When did the fascination with phylogenetic trees begin?

Tom DiBenedetto tdib at UMICH.EDU
Tue Feb 25 10:00:34 CST 1997


> To Taxacomers:  I am trying to determine how and when the great emphasis on
> constructing (implicitly or explicitly) evolutionary or phylogenetic trees
> of (plant) taxa came about.  One might expect that it would have begun soon
> after Darwin's publication of "On the Origin of Species . . . " in
1859.

>In fact, Darwin's work included tree-thinking.  It is clear for example,
>from his diagrams (e.g., p 167 in Origins) that his thinking included
>tree-thinking.  Moreover, his thoughts apparently allowed for
>polychotomies.

Well, if the queston is when were explicitly evolutionary
classifications made (trees being merely graphical representations of
that), you have to go back to Lamarck. Although his organizing schema
was far more linear than hierarchical, it was explicitly
evolutionary.

>>  Have there been any review articles published on the history of the use of
>> evolutionary trees and phylogenies?  Thanks for any light you
>
>Mark Ridley's book The reformation of cladism has a decent historical
>accounting.  Numerical taxonomy and cladism emerged somewhat in tandem
>(see Sneath (1995) Syst Biol 44:281-298) for one accounting).

Given the contentiousness of the debates, it is not very likely that
one will find an objective rendering of the history. The above
mentioned refs are amongst the worst offenders. Nelson and Platnick
have an extended discussion of the use of branching diagrams in the
history of systematics in their book, Systematics and Biogeopgraphy
(1981, Columbia U. Press).

>It is fascinating to me that the main problems that persist in present-day
>phylogenetic systematics (accuracy, justified polarity assessment, and
>application (i.e., comparative method; character mapping) were recognized
>in 1923, by Clements of all people.

Accuracy is of course, a perennial issue in any endeavor. Polarity
assessments have always been a concern in evolutionary
systematics,,,no? (i.e. dating from well before 1923). Did Clements
ever actually try to apply phylogenetic information, or did he simply
realize that it might be useful (as did many people in the years
after Darwin)?

>  I also find it fascinating that Hall and Clements referred to phylogeny as a process (see
>above)

hardly surprising for an ecologist, you know,,,,

>, and did not conflate the lines on the page  (an
>evolutionary tree) with a phylogeny (the truth which is sought).

would you expect ecologists to be that dumb?   :)

>It is easy to argue that this pair had the concept of synapomorphy in
>mind; i.e., if the direction of evolution could be known, it requires no
>gigantic leap of inference to suppose the the "differentiating
>characters" they refer to are equivalent to Hennig's synapomorphy...

I think you are right here,,,derived characters were not of course, a
novel idea in evolutionary theory, but in the world of systematics,
the notion that one must rigorously discriminate between apomorphy
and plesiomorphy when reconstructing a phylogeny, was crucial. It
does seem that H&C had this sensitivity...or at least they
instinctivly chose to specify the right ones.




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