Reviewing a high-school book in biology

Biology: The Dynamics of Life
1995. 1186 pages. ISBN of the student's edition: 0-02-826647-1.
Glencoe/McGraw-Hill, 936 Eastwind Drive, Westerville, Ohio 43081.
(This company is a division of McGraw-Hill, Inc.)

This Book Is a Menace

David L. Jameson

Dynamics of Life probably meets the requirements of most of the adoption states, and state committees may be tempted to accept it because it is not as bad as the really horrible ones -- Glencoe's Biology: Living Systems, for example. (See the review of Biology: Living Systems in the January-February issue of The Textbook Letter.)

Dynamics of Life may also be accepted in local school districts where textbook-selection is controlled by sleepy teachers who have become accustomed to buying shallow, overdecorated books that weigh five pounds each. Those teachers will be able to use Dynamics of Life in the classroom without stretching their minds; students will gain a very superficial knowledge of "biology" while reading material that is out-of-date by a decade at least; and most parents will be unaware that the students are not receiving competent instruction.

For these reasons, Dynamics of Life is a menace to science education. Because it presents familiar content in a flashy format, and because it will look plausible to teachers who don't know much about today's biology, it may actually get into classrooms.

On the other hand, Dynamics of Life will not be acceptable to those biology teachers who have recently emerged from sound teacher-education programs and who know their subject. Such teachers will see that this book tries to include far too many topics, conveys little understanding of any of them, and reflects little appreciation of biology as an integrative science. Moreover, the book gives the student little idea of what is really going on in biology today; if a teacher were to use Dynamics of Life while trying to give an up-to-date course, the teacher would have to devote an inordinate amount of time to the preparation of supplementary materials.

In producing Dynamics of Life, Glencoe's writers and editors have repeatedly favored gee-whiz material while ignoring opportunities to present real science.

The section about classification, for example, is an insult. The writers recycle the outmoded five-kingdom scheme, they preserve polyphyletic groupings which ignore the contributions of cladistics to our knowledge of phylogenies, and they fail to show even one phylogenetic tree based on molecular characteristics. The fact that molecular investigations and cladistic analyses have extensively altered our understanding of phylogenies isn't reflected in the text about classification, and it isn't reflected in the taxonomy that prevails in the remainder of the book.

A vague acknowledgment of molecular studies appears on page 434, where a diagram -- purportedly based on DNA comparisons -- shows relationships among some primates. No data are given or cited, however, and the writers deliver a crowning insult by impeaching their own illustration. The diagram indicates that a major divergence took place some 8 million years ago, producing a lineage that evolved into modern gorillas and a lineage that gave rise to chimpanzees and humans. But then, on page 463, the writers say: "[Between 5 and 8 million years ago] a population of ancestral apes diverged into two lineages. One lineage would eventually evolve into the African apes -- gorillas and chimpanzees. The other would lead to modern humans." You can't have it both ways, fellows. Besides contradicting yourselves, you have lost a chance to discuss developing concepts, conflicting data, preponderant evidence, and the vital principle that scientists are always willing to revise their picture of nature when they gain new information. In short, you have lost a golden opportunity to demonstrate the difference between dogmatism and science!

Dynamics of Life is permeated by references to evolution, and selection is cited again and again to explain adaptations and evolutionary events, but nowhere can I find a statement of a central principle which all students must learn: The only scientific explanation for adaptation is natural selection.

The writers' failure to enlist molecular studies in explaining evolution is consonant with their general obliviousness to molecular biology. They say very little about the molecular bases of metabolic processes, and the even fail to make connections between the small amount of molecular biology that appears in chapter 10 ("Energy in a Cell") and the metabolic phenomena treated in chapter 38 ("Digestion and Nutrition"). The writers have missed an opportunity to integrate biological knowledge, and they have done a disservice to students.

The book's only consideration of developmental biology is a short passage, in chapter 41, about "Fetal Development" in man. The section about body plans (in chapter 28) mentions acoelomate, pseudocoelomate and coelomate organisms, but it fails to say anything about how they develop. Yet appropriate information about development has been available for many years and should be known to anyone who claims to be qualified to write a biology textbook. See, for example, these articles in the popular journal Scientific American: "Biological Regeneration and Pattern Formation" (July 1977), "Pattern Formation in Biological Development" (October 1978), "Compartments in Animal Development" (July 1979) and "Homeobox Genes and the Vertebrate Body Plan (July 1990).

