[Taxacom] Reproducibility of descriptive data

[Paul Kirk]

What is reproductive integrity? Many of the organism I work with do not
have sex (!). Is everyone (except Mike D.) arguing this point from the
narrow view of the organism they know (and love) ...?

It's Friday - yipeee ... ;-)

Paul

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Stephen Thorpe
Sent: 11 September 2009 06:59
To: Mike Dallwitz; TAXACOM
Subject: Re: [Taxacom] Reproducibility of descriptive data

>Genera can have moats at their boundaries, too
This is the nitty-gritty "nub of the jist"
Yes, genera can have real gaps (=moats) between them and all other
genera - most do!
The point though is that you can be a lumper or a splitter regarding
genera, and it is purely subjective
Example: A, B, and C are three distinct species There is a gap between A
and B, and a bigger gap between (A, B) and C All three of the following
possibilities are equally valid (let square brackets [ ] enclose
genera):
(1) [A], [B], [C]
(2) [A, B], [C]
(3) [A, B, C]
Only convenience/taste/... can decide between them BUT, if A, B, C are
individuals (or populations), and [ ] enclose species, then the correct
option above is determined by facts of reproductive integrity. Even if
reproductive integrity is vague and a definite exact level of it must be
(subjectively) chosen, there is still a HUGE difference in what is going
on here as opposed to the generic case above, where our choice of option
(1, 2 or 3) was entirely unconstrained by objective facts. So people,
like Richard Pyle, who seem to think that a gap is a gap is a gap,
regardless of taxonomic level, and that there is nothing "special" about
species, are quite wrong! 

Another analogy: statistics is all about discovering objective facts
about the world, given a chosen significance level. The fact that the
significance level is chosen doesn't make the results any less
objective! A chosen level of reproductive integrity doesn't make species
any less objective! But there is no level of anything IN THE WORLD (=no
level of anything OBJECTIVE) that you can choose to find out anything
about genera. Maybe ... :)

Stephen
________________________________________
From: taxacom-bounces at mailman.nhm.ku.edu
[taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Mike Dallwitz
[m.j.dallwitz at netspeed.com.au]
Sent: Friday, 11 September 2009 5:13 p.m.
To: TAXACOM
Subject: Re: [Taxacom] Reproducibility of descriptive data

Stephen Thorpe wrote:

> Robust! Another way of saying that species have a real, natural 
> boundaries! Absolutely, yes! :)

The principles I'm writing about have nothing to do with taxonomic
levels, as I tried to make clear by writing "a class ... (such as a
subspecies, species, or genus)". Indeed, they apply to classes of
non-living things too, e.g. books.

By 'robust description' or class definition, I mean one such that it
will usually be fairly obvious whether or not a new specimen belongs to
the class. If a new specimen matches the definition fairly well, we can
assign it to the class (and, if we can be bothered, adjust the
definition as necessary), without agonizing over it too much.

(Note that this is not, by any means, the detailed discussion that I
threatened to give!)

Of course, if the class has a 'natural' boundary, with a moat or wall
separating it from other classes (for whatever reason), making a robust
description will tend to be easier. Genera can have moats at their
boundaries, too.

>> Which comes first, the concept or the inclusions (exemplars)?
>
> Actually, you mean which defines the concept, the description or the 
> inclusions (exemplars)?

No, Jim and I were both talking (I think!) about the mental process of
forming classes - which everyone does, not just taxonomists. The process
of making definitions for communicating the class concept to others
comes later, if it's done at all.

--
Mike Dallwitz
Contact information: http://delta-intkey.com/contact/dallwitz.htm
DELTA home page: http://delta-intkey.com

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