[Taxacom] almost unbelievable (advisory)

Tue May 19 19:35:39 CDT 2020

Hi Rich,

All very reasonable questions:
1) Do you think your assertions concerning miraculous assumptions of chance
dispersal for the origin of allopatry apply to marine organisms as much as
they do to terrestrial organisms?

Yes. Just as allopatry occurs in birds which fly, so too does allopatry
occur in marine organisms. Like aerial and terrestrial organisms, some are
widespread, some are not. But there are certainly numerous examples of a
geographic structure (sometimes much to the surprise of researchers) in
marine taxa. Examples are covered in various publications by Heads. This
geographic substructuring has often been found through molecular studies
where previously morphological studies suggested very widespread
amorphous species.

2) Does 1966 (over half a century ago, mind you) really count as "modern"
in the context of biogeography? Especially when you consider that the
theory of Plate Tectonics didn't really start to become accepted widely
until a series of papers published around 1965-1967.

Modern in the sense that appeals to miracles and mysteries are still made
in recent times. Agreed, Carlquist was further back, but the same outlook
prevails. Plate tectonics was not necessary to take a different approach
(Croizat's findings came before plate tectonic theory provided
corroborating geology), and most biogeographers simply pasted their centers
of origin and chance dispersal theories onto the new tectonic geography (if
they thought their taxon was old enough).

I really don't want to start a debate (and I will not engage in one), but
I'm waiting for a server to update some software before I can get back to
my real job, so I figured I'd take a short break from that to understand
your position a little better.

No worries. Happy to clarify as needed. I just keep bringing these matters
to attention for those interested - regardless of their particular
perspectives for or against.

And to everyone, whether for or against these posts (hence the warning at
the beginning as I know the subject is irritating [or I am irritating :] to
some), best wishes for staying safe as possible at this time.

John Grehan

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On Tue, May 19, 2020 at 8:18 PM Richard Pyle <deepreef at bishopmuseum.org>
wrote:

> Hi John,
>
> I've been careful to dodge this particular/recurring [pan]bio[geography]
> discussion, in large part because, well, the discussion seems so
> "terrestrial" in nature.  But I'm going to stick my neck out on a  limb
> here, and ask you two specific questions:
>
> 1) Do you think your assertions concerning miraculous assumptions of
> chance dispersal for the origin of allopatry apply to marine organisms as
> much as they do to terrestrial organisms?
>
> And
>
> 2) Does 1966 (over half a century ago, mind you) really count as "modern"
> in the context of biogeography? Especially when you consider that the
> theory of Plate Tectonics didn't really start to become accepted widely
> until a series of papers published around 1965-1967.
>
> I really don't want to start a debate (and I will not engage in one), but
> I'm waiting for a server to update some software before I can get back to
> my real job, so I figured I'd take a short break from that to understand
> your position a little better.
>
> Thanks, and Aloha,
> Rich
>
> Richard L. Pyle, PhD
> Senior Curator of Ichthyology | Database Coordinator
> Bernice Pauahi Bishop Museum
> 1525 Bernice Street, Honolulu, HI 96817-2704
> Office: (808) 848-4115;  Fax: (808) 847-8252
> eMail: deepreef at bishopmuseum.org
> BishopMuseum.org
> Our Mission: Bishop Museum inspires our community and visitors through the
> exploration and celebration of the extraordinary history, culture, and
> environment of Hawaiʻi and the Pacific.
>
> > -----Original Message-----
> > From: Taxacom <taxacom-bounces at mailman.nhm.ku.edu> On Behalf Of
> > John Grehan via Taxacom
> > Sent: Tuesday, May 19, 2020 2:04 PM
> > To: taxacom <taxacom at mailman.nhm.ku.edu>
> > Subject: [Taxacom] almost unbelievable (advisory)
> >
> > Dear colleagues,
> >
> > Please do not read any further if biogeographic differences of
> perspective or
> > critiques are uncomfortable for you.
> >
> > As has been documented in the literature, the assumption of chance
> > dispersal for the origin of allopatry periodically generates 'miracles'
> and
> > 'mysteries' in the very words of the various authors. Despite this
> leaning
> > towards mysticism, faith in chance dispersal continues to be well
> > entrenched, and in recent decades bolstered by the charade of fossil
> > calibrated divergence estimates. An addition to this mysticism comes from
> > Carlquist (1966) in his exposition on long-distance dispersal (Q Rev.
> Biol.
> > 41) where he declares “A clear understanding of long-distance dispersal
> is
> > essential to an understanding of evolutionary trends on oceanic islands,
> > because immigrant patterns are different from relict patterns.” All very
> well,
> > until he runs into the land snail genera Tornatellides, Elasmias, and
> Partula.
> > He describes these as having “almost unbelievable distributions”.
> > Almost, but not quite it would seem. He recognizes that these
> distributions
> > would suggest “a kind of relictism” but he ignores this because “islands
> they
> > occupy are doubtless relatively recent in geological terms”.
> >
> > What Carlquist shows here is an inability to rethink his assumptions,
> even
> > when the distribution involved is “almost unbelievable”. The
> distribution is
> > unbelievable because it does not fit with the theory, and rather than
> throw
> > the theory out the data is just ignored. No matter how unbelievable, the
> > distributions still arose by long-distance chance, even though “further
> > observational and, if possible, experimental evidence is needed to
> > demonstrate the nature and causes of 'incompetent' in insular species.”
> As
> > with the medical sciences that use pejorative terms such as 'incompetent'
> > to describe medical defects (all to often in reference to female
> anatomy), so
> > to in biogeography are some taxa downgraded to incompetent. This is the
> > world of 'truth' (as determined by authority) over 'fact'. And of course
> it is
> > not as if Carlquist was without alternative possibilities as had already
> been
> > made abundantly clear by Croizat and confirmed in great detail in recent
> > literature. Chance dispersal becomes an excuse for anything and
> everything
> > according to whim rather than evidence, and therefore easily slides into
> a
> > world of 'science' where miracles, mysteries, and the unbelievable are
> quite
> > believable indeed. And this is supposed to be modern science?
> >
> > John Grehan
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> > Send Taxacom mailing list submissions to: taxacom at mailman.nhm.ku.edu
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> > http://mailman.nhm.ku.edu/cgi-bin/mailman/listinfo/taxacom
> > You can reach the person managing the list at: taxacom-
> > owner at mailman.nhm.ku.edu The Taxacom email archive back to 1992 can
> > be searched at: http://taxacom.markmail.org
> >
> > Nurturing nuance while assaulting ambiguity for about 33 years,
> 1987-2020.
>
>