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Evolution and Abiogenesis
Michael Behe's Criticism of Biochemistry Textbooks
v2.0 ©2006 Laurence A. Moran
Science v. Religion
Seen in the light of evolution, biology is, perhaps,
intellectually the most satisfying and inspiring science. Without that light it
becomes a pile of sundry facts—some of them interesting or curious but
making no meaningful picture as a whole.
s part of his effort to discredit evolution, Michael Behe looked at the scientific literature to see how many papers were published on evolution of biochemical systems. He claims there aren't many—a claim that comes as a great surprise to most researchers. Behe is not an expert on the latest research in molecular evolution so perhaps we can excuse his lack of knowledge in this area. Next Behe examines biochemistry textbooks to see if they mention evolution. Since Behe teaches university level biochemistry courses, we expect his criticism of textbooks to be closer to the mark. Behe said,
A survey of thirty biochemistry textbooks [reference omitted] used in major universities over the past generation shows that many textbooks ignore evolution completely.
This is a subject that interests me a great deal since I am an author of two of the textbooks that Behe examined (Moran et al. 1994; Horton et al. 1993).
Is Behe's statement correct? Is it true that biochemistry textbook authors ignore evolution? Of course it isn't true—and this should come as no surprise to those who are familiar with the tactics of the anti-evolutionists. Behe is deliberately misleading his readers in several different ways. His first strawman is the implication that biochemistry textbooks are about evolution. They are not. It is not the purpose of biochemistry textbooks to describe and explain evolution. Instead, the authors make the assumption that students have taken biology and are familiar with the basic concepts of evolution. Biochemists know that nothing in biology makes sense except in the light of evolution and they simply assume that intelligent students will understand the references to evolution scattered throughout the textbooks. The textbooks do not ignore evolution, they take it as a given fact.
The other major deception employed by Behe is to assume that all references to evolution in the biochemistry textbooks can be found in the indices. "Darwin's Black Box" contains a table of leading textbooks listing the total number of index entries and those that refer to evolution. This is an extremely poor way for Behe to search the textbooks for examples of evolution. Let me explain why. The indices usually point to explanations or definitions of things that are in the body of the textbook. For the most part, in these books there are few "explanations" of evolution, per se. There's a good reason for this. It shouldn't come as a surprise that there are few entries under "evolution" since that's not the subject matter of biochemistry. This doesn't mean that biochemistry isn't discussed in the context of an understanding of evolution, and it doesn't mean that there are no evolutionary explanations of biochemical processes. Behe seems to think that the indices in a textbook should refer to every single mention of a particular word, yet he knows that's not true, even in his own book. (Another problem is that textbook indices are usually compiled by editors hired by the publisher. Typically they're one of the last things done before publication and that's why they aren't so good. From my own experience I suspect that most authors are pretty sick of the book by that stage and don't pay a lot of attention to the index.)
Behe's next sentence is,
For example, Thomas Devlin of Jefferson University in Philadelphia wrote a biochemistry textbook that was first published by John Wiley & Sons in 1982; new editions followed in 1986 and 1992. The first edition has about 2,500 entries in its index; the second edition also has 2,500; and the third has 3,000. Of these, the number referring to evolution are zero, zero, and zero, respectively.
Does this mean that Devlin ignores evolution completely? Not bloody likely. Here's the opening paragraph on page 1 of the 3rd edition published in 1992.
By a process not entirely understood and in a time span that is difficult to comprehend, elements such as carbon, hydrogen, oxygen, nitrogen, and phosphorus combined, dispersed, and recombined to form a variety of molecules until a combination was achieved that was capable of replicating itself. With continued evolution and the formation of ever more complex molecules, the environment around some of these self-replicating molecules was enclosed by a membrane. This development gave these primordial molecules a significant advantage in that they could control to some extent their own environment. A form of life had evolved and a unit of space, the cell, had been established. With the passing of time a diversity of life evolved, and their chemistry and structures became more complex. Eventually, they were capable of extracting nutrients from the environment, chemically converting these nutrients to either sources of energy or to complex molecules, of controlling chemical processes they catalyzed, and of replicating themselves into other cells. The challenge of biochemical research is to unravel the chemical mechanisms behind the organized and controlled manner in which cells carry out their function.
Does this sound like someone who ignores evolution? As you might expect from the opening paragraph, evolution comes up again many times in the textbook, although it's fair to say that it isn't emphasized.