Chapter 5 ("Population Biology") has a short section on demography, almost all of which is given to definitions and elementary concepts. There is little indication that the writers understand the importance of those concepts, and some of the text is obscure because the writers hint at the concept of the demographic transition but do not actually state it. This is unfortunate. Even if you are not convinced that the demographic transition is a universal phenomenon, it is useful for explaining the self-regulation shown by some human populations. It also underlines the point that a human population must self-regulate or must sacrifice its quality of life.

The discussion of human longevity (on page 129) suggests that longevity can only increase. The writers don't disclose that longevity is currently decreasing in Russia and in other countries that have undergone social and economic degradation. Similarly, the book has no realistic discussion of the demographic characteristics and demographic effects of any epidemic. Shouldn't the student understand how extensive mortality caused by the HIV epidemic will subvert the economic vitality of countries in Africa?

Sometimes, looking at Dynamics of Life is almost fun. Can two populations of tree frogs really be isolated from each other by a stream? (Please tell me which species is involved here.) And if a rattlesnake "barely touches the ground," how does it get around? (Does it fly?) And where did Glencoe's illustrator hear that land floats on an underground lake called the "water table"? And -- well, that's enough; you get the idea.

Dynamics of Life may not be a really bad book, in comparison with some others that are currently on the market, but it surely is not a good book. One high-school book that is much better is D.C. Heath's Biological Science: A Molecular Approach.

Turn It Off

William J. Bennetta

Another expression from the realm of commercial television seems to be appropriate here -- "reality-based." Dynamics of Life is a reality-based product, which is to say that it is not entirely fictitious. It has some factual content that sometimes links it to reality, even if the reality has been chopped, twisted and defaced to make it vulgar, to make it simple-minded, and to force it into conformity with popular religious or social notions.

Dynamics of Life is marketed as a high-school book, but it is so fluffy that it seems to be aimed at middle-school students. It certainly shows the traits that I have come to associate with middle-school "science" books. First, its essential content is badly outdated -- sometimes by only ten or twenty years, sometimes by a century or two. Second, the book suffers from conspicuous incoherence in both its content and its structure: Glencoe's writers have repeatedly failed to link related topics, and Glencoe's designers have loaded the book with hundreds of boxes, sidebars and other disruptive decorations. Third, the book is giddy: The writers have staged a circus of mentioning, tumbling through a multitude of topics and pelting the reader with factoids, contradictions and throwaway lines. As examples:

• Page 119: The fluffy little passage about "life-history strategies" gives the impression that an organism's "life-history pattern" depends, in some simple and predictable way, on features of the organisms's environment. That is obviously wrong: Long-lived fishes and short-lived aquatic insects share the same waters; short-lived mosquitoes dwell with long-lived mammals; and so on.

• Page 122: "Predator-prey relationships are important for the health of natural populations. Usually, in prey populations, the young, old, or unfit [?] members are caught. This leaves the strongest and most adapted [sic] to reproduce and continue the population." Nonsense. The writers have merely restated a popular belief derived from natural theology, a 19th-century religious construct. (See my review of Glencoe's Biology: Living Systems in TTL for January-February.)

• Page 329: Though Dynamics of Life tells nothing about sexual selection, it has a silly sidebar about "sex selection" -- meaning medical techniques that enable a couple to choose the sex of a prospective offspring. The writers want to represent these techniques as objects of controversy, so they try a throwaway line: "Opponents argue that people would [sic] use such techniques for frivolous reasons, leading to further erosion of societal values." Do you know what that means? Neither do I. Maybe it means that some people (the "opponents") fear a decline in the frequency of infanticide. Infanticide is the traditional technique for shifting the sex ratio among newborns, so it presumably reflects traditional "societal values."

• Page 407, in a picture caption: "In 1992, a 135-million-year-old fossil named Sinornis (right) was discovered in China. Some scientists now believe that Sinornis represents the earliest bird because it is more birdlike than Archaeopteryx." What can that mean? According to this very textbook, a bird is defined as an organism that has feathers. Now, if Archaeopteryx had feathers (which it did), how could any other animal be "more birdlike" than Archaeopteryx was? If the only trait that matters in recognizing a bird is the presence or absence of feathers, then all feathered animals are equally "birdlike."

• Page 438: In a "Math" sidebar, the math of the Hardy-Weinberg law is chopped and squeezed until it barely qualifies as gibberish. Maybe the writers didn't think that the Hardy-Weinberg equilibrium was sufficiently entertaining, or maybe they just couldn't understand it. Be that as it may, their stuff is absurd, for they evidently think that the equation p + q = 1 applies only to "homozygous matings" and that p² + 2pq + q² = 1 applies only to "heterozygous crosses." In truth, both equations apply universally, and they are equivalent to each other: The second equation is obtained by squaring both sides of the first, though Glencoe's writers haven't explained this. Some math lesson!

