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Tree-thinking (was: they keep on growing despite early fusion)

The following snippet of this thread reminded me that I was planning
to recommend an article about tree-thinking to the list:

Baum DA, S DeWitt Smith, SSS Donovan. 2005. The Tree-Thinking
Challenge. Science 310 (5750): 979-980. DOI: 10.1126/science.1117727

The article found that many people, including many professional and
academic biologists, interpreted the relationships in a phylogenetic
tree by reading of the tips from left to right, rather than reading
the pattern of the clusters. The article clearly explains some of the
more common mistakes people make when reading trees, and also includes
two self-quizzes to help you test your tree-thinking abilities. I
found it to be an excellent teaching resource for my Evolution
students (who found it very clear and easy to read), and other TAs
have found it useful even in their Intro Bio courses. I also found it
helped me in teaching, because I could better anticipate the questions
and problems my students would have.

Best of all, Science has made this article (and its SI) available free
for everyone to download, regardless of their subscription status. You
can access it by going to the Tree-Thinking Group's website at:


Especially if you're new to phylogenetics, I think this article would
be a helpful read. But even if you've been doing this for a while,
there's still plenty to learn. I'm not trying to call anyone out as a
bad tree-thinker; I just figured some people might be confused by this

Another great resource for people interested in learning more about
phylogenetics is:



On 1/27/08, David Marjanovic <david.marjanovic@gmx.at> wrote:

> > > Because this one has Pterosauria as the sister-group to the rest of
> > > Archosauromorpha (fig. 17 and p. 154).
> >
> > But also next to Lepidosaurs and far from Euparkeria + all other
> > archosaurs.
> What do you mean by "next to"? The pterosaurs are next to the rest of
> Archosauromorpha in that figure, and Archosauromorpha as a whole, including
> the pterosaurs, is (by definition) next to Lepidosauromorpha (which still
> included the younginiforms).
> > Check the entirety of the literature. For all its faults, this is the one
> > and only time Lepidosaurs have NOT been excluded from consideration.
> > Benton 1985 was a breakthrough and a one-time-shot. Also, perhaps, an
> > unfounded embarrassment, because Benton dropped Lepidosaurs from all
> > subsequent lists. <<<<
> Sure, the lepidosaurs are fairly close to the pterosaurs in that matrix, but
> the archosaurs are _even closer_. While far enough from the orthodoxy (i. e.
> Pterosauria _within_ Archosauria, or, as Benton called the crown-group,
> Neoarchosauria), it is still closer to the orthodoxy than to your
> hypothesis. That is my point.

Sarah Werning
reply to: swerning@berkeley.edu
Museum of Paleontology and Department of Integrative Biology
University of California, Berkeley
1101 Valley Life Sciences Building
Berkeley, CA 94720-4780