[Taxacom] Phylogenetic classification?

Fri Aug 7 10:27:53 CDT 2009

It is the most popular, but the underlying issue is not really so much the choice between vicariance and dispersal as it is about how that choice is made. The popular molecular model is to argue that if a molecular clock date is more recent than a postulated vicariance event then the process giving rise to a disjunction is dispersal, not vicariance. Although almost universally popular, it is a misrepresentation of minimum divergence estimates as maximal or absolute.

John Grehan 

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Jason Mate
Sent: Thursday, August 06, 2009 4:48 PM
To: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Phylogenetic classification?

Risking sounding dumb but, as I understood the posts on the topic, founder dispersal speciation wasn´t touted as the only mechanism regarding biogeographic patterns, although it is the most popular. Just contributing my two cents.

Jason

> Date: Wed, 5 Aug 2009 20:39:17 -0700
> From: michael.heads at yahoo.com
> To: taxacom at mailman.nhm.ku.edu
> Subject: Re: [Taxacom] Phylogenetic classification?
> 
> Geoff,
>  
> All dispersal, in the sense of normal ecological dispersal, is founder dispersal because all individuals move from their place of birth to a new locality, even if it's just fruit dropping off the parent tree. (The few exceptions include the molluscs Crepidula fornicata and also the mistletoes Korthalsella where many branches are actually distinct individuals). So there's no question that founder dispersal in this sense exists. 
>    The problematic concept is founder speciation (which I think includes both founder effect speciation and founder dispersal speciation).
>    Conflating the two processes, founder dispersal and founder speciation, is more than just casual use of terminology - it's the whole conceptual basis of dispersal biogeography: 'you can *see* the seeds blowing in the wind (or pelagic larvae drifitng with the currents or whatever), therefore that is the process that explains the biogeographic distribution of the species, allopatry and so on'. You can also see the sun going around the Earth!     
>  
> Michael
> 
> Wellington, New Zealand.
> 
> My papers on biogeography are at: http://tiny.cc/RiUE0
> 
> --- On Thu, 8/6/09, Geoffrey Read <gread at actrix.gen.nz> wrote:
> 
> 
> From: Geoffrey Read <gread at actrix.gen.nz>
> Subject: [Taxacom] Re: Phylogenetic classification?
> To: taxacom at mailman.nhm.ku.edu
> Date: Thursday, August 6, 2009, 2:46 PM
> 
> 
> Michael, yes, I agree with you in that Teske et al have unnecessarily 
> limited themselves - right in the abstract too!
> And they use 'founder dispersal' as shorthand for 'founder dispersal 
> speciation' (whereas one can have a founder arriving, and descendants 
> thriving (or not) with or without subsequent divergence to 
> speciation). If that has been the accepted terminology in the field 
> then it is a rather casual usage.
> 
> Nevertheless, 'founder effect speciation' (a fairly narrow concept) 
> most definitely is not a synonym of dispersal (to me a vast topic) or 
> founder dispersal speciation either. It's disconcerting to see them 
> equated in argument.
> 
> Geoff
> 
> >>> On 6/08/2009 at 9:51 a.m., Michael Heads <michael.heads at yahoo.com> wrote:
> > Dear Geoff and colleagues,
> >
> > I don't conflate founder dispersal and founder effect speciation - 
> > the phylogeographers themselves do! For example, Teske et al. (in 
> > the paper you
> > cited) write: 'Founder dispersal (i.e. long-distance dispersal 
> > followed by founder effect speciation)'.
> >     Without founder effect speciation you can still maintain founder 
> > dispersal with the 'artificial life support' of other ad hoc 
> > hypotheses but it starts to get very complicated. This is why Mayr 
> > felt the necessity of invoking the completely theoretical process of 
> > founder effect speciation in the first place.
> >
> > Michael
> >
> >
> > Wellington, New Zealand.
> >
> > My papers on biogeography are at: http://tiny.cc/RiUE0
> >
> > --- On Thu, 8/6/09, Geoffrey Read <gread at actrix.gen.nz> wrote:
> >
> >
> > From: Geoffrey Read <gread at actrix.gen.nz>
> > Subject: Re: [Taxacom] Phylogenetic classification?
> > To: taxacom at mailman.nhm.ku.edu
> > Date: Thursday, August 6, 2009, 8:28 AM
> >
> >
> >
> > On Wed, August 5, 2009 10:33 pm, Michael Heads wrote:
> >> Dear Geoff and colleagues,
> >>
> >> I should clarify this. Nearly all phylogeographers follow 
> >> traditional biogeography and invoke 'dispersal', i.e. founder 
> >> effect speciation, all
> > the time.
> >
> > Michael, it is the subsuming or conflation of founder dispersal 
> > speciation into simply 'founder effect' then dismissing it (via the 
> > geneticists
> > evidence) that I wanted to draw attention to regarding your 
> > presentations of your argument.  Exactly as you've done again above. 
> > They're two different boxes, surely.
> >
> 
> 
> 
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