[Taxacom] Long-distance oceanic dispersal (rafting) of Nothofagus species
John Grehan
calabar.john at gmail.com
Sun Jun 3 10:17:29 CDT 2018
There is not doubt that some organism drift around, either frequently or
infrequently. But its a big leap to just say this is how endemic taxa arise
in different locations. Bit like when Darwin found that snails (or seeds, I
forget which) could survive for considerable time in seawater and therefore
they did and this was sufficient to explain disjunctive origins. Chance
dispersal has been widely promoted under molecular clock theory but its a
chimera resulting from the misrepresentation of molecular dating. Chance
dispersal continues to hold a very visceral appeal for evolutionary
biologists and perhaps this is not so surprising as we see plants (or their
propagules) and animals drifting about every day. But its the kind of
reasoning that gives a bad name to the science of evolution.
John Grehan
On Sun, Jun 3, 2018 at 11:02 AM, Barry OConnor <bmoc at umich.edu> wrote:
> A mite originally described from beach wrack in the Russian far east
> turned up in beach wrack on the Oregon coast after the big Japanese
> earthquake/tsunami. Could have always been there, just never discovered
> until later. Given all the Asian stuff found on beaches in the Pacific
> northwest after the tsunami, either way it's a possibility that its
> distribution was affected by tsunamis at some point. As John points out,
> however, neither scenario is testable without historical data, which is
> absent.
> All the best! - Barry
>
> On Sun, Jun 3, 2018 at 10:46 AM, John Grehan <calabar.john at gmail.com>
> wrote:
>
>> Ken,
>>
>> Its not a testable notion in any real sense any more than attributing the
>> connection to UFO's. Further, it is not an 'odd' distribution, but one
>> that
>> is very even (meaning standard). One can invoke any number of imaginary
>> events to toss plants and animals from one side of the Tasman to the
>> other,
>> or even just place them there by an Act of God, but there is no empirical
>> imperative to do so for this any more than imagining a tsunami to toss
>> frogs from Vancouver to New Zealand.
>>
>> John Grehan
>>
>> On Sun, Jun 3, 2018 at 8:38 AM, Kenneth Kinman <kinman at hotmail.com>
>> wrote:
>>
>> > Hi Stephen,
>> >
>> > But it could be somewhat scientifically testable if some organisms
>> > (mostly likely insects) have the same odd distribution in New Zealand
>> and
>> > Tasmania (or adjacent Australia). So I am hoping that some entomologist
>> > might know of insects that fit the bill. And if there were more than
>> one
>> > such organism, the more likely this dispersal scenario would become.
>> >
>> > And note that I cited two different Nothofagus species groups
>> with
>> > the same odd distribution (one in subgenus Lophozonia and the other in
>> > subgenus Fuscospora). And those two dispersals could have happened at
>> > different times. So that already increases the probability of
>> dispersal.
>> > Anyway, at least Fred understood what I was suggesting:
>> > http://mailman.nhm.ku.edu/pipermail/taxacom/2006-December/108388.html
>> >
>> >
>> > -----------------Ken
>> >
>> > ________________________________
>> > From: Stephen Thorpe <stephen_thorpe at yahoo.co.nz>
>> > Sent: Saturday, June 2, 2018 8:59 PM
>> > To: Kenneth Kinman
>> > Cc: taxacom at mailman.nhm.ku.edu
>> > Subject: Re: [Taxacom] Long-distance oceanic dispersal (rafting) of
>> > Nothofagus species
>> >
>> > "Could certain insects, mosses, or other organisms have hitched a ride
>> on
>> > such a Nothofagus raft?"
>> >
>> > Impossible to rule out just about anything that doesn't constantly
>> require
>> > running freshwater. If it happened during summer, there could be a
>> > desiccating effect, but at other times the amount of freshwater dampness
>> > could remain at acceptable levels.
>> >
>> > The problem though, as I see it, is that these dispersion events are
>> > entirely random and unpredictable, so it is hard to base much in the
>> way of
>> > science on it.
>> >
>> > Stephen
>> >
>> > --------------------------------------------
>> > On Sun, 3/6/18, Kenneth Kinman <kinman at hotmail.com> wrote:
>> >
>> > Subject: [Taxacom] Long-distance oceanic dispersal (rafting) of
>> > Nothofagus species
>> > To: "Kenneth Kinman" <kinman at hotmail.com>
>> > Cc: "taxacom at mailman.nhm.ku.edu" <taxacom at mailman.nhm.ku.edu>
>> > Received: Sunday, 3 June, 2018, 1:51 PM
>> >
>> > Hi all,
>> >
>> > The recent thread got me thinking about a debate that some
>> > of us were having on taxacom almost 12 years ago. Namely
>> > whether long-distance oceanic dispersal (by rafting) was a
>> > significant factor in the geographic distribution of some
>> > species of Nothofagus (sensu lato).
>> >
>> > My hypothesis was that large rafts of dislodged Nothofagus
>> > trees (due to tsunami or other massive flooding event) could
>> > have held some of their fruit above the ocean surface and
>> > rafted from Tasmania to New Zealand, where one or more new
>> > species could evolve (due to founder effect). This would
>> > be a relatively short rafting event compared to the much
>> > longer driftwood oceanic rafting that happened from South
>> > America to Tasmania: Barber, 1959, in the journal Nature;
>> > "Transport of Driftwood from South America to
>> > Tasmania". Is there other evidence that such dispersal
>> > of Nothofagus could have happened? Could certain insects,
>> > mosses, or other organisms have hitched a ride on such a
>> > Nothofagus raft?
>> >
>> > --------------Ken Kinman
>> > http://mailman.nhm.ku.edu/pipermail/taxacom/2006-December/108385.html
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>> > Nurturing Nuance while Assaulting Ambiguity for 31 Some Years,
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>> Nurturing Nuance while Assaulting Ambiguity for 31 Some Years, 1987-2018.
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>
>
>
> --
> -So many mites, so little time!
> Barry M. OConnor
> Professor & Curator
> Department of Ecology & Evolutionary Biology
> Research Museums Center
> University of Michigan phone: 734-763-4354
> 3600 Varsity Drive
> <https://maps.google.com/?q=3600+Varsity+Drive&entry=gmail&source=g>
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>
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