Introductory classes in biology should prepare students

Transcription

1 Animal Behavior in Introductory Textbooks: Consensus on Topics, Confusion over Terms PETER A. BEDNEKOFF I surveyed chapters on animal behavior in 11 introductory textbooks to see how well textbooks introduce current research in the field. Chapters on animal behavior were placed in or near the sections on ecology and often near sections on animals. Within chapters, the introductory textbooks tended to present the same topics in a standard sequence. This sequence generally agrees with the sequence of chapters in an advanced textbook. Textbooks showed little consistency, however, in the terms they presented in boldface type. Different textbooks presented different terms in boldface type, so most essential terms were featured in only one textbook. Terms in boldface from introductory textbooks were not often used in an advanced textbook or research articles in animal behavior. Textbooks rarely showed alternative hypotheses or data from control groups when presenting animal behavior. Textbooks seem to present an abundance of unnecessary terms and miss the opportunity to illustrate the process of science using observations of animals. Keywords: animal behavior, education, textbooks, introductory biology, jargon Introductory classes in biology should prepare students for advanced classes and help them to appreciate current research in the field. Introductory textbooks are huge, rich documents that generally contain something from all areas of biology. I examined the treatment of one area, animal behavior, to see how introductory textbooks reflect knowledge and practice in the field. I chose animal behavior for two reasons. First, it is my research area, so I have an informed view of current practices. Others will have to judge whether similar trends apply in other fields. Second, animal behavior is a particularly accessible area of biology. Because students have firsthand knowledge of animals and can observe them directly, teachers can readily use observations of animals to emphasize how scientists frame and test hypotheses about animal behavior. I examined how the treatment of animal behavior in 11 textbooks supports such teaching efforts. The textbooks were contemporary competitors sent to me for possible use in introductory classes and include the standard textbooks for introductory biology. This was not an exhaustive survey of available textbooks but represents a broad cross section of the sorts of textbooks that are commonly used. I examined (a) where animal behavior fits within introductory textbooks, (b) what topics are typically emphasized, and (c) how well textbooks agree with each other and with current practice in the field. Placement of chapters in textbooks The textbooks varied in length from 760 to 1254 pages and devoted 17 to 36 pages to animal behavior. The length of the section on animal behavior was not strongly related to the length of the textbook (r 2 = , P = ). Two textbooks, by Purves and colleagues (2001) and Raven and Johnson (2002), split the material into two chapters, one on animal behavior and the other on behavioral ecology. All other textbooks dealt with all animal-behavior topics in one chapter. All 11 textbooks placed animal behavior within or just before the unit on ecology (table 1). Six of the textbooks placed animal behavior as the last chapter in, or the first chapter after, the section on the biology of animals. These sections were near the end of the book in 9 of 11 cases (table 1). The two textbooks that presented animal behavior earlier were not obviously different in what they did within those chapters. Sequence of topics Within their animal behavior sections, the textbooks contained many of the same topics and often worked through them in Peter A. Bednekoff ( peter.bednekoff@emich.edu) is an associate professor in the Biology Department at Eastern Michigan University, Ypsilanti, MI His research centers on how birds survive during the nonbreeding season American Institute of Biological Sciences. 444 BioScience May 2005 / Vol. 55 No. 5

