Reviewing a middle-school book in life science

Science Insights: Exploring Living Things
1994. 654 pages. ISBN of the student's edition: 0-201-25728-9.
Addison-Wesley Publishing Company, Inc., 2725 Sand Hill Road,
Menlo Park, California 94025.

A Trite, Poisonous Book
That Glorifies Ignorance

William J. Bennetta

In the same article, I said that I soon would present a broader analysis of Exploring Living Things. That is what I am writing here, and I must begin with a word of clarification: I do not mean to suggest, by writing this review, that there is any question about whether schools should or shouldn't adopt Exploring Living Things. As far as I am concerned, Addison-Wesley's magic-mongering is an attack upon science education, and the use of Exploring Living Things in a science course would be unconscionable. On that score, nothing more needs to be said.

A recent publication of the National Science Teachers Association carried an advertisement in which Addison-Wesley plugged Exploring Living Things and two other middle-school books. According to that ad, the books would provide "The Right Connections at the Right Time." I don't know what "Time" the ad-writer had in mind, but -- after reading Exploring Living Things -- I suspect that he may have meant the early 1800s. Let me explain:

One of the great events in the development of modern science took place in 1824, when the German chemist Friedrich Wöhler synthesized urea by the thermal rearrangement of ammonium cyanate.

To appreciate the significance of that achievement, we must recognize that urea was classified, in those days, as one of the "organic" chemicals -- meaning chemicals that could be obtained only from plants or animals. The artificial synthesis of organic substances was generally regarded as impossible, because the formation of such substances was believed to require the action of a "vital force" or "life force" that existed only in living cells. This belief was a part of the doctrine of vitalism, which held that the properties and abilities of organisms transcended the ordinary laws of nature.

When Wöhler made urea from an ammonium salt, he dealt a decisive blow to vitalism and began the liberation of chemistry and biology from vitalistic metaphysics. By 1850 science had abandoned vitalism, and chemists were synthesizing and altering many substances that once had been available only from natural sources. By the 1870s German companies had founded an international dye business on synthetic derivatives of aniline, a compound which had been isolated originally from indigo leaves.

And not surprisingly, the chemical meaning of the word "organic" had undergone a change. The idea that "organic" chemicals were unique to living things had been discarded, and "organic" had begun to acquire its modern denotation. Today, organic compounds are broadly defined as compounds that contain carbon-to-carbon bonds. Today, our definition of organic compounds has nothing to do with organisms.

Now, that is well known history, and it is routinely recounted in college chemistry courses, biology courses, and history-of-science courses. The writers of Exploring Living Things, however, know nothing about it: In their chapter about chemistry they tell students that organic compounds are "carbon compounds that occur naturally in the bodies, the products, and the remains of living things."

In a way, that is a remarkable feat: Trying to guess what organic compounds may be, these writers have guessed up a definition that would have been roughly correct only 170 years ago! But in another way, what the writers have done isn't remarkable at all: Their retailing of guesswork instead of information bespeaks the dreary ignorance and the irresponsibility that we have seen so often in people who produce middle-school "science" books.

As a whole, Exploring Living Things is a conventional life-science book and conforms to the usual plan, presenting chopped-down, dumbed-down passages about most of the topics that appear in high-school biology books. The array of topics is huge, and the passages are typically so skimpy and jerky that they cannot serve for the teaching of concepts. These defects seem to be particularly severe in unit 8, "Ecology," which I regard as worthless. I can't imagine that students will learn any meaningful science from a unit that dismisses such topics as population size, competition and social behavior in two or three paragraphs apiece.

This book also reflects conventional practice by recycling traditional, phony material. On page 93, for instance, three photographs show a glass mug in which tea is being brewed, and the adjacent text says:

Look at Figure 5.1. What happens to the hot water when the tea bag is placed in the cup? Tea from the leaves moves out of the bag and into the surrounding water, flavoring it and coloring it brown. Movement of the tea throughout the water is explained by a process called diffusion (dih FYOO zhuhn). . . .

