[Taxacom] Reproducibility of descriptive data

Mon Sep 14 16:19:21 CDT 2009

You might say that the robin recovery program went "tits up"! :)
This example is no threat to BSC. At worst, it is just a threat to some people's understanding of it. Sticking a robin into a tit nest is hardly "natural conditions"! Other relevant info is missing like was Tobin fertile?

Stephen
________________________________________
From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of John Grehan [jgrehan at sciencebuff.org]
Sent: Tuesday, 15 September 2009 7:25 a.m.
To: taxacom at mailman.nhm.ku.edu
Subject: ***SPAM*** Re: [Taxacom] Reproducibility of descriptive data

This very question came up in a very real way in New Zealand when
conservationsts were confronted with hybridation that did not conform to
preconceived ideas of what nature should do.

A female black robin fosterling was given to Chatham Island tits to be
reared as part of a recovery program for black robins. The fosterling
decided to mate with a tit instead of another black robin. The result
was the hatching of a hybrid in 1990. This hybrid was named 'Tobin" and
then it was killed (I think it was shot).

The execution of Tobin was justified as removing a threat to black robin
survival. It seems that the conservationists were interested preventing
inpurities entering into their 'pure' species. Frighteningly reminiscent
of some political ideologies.

Those who have been on this list for years will recall an earlier
posting about this.

