[Taxacom] Biogeography of Australasia
Michael Heads
m.j.heads at gmail.com
Tue Mar 25 02:59:07 CDT 2014
Surprisingly, even species with long-lived, planktonic larval stages also
show very high levels of geographic structuring.
Michael
On Tue, Mar 25, 2014 at 7:26 PM, Stephen Thorpe
<stephen_thorpe at yahoo.co.nz>wrote:
> Yes, marine species with direct development (no larval stage) can show
> local endemism (the sea to them is like the air to us!)
>
> Stephen
>
> --------------------------------------------
> On Tue, 25/3/14, Michael Heads <m.j.heads at gmail.com> wrote:
>
> Subject: Re: [Taxacom] Biogeography of Australasia
> To: "Stephen Thorpe" <stephen_thorpe at yahoo.co.nz>
> Cc: "JF Mate" <aphodiinaemate at gmail.com>, "Taxacom" <
> taxacom at mailman.nhm.ku.edu>
> Received: Tuesday, 25 March, 2014, 6:14 AM
>
> A lot of reef
> organisms show very high levels of genetic/geographic
> structure (allopatry). This discovery has caused a paradigm
> shift in marine biology, and the recognition of local
> endemics. In much the same way, the high levels of
> geographic structure even in microrganisms have caused a
> revolution and the rejection of the old idea that
> 'everything is everywhere and the environment
> selects'.
> Michael
>
> On Tue, Mar 25, 2014
> at 5:11 PM, Stephen Thorpe <stephen_thorpe at yahoo.co.nz>
> wrote:
>
>
> Shallow water species would need to lack actively
> swimming or planktonic or phoretic larvae ...
>
>
>
>
>
>
> From: Michael Heads
> <m.j.heads at gmail.com>
>
> To: Stephen
> Thorpe <stephen_thorpe at yahoo.co.nz>
>
> Cc: JF Mate
> <aphodiinaemate at gmail.com>;
> Taxacom <taxacom at mailman.nhm.ku.edu>
>
>
> Sent: Tuesday,
> 25 March 2014 5:07 PM
> Subject: Re:
> [Taxacom] Biogeography of Australasia
>
>
>
>
>
>
>
> Many cases of vicariance in island groups are most
> easily explained if the organisms regularly move between
> nearby islands, as a metapopulation on individually
> ephemeral islands. If the island group is rifted apart, the
> metapopulation may be divided by vicariance into two, as
> between Vanuatu and Fiji for example. This process can
> operate on terrestrial biota, but also reef groups that
> require shallow water.
>
>
> Michael
>
>
>
>
> On Tue, Mar 25, 2014 at 4:50 PM, Stephen Thorpe <
> stephen_thorpe at yahoo.co.nz>
> wrote:
>
>
>
>
>
> The distinction between vicariance vs.
> dispersal scenarios really only makes sense for terrestrial
> allopatric species separated on oceanic islands. Then we can
> ask if one of the species is derived from ancestors which
> did not need to swim or fly from another island. This would
> be vicariance. Amphibians are good examples, as they
> can't fly (actively or passively) and they can't
> tolerate seawater.
>
>
> Stephen
>
>
>
>
> From: Michael Heads
> <m.j.heads at gmail.com>
>
> To: JF Mate
> <aphodiinaemate at gmail.com>
> Cc: Taxacom <taxacom at mailman.nhm.ku.edu>
>
> Sent: Tuesday,
> 25 March 2014 4:27 PM
> Subject: Re: [Taxacom]
> Biogeography of Australasia
>
>
>
>
>
> Hi Jason,
>
> You said:
>
> 'This is a play on words. There is no
> valid/clear-cut distinction
> between
> "chance dispersal", "range extension" or
> your "dispersal" vs
>
> the meaning of the word as used by most biologists. I
> understand that
> panbiogeography requires
> this (non-existant) difference to distinguish
> itself, but in the end you only need a few
> observed cases of organisms
>
> crossing barriers to show that, given the right conditions,
> dispersal
> is a valid mechanism.'
>
> The difference between normal,
> observed dispersal discussed by ecologists
>
> (e.g. weeds dispersing into a garden), and chance,
> 'jump' or 'long
> distance'
> dispersal as invoked by evolutionists, is that the former
> does
> not involve differentiation, whereas
> the latter is proposed as a mode of
> speciation.
>
> Dispersal theory explains range overlap by
> dispersal, but also explains
> allopatry by
> dispersal. Vicariance theory explains range overlap by
>
> dispersal, but explains allopatry by vicariance. Note that
> the dispersal
> invoked in vicariance theory
> is caused by geological change, whereas
> dispersal as invoked by dispersal theory to
> explain allopatry, is caused by
>
> chance.
>
> Michael
>
>
> On Sun, Mar
> 23, 2014 at 8:03 AM, JF Mate <aphodiinaemate at gmail.com> wrote:
>
>
> > Mostly a reply to John but a
> sprinkling to Michael as well
> >
> > The use of quotes
> such as "It was Darwin who invoked the concept of
> > miracles for anyone denouncing his theory
> of centers of origin and
> > dispersal.
> You are welcome to believe in extraordinary events
> ..."
