Pacific land snail phylogeography - grad student project

Ken Kinman kinman at HOTMAIL.COM
Wed Dec 4 15:40:47 CST 2002

     I don't see how favoring one particular geo-narrative necessarily
REQUIRES one to ignore other geo-narratives.  And besides, it seems to me
that the main purpose of this project is to discern patterns, and that such
patterns would be grist for your mill (as well as theirs).
     If Pacific dispersal of Succineids is mainly by rafts of vegetation,
that might yield a different pattern than if dispersal is mainly by hitching
a ride on birds (especially birds that can fly longer distances).  If it is
the latter, the particular geo-narrative would not be as critical.  Right?
        ----- Cheers,
                Ken Kinman

>From: john grehan <jgrehan at ADELPHIA.NET>
>Reply-To: john grehan <jgrehan at ADELPHIA.NET>
>Subject: Re: Pacific land snail phylogeography - grad student project
>Date: Tue, 3 Dec 2002 22:17:09 -0500
>Robert Cowie wrote
>>Because of the geological nature of the Pacific - islands formed in situ
>>by "hot spot" volcanism - the evolution of Pacific island biodiversity
>>is dominated by dispersal followed by intra-island radiation. Given this
>>general scenario, we will address several questions, based on hypotheses
>>we have generated from preliminary study, including:
>>1) How frequent is dispersal between islands and archipelagos?
>>2) What are the routes of colonization into the Pacific?
>>3) What is the pattern of intra-archipelago diversification?
>>4) What are the taxonomic (generic) affiliations of the Pacific island
>This seems to be a good example of the Darwinian model of biogeography
>where biogeography is treated as being independently uninformative of the
>past. Instead one relies on a selected geohistorical narrative as the basis
>for biogeographic narrative constructions. In this case the chosen
>geo-narrative is that of isolated island hotspot formation which requires
>one to ignore other geo-narratives (e.g. former island arcs) that might
>provide an alternative geohistory to that of colonization routes into the
>Pacific as proposed by Cowie. Biogeography is rendered methodologically
>incapable of providing explanations that exceed the boundaries of current
>'knowledge' (the 'knowledge' being the selected geological story).
>The stated goal of the project is said to be "To develop a hypothesis of
>the phylogenetic and geographic origins and diversification of Pacific
>island succineid land snails." Perhaps it should be reworded as "To develop
>a dispersal hypothesis of the phylogenetic and geographic origins and
>diversification of Pacific island succineid land snails according to the
>geo-narrative of isolated hotspot formation."
>John Grehan

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