[Taxacom] Evolutionary misconceptions (was: Ladderising phylogenetic trees)

[Steve Manning]

At 10:44 PM 3/10/2010, Curtis Clark wrote:
>On 3/10/2010 8:16 PM, Kenneth Kinman wrote:
> >         What I am talking about is more subtle and debatable---whether
> > there is actually a clear distinction between cladogenesis and
> > anagenesis (however they are defined) or if there is a continuum of
> > types that are really neither one nor the other.
>
>Whether anagenesis (broadly defined) accompanies lineage-splitting is an
>interesting question, but anagenesis within a lineage is clearly
>distinct, because no cladogenesis is happening.

Unless we are comparing the latest results to a fossil!

>  I think the only
>confusion is among those who don't think of phenotype shifts
>accompanying cladogenesis as anagenetic.
>
> >          When such reproductive isolation does finally evolve, is it the
> > result of cladogenesis or anagenesis?  Or is it really both?  And if you
> > are tempted to answer that the cladogenesis came first, can we know how
> > much anagenesis had actually previously occurred in the particular
> > mainland population which gave rise to the island population.
>
>Cladogenesis is the *result* of genetic isolation (keep in mind that
>allopatry is a kind of genetic isolation, and there has always been the
>debate over whether to count it). If separated populations re-merge,
>there wasn't any claodgenesis.
>
>In that reproductive isolation (*excluding* allopatry in this case) is
>almost always genetic in nature, it would seem to require anagenesis.
>
> >         My point is that the typical cladogram showing the difference
> > between anagenesis and cladogenesis is rather simplistic,
>
>No. Cladogenesis is lineage splitting. Anagenesis is genetic/phenotypic
>change within a lineage. Many are confused by that, but the principles
>are straightforward.
>
> > I am doubtful that Laura
> > appreciates such subtleties.  She is a psychologist, and I am frankly
> > doubtful than even a lot of trained biologists really understand such
> > subtle and complex biological concepts.
>
>She does seem to have read the books. I can make statements about
>psychology with which most psychologists will agree, even if I don't
>fully understand the underlying concepts.
>
> >        On the other hand, although some of the students she claims have
> > misconceptions may indeed have them (as you noted), but some of the
> > students she claims have misconceptions may actually have more insight
> > that she has, and in my opinion some of them may far be less subject to
> > tautology than she is.
>
>Ken, I've always assumed that you don't have a lot of experience
>teaching. I *aways* wonder whether some of my students don't have more
>insight than I do. But it doesn't matter how much insight a budding
>young scientist has if she's not able to put things in terms of the
>current paradigm.
>
> >        Likewise, I would not assume that all students (especially college
> > biology majors) have modern monkeys in mind when they say that apes (and
> > thus humans) evolved from "monkeys".
>
>I'll have to disagree on that one. Most biology *graduates* only have a
>conception of a few kinds of modern monkeys, unless they've had courses
>in mammalogy or primatology.
>
> > Perhaps some of them just a have a
> > more intuitive understanding that mother-daughter species
>
>There are no mother-daughter species, except arguably from peripatric
>lineage splits. Admittedly, your view of classification leads to
>mother-daughter higher taxa, but that's not the same.
>
> > Criticizing them may be the equivalent of
> > criticizing Einstein for disagreeing with students of mere Newtonian
> > physics.
>
>Or criticizing Wegener for disagreeing with the geologists of his day.
>But for every Wegener or Einstein, there are dozens of proponents of
>cold fusion, animal magnetism, morgellons, succussion, and many other
>ideas that also resulted from insights (on this list, there is even some
>disagreement as to which group Croizat belongs to).
>
> > In my opinion, stict cladism is in some ways at the Newtonian
> > stage (and therefore in some ways less helpful, and perhaps even
> > counterproductive).
>
>Of course, Einstein believed in a steady-state universe, and rejected
>quantum uncertainty. Fortunately, science advances through better
>explanations, no matter how dogmatic or persuasive any of us are at any
>given time.
>
>--
>Curtis Clark                  http://www.csupomona.edu/~jcclark/
>Director, I&IT Web Development                   +1 909 979 6371
>University Web Coordinator, Cal Poly Pomona
>
>_______________________________________________
>
>Taxacom Mailing List
>Taxacom at mailman.nhm.ku.edu
>http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
>
>The Taxacom archive going back to 1992 may be searched with either 
>of these methods:
>
>(1) http://taxacom.markmail.org
>
>Or (2) a Google search specified 
>as:  site:mailman.nhm.ku.edu/pipermail/taxacom  your search terms here