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from The Textbook Letter, March-April 1998

Reviewing a high-school book in biology

BSCS Biology: An Ecological Approach
1998. 774 pages. ISBN of the student's edition: 0-8403-9659-7.
Copyrighted by Biological Sciences Curriculum Study
(Colorado Springs, Colorado). Published by Kendall/Hunt
Publishing Company, 4050 Westmark Drive, Dubuque, Iowa 52004.

Editor's Introduction -- Kendall/Hunt's BSCS Biology: An Ecological Approach is the eighth edition of the book that is commonly called the BSCS Green Version, or simply "the BSCS Green." Earlier editions, the most recent of which was dated in 1992, carried the title Biological Science: An Ecological Approach. Two reviews of the 1992 edition appeared in The Textbook Letter, July-August 1992.

All in all, the eighth edition closely resembles the seventh -- and as you will read in the reviews below, it contains factual errors and other defects that were present in the seventh edition and that haven't been corrected.

The innovations in the eighth edition appear to consist chiefly of new typography, new color schemes, and some sales-promotion gimmicks. One gimmick is a faddish "Foreword," with some hype that tries to link the book to "national standards" and "benchmarks." (This "Foreword" appears in the student's edition, though it speaks only to the teacher.) Another gimmick, apparently concocted to provide some political correctness, is a silly article about a blind man who "has risen above his physical restrictions" to become "a premier level paleontologist and editor of Evolution, the field's most prestigious journal." There is no explanation of how a blind man can work as an editor of anything -- and the claim that Evolution is a paleontological journal is false. This article seems significant because earlier editions of the Green Version weren't sullied by such rubbish.

Given Some Careful Revision,
This Book Could Be Excellent

William Z. Lidicker, Jr.

In its eighth edition, the BSCS Green Version remains a good introduction to biology, and its ecological approach to studying the living world should be strongly encouraged. However, I am disappointed to find that the book is marred by many inconsistencies and contradictions -- probably because many individuals have contributed new material over the years, and the new material has not been fully integrated with the old.

I am further distressed to see that this eighth edition suffers from grossly incompetent editing. When Stuart H. Hurlbert reviewed the seventh edition for The Textbook Letter, he politely concluded that it was a worthy book but it needed considerable refinement. Unfortunately, Kendall/Hunt's editors have not heeded his criticism. In most cases, they haven't even corrected the errors that he identified.

Admirable Organization

In its overall organization, BSCS Biology: An Ecological Approach is an admirable text. It is divided into five major sections, and the first of these -- titled "The World of Life: The Biosphere" -- establishes the book's emphasis on ecology by introducing a number of ecological principles. The other sections are "Continuity in the Biosphere" (covering cell biology, reproduction, development, genetics and evolution) "Diversity and Adaptation in the Biosphere" (dealing with classification and a survey of the kingdoms), "Functioning Organisms in the Biosphere" (devoted chiefly to the physiology of humans and of flowering plants) and "Patterns in the Biosphere" (about behavior, paleontology, biomes, aquatic ecosystems, and "human-affected ecosystems"). That all five sections display "biosphere" in their titles seems contrived; "biosphere" is appropriate only in the titles of Section One and Section Five.

At the conceptual level, this book is strong. Topics such as evolution, the growth of the human population, and environmental deterioration are handled without apology or compromise. In chapter 2, when the writers consider the variables that affect population size, they include immigration and emigration -- factors that often are omitted by the writers of other introductory books. In chapter 3, the writers properly acknowledge the importance of cooperative (positive) interactions and indirect interactions among species. Chapter 8 has a good discussion of probability. Chapter 20 offers a solid treatment of the dichotomy between innate behavior and learned behavior. And in general, the writers succeed in conveying the open-ended, exciting nature of science.

The book concludes with four appendices. One of these is an illustrated "Catalog of Living Things" that, for some groups, goes down to the level of families. This is an extremely useful feature, although it is not free of errors.

Defects in the Artwork

While the book's basic framework and conceptual content are commendable, this does not mean that all is well. Awkward statements, contradictions and typographical errors are all too frequent. Sometimes a passage ends with a nearly meaningless paragraph, suggesting that someone made a crude attempt to prune a longer discussion of the same topic but didn't know how to tie up the loose ends. And errors abound, both in the illustrations and in the text.

The illustrations in BSCS Biology: An Ecological Approach are abundant but of inconsistent quality. Some are excellent -- e.g., figure 13.33, "Comparison of monocot and dicot characteristics" -- but many others act as decorations only. They are too small to disclose important features, they are inadequately explained, they contain errors, or they have erroneous captions. A handful of examples will serve to show that Kendall/Hunt's illustrators and editors have not paid adequate attention to their artwork:

Mistakes in the Text

There are many, many errors, confusing misstatements, and obsolete claims in the book's text as well. I cannot catalogue all of them here, but I can alert teachers by citing a few examples:

Critical Topics

I would like now to examine the book's treatment of evolution, and of natural selection in particular. An understanding of evolution is fundamental to all of biology, and natural selection is a critical component of the evolutionary process, yet the presentation of these topics is often one of the weakest aspects of biology education, at all levels. BSCS Biology: An Ecological Approach is pervaded by material about evolution, just as it should be, and the material generally is good. In my view, though, it is not as good as it could be.

