[Taxacom] Phylogenetic classification (and paraphyletic species)

[Kenneth Kinman]

Hi Stephen,
       That seems to reflect what I meant by "some element of founder
effect" leading to paraphyly in speciation.  Sort of a "founder effect"
sensu lato, including not only small dispersal events, but also small
vicariant populations, or even a larger vicariant population which
subsequently undergoes a bottleneck.  All three result in varying
amounts of restriction of the gene pool in the daughter population
(which can lead to speciation).  Not sure whether or not that indicates
my view is a bit closer to that of Michael Heads.
       ------Cheers,  
                      Ken    
P.S.  Since you use the phrase "paraphyletic species", does this mean
you are sort of warming up to the idea that species can be paraphyletic
(rather than just groups of species)?          
---------------------------------------------------
Stephen Thorpe wrote:
     If, however, the founder effect in itself does not lead to
speciation,  then the main factors will be random mutations acting
independently on the small population, leading to divergence from the
parent  population. Small population size may facilitate more rapid
divergence  (leading to "paraphyletic species" if the parent population
gives rise to multiple new species by vicariance and/or dispersal events
while itself remaining largely unchanged). In this scenario, even if
parent  and daughter populations started out with identical gene-pools,
the end products would be different. 
It does seem to me that both scenarios could be involved, with the
founder-effect magnifying the effect of "background" divergence ... 
Cheers, 
Stephen