Molecular clocks and the tree of life

micprf at lure.latrobe.edu.au micprf at lure.latrobe.edu.au
Sun Sep 15 20:36:24 EST 1991


It seems to me that part of the problem here in relation to what is
"primitive" and what is not may be a tendency to unconsciously
equate ancient with primitive. Could it not be argued that organisms
still undergoing rapid evolutionary change are doing so because there
is still room for "improvement"? On the other hand organisms that remain
"unchanged" for long periods are by definition those that are already
"highly adapted" so there is no "need" to change.  I put this deliberately
in teleological terms to illustrate that you can if you want actually
regard the organisms that change little as the more highly adapted and
hence less "primitive". Similarly, organisms that have been around the
longest have presumably been evolving for the longest time - are they
then to be considered more highly evolved, having done so for longer?
My conclusion is that the word "primitive" is not very useful anyway -
let's just say ancient as it carries no connotations of more or less
evolutionary progress.
				Just some thoughts,
				Paul Fisher.



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