falsifying evolution

[W.Wuster]

On Sun, 15 Aug 1999, John Grehan wrote:

> W.Wuster
> 
> >- Random stratigraphic distribution of phylogenetic groupings in the
> >fossil record (e.g, mammals, dinosaurs and trilobites gayly mixed up
> >across the entire stratigraphic column)
> >
> >- Total incongruence of phylogenies derived from different character
> >systems (especially molecular evidence and morphological characters)
> >
> 
> I guess I was looking at falsification in terms of what it already
> known about the world around us. Given that the pattern of phylogenetic
> groupsing is not random (at least as generally accepted), the alternative
> does not come into direct consideration so I would not see it as a
> practical test. Further, if such a situation were to occur, evolutionary theory
> might still have been proposed, only in a different form to that we have.
> 
> In phylogenetic systematics I understand that often we do get total
> incongruence of characters, hence the need to elaborate parsimony and
> other criteria.

We do not (normally) get "total incongruence of characters". Certainly
there is incongruence. However, if you do a good morphological
phylogenetic analysis with a large number of characters for a certain
group, and then another one using, say, some DNA sequence, you will see
a fair amount of congruence between the results. Perfect? No (unless you
are very lucky), but a very long way INDEED from a random pattern, which
you might expect from separately created "kinds". If molecular and
morphological phylogenies (or other phylogenies derived from independent
character sets) did show no significant association across a wide range
of taxa, then the hypothesis of descent from a common ancestor would be
very seriously weakened.

This is very different from invoking ad hoc hypotheses to explain what
homoplasy is present.

--
Dr. Wolfgang W?ster  -  Research Fellow
School of Biological Sciences    Voicemail: +44 1248 382301
University of Wales              Fax: +44 1248 371644
Bangor LL57  2UW                 E-mail: w.wuster at bangor.ac.uk
Wales, UK                        http://sbsweb.bangor.ac.uk/