John Grehan

> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Don.Colless at csiro.au
> Sent: Monday, September 14, 2009 3:48 AM
> To: s.thorpe at auckland.ac.nz
> Cc: taxacom at mailman.nhm.ku.edu
> Subject: Re: [Taxacom] Reproducibility of descriptive data
>
> I'm intrigued by the notion that one species can hybridise another
"out of
> existence". Surely the resulting population,with its new genome, has a
new
> status of some kind? How could it still be the "same" species as one
of
> the originals?
>
> Donald H Colless
> CSIRO Div of Entomology
> GPO Box 1700
> Canberra 2601
> don.colless at csiro.au
> tuz li munz est miens envirun
>
> ________________________________________
> From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Stephen Thorpe
> [s.thorpe at auckland.ac.nz]
> Sent: 13 September 2009 15:19
> To: Michael Heads; taxacom at mailman.nhm.ku.edu
> Subject: Re: [Taxacom] Reproducibility of descriptive data
>
> Hi Michael,
>
> Your duck example is a good one, and my previous attempts to deal with
it
> were not correct, but now I think I have the answer! My analogy with
the
> lowland species being forced up into the montane zone by lowland
forest
> clearance was bogus because the same effect could be had from purely
> natural events like a rise in sea level (not due to human activities)
or a
> fire resulting from a lightning strike! The "natural conditions"
caveat
> applies to the area where the two populations intermingle, which in my
> example was the montane area. The fact that the lowlands were changed
by
> an artificial means was irrelevant. This does however, suggest that
> "natural conditions" may still dispose of the duck example, because
the
> two populations are intermingling in New Zealand, which isn't in it's
> natural state. However, I am not going to persue that line of
argument, as
> I think I have a better one:
>
> >the introduced mallards (Anas platyrhynchos) hybridise with the
> indigenous grey ducks (A. superciliosa) and the latter are being
> hybridised out of existence
> Even if the grey ducks did get hybridised out of existence, this
doesn't
> mean that the level of reproductive isolation/incompatibility is zero!
> What matters is what proportion of matings lead to fertile offspring!
This
> proportion could be as low as you like, and yet, given enough time,
the
> grey duck could still get hybridised out of existence! If the mallards
> build their population up to vastly outnumber the grey ducks, then
even if
> only 1 in 100 matings lead to fertile offspring, the process could
still
> go to completion, could it not?
>
> So, nothing you have said suggests that the proportion of matings
leading
> to fertile offspring (=level of reproductive
isolation/incompatibility) is
> high enough for the two types of duck to be considered the same
species by
> the BSC! Phew! :)
>
> Cheers,
>
> Stephen
>
> ________________________________________
> From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Michael Heads
> [michael.heads at yahoo.com]
> Sent: Friday, 11 September 2009 9:30 p.m.
> To: taxacom at mailman.nhm.ku.edu
> Subject: ***SPAM*** Re: [Taxacom] Reproducibility of descriptive data
>
> Hi Stephen,
>
> Hybridism not the norm: a falsifier doesn't have to be the norm, you
only
> need one case and of course there are thousands.
>
> Morphotypes: there are plenty of distinct morphotypes below species
level
> (e.g. in birds).
>
> Species entering New Zealand: This is a common problem in
conservation. In
> one example, the introduced mallards (Anas platyrhynchos) hybridise
with
> the indigenous grey ducks (A. superciliosa) and the latter are being
> hybridised out of existence (Gillespie, 1985. The Auk 102: 459).
>
> Michael Heads
>
> Wellington, New Zealand.
>
> My papers on biogeography are at: http://tiny.cc/RiUE0
>
> --- On Fri, 9/11/09, Stephen Thorpe <s.thorpe at auckland.ac.nz> wrote:
>
>
> From: Stephen Thorpe <s.thorpe at auckland.ac.nz>
> Subject: RE: ***SPAM*** Re: [Taxacom] Reproducibility of descriptive
data
> To: "Michael Heads" <michael.heads at yahoo.com>
> Cc: "taxacom at mailman.nhm.ku.edu" <taxacom at mailman.nhm.ku.edu>
> Date: Friday, September 11, 2009, 8:01 PM
>
>
> Dear Michael:
> Simply restating one side of a debate doesn't in general add any
weight to
> that side over the opposing view! :)
> If hybridisation was the norm, then things would be very different,
but if
> reproductive isolation wasn't the norm, then we simply wouldn't find
> organisms falling as they do into identifiable morphotypes, and , for
> example, it wouldn't matter if a few breeding pairs of a vector of a
> deadly disease entered N.Z., because they would soon be diluted out by
> hybridisation with what is already here ...
> Cheers,
> Stephen
>
> ________________________________________
> From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Michael Heads
> [michael.heads at yahoo.com]
> Sent: Friday, 11 September 2009 7:41 p.m.
> To: taxacom at mailman.nhm.ku.edu
> Subject: ***SPAM*** Re: [Taxacom] Reproducibility of descriptive data
>
> Dear colleagues,
>
> Stephen wrote: 'the notion of species in biology makes no sense if you
> disregard the biological species concept'.
>
> Apart from those devoted to Mediaeval Idealist philosophy (Mayr,
Biology
> 101 classes, etc.) very few biologists actually believe species are
> special or that they can be defined somehow, e.g. by interbreeding.
> 'Species' is simply a point on a trajectory of differentiation,
somewhere
