>That's not exactly true. Perhaps you overlooked this:
>
>"Our own phylum (which we share with other mammals, reptiles,
>birds, amphibians and fish) was represented by a small, sliver-like thing
>called Pikaia. Plants were not yet present. Photosynthetic protists and algae
>were the bottom of the food chain."
>
>Aren't plants a new "body plan"? Rather radically different from algae.
>Also I think in the last 500,000,000 years we have come a long way since
>the "small sliver-like things" that represented our phylum in the Cambrian.
>Yes we are still vertebrate tetrapods, but saying (or implying) "and
>nothing new has happened since then" is astonishingly inaccurate--at best.
>Especially since that sliver-like thing is the ancestor of frogs,
>elephants, dogs, ostriches and ourselves.
>
>>This implies that a qualititatively different kind of evolution triggered
the
>>Cambrian explosion.
>
>There were a lot of open niches in the pre-Cambrian that are now filled.
>There have been other "explosions" after the Cambrian and die-offs also. I
>really don't see why the Cambrian is supposed to be so special.
>
>>>The UCSB website is creationist propaganda.
>>
>>As I was the first to point out, but so what? The topic was 'Cambrian
>>Explosion, yes or not really?', a scientific question.
>
>It was an explosion, but it took 65,000,000 years to "explode." You said
>the site seemed "creationistic" but you said that "the quotes are good."
>I'd like to know why you said that.
Some quotations from an article in Time magazine (When life exploded, TIME,
12/5/95 http://ucaswww.mcm.uc.edu/geology/huff/When_Life_Exploded.html) on
the origin of the Precambrian metazoa are instructive : The article pointed
out that all animal
phyla except perhaps bryozoa are present in early Cambrian, and that they
all appear
within a very small slice of time ("no more than 10 million years")
Steven Gould of Harvard: (paleontologist) "Fast is now a lot faster
than we
thought, and thatās extraordinarily interesting"
Samuel a Bowring, M.I.T.(geologist): "We now know how fast fast is, and
what I
like to ask my biologist friends is, How fast can evolution get before
they start
feeling uncomfortable?"
Rudolph Raff, Indiana U. (biologist): "There must be limits to change.
After all
weāve had these same old body plans for half a billion years."
G. M. Narbonne, Queens U. (paleontologist): "What Darwin described in the
Origin of Species 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 thatās where all the action is."