Re: Species [arbitrary to a degree]

[chris brochu <cbrochu@blue.weeg.uiowa.edu>]

> At 02:15 PM 10/22/2001, Ronald I. Orenstein wrote:
> > At 11:44 AM 22/10/01 -0500, Tim Williams wrote:
> > > Not a good criterion for deciding if a genus is valid, IMHO. 
> > > There are quite a few intergeneric mammal crosses on record.  For 
> > > example, a hybrid between a dromedary (_Camelus dromedarius_) and 
> > > a guanaco (_Lama guanicoe_):
> >
> > There are also many intergeneric hybrids in birds, notably in 
> > ducks, hummingbirds and birds of paradise.
>
> I have a friend who breeds kilifish and he says that he has had 
> several intergeneric hybrids.  They also had fertile offspring.


Something I once heard from Dave Hillis - ability to interbreed is 
the ancestral  condition, inability is derived.  There are cases 
where distantly-related frog  species can interbreed, but 
closely-related forms  within the same clade cannot.

Reproductive  isolation is  evidence  for separate-species status, 
not  the definition of it.




--
------------------------
Christopher A. Brochu
Assistant Professor
Department of Geoscience
University of Iowa
Iowa City, IA 52242

christopher-brochu@uiowa.edu
319-353-1808 phone
319-335-1821 fax

www.geology.uiowa.edu/faculty/brochu