In a message dated 10/15/2000 2:18:29 PM Pacific Daylight Time,
sejones@iinet.net.au writes:
Now the rest of the story on the Cambrian 'explosion'
http://home.flash.net/~mortongr/cambevol.htm
"This view is widespread among young and old earth creationists. But is it
true in light of modern data? What I will attempt to show in this note is
that the ‘gaps’ in the evolution of Cambrian life forms are now being
filled in by data obtained over the last 15 years; much of this data
coming in within the past 2 years. While there are older interpretations
of the Precambrian animals as being totally unrelated to modern
animals(such as Seilacher's Vendozoan hypothesis), the newer data is
showing evidence of relationships between the Ediacaran fauna and that of
the early Cambrian. We will look at the evolutionary sequences which lead
from Precambrian worm-like creatures to the arthropods, molluscs,
brachiopods, and annelids, four different phyla."
"ABSTRACT Molecular studies have the potential to shed
light on the origin of the animal phyla by providing indepen-dent
estimates of the divergence times, but have been criticized
for failing to account adequately for variation in rate of
evolution. A method of dating divergence times from molec-ular
data addresses the criticisms of earlier studies and
provides more realistic, but wider, confidence intervals. The
data are not compatible with the Cambrian explosion hypoth-esis
as an explanation for the origin of metazoan phyla, and
provide additional support for an extended period of Precam-brian
metazoan diversification."
Proc. Natl. Acad. Sci. USA Vol. 95, pp. 12386–12389, October 1998
Evolution. Testing the Cambrian explosion hypothesis by using a molecular
dating technique. LINDELL BROMHAM* † ,ANDREW RAMBAUT*, RICHARD FORTEY ‡
,ALAN COOPER § , AND DAVID PENNY ¶
Or
"This study suggests that the evolutionary history of both cnidarian
and bilaterian forms may extend many millions of years deeper in
Precambrian time than previous direct evidence so far indicates.
But this is only a beginning. Continued exploration of these
high-resolution phosphorite deposits may revolutionize palento-logical
insight into the evolutionary origins of animal forms."
PNAS u April 25, 2000 u vol. 97 u no. 9 4457–4462. Precambrian animal
diversity: Putative phosphatized embryos from the Doushantuo Formation of
China Jun-Yuan Chen* †‡ , Paola Oliveri †§ , Chia-Wei Li ¶ , Gui-Qing Zhou*,
Feng Gao*, James W. Hagadorn i , Kevin J. Peterson § , and Eric H. Davidson ‡§
"Still, in spite of the uncertainty about the exact dating, it seems to be
clear that the major evolutionary inno-vations did not occur suddenly as it
might seem from the fossil data alone."
TIG February 1999, volume 15, No. 2. Diethard Tautz
"Second, the topology of the tree suggests a new inter-pretation
of the famous Cambrian explosion that we have
described elsewhere 22 . Briefly, instead of a single radi-ation,
the topology suggests that at least three independent
events (corresponding to the diversification of the
lophotrochozoans, ecdysozoans and deuterostomes) have
occurred in a poorly diversified stem lineage. It follows
that animal diversification cannot be due to a single
‘genetic revolution’ but, instead, must have been triggered
primarily by external factors acting on a ‘pre-adapted’
(meaning possessing many features prone to further spe-cialization
or functional co-option), already genetically
complex metazoan. How long before the Cambrian the
initial protostome/deuterostome split occurred is still a
matter of harsh debate 26,27 , but even a conservative
estimate 27 suggests a long precambrian history of these
two branches."
Animal evolution the end of the intermediate taxa? André Adoutte et al. TIG
March 1999, volume 15, No. 3
> This fall, there has appeared a scientifically authoritative book casting
> grave doubt on the whole basis of these confident illustrations. Dr.
> Jonathan Wells, a molecular and cell biologist from the University of
> California at Berkeley who is a senior fellow of the Discovery Institute,
> in
> his Icons of Evolution does more than cast doubt.
>
> He takes 10 so-called "proofs" of evolution offered in current textbooks
> and shows where not one of them is in a fact a proof of anything, and
> several are actually frauds.
>
> The speckled moths were actually pasted on the trees, not found there.
> And while there may be rare instances of species that seem part ape, part
> human, there is no evidence the one came from the other.
>
It's fascinating how Wells seems to continue to ignore reality here. Majerus
own data show that moths are found on trees. That sometimes for illustrative
purposes moth were 'pasted' on trees does not diminish the importance of the
peppered moth.
From Evolution 53 (3), 1999, pp. 980-984, by permission of the Society for
the Study of Evolution. FINE TUNING THE PEPPERED MOTH PARADIGM Bruce S. Grant
Department of Biology, College of William & Mary, Williamsburg, VA 23187-8795
"Industrial melanism in peppered moths remains one of the best documented and
easiest to understand."
> Why, you wonder, do scientists ascribe credibility to these proofs?
> Because, says Wells, every scientist specializes. He may be aware the
> particular "proof" offered in his own area of expertise is fundamentally
> flawed, but he assumes those in all the other areas are not. In fact, he
> says,
> they all are.
>
>
Are they? So far that seems hardly self evident and even contradicted by
actual fact.
SE: Now, says Behe, we have opened the box; we can see how the
cell is constructed. It's about as simple as a jet engine. It is a
masterpiece
of design. There is no possibility, none whatever, he says, that it could
have come about by mere happenstance
Interesting assertion especially since Behe suggests otherwise. Has Behe done
his homework and shown that such particular routes cannot exist? Nope.
"One can never completely rule out such an indirect route, which is
tantamount to proving a negative. However, the more complex the
system, the more difficult it becomes to envision such indirect
scenarios and the more examples of irreducible complexity we meet, the
less and less persuasive such indirect scenarios become. It cannot be
that everything in life started out as something else.
" Behe, "Intelligent design theory as a tool" , pp. 179
It is clear that there is a problem for IC/ID here, if natural pathways
cannot be excluded beforehand then IC is not a reliable detector
of design. We can perhaps for individual IC systems try to show that the
possibility of a Darwinian (or non-Darwinian) pathway is diminishlingly small
but ICness itself is not a sufficient indicator of design anymore.
[...]
Behe:
"That definition has the advantage of promoting research: to state clear,
detailed evolutionary pathways; to measure probabilistic resources; to
estimate mutation rates; to determine if a given step is selected or not. It
allows for the proposal of any evolutionary scenario a Darwinist (or others)
may wish to submit, asking only that it be detailed enough so that relevant
parameters might be estimated. If the improbability of the pathway exceeds
the available probabilistic resources (roughly the number of organisms over
the relevant time in the relevant phylogenetic branch) then Darwinism is
deemed an unlikely explanation and intelligent design a likely one. "
[...]
So does Behe provide us with probability calculations showing the likelihood
of intelligent designed pathways? Nope.
"At no step --not even one-- does Doolittle give a model that includes
numbers or quantities; without numbers there is not science."
Behe pp. 95 Darwin's Black Box
SE: Both these books follow an earlier one by Berkeley law professor Philip
Johnson whose Darwin On Trial put the theory of natural selection before
a make-believe jury, and gave the evidence for it as it would be presented
in court. He shows how the supposed evidence, all of it, fails to vindicate
the theory.
Johnson's failure to comprehend evolutionary claims and their evidence has
been addressed by many including Lamoureux. Science is not decided in courts
using reasonable doubt, science is decided by the facts and the power of the
hypotheses to explain these facts.
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