At 09:06 AM 2/2/2005 -0500, Don Cunningham wrote:
>I wonder what the vote would be on gravity. That’s just a theory too.
LOL. As Don ironically points out, that evolution is a fact is almost as
clear as gravity is a fact.
But HOW evolution occurs is still a wonderful subject of theory (so is
gravity, BTW). Below is an article by Freeman Dawson at
that describes some interesting theorizing by Carl Woese.
The Darwinian Interlude
By Freeman Dyson March 2005
(Freeman Dyson is professor emeritus of physics at the Institute for
Advanced Study in Princeton, NJ. His research has focused on the internal
physics of stars, subatomic-particle beams, and the origin of life.)
Carl Woese published a provocative and illuminating article, “A New Biology
for a New Century,” in the June 2004 issue of Microbiology and Molecular
Biology Reviews. His main theme is the obsolescence of reductionist biology
as it has been practiced for the last hundred years, and the need for a new
biology based on communities and ecosystems rather than on genes and
molecules. He also raises another profoundly important question: when did
Darwinian evolution begin? By Darwinian evolution he means evolution as
Darwin himself understood it, based on the intense competition for survival
among noninterbreeding species. He presents evidence that Darwinian
evolution did not go back to the beginning of life. In early times, the
process that he calls “horizontal gene transfer,” the sharing of genes
between unrelated species, was prevalent. It becomes more prevalent the
further back you go in time. Carl Woese is the world’s greatest expert in
the field of microbial taxonomy. Whatever he writes, even in a speculative
vein, is to be taken seriously.
Woese is postulating a golden age of pre-Darwinian life, during which
horizontal gene transfer was universal and separate species did not exist.
Life was then a community of cells of various kinds, sharing their genetic
information so that clever chemical tricks and catalytic processes invented
by one creature could be inherited by all of them. Evolution was a communal
affair, the whole community advancing in metabolic and reproductive
efficiency as the genes of the most efficient cells were shared. But then,
one evil day, a cell resembling a primitive bacterium happened to find
itself one jump ahead of its neighbors in efficiency. That cell separated
itself from the community and refused to share. Its offspring became the
first species. With its superior efficiency, it continued to prosper and to
evolve separately. Some millions of years later, another cell separated
itself from the community and became another species. And so it went on,
until all life was divided into species.
The basic biochemical machinery of life evolved rapidly during the few
hundred million years that preceded the Darwinian era and changed very
little in the following two billion years of microbial evolution. Darwinian
evolution is slow because individual species, once established, evolve very
little. Darwinian evolution requires species to become extinct so that new
species can replace them. Three innovations helped to speed up the pace of
evolution in the later stages of the Darwinian era. The first was sex,
which is a form of horizontal gene transfer within species. The second
innovation was multicellular organization, which opened up a whole new
world of form and function. The third was brains, which opened a new world
of coördinated sensation and action, culminating in the evolution of eyes
and hands. All through the Darwinian era, occasional mass extinctions
helped to open opportunities for new evolutionary ventures.
Now, after some three billion years, the Darwinian era is over. The epoch
of species competition came to an end about 10 thousand years ago when a
single species, Homo sapiens, began to dominate and reorganize the
biosphere. Since that time, cultural evolution has replaced biological
evolution as the driving force of change. Cultural evolution is not
Darwinian. Cultures spread by horizontal transfer of ideas more than by
genetic inheritance. Cultural evolution is running a thousand times faster
than Darwinian evolution, taking us into a new era of cultural
interdependence that we call globalization. And now, in the last 30 years,
Homo sapiens has revived the ancient pre-Darwinian practice of horizontal
gene transfer, moving genes easily from microbes to plants and animals,
blurring the boundaries between species. We are moving rapidly into the
post-Darwinian era, when species will no longer exist, and the evolution of
life will again be communal.
In the post-Darwinian era, biotechnology will be domesticated. There will
be do-it-yourself kits for gardeners, who will use gene transfer to breed
new varieties of roses and orchids. Also, biotech games for children,
played with real eggs and seeds rather than with images on a screen.
Genetic engineering, once it gets into the hands of the general public,
will give us an explosion of biodiversity. Designing genomes will be a new
art form, as creative as painting or sculpture. Few of the new creations
will be masterpieces, but all will bring joy to their creators and
diversity to our fauna and flora.
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