2 Table 1. Placement of animal behavior within 11 introductory textbooks. Relation of Relation of animal-behavior animal-behavior Pages on First page on Total pages in chapter(s) to chapter(s) to Textbook animal behavior animal behavior textbook animal section ecology section Terms in boldface Biology: Understanding Life After Start 33 (Alters 2000) Biology: Life on Earth End Before 19 (Audesirk et al. 2001) Biology (Campbell and Not near Start, after overview 46 Reece 2002) Biological Science After Start 6 (Freeman 2002) Biology: A Guide to the Not near End 25 Natural World (Krogh 2002) Life (Lewis et al. 2002) After Start 29 Biology (Mader 2001) Not near Start 14 Life: The Science of Biology End Start 40 (Purves et al. 2001) Biology (Raven and Not near In 76 Johnson 2002) Biology (Solomon et al. 2002) End Before 59 Biology: The Unity and Diversity Not near In 31 of Life (Starr and Taggart 2004) a similar sequence. When I compared each chapter s list of contents, I found a consensus sequence consisting of (a) a vignette or case study; (b) proximate and ultimate causes; (c) genetics, innate behavior, and ethology; (d) learning and development; (e) physiology, hormones, and biological clocks; (f) communication; (g) migration; (h) territories, competition, and dominance; (i) mating and sexual selection; (j) social behavior, altruism, and kin selection; and (k) something to end on. The books generally followed this sequence, but varied in the emphasis they gave to each topic, and sometimes skipped elements of the sequence or dealt with them in a slightly different order (table 2). Communication was the least consistent topic, with five textbooks covering it according to the sequence and four combining it with social behavior. Within the standard sequence, I noted that thicker books had shorter starting vignettes or case studies but gave far more explanation of proximate and ultimate causes. The opening vignettes were all different, but seven of the textbooks closed with something about human behavior. Textbooks contained some additional topics, such as birdsong, play behavior, and the effects of hormones, but I found no way to summarize these insertions into the standard sequence by topic. Because I study foraging, I noted its presence in the texts. Feeding behavior was featured only in the four fattest textbooks. Terms in boldface I chose to analyze terms printed in boldface because these are presumably aspects of animal behavior that the authors wanted to stress. I compiled a list of all the terms in boldface type for each text, ignoring section headings. Textbooks often listed these terms at the end of the chapter. I excluded four terms (ecology, fitness, natural selection, and signal transduction) as terms from other chapters that happened to reappear in the chapters on animal behavior. Ignoring these terms, each of the 11 textbooks presented 6 to 76 terms in boldface for animal behavior (table 1). The number of terms in boldface was correlated both with the length of the animalbehavior chapters (r 2 = , P = ) and the total length of the textbook (r 2 = , P = ). I checked for consistency among textbooks by compiling a master list of terms. I counted as synonyms both different forms of the same word (e.g., navigate and navigation) and different terms for similar ideas (e.g., rituals and signals). Even after this lumping, I had a list of 168 terms. Most of the terms are presented in bold in only one of the textbooks (figure 1). A total of 15 terms appeared in bold in six or more textbooks (figure 1). The champion term, featured in boldface in 10 books, was imprinting. Texts generally accompanied this term with a photograph of Konrad Lorenz being followed by geese that were imprinted on him. If animal behavior has an iconic image, apparently this is it. Thus, the textbooks show a few small hints at consistency with each other over terms. Do the terms in boldface in introductory biology textbooks help prepare a student for an undergraduate course in behavior? To check their consistency with the material likely to presented in such a course, I compared my list of boldfaced terms with the glossary and index in the most frequently used textbook in animal behavior (Alcock 2001). The results were mixed. Happily, terms that appear in multiple introductory textbooks are more likely to appear in Alcock (χ 2 = 22.77, df = 1, P < ), with all but one of the terms that appeared in six or more textbooks meriting a mention. Less happily, only 78 (46.4%) of the terms in boldface appeared in Alcock s textbook. Thus, the terms placed in bold in introductory textbooks are a haphazard guide to advanced classwork in animal behavior. May 2005 / Vol. 55 No. 5 BioScience 445

3 Table 2. Consensus sequence of topics in animal behavior, or the order in which they appear in most sections on animal biology in introductory biology textbooks. Genetics, Physiology, Social Vignette Proximate innate hormones, Territories, Mating behavior, or and behavior, Learning and competition, and altruism, case ultimate and and biological and sexual and kin Something Textbook study causes ethology development clocks Communication Migration dominance selection selection to end on Biology: Understanding Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Life (Alters 2000) Biology: Life on Earth Yes Yes Yes Yes Yes Yes Yes Yes Yes (Audesirk et al. 2001) (slightly earlier) Biology: A Guide to Yes Yes Yes Yes Yes Yes At end of Yes Yes Yes Yes the Natural World (slightly (slightly sequence (slightly (slightly (Krogh 2002) later) earlier) later) earlier) Life (Lewis et al. 2002) Yes Yes Yes Later in Yes Yes Yes Yes Yes sequence Biology (Mader 2001) Yes Yes Yes Yes Later in Yes Yes Yes Yes (biological sequence (slightly (slightly clocks later) earlier) appear later, in a text box) Biology (Campbell and Yes Yes Yes Later in Yes Yes Yes Yes Yes Reece 2002) sequence Biological Science Yes Yes Yes Yes Yes Yes Yes (Freeman 2002) Life: The Science of Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Biology (Purves et al. 2001) Biology (Raven and Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Johnson 2002) Biology (Solomon et al. Yes Yes Yes Yes Yes Later in Yes Yes Yes Yes Yes 2002) sequence Biology: The Unity and Yes Yes Yes Yes Yes Yes Yes Yes Yes Diversity of Life (Starr and Taggart 2004) (earlier) (earlier) Yes indicates that a topic is covered where expected in the sequence. Dashes ( ) indicate that the topic is skipped. 446 BioScience May 2005 / Vol. 55 No. 5