>
> > suggests that, either by accident or design, you (John)
> are implying
> > dispersal is a mechanism
> akin to religion. That and the daily readings
> > suggest baiting.
> >
>
> > As to why congruence of phylogeny and known geological
> events is
> > important (your words):
> "...sequence of geological events may
> > indicate that the phylogeny predates the
> geology, is related to a
>
> > different geology, or that the geological
> reconstruction is wrong."
> > John,
> this makes Panbiogeography unfalsifiable. Your fallback line
> is
> > "geology/genes/phylogeny"
> could be wrong if they don´t
> match a purely
> > vicariant model. Yes, I
> am sure that as more evidence acumulates the
> > biogeographical scenarios of certain
> groups will have to change. But
> > where
> panbiogeography fails is in the closed, one size-fits-all
>
> > mechanism department. Science is never "the last
> word" but the best
> > fit to facts.
> By using this to shield Panbiogeography you are
> > purposefully using scientific uncertainty
> to protect your ideas.
>
> >
> > As to "The significance of
> observed cases of dispersal of highly
> >
> vagile species as evidence of chance dispersal being a
> significant
> > force in biogeography is
> questionable and does not predict the
>
> > tectonic correlations between good and poor dispersers
> (in the sense
> > of means of
> dispersal)." There are plenty of examples of
> species
> > (mostly good flyers) which
> have crossed significant barriers (even
> >
> oceans) and colonized new areas in recent history. How are
> these
> > examples not appropriate to the
> discussion? As for successful
>
> > colonization, just look at gardeners in Europe or NA.
> Thousands of
> > introduced, carefully
> nurtured plants, often cultured for generations
> > and only a small fraction ever becomes
> naturalized. I acknowledge the
>
> > fact that successful dispersal over significant
> barriers (sea, major
> > ranges) can be an
> unlikely event on a daily event but over millions of
> > years a small probability can really make
> a impact. The mechanism is
>
> > certainly common enough to suggest it does not require
> divine
> > intervention to happen.
> >
> > "Similarly,
> repopulation does not substanciate chance dispersal as a
> > significant force in the sense of chance
> dispersal being a major
> > mechanism in
> biogeography." and Michael "No-one is arguing
> that
>
> > dispersal is a significant force. All organisms have
> dispersed to
> > their current locations.
> Dispersal can be observed every day.
> >
> Vicariance biogeography has never denied dispersal - you
> can't just
>
> > have vicariance otherwise there would only be a single
> taxon in any
> > area."
> >
> > This is a play on
> words. There is no valid/clear-cut distinction
>
> > between "chance dispersal", "range
> extension" or your "dispersal" vs
> > the meaning of the word as used by most
> biologists. I understand that
> >
> panbiogeography requires this (non-existant) difference to
> distinguish
>
> > itself, but in the end you only need a few observed
> cases of organisms
> > crossing barriers to
> show that, given the right conditions, dispersal
> > is a valid mechanism. Maybe not 99% of the
> time, but chance plays a
>
> > bigger part in evolution than 0, and that is what
> matters.
> >
> > Best
> >
> > Jason
> >
> >
> _______________________________________________
>
> > Taxacom Mailing List
> > Taxacom at mailman.nhm.ku.edu
> > http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
>
> > The Taxacom Archive back to 1992 may be
> searched at:
> > http://taxacom.markmail.org/
>
> >
> > Celebrating
> 27 years of Taxacom in 2014.
> >
>
>
>
> --
> Dunedin, New Zealand.
>
>
> My recent books:
>
> *Molecular panbiogeography of the
> tropics.* 2012. University of California
> Press, Berkeley. www.ucpress.edu/book.php?isbn=9780520271968
>
>
> *Biogeography of Australasia: A molecular
> analysis*. 2014. Cambridge
> University Press,
> Cambridge. www.cambridge.org/9781107041028
>
>
> _______________________________________________
> Taxacom Mailing List
> Taxacom at mailman.nhm.ku.edu
>
> http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
> The Taxacom Archive back to 1992 may be
> searched at: http://taxacom.markmail.org/
>
>
> Celebrating 27 years
> of Taxacom in 2014.
>
>
>
>
>
> --
>
>
> Dunedin, New Zealand.
>
>
> My recent books:
>
> Molecular panbiogeography of the tropics.
> 2012.University of California Press, Berkeley.
> www.ucpress.edu/book.php?isbn=9780520271968
>
>
> Biogeography of Australasia: A molecular
> analysis. 2014. Cambridge University Press, Cambridge.
> www.cambridge.org/9781107041028
>
>
>
>
>
> --
> Dunedin, New Zealand.
> My recent
> books:
> Molecular panbiogeography of the tropics.
> 2012. University of California Press, Berkeley.
> www.ucpress.edu/book.php?isbn=9780520271968
> Biogeography of Australasia: A
> molecular analysis. 2014. Cambridge University Press,
> Cambridge. www.cambridge.org/9781107041028
>
>
>
>
--
Dunedin, New Zealand.
My recent books:
*Molecular panbiogeography of the tropics.* 2012. University of California
Press, Berkeley. www.ucpress.edu/book.php?isbn=9780520271968
*Biogeography of Australasia: A molecular analysis*. 2014. Cambridge
University Press, Cambridge. www.cambridge.org/9781107041028
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