Wesley R. Elsberry
Posts: 4991
Joined: May 2002
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| Quote (Quack @ June 22 2013,04:54) | | Quote (Wesley R. Elsberry @ June 21 2013,22:02) |
Thanks. Had to add a response to the knee-jerk antievolution response that Matzke is unworthy to comment on Meyer. |
Seems a link to UcD is the ultimate trump card... |
And here's my reply to the comment linking to Uncommon Descent:
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I checked the link, and I concur that it is BS, but the author is clearly stated to be "DonaldM", not Nick Matzke. It isn't like they are similar authors or anything.
It isn't surprising that antievolutionists can't be bothered to acknowledge plain error on their part, such as the blatant but erroneous credentialism Galkat led with. Even when avoiding taking responsibility for error, Galkat persists in going for the ad hominem.
"DonaldM" insists that the figures that Nick used are a bluff and that they convey the same thing Meyer is claiming, which includes the "geologically sudden appearance of complex and novel body plans" with a graph strongly implying that the "sudden appearance" is also *simultaneous* across groups. But even casual reference to the Peterson et al. 2004 Figure 4 that "DonaldM" presented shows that it in no way can be claimed to be saying just what Meyer is saying. For nine groups in different phyla, the graph shows at least six different "first fossil appearance" times spanning some 50 million years. ("DonaldM" claims the figure he notes is the same as the one Nick used in his PT post, but "DonaldM" is wrong: Nick's figure is Figure 2 in Peterson et. al. 2005. Not that it would have much helped "DonaldM" any to have competently identified the figure: it shows 5 separate first fossil appearance times for representatives of 9 phyla spanning about 50 million years.)
"DonaldM" also doesn't bother to quote Nick's summary statement:
"All of this is pretty good evidence for the basic idea that the Cambrian “Explosion” is really the radiation of simple bilaterian worms into more complex worms, and that this took something like 30 million years just to get to the most primitive forms that are clearly related to one or another living crown “phyla”, and occurred in many stages, instead of all at once. But, the reader gets very little of the actual big picture from Meyer."
Nick is clearly taking Meyer to task for Meyer's characterization (or mischaracterization) of the Cambrian period. This needs to be kept in mind as one looks at "DonaldM"'s discussion of a snippet he took from Peterson et al. 2004 as "bilaterans do not have a significant precambrian evolutionary history." "DonaldM" continues:
"Note that Peterson et.al.‘s point is exactly the point that Meyer is making with the diagrams he used. The bilateran body plans found in the Cambrian fossils appear to have no evolutionary history. That is Meyer’s main point in this section of the book. So all of Matzke’s moaning about Meyer’s “oversimplified” diagram is just bluffing on his part. Somehow he thinks that the fancier more detailed diagrams refute Meyer, I guess, when in fact, they’re making the exact same point."
Nick's point, though, primarily concerned the duration and progression of the Cambrian explosion itself, and his graphs do demonstrate that there is not the sort of simultaneity that the figure used by Meyer implies within the Cambrian; "DonaldM" is apparently trying to divert attention away from what Nick *actually* argued to something else. Nor does "DonaldM" do well when we note that his highlighted sentence snippet cannot be be interpreted except in light of what the rest of the article discusses. The "significant precambrian evolutionary history" refers to what uncorrected molecular clock studies proposed, not a blanket statement that there is no precambrian history to the bilateria. Here's Peterson et al. 2004 on the alternative, "significant", precambrian history:
"A number of previous clock studies (reviewed in refs. 3 and 4) have suggested that the last common ancestor of bilaterians (LCB) lived well over one billion years ago (5, 6), whereas others suggest that LCB arose 900 million years ago (Ma) (e.g., refs. 7–10), and still others are more consistent with an origination closer to the Cambrian (11–13). These deep estimates for the origin of LCB raise the question of how hundreds of millions of years of bilaterian evolution can escape detection, given that LCB and its near relatives should have had the capability of leaving both body and trace fossils (14–16)."
And later we have Peterson et al. 2004 saying this:
"Interestingly, both our analysis and the analyses of Aris-Brosou and Yang (11, 12) conclude that LCB evolved 570 Ma and split from cnidarians somewhere between 600 and 630 Ma (Fig. 4)."
The authors of Peterson et al. 2004 can hardly be claimed to have disputed any precambrian history of bilateria when they explicitly provide an estimate of the last common bilaterian having lived at 570 mya, well within the precambrian.
"DonaldM"'s discussion of Nick's deployment of the first figure similarly fails to note what Nick was actually arguing. That figure does show that the evidence within the Cambrian period does show a history of increasing diversity over millions of years. "DonaldM"'s obsession with the precambrian part of the figure ignores the fact that Nick clearly was making a point about the part that was within the Cambrian. "DonaldM"'s self-congratulatory closing is pathetic; Meyer does invoke the Cambrian explosion, so acting as if only the precambrian fossil record has any bearing on things is simply a strawman.
Nick was making a point about Meyer, scholarship, and a responsibility to inform his readers about the actual state of the science. "DonaldM"'s rejoinder is that Meyer didn't need to include detail that did not favor Meyer's argument; ironically, that reinforces rather than rebuts Nick's argument.
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"You can't teach an old dogma new tricks." - Dorothy Parker
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