> between 'subspecies' and 'subgenus', in any given group. Investigating
> this trajectory of differentiation will lead somewhere, not trying to
> define species (the so-called 'species problem'). In second year
biology
> we learn that in practice species cannot be defined by actual or
potential
> interbreeding, as there are hybrids between good species. This is very
> common in plants and also in terrestrial and freshwater animals, but
is
> now being recorded more often in marine animals, especially around
> Indonesia- see Hobbs, J.P. et al. 2009. Marine hybrid hotspot at Indo-
> Pacific biogeographic border. Biology Letters 5: 258-261.
>
> Michael Heads
>
> Wellington, New Zealand.
>
> My papers on biogeography are at: http://tiny.cc/RiUE0
>
> --- On Fri, 9/11/09, Stephen Thorpe <s.thorpe at auckland.ac.nz> wrote:
>
>
> From: Stephen Thorpe <s.thorpe at auckland.ac.nz>
> Subject: Re: [Taxacom] Reproducibility of descriptive data
> To: "Jim Croft" <jim.croft at gmail.com>
> Cc: "TAXACOM" <taxacom at mailman.nhm.ku.edu>, "Mike Dallwitz"
> <m.j.dallwitz at netspeed.com.au>
> Date: Friday, September 11, 2009, 1:10 PM
>
>
> [Jim said] Your 'country' analogy is spurious.  Like the US, Australia
is
> an historical federation, defined by inclusion of various bits of
land,
> including disjunct offshore islands and territories.  That the bulk of
> Australia happens to coincide with recognizable continent is an
irrelevant
> artefact.  Notions of artificial or real in this context have no
meaning.
>
> [reply] You misrepresent my analogy. It is indeed intended to
demonstrate
> a distinction between natural and artificial taxon boundaries, and I
think
> that, properly understood, the analogy does just that. It is
irrelevant
> how Australia is ACTUALLY defined, only that it could have been
defined by
> natural boundaries as I suggest in the analogy. On the other hand,
U.S.A.
> is not defined by natural boundaries. So, there is a difference
between
> U.S.A. as actually defined, and Australia as it could have been
defined.
> This difference is analogous to species (Australia) compared with
genera
> (U.S.A.)
>
> In other words, I am saying that when we talk about species, as
opposed to
> genera, we are implicitly choosing to follow natural boundaries (which
may
> not be 100% clear cut, but that is a different issue), and the notion
of
> species in biology makes no sense if you disregard the biological
species
> concept.
>
> Consider this: males and females can sometimes be so dimorphic that
they
> have little or no morphological similarity. But, NOBODY would consider
> them to be different species (if they realised that the differences
were
> due to sexual dimorphism), not even people who would claim to be using
a
> morphological species concept instead of a biological one! So, the
> biological species concept is firmly entrenched in our notion of
species
> in biology, and it provides natural species boundaries (not
necessarily
> 100% clear cut boundaries). This is completely lacking in the case of
> genera, families, etc. These supraspecific taxa are just "convenient
> monophyletic groups", but species are not...
>
> MAIN CONCLUSION 1: There is a fundamental difference in kind between
> species boundaries on the one hand, and generic (or other) boundaries
on
> the other hand, namely that species (and only species) follow natural
> boundaries (of reproductive isolating mechanisms). To ignore this
> fundamental difference is likely to lead one astray...
>
> [Jim said] Descriptions do not 'define' a concept (at any level).
They...
> um...describe it. If you want a definition, you could use the list of
> those thing you might include in that concept. Species in genera,
> specimens in species, etc.
>
> [reply] Take the case of genera: a taxonomist who describes a new
genus
> will include various species in it, say A, B, and C. These species
must
> agree with the description of the genus, or else something has gone
wrong!
> Now suppose another taxonomist discovers new species D, and places it
in
> the above genus. You would have to say that the two taxonomists have
> different concepts of the genus, because the second one includes D,
but
> the first guy/girl doesn't. Most taxonomists, I suggest, would say
that
> the concept of the genus has changed only if the description needs
> rewriting to accommodate D. If D already fits the description
perfectly
> well, then the concept of the genus remains the same. Hence, I suggest
> that descriptions do in fact define generic concepts!
>
> In practice, taxon concepts for species are never "settled by
inclusion"!
> If the describer of a new species has only a single specimen, that
> specimen does not fully represent the describer's concept of the new
> species! The describer will have some hypothetical notion of what it
would
> take for another (non-identical looking) specimen to belong to the
same
> species. Species descriptions based on a single specimen are not, I
> suggest, typically just descriptions of that single specimen! Instead,
> they EMPHASISE THE CHARACTERS OF THAT SPECIMEN WHICH THE DESCRIBER
THINKS
> ARE LIKELY TO BE IMPORTANT! The describer's concept will either be
> confirmed or else falsified by other specimens as they turn up,
depending
> upon WHERE THE NATURAL BOUNDARIES ACTUALLY LIE...
>
> Stephen
>
> ________________________________________
> From: Jim Croft [jim.croft at gmail.com]
> Sent: Friday, 11 September 2009 9:15 a.m.
> To: Stephen Thorpe
> Cc: Mike Dallwitz; TAXACOM
