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ON THE WORLD SCENE
THE HUNT IS OVER FOR "MISSING LINKS:" EVOLUTIONISTS NOW SPEAK OF "PUNCTUA
TIONALISM" For a change of pace this week away from world news, especially
the gruesome self-inflicted holocaust in Guyana, I thought I'd comment
on a new theory of evolution as presented in an article in the Los
Angeles Times on Nove-mber 19.
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After decades of futily probing the geologic strata, scientists are now
talking of abandoning their fruitless search for evolutionary "missing
links" between living creatures. The reason? According to Dr. Niles
Eldredge of the American Museum of Natural History in New York City,
such creatures probably never existed as distinctive, transitional types!
Evolutionists have long held to a school of thought known as "gradualism"
or "transformationalism," which states that each species evolved as a
result of a slow accu�ulation of small changes in its genetic makeup.
Throughout the course of tens or hundreds of millions of years, the
theory went; enough of these changes became incorporated into a given
number of creatures to justify their classification as separate species.
Dr. Eldredge observed recently at a science writer's conference called
"New Horizons in Science" that if this long-standing paleontological view
of the evolution of life was correct, one would naturally expect to find
such intermediate forms. In other words, if such a gradual, "little-by
little" evolutionary process had really been in effect, there should
logically be some fossil evidence of those changes; that is, one should
find transitional creatures that were a little bit like what went before
them and a little bit like what came after them. But no such creatures
have ever been found.
Up until now, scientists confidently held that the fossil record was
simply "inadequate" -- that someday the "gaps" would be filled in when
rock strata of the proper antiquity were located. But faced with the
growing realization that no such in-between creatures have been dis
covered in the hard evidence of the fossil record, many scientists are
coming to believe that the gradualist view of evolution is an inaccurate
portrayal of how life developed. According to Dr. Eldredge, "The old
explanation that the fossil record was inadequate is in itself inadequate
to explain what is actually known."
Instead, an alternate theory has now arisen to explain the so-called
"gaps" in fossil records. This theory is called "punctuated equili
brium" or "punctuationalism." According to this idea, today's tremendous
diversity of life has come about through sporadic leaps forward--brief
bursts of evolutionary activity--by small, well-defined groups of crea
tures, interspersed with long periods of little or no change.
Such a theory is much easier to support based on the observed facts of
paleontology. Far from finding examples of a species in which small,
gradual changes can be noted continuously down through time, Dr. Eldredge
notes that "what you really see is a fossil with no significant change
over periods of up to 10 million years." And the new theory is also
seemingly compatible with the rather abrupt emergence of species through
out time as observed in the fossil record.
What is interesting in the entire story of this changing attitude among
scientists is that none of them has as yet come forward suggesting that