False. The effect of diffusion is not significant here, and it surely is not discernible in the photos. What the photos show is the effect of convection. Addison-Wesley's writers have reproduced a folly -- the misrepresentation of convection as diffusion -- which has appeared in many other schoolbooks and which promotes false notions about physiological functions. For a valuable discussion of this matter, see "Dealing Honestly with Diffusion," by Steven Vogel, in the October 1994 issue of The American Biology Teacher.

There are many other manifestations of fakery in Exploring Living Things, and one of these is especially irritating because it negates one of the book's few virtues. Commendably, Addison-Wesley's writers introduce evolution and classification together (in unit 3), and they mention that modern classification is based on evolutionary relationships. They don't carry that idea into the rest of the book, however, and they eventually fake their way through a survey of the animal kingdom by following the notion of "nature's ladder" and by recycling old, fake material in which the grouping of animals does not show evolutionary connections.

In their chapters about vertebrates, for example, they lump mammals with birds! And as many fakers have done before, they put the birds into phony categories: "There are almost 9,000 species of birds. They are often grouped into four main types: birds of prey, perching birds, water birds, and flightless birds."

Those "four main types" are unknown to science and exist only in shabby schoolbooks. Moreover, the idea that birds can be grouped in that way is just dumb. (Is a penguin a water bird or a flightless bird? Is a kingfisher a perching bird or a water bird?) To make things even dumber, the page that tells about the four types has pictures of five types. The artist has invented another phony category called "seed eaters."

Even if we neglect the fake taxonomy and the absence of an evolutionary perspective, the material about vertebrates in Exploring Living Things is unacceptable. It is disjointed and brainless, recycling the superstitions and distortions that schoolbook-writers have always used for endorsing "nature's ladder." That hokum has no place in a 20th-century science class.

Exploring Living Things does the same thing, in a bunch of "Consider This" sidebars that conform to a very nasty pattern. First the writers state a question and give a tiny, compressed account of some "issues" that supposedly are related to it; then they ask the student to take a position on the question, though the student doesn't have enough information to form any kind of rational judgment. The "issues" are often distorted or based on false dichotomies, and some of the topics are inherently too complicated for middle-school students to grasp.

On page 44 the question is "Should Animals Be Kept in Zoos." The "issues," presented in 100 words or so, are just some vague claims, and they implicitly assume that all zoos are the same, are stocked and operated in the same ways, and can be subjected to the same judgments. After reading that drivel, the student is supposed to "Write a paper stating your position for or against keeping animals in zoos." On page 204 the question is "Should Food Be Irradiated?" Again, the writers present "issues" in the form of vague claims that are nearly meaningless; then they tell the student to "Write a paper stating your position for or against food irradiation." On page 350 the question is "Should Sharks Be Protected?" (What sharks? Where? Protected how? The 64-word statement of "issues" says nothing about such matters.) On page 505 we find the question "Should Tobacco Advertising Be Allowed?" The writers' statement of the "issues" is ridiculous, but that is beside the point. Even to ask the initial question, in a middle-school book, is absurd: The question lies in the realm of constitutional law, and it has a history that involves difficult legal doctrines. A middle-school student can't hope to deal with it in any meaningful way.

These cases exemplify what I mean by the glorification of ignorance. The student is led to believe that any question can be answered categorically by yes or no; he is urged to spout answers although he doesn't know what he is talking about; and he is taught that answers conceived in solid ignorance are just fine. Such anti-intellectual attitudes are directly antagonistic to science and poisonous to science education.

