Doubts About The Modern Synthetic Theory of Evolution
Doubts About The Modern Synthetic Theory of Evolution
Doubts About The Modern Synthetic Theory of Evolution
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By FRANKB. SALISBURY
C ould our modern synthetic theory of evolution be emphasizes the importance of genetic recombina-
wrong, as were its predecessors, evolution through tions but ultimately rests upon mutations as the
the inheritance of acquired characters (Lamarck) source of the variability acted upon by natural selec-
and instant new species by mutations (De Vries) ? tion. This is where I run into problems.
What will scientists say a hundred years from now First, let me emphasize that it is quite foolish to
about Neodarwinism, the current theory? doubt most of the evolutionary story. The fossils are
I have my doubts about one point in the concept. there, and their mute testimony is overwhelming
Of course, that isn't bad; it is how science progresses. evidence that numerous forms of life have existed on
Someone doubts an accepted point, and other sci- earth over immense spans of time. Furthermore, the
entists, being fundamentally conservative about the most primitive ones existed at earliest times, the
things they have learned, immediately pounce on the most complex ones most recently. Fundamentalist
doubter (providing the point he brings up can be writers and others have tried to provide reasonable
taken seriously). Eventually this leads to one of two alternative explanations for the fossils, but these are
situations, both of them good for science: either the never convincing. Furthermore, Ahe mechanism of
doubter is proven wrong or he is proven right. If natural selection as described by Darwin and the
he is wrong, much will have been learned in marshal- modern embellishments upon it provided by popula-
ing the facts required to settle the question. If he is tion geneticists can hardly be questioned. Gene
right, whole new areas of understanding may have frequencies do change in populations as a result of
been opened. My particular doubt has been pub- selection pressures. This has been observed in the
lished (Salisbury, 1969), scientists have taken their field and duplicated in the laboratory. No scientific
shots at it (Smith, 1969), and it has been defended fact could be demonstrated more clearly.
(Spetner, 1970). But will changes in gene frequencies in response
to selection pressures account for evolution in the
The Originof Variability broadest sense: life originating in the ancient soupy
The problem is the origin of variability. Both seas and developing over eons of time until the earth
Lamarck and De Vries put forth their theories to is covered with flowering plants and thinking men?
account for this. Darwin was fully aware of the Only if there is a continual source of new genes for
seriousness of the problem, and he retreated with selection to act upon. If, somewhere back in the dim
misgivings to Lamarck's ideas. The modern theory reaches of time, a cell evolved the process of photo-
synthesis, it is because, according to the present
theory, the proper genes and their enzymes were
The author prepared this essay for his textbook of botany there for selection to act upon. Could random
(of which William A. Jensen, of the University of California changes in the nucleotide sequences of DNA (muta-
at Berkeley, is senior author), to be published by Wadsworth tions) provide these genes and ultimately the en-
Publishing Co., Belmont, Calif. Salisbury is professor of plant
physiology, Plant Science Dept., College of Agriculture, Utah zymes? At the moment, I doubt it, and my reasons
State University, Logan 84321. for doubting are based upon discoveries during the
335