Comments to Cladistics/Eclecticism, part 3

[Robin Leech]

Dr Singh,
I agree with Susanne and I disagree with you.  There can be physiological
differences that create real species - i.e., sexual species that are
morphologically indistinguishable (with today's methods!) that do not breed
with one another.  We call them cryptospecies, and a few other names.
Perhaps one of the best examples is the crickets which breed and chirp at
different times of the year, and when last I read, they were morphologically
indistinguishable.  A barrier does not have to be an eye-ball (or
microscope) observable physical difference.  Not all physiological
differences are expressed by an observable physical difference.
Robin Leech
----- Original Message -----
From: "Gurcharan Singh" <singhg at SATYAM.NET.IN>
To: <TAXACOM at USOBI.ORG>
Sent: Friday, February 08, 2002 9:53 PM
Subject: Re: Comments to Cladistics/Eclecticism, part 3


> 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way, is completely outdated.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