The title page of this textbook lists five "authors": Michael DiSpezio, M.A., Science Consultant, North Falmouth, Massachusetts. Marilyn Linner-Luebe, M.S., Former Science Teacher, Fulton High School, Fulton, Illinois. Marylin Lisowski, Ph.D., Professor of Education, Eastern Illinois University, Charleston, Illinois. Bobbie Sparks, M.A., K-12 Science Consultant, Harris County Department of Education, Houston, Texas. Gerald Skoog, Ed.D., Professor and Chairperson, Curriculum and Instruction, Texas Tech University, Lubbock, Texas. Readers may recall that Skoog also has been listed as an author of the 1990 version of Prentice Hall Biology, a memorable book written by people who didn't even know how to represent the scientific names of organisms. [See TTL, September-October 1990, page 6.]

Though It Has Some Virtues,
This Book Is Not Acceptable

Ellen C. Weaver

Offsetting those advantages are egregious errors, fictions and fundamental misunderstandings which, if foisted onto unsuspecting teachers and students, will prevent their acquiring any coherent understanding of nature.

Addison-Wesley claims that this book is the work of five authors and seven "content reviewers" -- none of whom is a scientist. In one respect, that claim is credible. While I don't know whether any of the listed authors or "content reviewers" actually contributed anything to Exploring Living Things, I can readily believe that the book was produced without the intervention of anyone who had a professional knowledge of science. I think that a far better product would have emerged if the writers or reviewers had included even one academic biologist: one person who had earned a PhD in biology and who had taught introductory biology at a university. If Addison-Wesley had hired such a person, I suggest, this book would not have gone to press while retaining so many falsehoods, misconceptions, senseless statements and wrong illustrations.

• Page 5: The writers correctly tell that "Living things, or organisms, are classified into groups that share common ancestors." And later, on page 181, they teach that "Classification shows the evolutionary relationships among living things." (However, they don't always honor those points in the rest of the book. They sometimes group organisms in obsolete, artificial ways that do not reflect evolutionary relationships.)

• On page 9 the writers explain that the word theory, as used in a scientific setting, doesn't mean a mere guess or speculation. "A scientific theory," they say, "is an idea that has been tested again and again. It is based on many separate, but related, hypotheses that have been repeatedly tested."

• Page 12: Instead of leaving the abbreviation SI unexplained, or giving an explanation that is false, Addison-Wesley's writers try to tell what it means. Their account isn't quite right because they have misspelled unités, but they can correct this easily if they issue a new edition. (They can also correct the caption over figure 1.9. The numbers on that metric ruler represent millimeters, not centimeters.)

• Pages 18 and 19 offer good information about circle graphs, bar graphs and line graphs. (There is nothing, however, about logarithmic scales, even though a diagram involving a logarithmic scale will appear on page 625.)

• Page 97: The description of photosynthesis avoids the obsolete term dark reactions.

• On pages 111 through 113 there is a reasonably good account of Mendel's work.

• Pages 148 through 150: In sketching ideas about evolution, the writers avoid inflating Lamarck and avoid relating false stories about him; in fact, they give only a few lines to him. In the text about Darwin, natural selection is presented correctly.

• Pages 167 through 169 give a good summary of the history of primates.

• The "Science and Technology" article on page 182 tells about DNA sequencing as a tool for tracing evolutionary relationships.

• The section about fertilization, pregnancy and birth in humans is factual and straightforward, and it avoids moralizing.

• Page 42, in a diagram of a pond: "Freshwater plants and animals need very little water."

• Page 43: In a section about the effects of temperature on organisms, the writers try to introduce the terms endothermic and ectothermic, instead of using the old, misleading terms warm-blooded and cold-blooded. That is commendable, but I see that the writers don't really know what endothermic and ectothermic mean. They allege that endothermic animals "can maintain a stable body temperature regardless of their surroundings," and they categorically say that ectotherms "can't regulate their body temperatures." Both claims are false, and the second claim is directly contradicted in a later section of the book. On page 358 the writers say: "Even though reptiles are ectotherms, most are very good at regulating their internal temperatures. They bask in the sun when the air is too cool and seek shade when it is too hot. Through these behavioral adaptations, many reptiles keep their body temperatures about as warm as yours throughout much of the day." I conclude that no qualified person examined the entire book, before it was printed, to make it accurate and consistent.

