On Mon, 18 Dec 95 13:25:39 MST you wrote:
JF>The Ediacaran fauna is Precambrian (i.e. before the Burgess
>fauna), and quite different from the Burgess Shale stuff, so the
>"failed experiment" explanation is still viable.
SJ>Even before this latest discovery, Gould seems to have been
>backpedalling away from this "failed experiement" line:
>"...The nature of the Ediacaran fauna is now a subject of intense
>discussion. These creatures do not seem to be simple precursors of
>later forms. They may constitute a separate and failed experiment in
>animal life, or they may represent a full range of diploblastic
>(two-layered) organization, of which the modern phylum Cnidaria
>(corals, jellyfishes and their allies) remains as a small and much
>altered remnant." (Gould S.J., "The Evolution of Life on the Earth",
>Scientific American, October 1994, p67).
JF>Hardly a huge backpedal. This supports what I said above. Even if
the second interpretation is the correct one, the Ediacaran fauna is
still "mostly failed", as one part of it gave rise to one of our
modern phyla.
I did not say it was a "huge" backpedal. That it *is* a backpedal is
enough! :-) And it might need to be a bigger backpedal:
"Bruce Runnegar, a paleontologist at the University of California, Los
Angeles, disagrees, however, with Seilacher. Runnegar argues that the
fossil known as Ernietta, which resembles a pouch made of wide-wale
corduroy, may be some sort of seaweed that generated food through
photosynthesis. Charniodiscus, a frond with a disklike base, he
classifies as a colonial cnidarian, the phylum that includes
jellyfish, sea anemones and sea pens. And Dickinsonia, which appears
to have a clearly segmented body, Runnegar tentatively places in an
ancestral group that later gave rise to roundworms and arthropods.
The Cambrian explosion did not erupt out of the blue, argues Runnegar.
"It's the continuation of a process that began long before."
(Nash J.M., "When Life Exploded", TIME, December 4, 1995, p75)
In any event, PC would have no problem with a "mostly failed"
experiment. Judeo-Christian theology contains the idea of a surviving
remnant that results from God's filtering process (2Chr 30:6; Isa
10:21; Jer 44:14,28; Mic 5:3). The surviving remnant from the
Ediacaran fauna may have had an important part to play in the Cambrian
Explosion.
SJ>"The key to the Cambrian Explosion researchers are now convinced,
>lies in the Vendian, the geological period that immediately preceded
>it...no one knows quite what to make of the singular frond-shape
>organisms that appeared tens of millions of years before the
>beginning of the Cambrian, then seemingly died out." (Nash, p74-75).
SJ>Are we talking about *two* pre-Cambrian faunas dying-outs in the
>one area? I doubt it, so I conclude that it is the Ediacaran that is
>being now re-dated and re-named to be continuous with the Cambrian:
JF>S.J. Gould's article on the Ediacaran fauna in "The Flamingo's
>Smile" implies that "Vendian" is another word for the same fauna (it
>is used in the illustration from Seilacher).
Thanks. I have "The Flamingo's Smile" but "Vendian" is not in the
index.
SJ>"We now know," says Grotzinger, "that evolution did not proceed in
>two unrelated pulses but in two pulses that beat together as one."
>(Nash, p76).
JF>I have no idea what this means either.
I think it means that the Ediacaran is now contiguous with the
Cambrian. The diagram shows the Vendian (which now includes the
Ediacaran) as the 20 MY immediately prior to the Cambrian.
This makes Biology's Big Bang even bigger! :-)
The article has a heading called "Beyond Darwinism" in which it says:
"The more scientists struggle to explain the Cambrian explosion, the
more singular it seems. And just as the peculiar behavior of light
forced physicists to conclude that Newton's laws were incomplete, so
the Cambrian explosion has caused experts to wonder if the twin
Darwinian imperatives of genetic variation and natural selection
provide an adequate framework for understanding evolution. "What
Darwin described in the Origin of Species," observes Queen's
University paleontologist Narbonne, "was the steady background kind of
evolution. But there also seems to be a non-Darwinian kind of
evolution that functions over extremely short time periods- and that's
where all the action is." (Nash J.M., "When Life Exploded", Time,
December 4, 1995, p78)
Of course PC would argue that this "non-Darwinian kind of evolution"
that "functions over extremely short time periods" and "where all the
action is", is not "evolution" at all, but rather the result of direct
intervention by an Intelligent Designer at strategic points to bring
about the kind of biosphere He wants.
Happy New Year!
Stephen
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