The principal exposition comes in chapter 9, "Continuity Through Evolution," which puts so much emphasis on Darwin that the field of evolutionary biology seems to be a one-man show. This is not a realistic image.

The chapter's formal definition of evolution, given on page 208, is unfortunate: "a change in a species or population through time." But populations continuously undergo changes which are not evolutionary -- changes in size, density or distribution, for example -- so a correct definition of evolution must specify genetic change. Another goof is the equating of assortative mating and sexual selection (page 211). These two processes are quite distinct, though both processes involve the choosing of mates.

Turning now to the book's treatment of natural selection, we note that this phenomenon is defined in three ways, and all three definitions are inadequate. In the main text, on page 206, we read that natural selection is "the process by which those characteristics that permit survival and reproduction are continued and eventually replace less advantageous characteristics." This is awkward and trivial. The statement that traits which do not permit survival and reproduction will be replaced (by those that do) hardly suggests any profound insights. In the chart on page 223, natural selection is simply equated to differential survival; reproduction is not mentioned. In the glossary, on page 737, there is a better definition that at least captures the idea of differential survival and reproduction among members of a population and ties these results to adaptations.

In my view, the process that we call natural selection has two critical features that students must grasp. The first is that the individuals in a population are not equally successful in passing their genetic material to future generations. The second is that the disparities in success are not random with respect to the individuals' genetic endowments. Some individuals, because they carry certain genes, will be more successful in a given environment. They will make a disproportionately large contribution of genes to the next generation, and (on average) the population's level of adaptation to that given environment will improve. Success is not merely survival and reproduction. Success means producing offspring that will produce successful offspring that will produce successful offspring . . . and so on, into the future.

So far, the selection scenario is rather simple, but now we must add the point that the individual's environment is constantly changing. The environment's biotic and abiotic components inflict a dynamic mix of influences on the entire population, and the population provides a variable genetic context for each individual. As an example: A male in a population that consisted mostly of females would experience selective forces quite different from the forces acting on a male in a population that consisted mostly of males. Moreover, short-term gains in fitness can carry a penalty in the form of an inability to adapt to some future alteration in conditions. Nevertheless, natural selection is the one evolutionary mechanism which ties genetic composition to the environment and, therefore, can lead predictably to improved adaptations.

Maybe Next Time

My final comment concerns the book's treatment of conservation. At appropriate places throughout the text, the writers have inserted passages about the need for conservation, but their material appears unduly narrow. For the most part, it is limited to remarks about the preservation of wilderness areas and about captive-breeding programs in zoos (complete with embryo transfers and other high-tech procedures). I hope that, in their next edition, the writers will do more to show that the conservation of biodiversity is inherently valuable for promoting human survival and well-being.

We should accept nothing less than excellence in our biology textbooks, since the scientific literacy -- and specifically, the biological literacy -- of our citizenry is at stake. BSCS Biology: An Ecological Approach has a chance of making the grade. Taken as a whole, it already is an impressive production. With a healthy dose of loving care and attention, it could be terrific.

Many Commendable Aspects,
Much Room for Improvement

Wanna D. Pitts

BSCS Biology: An Ecological Approach -- the new edition of the BSCS Green Version -- tries to view the biosphere and the science of biology through an ecological lens. Because I am a plant ecologist, I applaud this approach.

When I taught plant biology to college freshmen, the course began with topics that were familiar to students, then expanded to embrace matters that the students probably had not encountered before. In BSCS Biology: An Ecological Approach, the first of the book's five principal sections reflects a similar strategy. The section is called "The World of Life: The Biosphere." Its first chapter, "The Web of Life," starts with information that already is known to everyone: Some organisms "interact" with other organisms by eating them. This leads to a more formal examination of how organisms obtain and use energy. Then, as the scope of the section expands, the student reads chapters titled "Populations," "Communities and Ecosystems" and "Matter and Energy in the Web of Life."

Section Two of the book is called "Continuity in the Biosphere," and the titles of its five chapters have been chosen so that "continuity" appears in each: "Continuity in Cells," "Continuity Through Reproduction," "Continuity Through Development," "Continuity Through Heredity," and "Continuity Through Evolution." This is a stretch, but the sequence is not flawed, and the chapters themselves generally present information in a clear manner.

The three remaining sections are "Diversity and Adaptation in the Biosphere," "Functioning Organisms in the Biosphere" (including three chapters on "The Human Animal"), and "Patterns in the Biosphere." This last section is very broad, with chapters titled "Behavior, Selection, and Survival," "Ecosystems of the Past," "Biomes Around the World" (yes!), "Aquatic Ecosystems," and "Managing Human-Affected Ecosystems."

