William Morse  wrote:

> john_SPAM{at}wilkins.id.au (John Wilkins) wrote in
> news:c7o7jd$2jr0$1{at}darwin.ediacara.org: 
> 
> > William Morse  wrote:
> > 
> >> john_SPAM{at}wilkins.id.au (John Wilkins) wrote in
> >> news:c7hmdm$i0l$1{at}darwin.ediacara.org: 
> 
> > 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?
> 
> Thnaks for the clarification, At first I thought Eldredge might have been
> objecting to the idea that the number of species has increased over time,
> which has been a bone of contention. As I understand it now, his 
> objection is your objection - that even though species create other 
> species, those other species do not inherit anything that affects their
> success as a species. 

Now why can't *I* say things that well? Put it down to philosophical
training - never say anything so simply you can't get at least an
article out of it explaining what you meant...
>  
> > 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 understand the concept of sampling. The problem is that sampling is a
> population genetics concept, and that may be  irrelevant to the question,
> which is an ecological niche concept. Remember (I know that you know the
> history a minimum of 16.3 times better than I do) that Darwin and Wallace
> came up with the concept of evolution without any knowledge of genetics.

But not of inheritance. Genes are merely the proximate mechanism of
heredity. They could not have developed their conceptions (plural; they
did not agree entirely) without understanding that parents and progeny
resemble each other because they inherit some substrate that makes them
have the traits they do.

In fact, it is my opinion that the word "gene" does not apply to
evolution except as a placeholder for hereditable traits. But that's
another oddity for another time...

> The fact that they did this is an argument that the genetics is not 
> necessary to the argument. It adds to our understanding in many cases but
> in other cases (such as this) is only obfuscating. My point was that, at
> the time of their geographic isolation, both populations shared the same
> niche. Until the niche changes, whether or not they share the same 
> genetics (we know that thanks to drift they will not), both populations
> will remain substantially identical (with respect to the niche) other
> than that they may no longer be able to interbreed (I can explain how
> this can occur based on gene duplication, but I would prefer not to waste
> the time at this point). I understand quite well that sympatric 
> speciation requires niche differentiation, which is why I noted the 
> difference between sympatric and allopatric speciation, which you appear
> to not have understood based on the following paragraph: 
> 
>  
> > 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.

I understand and approve of sympatric speciation models through resource
adaptation and sexual selection. But it is still slightly controversial
despite Berlocher's work, and I am already treading on toes...
> 
> 
> As I explained above, the frequencies are a red herring. What is 
> important is the niche, and that is initially conserved in allopatric
> speciation but not I think in the other cases. Sympatric speciation would
> seem to require niche differences. 

Actually it isn't conserved under allopatric models - Mayr in particular
makes great play of the argument that isolated populations are at the
extreme of the range of the main species, and will tend to have
divergent niches and ecological pressures to the centre of the range,
from which introgressive breeding will spread to ensure the genetic
cohesion of the original species. Please don't make me go and find this
in the literature :-(
> 
>  
> > 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.
>  
> Others have answered this, and I think in general we have pretty much
> flogged the subject to death. I understand that you do not think the fact
> that a species consists of individuals that fly means that I can include
> the species in a set of "flying species". So even though I can 
> demonstrate that "flying species" are more likely to
colonize islands and
> undergo subsequent speciation, this will not imply species selection. I
> disagree on the grounds of utility, but your position appears to be 
> logically consistent, and you show no signs of being convinced by any of
> the rest of us who have argued against that position. 

Nope. I am resistant to all argument :-) 

This is, I think, a matter of what we consider to be a selection
process. There is a backstory here that I should perhaps have given.
Suffice it to say that I think selection involves

1. Reproduction (at the extreme of fidelity, replication, but I am not a
strict Dawkinsian on this, and am persuaded by Wimsatt that reproducers
are the "primitive" concept type);

2. Interaction - what is reproduced must be economically significant;

3. A selective regime - there must be sufficient constancy of selection
pressures (a phrase I dislike, BTW); and 

4. A population large enough for competitive advantages between variant
forms to exceed sampling errors

and each of these must operate at the level of the reproduction of
traits.
> 
> Note that Wilson has argued that species that have mechanisms that damp
> out population fluctuations (which is at least selection at the 
> population level, since individuals cannot exhibit fluctuations in 
> population size) will tend to go extinct less frequently than species
> with large swings in population size. It is not clear to me that this
> characteristic will be reliably inherited by daughter species, so I am
> reluctant to press this issue too hard.

Which Wilson? E.O is a proponent of the superorganism conception of
species, which I do not like muchly. Or David Sloan, whose ideas I am
happier with in this respect?

-- 
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
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