[Taxacom] Phylogenetic classification?

[Michael Heads]

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. But they are simply inferring it from the distributions and a phylogeny. Population geneticists are a different breed altogether and look in detail at mechanisms of the speciation process per se, including lab experiments, small-scale population sudies, etc. These are the ones I was referring to (e.g. Coyne & Orr's book Speciation which summarises this work). 
 
I've just been reading M.C. Whitlock (a pop gen man) (2009) 'Founder effects' in 'Encyclopedia of islands' (ed. R. Gillespie & D. Clague, University of California Press).  He concludes: 'There have been many attempts to mimic the conditions for founder effect speciation in laboratory experiments. Although some experimental populations develop a small level of reproductive isolation, the effect is rare and of limited magnitude. The majority of evolutonary biologists [pop gen people don't include biogeographers here!] believe that the environmental differences between island populations and their progenitors are more likely to be important in developing reproductive isolation than are founder effects'. 
   Of course there is a founder effect, but it's not enough for speciation. Mayr thought it was and proposed a 'genetic revolution' in founders, but this is what the geneticists have become sceptical about. As for 'ecological speciation' - that's another can of worms!   

Michael

Wellington, New Zealand.

My papers on biogeography are at: http://tiny.cc/RiUE0

--- On Wed, 8/5/09, Geoff Read <gread at actrix.gen.nz> wrote:


From: Geoff Read <gread at actrix.gen.nz>
Subject: [Taxacom] Re: Phylogenetic classification?
To: taxacom at mailman.nhm.ku.edu
Date: Wednesday, August 5, 2009, 9:07 PM


>>> On 2/08/2009 at 2:24 p.m., Michael Heads <michael.heads at yahoo.com> wrote:
>>> Dear Steve et al.,
>>>
>>> This is what you'd expect based on Mayr's (1942) ideas that we were
>>> all brought up with. But after looking very hard for many decades,
>>> the geneticists now say there is little evidence for founder effect
>>> speciation.

A pity, it seemed so logical. But after seeing that comment about the
undemonstrated founder effect made more than once by Michael Heads, I
would like to add that on the other hand there are scientists happily
reporting phylogenetic evidence for marine animal speciation via the
broader process of _founder dispersal_, whilst also taking into account
the vicariance speciation possibilities that Michael much prefers .

D’Amato M, Harkins G, de Oliveira T, Teske P, Gibbons M 2008. Molecular
dating and biogeography of the neritic krill Nyctiphanes. Marine Biology
155: 243-247.

Teske PR, Hamilton H, Matthee CA, Barker NP 2007. Signatures of seaway
closures and founder dispersal in the phylogeny of a circumglobally
distributed seahorse lineage. BMC Evolutionary Biology 7: 1-19.
(open access at:
http://www.biomedcentral.com/content/pdf/1471-2148-7-138.pdf )

Geoff




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