>At 11:28 PM 11/18/97 -0600, bpayne@voyageronline.net wrote:
>>
>>My primary question at this point is: If evolution is universal, driven
>>by random mutations, then how could even one group, like blue-green
>>algae, escape the mutations? If blue-green algae did not evolve, why
>>not? In short, how can we have both stasis and evolution? The two seem
>>to be antithetical.
>
>I don't think you have proven your case that they are the same.
>
For three decades J. William Schopf had data indicating that many species
species of precambrian cyanobacteria (formerly called blue-green algae)
were morphologically identical to extant species, which seemed puzzling to
him. He didn't publish this widely until he came up with an
evolutionary explanation for it: "Static Evolution". He reported that of
about 300 species described, 90 had modern look-alikes. (There was a
popular article with color photos in Science News 145:168-169).
This doesn't mean that there have been no mutations in the cyanobacteria.
His idea was that there most probably were many mutations, but they didn't
show morphologically. That is probable -- we can observe such mutations
today.
The way the word "evolution" is used today, probable but non-observable
mutation could be called "evolution". The way the word "creation" is used
today, when a genetic engineer changes one gene in an organism, he is said
to have "created" a "new" organism! I try to be very careful with these
words. I would say simply that there is no significant observable
morphologic change in the cyanobacteria.
I believe we do have both stasis and change. There has been a lot of
genetic change through time, from small genetic mutations to significant
morphological adaptations, and there is a still adaptation and speciation
today. Yet there is also considerable stability in the biota -- we still
have cyanobacteria, various sponges, mollusks, annelids, fish, etc.
similar to those seen in Lower Paleozoic faunas, and the "higher" animals
seen as fossils in higher layers.
The question is whether you think that the change includes transformation
of cyanobacteria to sponge-like organisms to mollusks and annelids and
echinoderms and fish etc, (which is called evolution), or that the change
is limited to the observable dynamics we can see in genetic experiments
and biogeographic patterns
today (which is also called evolution).
The Precambrian cyanobacteria may well not be genetically close enough to
interbreed with their look-alikes today (i.e, they may not be the same
species), but evidently they are morphologically almost "the same". It is
apparent to me that what we have here is change of species and stasis of
"kinds", if I may use that word.
Shalom.
Karen