• Page 459: A bogus diagram shows "apes" and "humans" as two separate groups, as if humans were not apes. This reflects a popular religious notion, but it isn't biology.

• Page 475: The "Technology" sidebar on "Computers and Cladistics" is reality-based junk at its worst. The writers fill a page with gee-whizzery, but they show no awareness of the significance of cladistic analysis, and they fail to relate cladistics to the classification used in their own book!

• Page 488: "Long thought to be rodents, guinea pigs were reclassified in a separate group . . . ." When? By whom? And if those guinea pigs were taken out of the Rodentia, into what order were they placed? -- the Guineaporkia? The writers' claim is inane, and it is contradicted by the classification table given in their own book. (Besides failing to show any guinea-pig order, the table explicitly says that the order Rodentia is exemplified by the genus Cavia -- the genus to which the guinea pigs belong!) Elsewhere on page 488, the writers try to make their guinea-pig stuff even more entertaining by stating: "Of the 51 amino acids in insulin, a protein hormone, guinea pigs and mice have differences in 18. Humans and mice also differ by the same number of amino acids in their insulin molecules. Thus, guinea pigs are no more related to mice than are humans." (That's what happens when a TV comic plays with chemical anecdotes.)

• Page 777: "Adaptations that enable flies to land on ceilings are among the many that make insects the most successful arthropod group." Gee, that's entertaining! But let's look at some facts: Roughly three-fourths of the surface of Earth is covered by seas; only a handful of insect species have adapted to living on or in seawater; but countless species belonging to other arthropod lineages have populated the oceans from pole to pole, the world around. Now, why would anyone say that the insects are "the most successful arthropod group"?

• Page 817: "The angler fish has perfected a unique way to catch a meal. They [sic] live deep in the sea where there is total darkness, and use a 'rod and bait' to attract and catch other fish. . . . Making the lure even more effective is its luminescence, which can be switched on and off." Golly, that's amusing! It's also silly. There are scores of species of anglerfishes, not just one; some of them live in the deep sea, but most do not; and most do not have luminescent lures. But what is most objectionable here is the claim that a fish "has perfected" something. That is a teleological fancy, and the notion of a "perfect" structure or a "perfect" organism is another leftover from and earlier century.

• Page 849, in an illustration: "Birds have horny beaks. The lack of a bony jaw reduces the bird's weight . . . ." That "lack of a bony jaw" is imaginary. A bird's horny beak is built around bones, as everyone knows who has looked at a bird's skeleton.

• Page 1055: "[Amniocentesis] is often used to determine if a child will have a genetic disorder or chromosomal abnormality such as Down syndrome." Why? Is there some purpose or value in making such a determination? Evidently not.

Ornamental Contrivances

The splurge of sidebars and other ornamental devices in Dynamics of Life is lunatic. There are "BioLab" pages, "MiniLab" boxes, "Thinking Lab" diversions, "People in Biology" pages, "Biology & Society" fancies, and others besides. Some of them are outrageous inventions, decked with bogus and misleading titles, that can only deceive the student. For example, the "BioLab" entitled "Is blubber a good insulator?" has nothing to do with blubber or even with comparing the effectiveness of insulators. The "BioLab" called "What makes a good feeding puppet for sandhill crane chicks?" has nothing to do with crane chicks and does not yield any answer to the title question. The "BioLab" called "What is the ideal length and width for a bird's tail?" is just a stupid game, oblivious to what we know about the lives of birds. The "MiniLab" called "How do scientists interpret fossils?" is just the old plaster-casting exercise that has been used in middle-school books for as long as I can remember. The "Thinking Lab" called "Is egg size related to survival of salamander larvae?" does not make sense. The aforementioned sidebar "Computers and Cladistics" carries the rubric "Biology & Society," but it fails to demonstrate that the use of cladistics has any societal import at all. And so on.

Glencoe says that two dozen "Teacher Reviewers" were involved in the creation of Dynamics of Life. If that claim is true, then Glencoe evidently has found 24 of the sorriest teachers in the land.

Recommendation

David L. Jameson is a senior research fellow of the Osher Laboratory of Molecular Systematics at the California Academy of Sciences. He has written books about evolutionary genetics and the genetics of speciation, and he is a coauthor of a college-level general-biology text.

William J. Bennetta is a professional editor, a fellow of the California Academy of Sciences, the president of The Textbook League, and the editor of The Textbook Letter.

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