As a whole, BSCS Biology: An Ecological Approach is a good text. As a whole, it's well written, and the graphics are excellent. The text has a Socratic flavor, often presenting questions that impel students to think about the matters at hand. Indeed, almost every chapter opens with a photograph and several questions (pertaining to the photo) that foretell some of the science that the chapter will teach. Chapter 2, for instance, starts with a photo of some king penguins, and the caption says:

A population is a group of organisms of the same species that live and interact in the same place at the same time. What is the evidence of a population in this photo? What is the evidence that the penguins are the same species? Identify some of the variations among individuals. How can the penguins have these individual variations and still be a population?

In teaching about the processes of science, this book offers a strong, hands-on approach. Every chapter has at least one "Investigation," and most chapters have two, three or four. Another strength is the continual attention to the effects of humans on the rest of the living world. The student learns that we humans exert major forces on our planet's health, and one proposition stands out clearly: All environmental issues are connected to the growth of the human population.

There is very little equivocation. The passages about topics such as birth control, deforestation, global warming, venereal disease and water pollution seem refreshingly frank. I particularly admire the clear, uncompromising discussion of birth control in the "Biology Today" article on page 135.

Of the book's four appendices, my own favorite is "Appendix Four: A Catalog of Living Things." Here, in fewer than thirty pages, is a beautifully illustrated compendium of the living world. Well done!

Carelessness and Errors

My most serious overall criticism of BSCS Biology: An Ecological Approach is that it presents too much material, too much jargon, and too many terms. There is about enough material here to support separate courses in plant biology, animal biology, cell biology, and introductory ecology! It must be a nightmare for a high-school teacher to have to pick, from a book like this, the material that students can actually try to learn.

My specific criticisms focus on factual mistakes, on instances of carelessness, and on the inadequate handling of two major topics: homeostasis and natural selection. Let me start by citing some cases involving carelessness or outright errors of fact:

Major Failings

Some of the mistakes that I have just cited may seem minor. There is nothing minor, however, about the book's confused mishandling of homeostasis -- one of the bedrock concepts of biology.

The term homeostasis is introduced on page 29, where it is flatly defined as "the tendency for a population to remain relatively stable in size." This definition may be acceptable in some circumstances, but it certainly does not reflect the primary meaning of homeostasis in the vocabulary of biology. The definition given in the book's glossary -- "the tendency for an organism, or a population of organisms, to remain relatively stable under the range of conditions to which it is subjected" -- is equally eccentric.

Not until page 428 do the BSCS writers even hint at the most common meaning of homeostasis, i.e., an organism's capacity to maintain relatively constant internal conditions in spite of alterations in the external environment:

The cells of the human body are surrounded by a liquid that is remarkably constant in its properties. The continuous regulation of the many dissolved compounds and ions in this internal environment is referred to as homeostasis.

Even here, what the writers say is so narrow that it is misleading. Homeostasis, in its physiological sense, refers to a good deal more than just the regulation of "the many dissolved compounds and ions" in an intercellular liquid.

Homeostasis receives one more brief mention on page 443, where the writers say, "Even before you were born, the endocrine (EN doh krin), or ductless, glands and the hormones they secrete were functioning in the homeostatic control of your body." And that's all for homeostasis.

When the seventh edition of this book was reviewed in The Textbook Letter, David Cobb remarked that the writers had failed to view homeostasis as a fundamental characteristic of living systems. In the eighth edition, they have failed again.

The writers' account of evolution by natural selection is uneven and unsatisfactory. Page 223 has a good summary of the work of Charles Darwin, but some of the earlier material about Darwin is poor. On page 205, for example:

During his studies, Darwin came across an essay by Reverend Thomas Malthus (1766-1834) that warned about the dangers of human overpopulation. . . . Darwin applied [Malthus's] idea to his own work and concluded that most species have a high reproductive potential but not all individuals reproduce. Populations, he argued, are kept in check in part because some organisms fail to reproduce.

That emphasis on the idea that some individuals "fail to reproduce" is misleading. Darwin saw that the production of more individuals than the environment can support engenders a "struggle for existence" among members of a population, and that only a fraction of the offspring produced in each generation can survive. This struggle for existence is not a contest in which the winners leave surviving offspring while the losers categorically "fail to reproduce" and leave no descendants at all. The contest is more subtle than that. It revolves around numbers of offspring, and even an individual that leaves surviving offspring can be a loser. The winners are the individuals that, in the long run, leave the greatest numbers of descendants. Darwinian fitness, then, is usually a matter of relative, not absolute, reproductive success. It seldom is the all-or-nothing business implied by that phrase "fail to reproduce."

To conclude: BSCS Biology: An Ecological Approach is a good and useful text. It has much room for improvement, however, and I particularly hope that the writers, in their next edition, will clean up all the defects that have been noted here and in earlier reviews.


William Z. Lidicker, Jr., is a professor emeritus in the Department of Integrative Biology at the University of California at Berkeley, a curator emeritus of mammals in that institution's Museum of Vertebrate Zoology, and a fellow of the California Academy of Sciences. His research deals with the evolution, ecology and conservation biology of vertebrates.

Wanna D. Pitts is a retired professor of biology from San Jose State University, where her teaching included courses in plant biology, general ecology, plant ecology, biodiversity, and pollination biology. She is a co-author of the third edition of Terrestrial Plant Biology, published by Addison Wesley Longman.

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