Re: vital effect and genetics

From
Date
>To: 76653.1410@compuserve.com
>From: c583scb@semovm.semo.edu (Dr Peter Roopnarine)
>Subject: Re: vital effect and genetics
>
>>	I'm doing a little paper in my geochem class and I'm looking for
>>resources.
>>	My topic is the vital effect and it's possible use in determining
>>paleospecies.  The basic premise is that the vital effect is a biological
>>influence on the isotopic composition of shells and tests.  Suppose you had a
>>bunch of forams (or something) and you wanted to know how many species are
>>represented.  They all look about the same, so physical characteristics won't
>>help much.  So, you turn to isotopes.  Given that these forams were living in
>>the same region at the same time, then any isotopic differences must be
genetic.
>>You can eliminate such other factors that can influence the isotopic
composition
>>as diet (they look the same, they probably lived that same), temperature,
water,
>>and climate.  That leaves the vital effect.  Since the vital effect is
>>biological, it must have genetic roots.  Therefore, different but closely
>>related species ought to have subtle differences in their vital effect.  The
>>question is, is this difference detectable?
>>	I've found five references, but I'd like more.  I'll provide a list of
>>what I've got if you want.
>>	Thanks for your help.
>>
>>Eric SImpson
>>Dept. of Geosciences
>>Texas Tech University
>>Box 1053
>>Lubbock, TX  79409-1053
>>(806)-742-3132
>>76653,1410@compuserve.com
>>
>>
>
>I could be wrong, but it seems that so-called "vital effects" are probably
not so easily assignable to genetic causes. There is always the possibility
of ontogenetic changes in physiology and/or ecology. These would also affect
the isotopic composition of the foram. test. We need adequate tests and
controls derived from Recent species. Without a clear understanding of the
causes of vital effects (=deviates from what you think it should look like),
why trust isotopic signals more than morphological discrimination (or lack
thereof)?
>
>Peter Roopnarine
>Department of Biology
>Southeast Missouri State University
>Cape Girardeau MO 63701
>proopnar@biology.semo.edu
>http://biology.semo.edu/web/peter/personal.html
>