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Review of
Jonathan
Wells' Icons of Evolution published in Science 6/01
EVOLUTION:
Fatally Flawed Iconoclasm - A review by Eugenie C. Scott*
Icons of Evolution Science or Myth? Why Much of What We Teach About
Evolution is Wrong
Jonathan Wells - Regnery, Washington, DC, 2000. 352 pp. $27.95. ISBN
0-89526-276-2.
If someone were to charge that textbooks present
atomic theory using evidence that is erroneous, misleading, and even
fraudulent, and that we should therefore question whether matter is
composed of atoms, eyebrows would be raised--at least at the accuser. If
someone further claimed that distinguished physicists crassly
participate in this fraud to keep the research dollars rolling in or to
promote a materialist philosophical agenda, scientists would be angry at
the attempt to besmirch the reputations of respected scholars. And if
the
same person proposed that citizens should encourage local school boards
to insert anti-atomic theory disclaimers in science textbooks,
discourage Congress from funding research in atomic theory, and lobby
state legislatures to restrict its teaching, it is doubtful that such
exhortations would receive much attention.
Such would be the fate of Jonathan Wells' call to arms in Icons of
Evolution, if biological evolution were not substituted for atomic
theory in the above scenario. But rather than being ignored, Wells' book
has already inspired attacks on textbooks and at least one lawsuit
against a local school board (1). Unlike atomic theory, evolution has
obvious theological implications, and thus it has been the target of
concerted opposition, even though the
inference of common ancestry of living things is as basic to biology as
atoms are to physics.
Wells claims "students and the public are being
systematically misinformed about the evidence for evolution" because
high school and college textbooks rely on invalid or misleadingly
interpreted "icons": the peppered moth, the Miller-Urey experiment,
vertebrate limb homology, Haeckel's embryos, Archaeopteryx, Darwin's
finches, the tree of life, four-winged fruit flies, fossil horses, and
the familiar fossils-to-modern-humans
series of striding men. These are well-known and frequently repeated
examples of principles or mechanisms of evolution, or episodes from the
history of the field. Textbooks use them because they communicate these
basics clearly to uninformed students. But Wells' premise that textbook
examples are the best evidence for evolution is wrong; evolution does
not stand or fall on whether a high school book simplifies an example of
natural selection.
I examined the books reviewed by Wells and found
that things are not always as he portrays them. For example, textbooks
don't uncritically rely upon Haeckel or his drawings in their
discussions of embryology. Only two of the ten books reproduce Haeckel's
embryo drawings, although all of them present, in varying degrees of
detail, the scientifically accepted inference that comparative
embryology reflects common ancestry. Some of
the other "icons" don't occur in most of his sample, and even when they
do, they are often accorded only a few paragraphs (2).
Textbooks are, alas, far from perfect, but authors
and publishers would do little to improve their wares by altering their
texts to suit Wells. This is because Wells presents a systematically
misleading view of evolution. Individual sentences in Icons are usually
technically correct, but they are artfully strung together to take the
reader off the path of real evolutionary biology and into a thicket of
misunderstanding. The Cambrian explosion is supposed to be a "serious
challenge to Darwinian evolution" because "phyla and classes appear
right at the start." Wells is wrong to claim that the Cambrian
appearance of major body plans supposedly puts paleontologists into a
tizzy; actually, they regard it simply as a phenomenon yet to be
explained. Unexplained is not unexplainable. More misleading to
nonscientists is the implication that most modern phyla and classes
occur in the Cambrian, which doesn't hold true for either animals or
plants. Wells neglects to mention that insects, amphibians, reptiles,
birds, and mammals are all post-Cambrian (and even Cambrian "fish" are
problematic). Wells correctly notes that chordates appear in the
Cambrian, and he correctly describes chordates as "tunicates, lancets,
vertebrates." But a layman hearing "vertebrates" is more likely to think
of lions and tigers and bears than of the very primitive, worm-like
Cambrian chordate Pikaia. Here, and with the other "icons," what Wells
leaves out of his discussion is often critical.
The author's discussion of the admittedly complex changes
in populations of the peppered moth is both incomplete and incorrect. He
excoriates textbooks for showing "fraudulent" photos of light and dark
moths glued to lichen-covered tree trunks. Wells argues that moths don't
rest on tree trunks and that lichens are not associated with moth color
changes. But he ignores research showing that moths rest on all parts of
trees (including the trunks) and that the color of the surface upon
which moths alight is what counts in predation. Dark moths against light
backgrounds get nabbed, whether or not lichens form those backgrounds.
Textbooks show staged photos of moths affixed to trees to illustrate
crypsis of dark and light moths against dark or light backgrounds; not
unreasonably, photographers
didn't sit patiently by waiting for the right combinations of moths and
backgrounds. Researchers glued moths to trees to test whether birds
differentially prey upon moths that contrasted against their surface, an
experiment necessary to test the hypothesis of bird predation. This is
not fraud, it's research.
Space limits a full treatment of the book's errors and misdirections,
but as a physical anthropologist I must mention that Wells cites science
writer Henry Gee on the paucity of human fossils from 5 to 10 million
years ago. Yet he leaves out the abundance of such fossils over the last
5 million years, which is when humans evolved. Combining this deflection
with a 20-year-old citation from another journalist about the scarcity
of human
remains, the lay reader may incorrectly conclude that the human fossil
record is unusually weak. Wells also ignores the many significant
discoveries of the past two decades.
Even more misleading, however, is Wells' steady drumbeat of
accusation of fraud, misconduct, deception, and incompetence against
evolutionary biologists and his claim that evolution is shoddy science
maintained by ideology rather than evidence.
Although his targets have treated the book with
derision, Icons of Evolution has high potential to mislead the
nonscientific public, and scientists should be prepared to respond.
Notes
1.Arkansas legislation HB 2548 (2001) would ban textbooks which
included the icons. Patty Pulliam, a West Virginia
parent, listed the "icons" in her lawsuit against Kanawha County
concerning alleged textbook inaccuracies. Joe
Baker, a senior at a Perkasie, PA, high school, is lobbying his
school board to insert icons disclaimers into the
textbooks.
2.The set reviewed by Wells is a miscellany of ten high school and
college biology books, which curiously omits
some best-selling texts and other titles with comprehensive
treatments of evolution. It is unclear whether his results
can be generalized. Wells's critique is discussed further in A.
Gishlick and E. C. Scott, "Do textbooks mislead
students about evolution? A look at Icons of Evolution," Reports
of the NCSE, in press.
The author is at the National Center for Science Education, 420 40th
Street, Suite 2, Oakland, CA 94609-2509, USA. E-mail:
scott@ncseweb.org
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