Allan Harvey, responding to Todd Greene, wrote:
>> What is it about "macroevolution," what are the
>> characteristics of this evolution that are the cause
>> for raising some kind of distinction from
>>"microevolution"? Is this a distinctive kind
>> of evolution recognized through scientific
>> observation? Or is this concept something in
>> the eye of the creationist beholder?
>
> Somebody, I think on this list, once remarked that
> "microevolution" is usually effectively defined as
> "evolution I believe in" while "macroevolution" means
> "evolution I don't believe in." I too would like to
> see anti-evolutionists give the terms scientific
> definitions and use them consistently. I'm not
> holding my breath.
The terms "microevolution" and "macroevolution" were
coined by Russian evolutionary geneticists in the late
1920s, and were already common parlance in the
evolutionary literature by the mid 1930s. See, for
instance, the introduction to Dobzhansky's _Genetics
and the Origin of Species_, where he describes the
"reluctant sign of equality" that biologists have placed
between micro- and macroevolution:
"...there is no way toward an understanding of the
mechanisms of macro-evolutionary changes, which
require time on a geological scale, other than through
a full comprehension of the microevolutionary processes
observable within the span of a human lifetime and
often controlled by man's will. For this reason we
are compelled at the present level of knowledge
reluctantly to put a sign of equality between the
mechanisms of macro- and micro-evolution, and,
preceeding on this assumption, to push our investigations
as far ahead as this working hypothesis will permit."
(T. Dobzhansky, _Genetics and the Origin of Species_
[New York: Columbia University Press, 1937], p. 22)
A "working hypothesis" can fail under contrary evidence,
of course, and today many evolutionary theorists argue
that there is in fact an inequality between micro- and macro-
evolution. See, for instance, this recent paper by
paleontologist Douglas Erwin:
Douglas H. Erwin
Department of Paleobiology
MRC-121
National Museum of Natural History
Washington DC 20560
"Macroevolution is more than repeated rounds of microevolution"
_Evolution & Development_ 2 (2000):78-84
SUMMARY [Erwin's abstract]: Arguments over macroevolution versus
microevolution have waxed and waned through most of the twentieth
century. Initially, paleontologists and other evolutionary biologists
advanced a variety of non-Darwinian evolutionary processes as
explanations for patterns found in the fossil record, emphasizing
macroevolution as a source of morphological novelty. Later,
paleontologists, from Simpson to Gould, Stanley, and others,
accepted the primacy of natural selection but argued that rapid
speciation produced a discontinuity between micro- and
macroevolution. This second phase emphasizes the sorting of
innovations between species. Other discontinuities appear in
the persistence of trends (differential success of species within
clades), including species sorting, in the differential success of
clades and in the origination and establishment of evolutionary
novelties. These discontinuities impose a hierarchical structure to
evolution and discredit any smooth extrapolation from allelic
substitution to large-scale evolutionary patterns. Recent
developments in comparative developmental biology suggest
a need to reconsider the possibility that some macroevolutionary
discontinuities may be associated with the origination of
evolutionary innovation. The attractiveness of macroevolution
reflects the exhaustive documentation of large-scale patterns
which reveal a richness to evolution unexplained by microevolution.
If the goal of evolutionary biology is to understand the history of
life, rather than simply document experimental analysis of evolution,
studies from paleontology, phylogenetics, developmental biology,
and other fields demand the deeper view provided by macroevolution.
[end abstract]
In short, the distinction between micro- and macroevolution was
formulated by evolutionary biologists (not creationists or design
theorists), and remains a topic of active research and debate
within evolutionary theory.
Paul Nelson
Senior Fellow
The Discovery Institute
www.discovery.org/crsc
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