Behe is misleading about textbooks

NOTE: This was first published here on 8.20.08, and is simply being re-published as a separate post now.

From pages 180 to 183 of Darwin’s Black Box, Behe discusses, of all things, biochemistry textbooks with respect to the numbers and types of mentions of evolution in the indexes of these texts. Not molecular biology textbooks, cell biology textbooks, or genetics textbooks, apparently the standard is biochemistry textbooks. Is that perchance a result of his being a biochemist? Possibly?

His point is, of course, that evolution is not discussed much in biochemistry texts, and he disparages many that are there.

There are several rebuttals to make. One is that biochemistry is mostly about unchanging chemical processes, and fairly well conserved biochemistry. Another is that there are many mentions of evolution in at least my old biochemistry text which do not appear in the index. Furthermore, my biochem text uses evolution to justify its discussions of “model organisms”. And the last point is that non-biochemistry biology texts of the time did mention evolution a good deal more than his biochemistry textbooks.

Behe makes a sloppy case in just about everything he discusses (with relation to ID, anyway). It is impossible to know how much of this is due to ignorance, and how much is due to lack of concern for the facts. However, I can show how meaningless his little table of numbers of mentions of evolution in biochemistry textbooks is, by listing a considerable number of mentions in my biochemistry textbook. Behe has a table of 30 biochemistry textbooks (many are different editions of single textbooks) on page 182 of DBB, many of which have zero mentions of evolution in their indexes, and none of which has more than 22. The textbook I used in my biochemistry course is in the median, at 12 index entries. This textbook is titled Biochemistry, written by Moran, et al., 2nd edition, published by Neil Patterson, and copyrighted in 1994 by Prentice Hall.

In the first place, even the count of 12 entries is misleading, since there are 16 places in the text indexed, since some entries have multiple text references. That’s still not a lot, however.

When we consider mentions that are not in the index, however, the number doubles, just using the ones that I found by scanning. I couldn’t have found all of the times evolution was brought up, but here are the ones I found fairly quickly which are not in the index, with representative text (so you know it’s really about evolution):

1. 2-2 “The basic plan of the ancestor cell has been elaborated upon with spectacular inventiveness by billions of years of evolution.”

2. 2-4 “Yet evolution has produced tremendous diversity…”

3. 27-4 “The distribution of antigenic determinants in the B components of DNA-dependent RNA polymerases of archaebacteria, eubacteria, and eukaryotes suggests the primeval character of the extremely thermophilic archaebacteria.” [the accompanying figure compares RNA polymerases across the three domains of life]

4. 27-23 “The deduced amino acid sequences show considerable similarity in spite of their distant evolutionary relationships”

5. 29-7 “In plant mitochondria and in chloroplasts, the standard genetic code is used. But in mitochondria of all other organisms, there are some deviations from the standard code (…). …And it has been suggested that the altered genetic code allows translation to proceed efficiently…”

6. 29-12 “Conservation of the nucleotide sequence in the D arm is more pronounced among eukaryotes than between prokaryotes and eukaryotes.”

7. 32-8 “These parallels suggest that bacterial transposons and retroviruses might be distantly related. As we will see in the next section, eukaryotic transposons and retroviruses are even more intimately related.”

8. 32-17 “Most mammals appear to be descended from a common ancestor that lived approximately 100 million years ago, indicating that the organization of genes can be preserved for a considerable time.”

9. 32-19 “Closely related species, such as mouse and rat, which diverged only 30 million years ago, can differ significantly in the amount of repetitive DNA.”

10. 32-20 “These pseudogenes share a common ancestor with a corresponding intact gene.”

11. 32-22 “This is probably because the various genes that make up each family were generated by localized gene duplications that occurred relatively recently.”

12. 32-33 “Any theory concerning the evolutionary origin of introns must satisfactorily explain why the vast majority of prokaryotic genes do not contain introns.”

13. 32-25 “As is the case in bacteria, there has likely been selection for a small genome in this organism.”

14. 32-27 “We have seen that the organization of the genome can change as a result of evolution, but large-scale reorganizations are only evident after millions of years.”

