[Taxacom] [Biogeography Portal] Re: Hypothesis: How Nothofagus rafted to New Zealand

[John Grehan]

I would agree that dispersal is a falsifiable hypothesis in the sense that Darwin predicted that once we know the means of dispersal in general we would then be in a position to predict former land connections (or words more or less to that effect as I do not have the quote to hand). A century of dispersalism failed to achieve that goal. Instead it was Croizat who presented the empirical test of dispersalism by showing that means of dispersal are not correlated with biogeography, and that spatial analysis lead to novel predictions about former land connections that dispersalism was unable to uncover. The panbiogeographic method actually works in the real (as opposed to the theoretical) world. Its as simple as that.

John Grehan

-----Original Message-----
From: Ken Kinman [mailto:kinman at hotmail.com] 
Sent: Sunday, December 24, 2006 12:29 PM
To: taxacom at mailman.nhm.ku.edu
Cc: biogeography at bohm.snv.jussieu.fr
Subject: [Biogeography Portal] Re: [Taxacom] Hypothesis: How Nothofagus rafted to New Zealand



Okay Curtis,
      Granted, that first sentence is not a testable hypothesis, but it is the beginnings of one.  Dispersal of some kind is indeed a testable hypothesis, and I'm glad to see Fred Schueler understands what I am trying to do.  Note that the Cyttaria evidence has already shifted my attention from birds to ocean rafting as the more likely mechanism, so I am testing and modifying the hypothesis as I go along.

      Anyway, onto mosses and insects to seek even more evidence that dispersal is more likely than vicariance in this case.  And by the way, it looks like Cyttaria gunnii might have speciated in New Zealand (if Cyttaria pallida is it's closest relative).  Unfortunately NCBI only shows one sequence for the entire genus, so I guess we have to rely on morphology for now (Cyttaria would be a great project for a molecular mycologist!!!).  But it is Christmas eve, so Nothofagus and Cyttaria have to go on my back burner for a few days.
   ----Merry Christmas,
               Ken Kinman
*********************************
Curtis Clark wrote:
>On 2006-12-23 20:03, Ken Kinman wrote:
> >     My hypothesis is that one (or more) Nothofagus cunninghamii 
> > trees rafted to New Zealand carrying on their branchs both their own 
> > fruit and their unique fungus Cyttaria gunni.  The tree or trees 
> > could have been dislodged due to land slides, massive floods, or 
> > even a tsunami---pick your favorite disaster.
>
>This is not a hypothesis, since it's not testable. It's evolutionary 
>"tall tales" such as this that give the panbiogeographers ammunition.

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