[Taxacom] Biogeography of Australasia

Tue Mar 25 01:26:26 CDT 2014

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 