FW: Platnick's recent lecture (URL link)
sdmanning at ASUB.EDU
Thu Mar 7 16:45:12 CST 2002
It seems to me that reproductive isolation isn't necessarily a good
indicator of homology - there probably is a positive correlation but, I
would expect, a weak one. For example, single mutations could cause
reproductive isolation if they resulted in flowers of the wrong shape for
traditional pollinators, or physical impossibility of copulation in
insects, etc. On the other hand, Catalpa species which supposedly were
disjunct (isolated) between Asia and eastern North America for several
million years are quite interfertile after all those years despite
significant morphological and molecular divergence.
At 03:21 PM 3/7/02 -0600, Thomas Lammers wrote:
>Well, it's BOTH, really.
>I prefer to think of the ability to interbreed as an indicator of the
>degree of HOMOLOGY of the respective genomes. Surely that concept of
>homology can be made to fit a cladistic viewpoint somehow ...
>At 04:14 PM 3/7/02 -0500, Bill Shear wrote:
>>a common misunderstanding of the Biological Species
>>Concept. Norm states that the retention of the ability to interbreed is a
>>plesiomorphy and so could not be used to define a species. However, the
>>ability to interbreed is not the criterion used in the BSC to define a
>>species--it is the reproductive isolation of that population from other such
>>populations, and that, surely, is an acquired apomorphy.
>Thomas G. Lammers, Ph.D.
>Assistant Professor and Curator of the Herbarium (OSH)
>Department of Biology and Microbiology
>University of Wisconsin Oshkosh
>Oshkosh, Wisconsin 54901-8640 USA
>e-mail: lammers at uwosh.edu
>Plant systematics; classification, nomenclature, evolution, and
>biogeography of the Campanulaceae s. lat.
>"Today's mighty oak is yesterday's nut that stood his ground."
> -- Anonymous
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