Creationism is beside the point, and Darwin's explanation is probably
far off the mark in many cases. Ross Mayhew couldn't have expressed the
relevance of this discussion more clearly:

> ...   ... has been
> replaced in the mainstream scientific community over the past few
> decades, by an extremely diverse range of opinions and approaches to
> speciation: "puctuated equillibrium", where rapidly changing
> environmental conditions on a local, regional or even global scale
> favor
> and promote the equally rapid development of new species...  ...

Rather than seeking competition as an explanation for close --or not so
close-- differences in species,  it would be far more useful for
malacologists to more systematically seek out and catalog niche factors
affecting a particular species --things like water chemistry, frequency
of extremes in weather & salinity variables, other species associations
especially at the micro level (e.g., type a frequency of diatom
blooms), etc.

Developmental plasticity and morphological switches are now well known
across just about every phylum, and in numerous cases these phenomena
have led to misidentifying genetically identical organisms as separate
species. Such epigenetic switches are the result of  chemical/physical
factor(s) triggering a control gene somewhere in the developmental
process. Offspring can often revert to ancestral form when the
triggering factor disappears. These are more or less everyday
phenomena. What we usually lack is enough information about particular
niches, that would enable us to see what is actually going on.

Burt Vaughan
Evolutionary Biology
WSU-TC

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