"The evolutionary history of the largest salamander family (Plethodontidae) is characterized by extreme morphological homoplasy. Analysis of the mechanisms generating such homoplasy requires an independent molecular phylogeny. To this end, we sequenced 24 complete mitochondrial genomes (22 plethodontids and two outgroup taxa), added data for three species from GenBank, and performed partitioned and unpartitioned Bayesian, maximum likelihood, and maximum parsimony phylogenetic analyses. We explored four dataset partitioning strategies to account for evolutionary process heterogeneity among genes and codon positions, all of which yielded increased model likelihoods and decreased numbers of supported nodes in the topologies (Bayesian posterior probability >0.95) relative to the unpartitioned analysis. Our phylogenetic analyses yielded congruent trees that contrast with the traditional morphology-based taxonomy; the monophyly of three of four major groups is rejected. Reanalysis of current hypotheses in light of these evolutionary relationships suggests that (i) a larval life history stage reevolved from a direct-developing ancestor multiple times; (ii) there is no phylogenetic support for the "Out of Appalachia" hypothesis of plethodontid origins; and (iii) novel scenarios must be reconstructed for the convergent evolution of projectile tongues, reduction in toe number, and specialization for defensive tail loss. Some of these scenarios imply morphological transformation series that proceed in the opposite direction than was previously thought. In addition, they suggest surprising evolutionary lability in traits previously interpreted to be conservative."
Spin doctors needed.
- Thread starter bob b
- Start date
Stratnerd
New member
I don't get it...
If there's "extreme morphological complexity" then we expect trees based on morphology to be misleading since characters in such analysis are supposed to be markedly apomorphic; that is informative. And this is a case where it's obvious they weren't (based on analysis)
As for the characters "[the analyses] suggest surprising evolutionary lability in traits previously interpreted to be conservative." - another conclusion based on analyses. :yawn:
Now if you think that the evolution of these traits is difficult then how do you explain their rapid post-flood evolution since these species are all probably from the same type?
Or just tell us what we're supposed to get from this [another] uncited post.
If there's "extreme morphological complexity" then we expect trees based on morphology to be misleading since characters in such analysis are supposed to be markedly apomorphic; that is informative. And this is a case where it's obvious they weren't (based on analysis)
As for the characters "[the analyses] suggest surprising evolutionary lability in traits previously interpreted to be conservative." - another conclusion based on analyses. :yawn:
Now if you think that the evolution of these traits is difficult then how do you explain their rapid post-flood evolution since these species are all probably from the same type?
Or just tell us what we're supposed to get from this [another] uncited post.
Last edited:
Why am I not surprised?
That's easy. They didn't "evolve".
Why would you assume that?
I don't give citations until after the evolutionists in training commit themselves regarding the competency of the authors of the article or its content. That helps keep them more honest in their comments.
Well it was only a couple years ago when Stratnerd was deemed "TOL's thickest skull".
aharvey
New member
Ah, there's that slippery YEC definition of "evolution" again. Specifically, I've wondered how folks can so confidently assert that there's "no evidence for evolution." Here at TOL, my first surprising answer was that for at least some YECs, this is achieved by defining evidence to be information consistent with a literal interpretation of the Bible. Therefore, by definition of the term evidence, there can be no "evidence" for evolution!
The second approach is similar except that it defines evolution itself out of existence.
1. You vigorously insist that small-scale changes "have nothing to do with evolution." In fact, you explicitly exclude changes within "created kinds" from the concept of evolution, thereby restricting your concept of "evolution" to "changing from one created kind to another." As has been mentioned by many people in this forum, this is not what scientists mean by "evolution," so in let's refer to this version of "evolution" as "Evolution-CK."
2. By "created kinds," you mean "independently created kinds." So created kinds by definition do not share a common ancestor.
3. Therefore, Evolution-CK cannot occur! This appears to be the essence of the entire YEC case against evolution.
Well, guess what, folks? No scientist on the planet would disagree that premises 1 and 2 above lead inescapably to the conclusion (#3) above! It's a trivial conclusion. I could just as easily prove that life does not exist by defining it as an attribute of dead things only (since dead things are by definition not alive, then life cannot exist!).
At best, all you've done is change the wording of the dispute between evolutionary biologists and YECs. How many independent originations of life were there? Evolutionary biologists say one, based on life's shared basic biological systems (you know, DNA, cells, tissues, organs, metabolism, oxygen-carbon dioxide respiration, etc.). YECs say ____, based on ______. I'm still not at all clear how to fill in the blanks.