By the way, Devlin's affiliation is the Dept. of Biological Chemistry, Hahnemann University, Philadelphia and not Jefferson University as Behe states in his book. The affiliation is clearly stated on the title page of the biochemistry textbook, 3rd edition—the one that Behe supposedly examined so closely. Devlin did not write the textbook. He is clearly identified on the cover as the editor. There are 28 chapters written by a total of 27 authors. The authors of each chapter are prominently identified in several places in the book. In case anyone is interested, the latest edition is:
Devlin, T.M. (editor) (1997)
This is an excellent book for those who want to learn about human biochemistry and clinical aspects.
A textbook by Frank Armstrong of North Carolina State University, published by Oxford University Press, is the only recent book to include an historical chapter reviewing important developments in biochemistry, begining with the synthesis of urea in 1828. The chapter does not mention Darwin or evolution. In three editions Armstrong's book has found it unnecessary to mention evolution in its index.
I have a copy of the 3rd edition (1989)—this is the latest edition in Behe's list. It's true that there is no index entry under "evolution." However, there are plenty of references to evolution in the textbook. In chapter 8, for example, there's a whole section entitled "Biochemical Evolution." Perhaps Behe should have scanned the Table of Contents and not the index?
Armstrong doesn't mention Darwin in his introductory historical chapter. Many biochemistry textbooks don't, although I've inserted a photo of Charles Darwin in my latest book just to spite Behe. It's not true that biochemistry textbooks, in general, ignore evolution in their opening chapters as Behe would have us believe. We saw that Devlin begins his book with evolution and others point out that an understanding of evolution is important in understanding biochemistry. One of my earlier books (Horton et al. 1993) is on Behe's list and in chapter 1 I wrote a section entitled "All Organisms Have Evolved from an Ancient Ancestor." I guess Behe missed this when he was collecting his data.
Behe continues to make a fool of himself,
Another textbook published by John Wiley & Sons has one citation to evolution in its index out of a total of 2,500. It refers to a sentence on page 4: 'Organisms have evolved and adapted to changing environments on a geological time scale and continue to do so.' Nothing else is said.
Behe refers to a book by Conn, Stumpf et al. (1987). There is a single entry under "evolution" in the index. It refers to page 4—here's the entire paragraph.
The biochemist must be aware of the abilities of organisms to change and adapt, not only in the time frame of an individual organism but also on an evolutionary time scale. It is not enough to consider any noncellular, single cell, or multicellular organism in isolation as it exists today. Organisms can be classified as belonging to species or similar taxonomic or functional groupings. Organisms exchange, or at least transmit, symbolically encoded, controlling information. That is, they have genetic systems. Capabilities of the progeny reflect the capabilities of the parent(s), and the progeny follow definite plans of development. Those plans, though definite, are not rigid. They are modified by the environment and time. Organisms cannot be understood without a consideration of what their antecedents must have been like. Organisms have evolved and adapted to changing environments on a geological time scale and continue to do so. Thus, biochemists seek chemical explanations of how organisms adapt to their environment both in the short term and over eons." [emphasis added]
One might expect there to be more about evolution in such a textbook and you wouldn't be disappointed. Chapter 3 discusses phylogenetic trees based on amino acid sequences, chapter 11 introduces the pentose phosphate pathway in the context of an evolved system, and chapter 15 presents the evolution of photosynthesis. These are just a few of the many examples that Behe must have missed when he read this textbook.
Behe goes on,
Some textbooks make a concerted effort to inculcate in students an evolutionary view of the world ....
This is correct. What's the problem? Isn't it an important part of education to teach the correct scientific view of the world?
Behe concludes with,
Many students learn from their textbooks how to view the world through an evolutionary lens. However, they do not learn how Darwinian evolution might have produced any of the remarkably intricate biochemical systems that those texts describe.
It's true that the biochemistry textbooks do not contain complete descriptions of all of the evolutionary pathways that lead to intricate biochemical systems. In most cases we don't know the exact evolutionary pathway. Even if we did we wouldn't put them all in a biochemistry textbook because the texts are about biochemistry and not about evolution. What textbook authors do is point to examples of biochemical evolution and explain how some of the data is acquired (e.g. amino acid and nucleotide sequences). Furthermore, most of us wouldn't emphasize "Darwinian evolution" since that's an outmoded concept - especially at the molecular level. We talk about the modern version of evolution in recent textbooks.
In conclusion, Behe is way off base with his criticisms of biochemistry textbooks. He seems to have gone out of his way to set up and knock down a strawman version of the importance of evolution in biochemistry textbooks. In addition, he deliberately chooses to select index entries as his criterion when he should know that this gives a totally false impression of what's actually in a book. All in all, this is a very poor example of scholarship.