>what exactly do you mean by "fully developed"? They were complete animals.
>Incomplete animals usually don't survive beyond the zygote stage.
I shouldn't have said 'developed', since I was talking about evolution,
not development. And 'fully' doesn't have much objective meaning.
If the geological record tells you the anatomy of the Cambrian fauna
arose through the same slow processes of subsequent evolution, then
nobody's going to convince you otherwise.
>>The
>>rapid origin of the basic body plans is a mystery, why not enjoy it? Why
>>assume it happened gradually, when the evidence does not support this?
>
>Are we to assume that things "were different back then"? What compelling
>reason do we have to assume that?
The evidence shows that before the Cambrian, predators were far less
sophisticated. In this context, radical mutations could have a chance.
>>Since that creative period, zero new basic body plans have evolved.
>
>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.
>...
>Especially since that sliver-like thing is the ancestor of frogs,
>elephants, dogs, ostriches and ourselves.
How can you assert this? Is it because Pikaia resembles a vertebrate
embryo? No way, you don't believe in recapitulation theory. Because
they are simple creatures, and vertebrates are complex? No, because
you know that evolution can proceed by reduction. Is it because you
can trace the course of evolution from Pikaia to vertebrate in the
fossil record? No. Is it because you know how it must have happened,
how Pikaia sprouted segmented limbs etc? No. You're working on faith.
>There were a lot of open niches in the pre-Cambrian that are now filled.
As you say, 'Are we to assume that things "were different back then"?'
Niches are biotic, not geological. No organisms, no niches. I don't think
there's much point in theorizing about niches in the abstract.
>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.
Simply because it's the emergence of a new level of anatomical complexity,
the level that has persisted ever since.
>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.
Isn't it conceivable that a creationist could put forth something sensible
or worthwhile? Creationists are free to consider and criticize evolutionary
theory, more free than those who must argue for gradualism where the
evidence doesn't support it.
Cliff Lundberg ~ San Francisco ~ cliff@noe.com