• Page 65: "Carbohydrates and proteins combine in living cells to form nucleic acids." How could Addison-Wesley's writers get something so wrong? There are no proteins or carbohydrates in the nucleic acids (DNA and RNA), and the synthesis of nucleic acids doesn't involve combining proteins or carbohydrates with anything. If we turn to page 123 we find a reasonably good description of DNA as such, but the writers never tell that DNA is one of the nucleic acids -- the substances that were introduced, although incompetently, on page 65. Here is another case of incoherence.

• On page 77: In a worthless "Science and Technology" article about microscopy, the writers say that a transmission electron microscope uses beams of electrons, and that "The beams create a vacuum." That is dead wrong. The beams don't create a vacuum; the vacuum is a necessary condition for creating the beams.

• Page 106: "In plant cells, spindle fibers don't attach to centrioles during mitosis." That odd statement misses and obscures what is really important here: The spindle fibers in plant cells don't attach to centrioles because plant cells don't have centrioles.

• Pages 244 and 275: Glucose as such does not accumulate as a product of photosynthesis in green plants, no matter how many schoolbooks have mistakenly said that it does, and glucose does not "travel" around in plant tissues. Addison-Wesley's writers need to learn that repeating a false statement doesn't make it true! They also need to learn that plants convert glucose into two important polymers: starch and cellulose. Cellulose is unquestionably the most abundant substance in the living world.

• Page 344: Here and on later pages, the writers divide the vertebrates into endotherms (i.e., birds and mammals) and ectotherms (i.e., fishes, amphibians and reptiles), as if this division had some phylogenetic or taxonomic significance. It doesn't. It is an old scheme that scientists abandoned long ago, and textbook-writers have no excuse for continuing to foist it onto students. Middle-school students don't have to know vertebrate phylogeny and taxonomy in great detail, but they do have to understand the relationships among the major groups, and they shouldn't be led to believe that birds form a natural group with mammals. [See Kevin Padian's article about vertebrate evolution in TTL for November-December 1993.] Strange to say, the diagram on page 346 depicts vertebrate relationships in an acceptable way and avoids the endotherm-ectotherm error. I interpret this as further evidence that no one at Addison-Wesley examined the whole of Exploring Living Things with an eye to eliminating contradictions and making the book consistent.

• Page 594, in a paragraph about adaptations of aquatic organisms, the writers say that an aquatic plant "releases water through openings on the undersides of its leaves." This is apparently a reference to stomata, and it is wrong. Stomata function in the exchange of gases, not in the exchange of liquids.

As is customary in life-science books, the writers of Exploring Living Things present a section about scientific names, and they make a case for using such names, but in the rest of the text they use common names only. This is self-contradictory, and it sometimes makes the text vague and inaccurate. (What do the writers mean by "redwood tree"? That name is applied to species in three different genera.) It also deprives students of some fun; many young people enjoy mastering sonorous binomials and enjoy the sense of sophistication and scientific precision that they get from using such names.

The writers also observe the custom of making things simple by making them false. For example, it is just false to say that "All red algae are many-celled" (page 220). Most red algae are multicellular, but I worked for many years with an elegant, unicellular member of that order, Porphyridium.

Some of the illustrations in Exploring Living Things are absurd. In the diagram of mitosis, on pages 104 and 105, the captions are so murky that the entire diagram is beyond comprehension. (If chromosomes and chromatids are the same things, why do they have different names? What does "double chromatid" mean? Why are some of the chromatids -- or are they chromosomes? -- colored red while others are blue? If the unexplained colors are supposed to denote homology, then Addison-Wesley's artist must believe that homologous chromosomes differ in length. But that is wrong and contradicts the text on page 117.) The diagram of meiosis, on page 118, is just a fantasy. The artist simply made it up. (Six chromosomes somehow become twelve separate chromatids that have no centromeres, and reduction takes place during the second meiotic division instead of the first! This alone should suffice to show alert teachers that Exploring Living Things isn't a sound book and isn't fit for use in a classroom!)

