Comments to Cladistics/Eclecticism, part 3

[Gurcharan Singh]

Susanne Schulmeister writes:
>6. Speciation backwards?
>We had this example with some humans flying to Mars.
>If these guys come back after some time and they are
>still able to interbreed with the humans on Earth, it
>is obviously still the same species. If they have been
>completely isolated from us, with no exchange of
>genetic material, long enough, there might develop a
>reproductive barrier. If the humans from Mars then
>come back and they cannot have fertile offspring with
>the humans on Earth, the Martians and Earthlings must
>be considered different species.

Well yes  they should have also developed some morphological differences
along to go with reproductive barriers otherwise it will be futile. The very
purpose of systematics is defeated if the species recognised are not
identifiable (for which we need some morphological features), should
maintain these features through generations (should produce similar
offsprings true and not interbreed with other species in nature). We have
first to identify Martians and Earthlings before you can call them different
(species).


>You circumscribed this as: “Species A budds off
>species B.”
>This thinking is based on a morphological species
>concept, which sees species as morphologically
>distinguishable entities. As I said above, this
>concept is incompatible with Cladistics and, by the
>way, is completely outdated.

I think we are going back to the same  bebate when Experimental taxonomists
during the middle of last century thought they are much superior to orthodox
taxonomists. The problems arise when one category of workers start feeling
themselves superior. To me there is no conflict between Morphological
species concept and others particularly those based on reproductive
barriers. To me almost all (with a minuscule number of exceptions) species
recognised on morphological basis by Linnaeus, his predesors and followers
and which exhibit sexual reproduction are still recognisable distinct
species because they have also developed reproductive barriers with other
species.

It is time we started respecting those practicing other approaches of study,
identify areas of understanding and find solutions to critical problems, and
I am sure they are few (like vicariants, sibling species, microspecies).

Gurcharan Singh
****************************************************************************
****
Dr. Gurcharan Singh
Department of Botany                                                    Res:
932 Anand Kunj
Sri Guru Tegh Bahadur Khalsa College                            Vikas Puri
University of Delhi , Delhi-110 007, INDIA                          New
Delhi-110018
Email: singhg at satyam.net.in; singhkg at id.eth.net
Phone: 5531534  Cell: 9810359089