Darwin-L Message Log 1:47 (September 1993)

Academic Discussion on the History and Theory of the Historical Sciences

This is one message from the Archives of Darwin-L (1993–1997), a professional discussion group on the history and theory of the historical sciences.

<1:47>From tclarke@uoguelph.ca  Mon Sep  6 23:50:40 1993

Date: Tue, 7 Sep 1993 00:30:43 -0400 (EDT)
From: Tom Clarke <tclarke@uoguelph.ca>
Subject: A reply to ordered changes
To: darwin-l@ukanaix.cc.ukans.edu

   I'm not sure where the concept that evolution means ordered change
 came from in this list, but I don't think that I can agree with this
 new definition.  Evolution, in a biological sense, is simply a change
 in allele frequencies through time.  In a non-biological sense it can
 be taken as simply change through time.  No order is implied, or even
 necessary.  As Jacob Kenneth stated, ordered change presupposes that
 there is a predestined end result, and that the organism or system is
 simply progressing upon a well defined pathway to reach this end result.

  Evolution is rarely as neat and clean as some would have it - selection
 preassure can produce a 'desired' outcome, but it can also produce a lot
 of unthought of outcomes that still satisfy the main requirement of
 selection - survival.  Look at the selection preassure on parasitic
 wasps to find hosts - as well as the most obvious result, that of
 increased host-detection systems and modified ovipositors to reach
 host insects and lay eggs within them, there are the novel approaches
 taken by such families as the Perilampidae, which utilize active first
 instar larva that seek out their host, and the Trigonalidae which lay
 large numbers of eggs on the leaves of plants in hopes that they will
 be eaten by a parasitised caterpillar.  From a single selection preassure,
 the need for host insects, the parasitic wasps have produced a great
 diversity of reproductive strategies.  Nothing particularily ordered
 about it.

   As well, even without selection preassure there can be change
 through random loss of alleles that would fix new traits within a
 population.  In this especially there is no sign of order - what
 traits emerge through genetic drift are entirely up to random chance.
 (I'm not sure how this would apply to non-organic systems).

  Anyway, its past midnight over here, so I'll stop writing...

 ...it will be interesting to see where this discussion heads.

   -Anax-