I applaud the writers' efforts to draw connections between science and familiar things, but I do wish that they had tried harder to get their facts straight and to avoid wrong or misleading implications. For example, the table on page 247 wrongly suggests that wheat and bananas are significant sources of oil, and it wrongly suggests that soybeans and "corn" (maize) are not. (Is it possible that the writers have never seen corn oil on a supermarket shelf, or that they do not know about the commercial importance of soybean oil in the making of margarine and other edible products?) Some of the writers' other efforts seem desperate. Looking at the "Career Corner" on page 10, I question whether "scientific skills" gained through the study of physics really have much to do with pursuing a career as an artist, and I have no idea of what a "chemical machinist" is? Will the student know?

Human biology, which usually takes an inordinate amount of space in life-science books, gets only 144 pages in Exploring Living Things (about 23% of the text pages). Most of the material in the human-biology unit seems to be straightforward, but certain items strike me as strange. On page 436, for example, the description of the kidneys says that substances such as water, some salts and "nutrients" leave the bloodstream, enter the renal capillaries, pass through tubes in the nephrons, and then are absorbed back into the bloodstream. This process seems to have no net effect on anything, since all the water, salts and nutrients are returned to where they came from! The hapless student then reads that "The liquid that remains in the collecting tube of the nephron is urine"; but according to what the student saw earlier, the nephron retains nothing.

The chapter about the human nervous system has a "Science and Technology" article (page 449) in which the writers try to say something about the use of radiation for making images of the brain. Their approach is uninformed and misleading:

At one time, X-rays were the only method for obtaining information about the inside of a human body. This method often gave insufficient results because X-rays are most sensitive to bony structures. CT [computed tomography] imaging is different. It is like taking a slice out of a loaf of bread without cutting the bread. . . .

The first statement is obviously false, the fourth statement is ridiculous, and the second and third statements combine to imply that CT doesn't use X rays. Actually, of course, the best-known CT technique -- computed axial tomography, or CAT -- does use X rays, notwithstanding the fact that X rays "are most sensitive to bony structures." In fact, the writers later mention that a CAT-scanning machine "shoots an X-ray beam into the skull." This will leave the student baffled, because it plainly contradicts what the writers implied earlier. The "Science and Technology" article seems all the more ignorant because it makes no mention of magnetic-resonance imaging, which is used extensively for exploring the living brain.

I also object to table 20.1, "Digestive Disorders," which says that the treatment for constipation is medication. That may help to sell patent medicines, but constipation in a young person can usually be relieved by putting more fruits, vegetables, whole grains and water into his diet.

Exploring Living Things has a lot of sidebars that supposedly tell the student how to make observations and reach conclusions. Most of these exercises don't seem to merit comment, but a couple of them are worth noting because they don't make sense. The "SkillBuilder" exercise on page 245 involves a graph of photosynthetic activity in "two plants," but it doesn't say whether this means two different species or two individuals of the same species. Whatever it means, the final question in the exercise can't be answered. The "Activity" on page 266 is crazy. The student takes three samples of "nonflowering plants," wets them, and then supposedly determines which plant absorbs the most water. But the student does not measure the masses of the samples, and he doesn't determine how much water the samples contain before he wets them, so the results of his manipulations are worthless.

Finally, I observe that the index in Exploring Living Things is inadequate and fails to show where some significant topics are mentioned in the book's text.

Exploring Living Things is better than the life-science books that I saw a few years ago, but it is still disappointing. It will have to be revised extensively before it can be judged acceptable.

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. He writes frequently about the propagation of quackery, false "science" and false "history" in schoolbooks.

Ellen C. Weaver is a professor of biological sciences, emerita, from San Jose State University, a fellow of the American Association for the Advancement of Science, a past president of the Association for Women in Science, and a director of The Textbook League.

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