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Re: Linnean Classification and Creationism



Chain species (or clines) do get interrupted by chromosomal rearrangements
which lead to irreversible speciation events.  For example chimps and
gorillas are ~98% identical genetically with humans (chimps slightly more so)
but they have 24 pairs of chromosomes compared to our 23.  There was a
balanced translocation of one ape chromosome onto two others in the human
lineage somewhere in the past (Autstralopithecines? Hominids?).  In attempts
at fertilizing ape ova with human sperm, the disparate numbered chromosomes
do not line up properly in the fertilized egg and no true zygote forms.  Thus
common descent may not allow the free flow of genes in both directions across
such a species boundary.  To me, the ability to fix the time of such
chromosomal rearragements makes better sense as the start of a true taxa than
anatomic similarities/differences.  

I would also recommend such chromosomal markers as the proper objective basis
for defining the limits of a "true" genus.  Organisms which are closely
related anatomically with the same chromosomal arrangement should be in the
same genus whether or not they can interbreed.  Daughter species which have
new chromosomal arrangements should be put into a new genus.  Since such
geners determination is impossible with extinct biota (ie. dinosaurs) the
standard rules should still apply for their classification. (See, I did get
us back onto the central topic of this list!)

Art