15. 32-33 “The available evidence suggests that introns in protein-encoding genes arose late in evolution.”

The best mention of evolution not in the index explains why model organisms are useful in general:

16. 2-31, 2-32 “How do we use knowledge gained from biological systems as evolutionarily remote from us as E. coli? As we probe deeper into the chemistry of life, we find that at the molecular level diversity gives way to unity, and themes emerge that pertain to all life. Knowledge gained from studies on an accommodating organism like E. coli can be applied to more recalcitrant model systems, such as the rat. With educated intuition developed from studies of simpler systems, researchers can devise experiments that coax more complex systems to reveal their own intricate mechanisms.

A proper appreciation of the balance between unity and diversity is essential when assessing results of biochemical studies. It is highly unlikely that glycolysis in E. coli will be regulated in exactly the same way as glycolysis in rat liver cells. Yet with experience, patterns of regulation are detectable.”

Granted, these do not bring the total up to anything enormous. Yet the authors recognize the importance of the relatedness of all life in the study of biochemistry, since evolution is responsible for relatedness, and for divergence. Note #9, evolution is mentioned when it has to be, such as where closely related organisms diverge in the amount of repetitive DNA.

Of course, evolution is a theory of biology, and biochemistry is, in the main, about chemistry. The explanation for why evolution is not dealt with greatly in a biochemistry text like mine is given in the first chapter of the same text:

One might at first assume that biochemistry is merely a combination of two major sciences, chemistry and biology. However, the defining feature of biochemistry is that it uses principles and language of one science–chemistry–to explain the other science–biology–at the molecular level (chapter one, page one, of Moran et al.)

Of course biochemistry texts aren’t especially heavy on evolution, as in many ways it’s an extension or application of organic chemistry to life. Even so, a text like the one I own does invoke evolution not infrequently, since design is hardly responsible for either the unity or divergence found in life. At the beginning of chapter 32, this is written:

Until now, we have assumed that a gene is unchanging, static over time. We have implied that a gene exists at a fixed locus in a chromosome and that its structure and function are not affected by rearrangement or recombination….

This gradual change in genetic information is the basis of evolution. (Chap. 32 p. 1 of Moran et al.–this, by the way, is found under “evolution” in the index).

Why would they ever treat the gene as if it were static? The answer is quite obvious to anyone who understands the issues, biochemistry is dealing with the chemistry of what is found, not being particularly interested in evolution as such. The basics are being taught, and then these basics can be applied to dynamic systems.

So as usual, Behe is misleading in DBB. While this is not an especially important matter, it goes to show that once again Behe has distorted the issues, particularly for the many naive people who are likely to read his book.

Although I have shown that at least my textbook finds evolution to be important despite its emphasis on applying chemistry to biology, I also took a look at my old cell biology book from around the same time period. It is Molecular Biology of the Cell, 3rd edition, by Bruce Alberts, et al., New York, Garland Publishing, 1994. I counted 81 entries for evolution in the index, many of which have multiple page listings. There are three more entries under “Evolutionary Relationships.” I didn’t bother even looking for mentions not found in the index.

Molecular biology is a lot more like what biochemistry is not, a combination of chemistry and biology. Is it at all surprising that it deals much more heavily in the biological theory of evolution?

This is part of a series of posts that I am combining into one long post, which may be found at Darwin’s Black Box.

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One Comment on “Behe is misleading about textbooks”

  1. athel Says:

    I’m not sure if anyone will read a comment posted two months after the original, but no matter.

    Even if Behe’s contention were true (which, for the reasons you give, it isn’t), one could still ask so what? Although biochemistry is best regarded as a sort of biology, it largely developed as a sort of chemistry, studied by people who wanted to know how things work, not how (and why) they got the way they are. In the past probably most authors of biochemistry textbooks were not much interested in biology in general, or even in physiology. One can regret that, of course (and I do), but one can’t conclude anything about how they thought about evolution. Even today well regarded biochemistry books are still being written (e.g. Cook and Cleland’s book on kinetics) that say nothing at all about the physiological roles of biochemical molecules.


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