[Taxacom] Dispersal paradigm (was: Antarctic dispersal)

[Michael Heads]

Hi Richard,

Sorry, I was referring to Ken's last message, on the Madagascar - New
Zealand pattern.

All the components of any geographic pattern have a wide range of
divergences (this was known in the 19th century) and a wide range of clock
dates. So if you believe the clock dates, all the patterns are rejected as
pseudopatterns and vicariance is rejected.


On Thu, Jun 19, 2014 at 11:21 AM, Richard Pyle <deepreef at bishopmuseum.org>
wrote:

> Hi Michael,
>
> > You wrote: 'That you can find examples where ecologically
> > disparate organisms fall into repeated patterns of distribution
> > across many different taxonomic groups is not at all surprising
> > to me, because I do not reject vicariance as a mechanism of
> > speciation...'
> >
> > I agree with this, although Ken doesn't - he believes the
> > molecular clock dates and so thinks the geographic patterns
> > are 'pseudopatterns' caused by chance, not vicariance.
>
> I won't speak for Ken, but I have not seen him reject vicariance.  I have
> seen him (usually with good and compelling reason) cast doubt on specific
> cases purported to represent support of vicariance as a contributing
> mechanism to speciation.  I am not familiar enough with the facts in those
> cases to know whether to agree with him or not.  And, if this debate is
> about specific individual cases fitting a pattern or not -- then I think
> that is very much a legitimate debate to have.  But that doesn't strike me
> as the main theme running through this ongoing dialog.
>
> Aloha,
> Rich
>
>


-- 
Dunedin, New Zealand.

My recent books:

*Molecular panbiogeography of the tropics.* 2012. University of California
Press, Berkeley. www.ucpress.edu/book.php?isbn=9780520271968

*Biogeography of Australasia:  A molecular analysis*. 2014. Cambridge
University Press, Cambridge. www.cambridge.org/9781107041028