You're obviously not familiar with plethodontid salamanders, are you?
Now there's a backhanded insult, er, assertion for which I'm sure you have lots of supporting evidence! Ah well, if that's what you're going to claim, then how about providing the entire article so we can evaluate its content? It's hard for us to make honest comments on material you're withholding from us. Also, you might want to give some indication of when this paper was published. The Plethodontidae is such a peculiar group of salamanders that they have attracted a lot of attention, and there have been, over the years, a rather large number of phylogenetic analyses based on a variety of different data sets and techniques. Older papers in systematics tend to suffer from limited character sets, limited taxonomic coverage, and inappropriate analytical techniques. The problem, ironically, is more severe in molecular studies.
You called my definition "slippery", but the fact is that you evolutionists are the slippery ones, for you use multiple definitions of the term and pick and choose as it suits your devious purposes, whereas I am the consistent one in always identifying that when I use the term "evolution" I am always referring strictly to the "protocell to man" paradigm.
aharvey
New member
Well, on the one hand, we've already discussed this, and in fact most of what you call "definitions" are not definitions per se, but either corollaries or predictions of evolutionary theory. For example, "protocell to man" is something that follows from evolutionary theory, it is not the definition of the term itself. The remaining various definitions (e.g., descent with modification, changes in gene frequencies within a population) are not internally inconsistent with each other, nor with the various corollaries and predictions of the theory.
Your definition doesn't even make any sense. Does this mean, for example, that the concept of evolution doesn't apply to plants? After all, they aren't exactly in the protocell to man trajectory.
How, exactly, does the "protocell to man" paradigm follow from evolutionary theory? The proposed theoretical mechanisms of evolution predict no such sequence. It is only when the mechanisms are applied exhaustively to the pattern of life on earth that we get the conclusion that they are responsible, however in such a case it only follows as a matter of definition, because it is contained in the premise. In other words, bob b is quite right to refer to it as a legitimate defintion of the theory of evolution, since it only follows inasmuch as it is assumed.
Last edited:
davidgeminden
New member
Hi,
Those that are interested in some of the latest creationist thoughts on genetic variability might like to read the article titled “Gentic Variability by Design� written by Christopher W. Ashcraft. The article is found at http://www.nwcreation.net/articles/recombinationreview.html ). I have copied the abstact of the article below.
“Abstract
Although most genes remain unchanged from one generation to the next, others are highly variable (hypervariable) in comparison, and new alleles are accumulating rapidly in living populations. Cellular mechanisms have not been adequately sought to explain the intentional production of these changes, but it is becoming clear that homologous recombination is involved. Since its discovery during meiosis, these reactions were assumed to occur randomly along the length of chromosomes, and only involved with gene crossovers. It is now well known that meiotic recombination is not the random process it was originally assumed to be, and controlled by highly organized regulatory systems. In addition, a form of homologous recombination has been discovered that is responsible for creating diversity in variable genes, and was recently linked to single base-pair substitutions in immunoglobulins. New allele formation may indeed be the key to explaining the rapid production of distinct breeds, but their presence in the genome has been assumed the result of random mutations. Therefore, the ability of the cell to purposefully edit genes requires evaluation.�
David G.
Those that are interested in some of the latest creationist thoughts on genetic variability might like to read the article titled “Gentic Variability by Design� written by Christopher W. Ashcraft. The article is found at http://www.nwcreation.net/articles/recombinationreview.html ). I have copied the abstact of the article below.
“Abstract
Although most genes remain unchanged from one generation to the next, others are highly variable (hypervariable) in comparison, and new alleles are accumulating rapidly in living populations. Cellular mechanisms have not been adequately sought to explain the intentional production of these changes, but it is becoming clear that homologous recombination is involved. Since its discovery during meiosis, these reactions were assumed to occur randomly along the length of chromosomes, and only involved with gene crossovers. It is now well known that meiotic recombination is not the random process it was originally assumed to be, and controlled by highly organized regulatory systems. In addition, a form of homologous recombination has been discovered that is responsible for creating diversity in variable genes, and was recently linked to single base-pair substitutions in immunoglobulins. New allele formation may indeed be the key to explaining the rapid production of distinct breeds, but their presence in the genome has been assumed the result of random mutations. Therefore, the ability of the cell to purposefully edit genes requires evaluation.�
David G.