> Subject: Re: [Taxacom] Reproducibility of descriptive data
>
> Descriptions do not 'define' a concept (at any level). They... um...
> describe it.
>
> If you want a definition, you could use the list of those thing you
> might include in that concept. Species in genera, specimens in
> species, etc.
>
> Having settled on a concept by inclusion, you can then go about
> describing it, listing the characters/attributes that, in your mind,
> set the boundaries.  It is conceivable that a taxonomist could account
> for all relevant specimens, species, etc.  This is, after all, why we
> do revisions.  Any character/attribute list is arbitrarily selected
> and can never be complete.
>
> Your 'country' analogy is spurious.  Like the US, Australia is an
> historical federation, defined by inclusion of various bits of land,
> including disjunct offshore islands and territories.  That the bulk of
> Australia happens to coincide with recognizable continent is an
> irrelevant artefact.  Notions of artificial or real in this context
> have no meaning.
>
> jim
>
>
> On Thu, Sep 10, 2009 at 9:26 AM, Stephen
Thorpe<s.thorpe at auckland.ac.nz>
> wrote:
> > Jim, put another way:
> >
> > Genera are defined by descriptions (= genus boundary
circumscriptions)
> >
> > Species are defined by nominating an individual as the type. Species
> descriptions (=species boundary circumscriptions) do not define the
> species. They can be incorrect descriptions of the true boundaries
(unlike
> generic descriptions)
> >
> > Analogy: Australia can be defined by sticking a flag in the ground
and
> saying "I hereby define Australia to be all the land in all directions
> from this flag to the sea". So, Australia is like a species (it has
> natural boundaries). U.S.A. is like a genus (it has artificial
> boundaries).
> >
> > Your "taxon concepts" are a mixture of two very different things:
(1)
> generic descriptions; and (2) species descriptions.
> >
> > ________________________________________
> > From: Jim Croft [jim.croft at gmail.com]
> > Sent: Thursday, 10 September 2009 9:46 a.m.
> > To: Stephen Thorpe
> > Cc: Mike Dallwitz; TAXACOM
> > Subject: Re: [Taxacom] Reproducibility of descriptive data
> >
> > Don't buy this.  At all.  And I do not think the codes do either.
Nor
> > many/most taxonomists.   The type does not define the species (which
> > are in nearly every case variable).  It is an exemplar (not always
> > 'typical' in the English sense) which anchors the name.  The extreme
> > example of this are species that have multiple synonymic types.  In
a
> > type-defined species, concepts of lumping and splitting have no
> > meaning - yet we all do it.
> >
> > Have a chat to Pete deVries.  He would argue that a species knows
what
> > a species is and does not care what we call it or think it is.
Humans
> > develop a concept of what we think it is, sometimes (maybe even
often)
> > a reasonably good approximation of what a species knows it is.  And
we
> > give a name to this human concept a name.
> >
> > There are three things: a species entity, a species concept and
> > species name.  The first is defined by biology and evolution, the
> > second by humans, and the third is defined by the code and selected
by
> > humans.
> >
> > The problem we have, and why taxacom exists at all, is someone
utters
> > the third, a listener assumes the first, without considering the
> > second, of which there are often several alternatives.
> >
> > jim
> >
> > On Thu, Sep 10, 2009 at 7:03 AM, Stephen
Thorpe<s.thorpe at auckland.ac.nz>
> wrote:
> >> [Mike Dallwitz wrote] _Whatever_ we want to say about a taxon (e.g.
> what its boundaries, distribution, abundance, or uses are), we need to
> define the
> >> taxon that we want to talk about. And the only way to do that is to
> describe it in a reproducible way, so that people can identify
individuals
> as belonging or not belonging to the taxon
> >>
> >> [reply] Species are defined by their name-bearing types (holotypes
or
> lectotypes or neotypes or syntypes). A description of a species is a
> circumscription of its boundaries, according to the describer. So, we
> don't describe a taxon in order to define it so that we can then talk
> about boundaries. Rather, by describing it, we ARE talking about its
> boundaries, but the species is defined by its type.
> >>
> >>>describe it in a reproducible way, so that people can identify
> individuals as belonging or not belonging to the taxon
> >> No, describing it in a reproducible way only allows people to
identify
> individuals as being within or else outside the boundaries of the
species
> as circumscribed in the description. These boundaries could be wrong,
so
> the description is certainly not a DEFINITION of the species
(definitions
> are true by definition and cannot be wrong!)
> >>
> >> What you say applies more to genera and other "subjective" taxa,
but
> not to species, which are objectively defined once a type is
designated...
> >>
> >> Stephen
> >>
> > --
> > _________________
> > Jim Croft ~ jim.croft at gmail.com ~ +61-2-62509499 ~
> > http://www.google.com/profiles/jim.croft
> > ... in pursuit of the meaning of leaf ...
> > ... 'All is leaf' ('Alles ist Blatt') - Goethe
>
>
>
> --
> _________________
> Jim Croft ~ jim.croft at gmail.com ~ +61-2-62509499 ~
> http://www.google.com/profiles/jim.croft
> ... in pursuit of the meaning of leaf ...
> ... 'All is leaf' ('Alles ist Blatt') - Goethe
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