
Faith writes: No population is *perfectly* homogeneous but the wildebeests are pretty homogeneous, both the black herd and the blue herd; No single genome is homogeneous. I don't know of any diploid species where the two copies of their genome in each cell both have the same exact alleles for every gene. I would strongly suspect that you are heterozygous for many alleles.
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Taq Member Posts: 10296 Joined: Member Rating: 7.4 |
Faith writes: Maybe if I write an article I'll discuss all of this, but it's nothing much: only mutations which you believe make new alleles and I don't; Can you please point to a specific allele and explain why it could not be produced by mutations? Which differences are you saying could not be product of mutations? Can you show us a single difference between the chimp and human genomes that mutations could not produce? If not, then your claims fall flat.
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Taq Member Posts: 10296 Joined: Member Rating: 7.4 |
Faith writes: I'm guessing about the high genetic diversity of the wildebeests but my evidence is that they rarely form new populations, they remain an enormous homogeneous population, If they have high genetic diversity then they aren't homogeneous. I don't think you understand the meaning of those words. Edited by Taq, : No reason given.
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Percy Member Posts: 22933 From: New Hampshire Joined: Member Rating: 7.1
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Faith writes: Percy writes: Faith writes: You are wrong that I'm ever talking from the genomic perspective... This isn't true. You frequently include genetics in your posts. So what? I guess I have two reactions to this. First, that saying "so what" in the face of blatant error is just so, uh, Faith. And second, it seems necessary to make the point again. You denied to HereBeDragons that you ever employed a "genomic perspective," yet I was able to quote you speaking from a "genomic perspective" a number of times. You can't avoid discussion of genetic issues by claiming that you never discussed them previously, because that is obviously untrue.
You define it all to suit yourself. There you go with the pronouns again. What does "it" refer to? You're just exhibiting the same old Faith. When you paint yourself into a corner then you incite confusion and diversion. Bottom line: You have obviously discussed things from a "genomic perspective." Please go back and answer HereBeDragons' Message 583 forthrightly, or as most us of would describe it, from an "honest perspective." --Percy
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Faith  Suspended Member (Idle past 1694 days) Posts: 35298 From: Nevada, USA Joined: |
Including genetics in my post isn't the same thing as arguing from the genomic perspective, I'm always arguing from how you produce new phenotypes. That's by reducing genetic diversity but I don't get into the genomic stuff that others here are getting into, I just point out that to get new breeds in breeding same as to get new species you have to lose the genetic material for the other breeds or species. I don't get into Mendelian squares or strings of codons. I figure everybody knows that breeds are created by losing the genetic stuff for other breeds. You choose not to mate with animals that don't have the traits you want. That is NOT arguing from genomics. I don't get into what's going on with the alleles etc.
Edited by Faith, : No reason given. Edited by Faith, : No reason given.
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Taq Member Posts: 10296 Joined: Member Rating: 7.4
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Faith writes: Including genetics in my post isn't the same thing as arguing from the genomic perspective, I'm always arguing from how you produce new phenotypes. That's by reducing genetic diversity That's false. You get new phenotypes by mutation. The step where genetic diversity is lost is during the selection phase which comes after the emergence of the new phenotype. A great example of this process is seen in the Lederberg plate replica experiment. In this experiment they select for antibiotic resistance. The mutations that confer antibiotic resistance happen early, and are only later selected for. Just a moment... Before selection you have a lot of variation caused by mutations, and a lot of phenotypes. When you apply selection, in the form of antibiotics, you reduce variation, but also selection for the pre-existing new phenotype.
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