Pacific land snail phylogeography - grad student project
jgrehan at ADELPHIA.NET
Tue Dec 3 22:17:09 CST 2002
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."
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