a question about assymetrical trees

[Jan Bosselaers]

Dear Gijs,

> Many cladograms that are shown in articles and presentations seem to be
> highly asymmetrical. That is, very often out of two branches only one is
> splitting into two, and only one of these is splitting etc. Thus everytime
> there seems to be a "chosen" branch which may radiate, while the other
> branch stays constant. This leads to a succesion of paraphyletic branches.
> I hope you can visualize and recognize this type of trees (I wish I could
> draw it for you). I can't imagine evolution working this way. So here is my
> question: could anybody tell me what may be the cause of these trees. Do
> the tree producing programs prefer this type of asymmetrical trees or is
> something else going on?

Maybe you might like to read Steve Farris' and Mari Källersjö's paper
"Asymmetry and explanations" (1998) Cladistics 14: 159-166.

Best wishes,

Jan
--------------------------------------------------------------
Jan Bosselaers
"Dochterland", R. novarumlaan 2
B-2340 Beerse, Belgium                       tel 32-14-615896
home: dochterland at village.uunet.be           fax 32-14-610306
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"I’ve discovered that truth is innate, and the lying is
 superficial, superimposed" Buckminster Fuller