William Morse  wrote:

> john_SPAM{at}wilkins.id.au (John Wilkins) wrote in
> news:c7hmdm$i0l$1{at}darwin.ediacara.org: 
> 
> > As Eldredge noted, species do not "moremake" in the
requisite manner
> > to be subject to selection. They split, bud and become disrupted, but
> > at the species level their properties are not inherited. The principle
> > of parsimony suggests that if we can account for what happens in terms
> > of a lower-level process (i.e., a population genetic process) then the
> > higher level explanation is otiose.
> 
> 
> It is interesting that both Tim and Jim chose this paragraph with which
> to disagree. While I appreciate the reference to the Darwinian conditions
> for selection, I am chiming in with my disagreement. First, species do
> "moremake", i.e. there are more species produced than survive. We know
> this because the overall number of species has increased over time (if
> you press me I will dig out the reference), yet we know that species go
> extinct. Second, at any level you care to name,  their properties _are_
> inherited, at least in the case of allopatric speciation, which is AFAIK
> generally agreed to be the dominant mode of speciation. The two species
> start off as identical except for geographic location, and it is only
> drift and in some cases differential selection to a slightly changed 
> environment that causes speciation. In my book identical means sharing
> all properties. 

As Eldredge admits, in his _Macroevolution_, the reproduction is not,
really, reproduction. That is why the term "moremaking" is introduced -
cars are made more of, Xeroxes are made more of, but what is lacking,
what is necessary for selection, is the idea of hereditable characters
which correlate with economic success. Do species reproduce in ways that
are successful relevant to their properties?

As to the sampling of gene frequencies - for a start, at least some
models of speciation (Mayr's peripatric, White's stasipatric, and, I
would argue, sympatric) do *not* sample identical alleles and
freqencies. Imagine, as a thought experiment, a species that is
identically divided, and the evolution of which is parallel in each
half. Are they (causally speaking) different species? Obviously not if
they will freely breed and not change alleles when in sympatry again.

Of course it is highly unlikely that isolates would evolve in parallel
even if they were identical to begin with, but leave that to one side.

Consider this illustration. I sample a bucket of pingpong balls of
different colours. Is the sample set the same as the ratio of colours in
the original bucket? Obviously that is dependent on the size of the
sample. Suppose it isn't - has the sample "inherited" its colour
frequencies? Suppose it is - can we say it *did* inherit the
frequencies, or is it a matter of chance? I say chance, and this applies
equally to allopatric speciation.

I think there is nothing about allopatric speciation that suggests that
the frequencies *are* inherited, and all other speciation modes rely
upon them *not* being. Hence the causal relationship between parent and
progeny is insufficiently fixed for selection. And hence it is a sorting
process. We are being misled by language here.
> 
> So we are left (assuming you agree with my first two points, and I 
> suspect you may have a problem with the second) with whether differential
> survival of the excess species is due to the inherited properties. Now
> here is where I agree with half of your argument. The differential 
> survival can be explained by the competition between individuals of the
> different species, based only on individual characteristics. Where I 
> disagree is whether this is the parsimonious explanation. In some cases
> it may be necessary to compare individual differences to determine why
> one species survived in a competition while another did not. But in many
> cases it is simpler to compare differences at a higher level. Komodo 
> dragons do not survive competitions with tigers. For the most part, 
> marsupials do not survive competitions with eutherians. In this case the
> lower level explanation is valid but a waste of time.

That there is comeptition between organisms, or even between
populations, is not objectionable to me. That there is anything about
*species* that allows them to be in competition (again, I wearily state,
*as species*) is. So far I can only see species competing when they are
a single population, or at best a cohesive metapopulation. 

-- 
Dr John S. Wilkins, www.wilkins.id.au
"I never meet anyone who is not perplexed what to do with their
 children" --Charles Darwin to Syms Covington, February 22, 1857
---
þ RIMEGate(tm)/RGXPost V1.14 at BBSWORLD * Info{at}bbsworld.com

---
 * RIMEGate(tm)V10.2áÿ* RelayNet(tm) NNTP Gateway * MoonDog BBS
 * RgateImp.MoonDog.BBS at 5/10/04 1:04:21 PM