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To: Ha Ha Thats Very Logical; CottShop; Coyoteman
==What you and your chortling buddies overlook, in your zeal to nitpick fragments of the evidence Coyoteman referred to, is that the various lines of evidence come together to support each other’s dates. Dendrochronology, radiocarbon dating, and historical information all give the same results...

Sorry Ha Ha, the historical record is replete with global folklore that all point to a global flood; even the experts in the field of dendrochronology recognize that it is notoriously unreliable, and radiocarbon dating is often calibrated using dendrochronology; moreover, radiocarbon dating does not take into account what the C14 to C12 ratio would have been before a global flood (for instance, what would the C14 to C12 ratio have been if the organic matter buried under the earth, estimated to be 175 times as large as the organic matter in our current biosphere, was deposited there by a global flood?); and finally, the paper Wiley posted acknowledges that there are serious problems with the mtDNA clock. Indeed, the authors of the paper Wiley cited as evidence against the Noahitic flood admit that previous dating estimates using mtDNA were too old by up to four fold! But the Evos are also encountering other problems with the mtDNA clock. For instance, scientists have discovered that mtDNA mutates at a rate up to 20 times faster than previously thought. Thus, according to the faster mtDNA mutation rates, the date of our most recent common ancestor (MRCA) would have to be reduced from 133,000 years ago to around 6,500 years ago! Of course, the Evos can’t have that, as the following makes clear:

“The rate and pattern of sequence substitutions in the mitochondrial DNA (mtDNA) control region (CR) is of central importance to studies of human evolution and to forensic identity testing. Here, we report a direct measurement of the intergenerational substitution rate in the human CR. We compared DNA sequences of two CR hypervariable segments from close maternal relatives, from 134 independent mtDNA lineages spanning 327 generational events. Ten substitutions were observed, resulting in an empirical rate of 1/33 generations, or 2.5/site/Myr. This is roughly twenty-fold higher than estimates derived from phylogenetic analyses. This disparity cannot be accounted for simply by substitutions at mutational hot spots, suggesting additional factors that produce the discrepancy between very near-term and long-term apparent rates of sequence divergence. The data also indicate that extremely rapid segregation of CR sequence variants between generations is common in humans, with a very small mtDNA bottleneck. These results have implications for forensic applications and studies of human evolution.

The observed substitution rate reported here is very high compared to rates inferred from evolutionary studies. A wide range of CR substitution rates have been derived from phylogenetic studies, spanning roughly 0.025-0.26/site/Myr, including confidence intervals. A study yielding one of the faster estimates gave the substitution rate of the CR hypervariable regions as 0.118 +- 0.031/site/Myr. Assuming a generation time of 20 years, this corresponds to ~1/600 generations and an age for the mtDNA MRCA of 133,000 y.a. Thus, our observation of the substitution rate, 2.5/site/Myr, is roughly 20-fold higher than would be predicted from phylogenetic analyses. Using our empirical rate to calibrate the mtDNA molecular clock would result in an age of the mtDNA MRCA of only ~6,500 y.a., clearly incompatible with the known age of modern humans. Even acknowledging that the MRCA of mtDNA may be younger than the MRCA of modern humans, it remains implausible to explain the known geographic distribution of mtDNA sequence variation by human migration that occurred only in the last ~6,500 years.”

http://www.ncbi.nlm.nih.gov/pubmed/9090380

431 posted on 01/23/2008 6:01:52 AM PST by GodGunsGuts
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To: metmom

See #431. I think I feel some more chortling coming on! LOL


432 posted on 01/23/2008 6:10:21 AM PST by GodGunsGuts
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To: GodGunsGuts
I have been reading your posts right along--you don't need to repeat your points.

even the experts in the field of dendrochronology recognize that it is notoriously unreliable

Could you show me something that supports that contention? I did a fair bit of reading about dendrochronology last night before I posted, and I didn't notice any widespread mistrust of the method. I did find one crackpot who forced very young bristlecone pines to grow extra rings under greenhouse conditions, but that's all.

for instance, what would the C14 to C12 ratio have been if the organic matter buried under the earth, estimated to be 175 times as large as the organic matter in our current biosphere, was deposited there by a global flood?

Can you explain to me why that would make a difference? From what I know of radiocarbon dating, it's based on the amount of C14 a given organism absorbs during its lifetime, and C14 originates in the atmosphere. How would the amount of buried matter affect that?

The paper you cite is interesting, but I can't find any more of it than you quote--and I can only find the second paragraph in an article on a creationist website. On the one hand, I've followed enough links to creationist websites to know they often post incomplete or out-of-context excerpts; on the other, I bet someone's done some work in the 10 years since that experiment was conducted to shed some light on the discrepancy. But since I don't have access to the entire original paper nor to any followups, I'll just acknowledge that that one 10-year-old experiment did reveal an apparent discrepancy.

I will point out, though, that this discrepancy was published in one of those peer-reviewed evo journals that are supposed to ruthlessly suppress any evidence that would challenge the Church of Darwin--to hear creationists tell it. How do you suppose this slipped through?
437 posted on 01/23/2008 8:33:21 AM PST by Ha Ha Thats Very Logical
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