Extending Hennig's Figure 4?

Richard Jensen rjensen at SAINTMARYS.EDU
Mon Sep 15 08:11:05 CDT 2003

Dear Rich,

I recall seeing just such a depiction, but....

It may have been one Kevin Nixon used at a conference 9-10 years ago - I have a
vague recollection becuase I had what I thought was an original thought until
Kevin shattered my image of immortality (or, perhaps immorality!).



Richard Pyle wrote:

> Dear List,
> A little over a year ago, one fine Saturday afternoon when I was looking for
> a diversion, I rambled on about the meeting of genealogy and phylogeny in a
> note to this list:
> http://usobi.org/archives/cgi-bin/wa.exe?A2=ind0207&L=TAXACOM&P=R10381
> (don't bother reading it...trust me....)
> At the time, the words flowed unimpeded from brain to fingertips, while I
> blissfully assumed the stream-of-conscious monologue was somehow an original
> thought (and in a sense it was, because I was basically making it up as I
> was writing).  Since the moment I wrote that, I've been thinking about how I
> might represent the basic concept visually, and even got to the point where
> I started making some simple sketches.
> Quite recently, I came to the realization that my thinking was not quite as
> original as I had once naively imagined (big surprise...), when I was
> flipping through the pages of the Davis & Zangerl translation of Hennig's
> "Phylogenetic Systematics", and came across Figure 4.  Given the
> similarities between my sketches and this figure (to be fair, I used black
> dots for males, and white dots for females; whereas Hennig used the
> opposite), I would have accused him of copying my ideas -- except for the
> minor and inconvenient fact that Hennig's version was originally published
> some 45 years before my own "original" thought....
> ...But!...there is hope for me yet!  It seems that Hennig might have missed
> out on a perfect opportunity to scoop me entirely -- and that leads me to
> the real point of this message (sorry for the long meandering intro....).
> Has anyone taken this basic idea of a diagram (showing the transition from
> genealogy of sexual reproduction into species diversification) to the next
> logical extensions?  That is, has anyone illustrated the alternative fates;
> e.g., cases where the isolating event is less...um..."vicariant", and more
> gradually drawn-out; or what might happen if/when divergent populations
> subsequently hybridize/coalesce/reticulate? Or (for those who either have
> freakish memories, or discounted my advice not to go back and read the cited
> archive message), has anyone shown it on a larger scale with some "holes" in
> the mesh re-closing, while others remain as the genesis of permanent future
> chasms?
> I'm trying to get this whole notion of the transition between genealogy and
> speciation down in a clever PowerPoint format (for a variety of reasons),
> and I want to find out if anyone (besides Hennig) has illustrated it like
> this already.
> Many thanks, and sorry for the somewhat goofy tone and more or less
> unnecessary length of this request.
> Aloha,
> Rich

Richard J. Jensen              | tel: 574-284-4674
Department of Biology      | fax: 574-284-4716
Saint Mary's College         | e-mail: rjensen at saintmarys.edu
Notre Dame, IN 46556    | http://www.saintmarys.edu/~rjensen

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