systematics

Dennis R. Rasmussen PIPIAPAN at VMS3.MACC.WISC.EDU
Sun Apr 28 08:40:00 EST 1991


 
 
 
>From:    IN%"kuento at kuhub.cc.ukans.edu" 27-APR-1991 05:12:09.28
>To:      bionews at kuhub.cc.ukans.edu
>Subject: basic behavioral systematics (once again!)
>
>Hello again (for those who have read my previous request for opinions)
>
>As I had previously stated, I will post the paper that emerges from
>this discussion (as well as the concomitant literature search
>material) as soon as I am through with revisions.
>
>I have another question re: behaviors and cladistics, this time having
>to do with basic methodology in systmatics not just behavior.--
>
>That is: traditionally, systematicians have looked for those
>characters that they view as being completely (or nearly so) from the
>force of natural selection.  The reasons for doing this are unclear to
>me (if you think you have a good feel for this, please let me know)
>but i think they have to do with wanting to separate the causative
>agent of evolution from the process of evolution - in an effort to
>avoid circularity??  However, in practice this is only weakly followed
>>at best.  Most systematists that I know have openly admitted that they use
>whatever character that is most helpful.
>
>Including all of the aspects of an organism into the phylogenetic
>analysis seems to me to be the only logical process.  After all,
>evolution works on more than just the morphology.  In fact some would
>say taht evoltion doesn't work on the morphology and tht what is
>selected is the behviors that are performed with the morphology!
>
>In brief my question is threefold:
>    a) if the characterization of the traditional approach to
>       character selection appropriate?
>
>    b) if so: why is it thought that the separation of the causes
>       from the process necessary?
 
>    c) lastly, how does this philosophically affect someone who
>       desires to include behavior into their phylogeny?
>       -does it mean that we should look for behav. patterns
>        that presumably evolution doesn't act upon?
>       -if so, how can we characterize those patterns that
>        are immune from evolution's action?
>
>Please respond to me directly, as well as to the board.  Thanks in
>advance for your interest, it is highly appreciated!
>
>Jim D-B
>------(please include "JDB" in subj header of mail to this user)------
>Jim Danoff-Burg     (Snow Museum, Univ. of Kansas, Lawrence, KS 66045)
>Bitnet: KUENTO at UKANVAX     "Myrmecophiles-R-Us"
 
April 28, 1991
 
Systematicians may have appropriately looked at characters
which they believe to be the result of natural selection
since the results of past natural selection are the
genotype of the organism.  Behavior, chance,
environmentally acquired characteristics may all have
contributed to current genotypic differences between
populations.
 
Including all characteristics, no matter what their source,
is, of course, quite relevant if one is looking at the
CURRENT process of natural selection.  Non-genetic and
environmentally acquired differences between individuals
may influence differential reproductive success.
 
If for example, someone dyed a population of snowshoe hares
brown in the winter in the arctic they would be likely to
have greater mortality than white showshoe hares.
Predators would, presumably, be more likely to sight and
catch the dyed hares. Yet this characteristic would not be
valuable for cladistics. (Unless selection of individuals
to be dyed brown had a genetic correlate, such as
probability of being trapped).
 
The genetic differences between current populations are the
result of historical and past selection pressures, not
current selection pressures.  This is probably the primary
reason for reliance on characteristics that are believed to
differ between populations due to genetic factors. While
evolution selects phenotypes it is the genotypic basis of
phenotypes that is modified by natural selection.
 
I have found the following reference to be very useful and
have always found more upon every reading:
 
Tinbergen, N. (1965). Behaviour and natural selection.  In:
Moore, J. A. (ed.), Ideas in Modern Biology.  Natural
History Press, New York. pp. 521-542.
 
Surely you are aware of the complex and long history of
this topic that may be traced from Huxley and Lorenz. The
following are some of my papers that deal tangentially with
some aspects of your questions:
 
Rasmussen, D. R. (1981).  Evolutionary, proximate and
functional primate social ecology.  In: Bateson, P. P. G. &
Klopfer, P.  R. (eds.), Perspectives in Ethology, Vol. 4,
New York, Plenum, pp. 75-1O3.
 
Rasmussen, D. R. (1988).  Studies of food enhanced primate
groups: current and potential areas of contribution to
primate social ecology.  In: Fa, J. E., & Southwick, C. H.
(eds.), Ecology and behaviour of food-enhanced primate
groups.  Alan R. Liss, New York, pp. 313-346.
 
A major problem that I deal with in the 1988 paper is that
complex behavioral-genetic analyses are often necessary to
prove a difference in behavior between populations has a
genetic basis.  If the behavioral difference between
populations  does not have a genetic basis then we may have
a situation analogous to our white and brown snowshoe
hares.  One could see how a whole line a falacious
reasoning might be developed to explain the adaptive
significance of a dark pelage (and hence for its genetic
basis).
 
I hope this helps.  I look forward to reading your paper.
 
 
 
Dennis R. Rasmussen, Ph.D.



More information about the Bioforum mailing list