[Taxacom] Dispersal example

[John Grehan]

The foundation for an orthogenesis concept in panbiogeography has not been
tied to any phylogeny. Discussions among botanists regarding orthogenetic
processes was superseded by discussions in the 1980?s and later in
biogeography.



John Grehan


On Mon, Apr 21, 2014 at 10:34 AM, Curtis Clark <lists at curtisclark.org>wrote:

> On 2014-04-21 2:41 AM, Michael Heads wrote:
> > Accepting mutation-driven evolution, or any other theory, is certainly
> > not necessary. But Nei's idea is very interesting, and it means that
> > you don't have to accept that particular morphology has been
> > 'designed' for the 'good' for the species.
>
> I've had the acquaintance of some panselectionists (there's that "pan"
> again), who even discount neutral mutations, and have not been convinced
> by their arguments. On the other hand, I've seen enough examples of
> "strong selection" to not discount selection as a major feature in
> evolution, and I've seen the 20th C "orthogenetic paradigm" in
> angiosperm evolution fall apart in the light of phylogenetic evidence.
> Many botanists accepted orthogenesis even absent a mechanism, and as
> recently as the 1970s there was still a tension between those and other
> botanists who were in the "modern synthesis" camp (I remember arguments
> between Cronquist and Stebbins when I was a grad student).
>
> --
> Curtis Clark        http://www.csupomona.edu/~jcclark
> Biological Sciences                   +1 909 869 4140
> Cal Poly Pomona, Pomona CA 91768
>
>
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