[ExI] Multiplicity of similar species: what's the mechanism/explanation?

[Max More]

The Angry Evolutionist
By Richard Dawkins
http://www.newsweek.com/id/216140

(1) Dawkin says: "My favorites, however, are the 
free-living turbellarian worms, of which there 
are more than 4,000 species: that's about as 
numerous as all the mammal species put together."

That made me think again about the curious fact 
(I least I think it's a fact, without checking) 
that there are vastly more species of insects 
(especially ants) and arachnids as there are 
mammals or "more complex" creatures. I realized 
that I don't really know why that's the case. 
Right now I'm too lazy to try to find an answer 
in my biology books. I can make some guesses 
(like "a simpler/smaller genome varies more, and 
each variant finds sufficient room in the same 
ecological niche"), but I'd like to hear if there 
is a well-developed and compelling explanation.

(2) A quite different thought from the foregoing: 
Why isn't Dawkin's question (in his 8th 
paragraph) answered (at least somewhat plausibly) 
by creationists with this?: "Because tapeworms 
have no skeleton" I'm not sure he can really 
conclude that "This argument, at a stroke, 
completely and finally destroys the creationist 
case that the Precambrian gap in the fossil 
record can be taken as evidence against 
evolution." -- until he addresses the skeleton point.

Indeed, right after Dawkin's has made his argument, he comments:
"Probably, most animals before the Cambrian were 
soft-bodied like modern flatworms, probably 
rather small like modern turbellarians­just not 
good fossil material." Dawkins (rightly) says the 
creationists can't have it both ways, but isn't 
he having it both ways here? He's (a) using the 
tapeworm example against the creationists -- a 
case that seems to require that we should expect 
ready fossilization despite their lack of a 
skeleton, and also (b) explaining the gaps in the 
fossil record on the basis that most pre-Cambrian 
creatures (or "evolutures"!) were "soft-bodied".

Of course, I'm very sympathetic to Dawkins, but 
his argument, as presented, bothers me. Am I missing something?

(For the record, I have read no book and not much 
else by Dawkins since The Selfish Gene. Has 
anyone yet read his latest: The Greatest Show on 
Earth: The Evidence for Evolution?)

Max


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Max More, Ph.D.
Strategic Philosopher
Extropy Institute Founder
www.maxmore.com
max at maxmore.com
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