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Author | Topic: The End of Evolution By Means of Natural Selection | |||||||||||||||||||||||||||||||||||||||
Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0 |
Welcome back Faith
You are right Faith. Genetic bottlenecks do reduce the number of alleles available in a population. The most extreme form of genetic bottleneck, in sexually reproducing species, involves just one breeding pair, which means that the largest number of alleles available of each gene is 4 (not counting multiple copies of the same gene). Selective breeding is an example of this kind of bottleneck, although breeders often breed in from other lines that also have characteristics they want. Many of the species that have conservation biologists concerned today are going through a genetic bottleneck. Without human interference to reduce the selective pressures in nature they will go extinct, in fact, many species have gone extinct in the recent past. IN FACT, every species that has ever gone extinct has gone through a genetic bottleneck, unless they were all wiped out in some cataclysm. Extinction is obviously the usual outcome of genetic bottlenecks, but sometimes species do survive and eventually build up to thriving populations again. Large breeding populations will usually have a Gaussian (bell curve) distribution of the alleles for any given gene. A sub-populations will likely also have a Gaussian distribution, but the frequency for any given allele may be different from the other population. If there is a fantastic allele in the new population that confers higher survival and reproductive success, but that is in low frequency, it will still take it many, many, many generations to reach high frequency in the population and it will probably never reach 100%, because while it is increasing in frequency, new alleles are also appearing through mutation. If the new sub-population is really small and the number of alleles for the gene of the fantastic allele is reduced it may indeed come to be the only allele for that gene. The likely outcome for this population though is still extinction because there is just not enough variability to cope with all the selection pressures that nature throws at it. If this population does beat the odds and thrive, new mutations (alleles) of the fantastic gene may appear, and if they are not lethal, they will remain in the population which increases the variability of that gene. Through this whole thread you have been arguing a hypothetic scenario where you focus on the variability of one gene and what happens to it in various instances, i.e. bottlenecks, selective breeding, isolation, speciation, etc. You say this ALWAYS leads to a reduction of variability and an end to evolution, but when we look at the bewildering variety of life on this planet that is not what we see. We only see it in species that are on the brink of extinction, and I am not saying that there are not a lot of them, because in the Human era there are. You are right, in bottlenecks genetic variability is reduced and if evolution comes to a dead end the species goes extinct. The same would be true with selective breeding, especially when we only breed within the variety (Dobermans with Dobermans, etc.), but humans intervene and keep them from going extinct. Your repeated denial of the reality of mutations and that they are the source of all alleles and genetic variability is just plain silly. You have not given a single shred of evidence to support your assertions, only your own incredulity. Mutations are one of the underlying basic principals of genetics. Genes mutate it is a LAW OF GENETICS! Your repeated assertions the we do not understand your hypothesis are incorrect. We understand exactly what you are saying, but the narrow range of situations where there is reduced variability in a few alleles cannot be extrapolated to the whole genome or to all species. The phenotype of a species includes all the variation in the whole population (or sub-population) and it can be represented by a Gaussian distribution. The genotype of a species includes all the alleles for all the genes in the whole population (or sub-population) and it also can be represented by a Gaussian distribution. Enjoy What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0 |
Hi Buz,
Buzsaw writes: Isn't this bordering on circular reasoning, Tanypterix, interpreting observation of the bewildering variety of life as evidence for evolution, evolution being the assumed agent of bewildering variety I was not saying that the bewildering variety was evidence of evolution. I was using bewildering variety as a flowery way of saying there is a really large total number of species and when we look at the majority of them we do not see evidence of the reduction of genetic variation within each individual species that Faith is claiming. Sorry that I was not clearer, I guess flowery prose is not my forte.
Buzsaw writes: given the aggregate biodiversity of species is declining? I am not sure what this means, but if you mean that lots of species are going extinct, then I agree that that represents a decline in total biodiversity, especially within the vertebrates. At the same time, we are conducting a huge experiment by introducing non-native species around the globe, opening new habitats for them to diversify into, without the predators that normally act as forces of natural selection, but this is off topic. What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0
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I have read all the way through both of the Biology threads that Faith has been posting in. My level of frustration has been increasing the further this goes on.
She is just making shit up. Not once has she posted any evidence to back up this drivel. Not once has she posted a single reference. Quite a while back RAZD posted (message 240) a very detailed explanation why her her scenario cannot explain what we actually see in ring species and she just blew him off. It is clear she did not understand it.
Faith is clearly not here to learn anything. She whines that we just don't understand what she is saying. The crap she says just is not that complicated. It is just wrong and not supported by a single scientific study in the history of science. She accuses scientists, biologists, evolutionary biologists, science itself of lies and fraud.....repeatedly. Several dozen participants have put a lot of thought and effort into responses to her, trying to correct the glaring errors and made up shit that she spews and her response is just more made up crap. She is exactly the same agent of chaos on this forum that she was 5 years ago and she has not learned a thing or changed one iota since then. Faith is a TROLL and a damn good one! She suckered all of us into wasting our time reading her drivel and responding. What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0 |
Hi Faith,
You have repeated this many times.
Faith writes: It's the thousands of known genetic diseases in human beings that belies it to my mind. Thousands of known genetic diseases in human beings? Do you have a book or something that lists all these thousands? Can you list 100? Or even 50? Can you give us a credible reference? thanks, What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0
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Hi Faith,
faith writes: If that is really the case in your example then you don't have anything remotely approaching speciation, no new variety, no real change, which is another subject from the one I am pursuing. My argument is about the changes that isolation produces in new populations. Your scenario does not have anything remotely approaching speciation, no new variety, no real change. Can't you see that your isolated population is just a sub-set of the parent population? It has almost all the same genetic makeup of the parent population. Isolation alone is not going to create a new species (populations that cannot or will not interbreed). The only thing that will make a new species is enough new genetic differences building up in both populations to interfere with them interbreeding. Reshuffling the genetic mix in the new population will not be a genetic barrier because they are still the same genes (alleles) that were there when the population was one. Your scenario does not introduce the change necessary for speciation.
I also suggested that it IS possible for the daughter population to take 100% of the individuals in the parent population that possess a particular allele, thus robbing the parent population of that allele completely. This may be possible, but the probability that this would happen with many (a lot of) genes is very low. Since the population could interbreed just fine before those alleles were removed, can you explain how this would suddenly create a barrier to interbreeding? The probability that the removal of any specific allele would interfere with interbreeding is very low. It takes a long time for two populations to become so genetically diverse that they can no longer interbreed and can be considered separate species. It certainly is seldom, if ever, caused by differences in just a few genes. thanks. What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0 |
Hi Faith, thanks for the reply.
Faith writes: But even that many compared to the number of known positive benefits of mutation in humans is staggering. Really? How many positive benefits of mutations are there that you are comparing against? I am not sure how many genes there are in humans (somewhere between 20,000 and 30,000 estimated from the human genome project, I think). When you add in all the alleles for each gene it must be a pretty big number. Compared to how many known genetic diseases? So you think that almost all mutations cause genetic diseases, but most of us (Humans) do not have any noticeable genetic diseases and geneticists (the people who actually study and know something about genetics) estimate that, on average, every human has between 60 and 100 mutated alleles. These are alleles that are not found in either of our parents. Can you produce any evidence or research that refutes these findings?
compared to the number of known positive benefits of mutation in humans is staggering. What is staggering is the 20,000 to 30,000 genes, times all the alleles for each, that are functioning in the human population without causing genetic diseases, compared to the few mutations that cause genetic diseases without being lethal. Every one of those functioning alleles is the result of a mutation. What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0
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Hi Faith,
Faith writes: It's a population with new gene frequencies because of the isolation itself. I don't see why YOU don't see THAT. Drift can bring about speciation, migration can, selection can and so on. I DO SEE THAT, but I disagree! The change in gene frequency does not cause speciation. THEY ARE THE SAME GENES THAT WERE ALWAYS THE IN THE ORIGINAL POPULATION ACCORDING TO YOUR SCENARIO. They are just a sub-set of the original population's genes. They are still the same species. Once again, the change in gene frequency does not cause a new species! In your dog breeding examples the breeders have only isolated a few genes for the traits that they are breeding for. The rest of the genes in their variety are still dog genes. For example you have the Doberman specific genes and the rest of the genome is dog genes. For the record, the simplest definition of evolution is the change in allele frequency in a population from generation to generation. That is evolution. The differences from generation to generation are partly caused by mutations of alleles. Speciation is also part of evolution that happens when two populations have accumulated enough genetic changes. For the life of me, I do not know why I am continuing to respond to you. And I don't understand why you are participating here at EvC. Are you proposing a new scientific hypothesis of genetics and you want our input before you publish and win the Nobel prize? Or do you just like to argue even if you do not understand the basics of the subject? Are you trying to learn something about a subject that obviously interests you? Are you trying to actually convince us that you are right?
What do you want? What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 10.0
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I think the saddest part of Faith's short participation here is the amount of effort she put into defense of a flawed argument.
If she put that much effort into studying the actual science of genetics and what geneticists and evolutionary biologists have discovered from their research she could have understood why it makes so much sense to them. Instead she grabs little shreds of information from numerous sources and creates an odd composite idea of how biology and genetics works that does not fit a single example of what can actually be observed in all of the many thousands of species that have been studied in nature and the laboratory. She endlessly repeats her fantasy idea with out once supporting it with actual observations of actual populations of organisms while dismissing every single example of evidence that contradicts her. She would be the perfect example of a really bad scientist, (who defends a flawed argument, no matter how much the evidence shows she is wrong) if she actually knew anything about science. Fortunately, that type of scientist really only exists in really bad movies about scientists. She does not let her ignorance of any subject stand in the way of her desire to spout gibberish about her concocted fantasies over and over while she mis-understands and misinterprets every response from those who disagree with her. Surprisingly, she lasted a week longer than I thought she would and left a lot of us (who were drawn to read her threads like moths to a flame) with headaches. What if Eleanor Roosevelt had wings? -- Monty Python You can't build a Time Machine without Weird Optics -- S. Valley
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