4 I checked how the terms would prepare a student for research in the field by searching for them in the 1370 articles publishes by the journal Animal Behaviour for the years 1998 to 2002 within the Science Citation Index using the Web of Science database. I chose this journal because it is the flagship journal for the field and publishes many articles each year on the broad range of topics within the study of animal behavior. I searched under all synonyms in the title, keywords, and abstracts of all articles. I excluded the results for behavior and period because these terms were used in multiple ways unrelated to their textbook delimitations (e.g., study period). The results showed that most of the terms found in textbooks are actually used in the field. Unfortunately, many of the terms are used rarely. A term in boldface appeared in a median of 4 of the 1370 articles during the five-year span. Only 33 terms in boldface appeared 20 or more times in five years. Those terms that appeared in multiple textbooks appeared more often in articles, although this relationship accounted for less than 10 percent of the variance in term use (figure 2; r 2 = , P < 0.001). Discussion and suggestions The topic of animal behavior makes up a small fraction of introductory textbooks and is placed in or near sections on ecology and aspects of animal biology. As a behavioral ecologist, I concur that animal behavior is connected with ecology. I also see that animal behavior is related to the structure and function of animals. I do not understand, however, why animal behavior and ecology are usually placed at the end of introductory textbooks rather than at the beginning. Students might be better served if animal behavior and ecology followed directly from the introduction of the process of science. If students learn science by doing science, they need to make observations and formulate and test hypotheses. Animal behavior provides a great opportunity to learn science because students can directly observe animals and draw on their everyday experiences when formulating hypotheses. For instructors who choose the traditional march through carbon chemistry, cellular structure, and so on, before ending with ecology, I have an alternative suggestion. Animal behavior could be the capstone subject on which students formulate and test hypotheses. Whether early, late, or in the middle of the sequence, learning of science would be better supported if textbooks emphasized how scientists formulate questions and test hypotheses about animal behavior. The standard sequence of topics within the chapters on animal behavior surprised me Number of terms in bold Figure 1. Number of terms referring to animal behavior that appear in boldface in introductory biology textbooks. Most terms in boldface appear in only 1 of the 11 textbooks sampled. Number of articles containing the term in Animal Behaviour [In (number articles using the term + 1)] Number of textbooks Number of textbooks with term in bold Figure 2. Relationship between the number of introductory biology textbooks (from a sample of 11) that use a term referring to animal behavior in boldface and the number of articles containing the term published in the journal Animal Behaviour from 1998 through Textbook use only very roughly predicted the use of these terms in research articles. The area of each cross is proportional to the number of overlapping results; thus, the large cross in the bottom left corner represents the 39 terms that were found in one textbook and in none of the research articles searched. May 2005 / Vol. 55 No. 5 BioScience 447

5 because the textbooks look quite different, and I only noticed the sequence when I listed the contents of several chapters. I do not object to this sequence. All the topics are important either to the historical development or to the current practice of the field. The sequence is roughly mirrored in textbooks in animal behavior (e.g., Alcock 2001). My biggest disappointment is that 4 of the 11 textbooks did not mention proximate and ultimate causes (table 2). Without understanding the sorts of questions that scientists ask about animal behavior, it may be difficult for students to understand how scientists test hypotheses about animal behavior. The mismatch of textbook terms with those in research literature can be divided into three parts. First, many of the boldfaced words in the textbooks are not specialized terms essential to the study of animal behavior. Animal behavior can often be described using no novel terms. In the textbooks, descriptions of behavior often had no terms in boldface. Textbooks should use simple language where appropriate and avoid confusing students by using terms in boldface without good reason. Second, some of the terms in bold were important in the past but have not been central to research in animal behavior for decades (see Alcock 2003). Ethological terms such as fixed action pattern, sign stimulus, and releaser are important to the history of animal behavior, but long since retired from active duty in science. The current state of the field can be introduced without mentioning these terms. Third, some terms commonly used in current research are not featured in textbooks. With some trepidation at the prospect of increasing lists of essential terms, I give the 10 terms in boldface that appeared most often in research articles: mating, competition, foraging, sexual selection, mate choice, display or signal, reproductive success, aggression, dominance, and territory. Of these, only dominance and territory appear in multiple textbooks. From these terms, we can see that animals acquire food and mates, compete, and communicate. The essential phenomena of animal behavior are actions and can be described using verbs rather than nouns. For example, a predator may become confused when attacking a group of potential prey and may end up not capturing anything. We may label this the confusion effect, but creating a noun does nothing to clarify the behavior of predators and prey (see also Bednekoff and Lima 1998a, 1998b). When animals acquire food and mates, compete, and communicate, we can usually describe their actions using familiar words. I suggest that introductory textbooks could reflect current research in animal behavior with little need to expand students vocabularies, and that textbooks with fewer terms in boldface could better convey both the marvels of animal behavior and the process of science. The textbooks generally short-circuited the process of science in their presentations of animal behavior. Most often, principles were stated and then examples given as support. Although all the books mentioned hypotheses somewhere in their chapters on animal behavior, almost all hypotheses were followed with supporting evidence, as if science consisted largely of instant gratification. More seriously, control treatments and critical comparisons were often hidden from view. I only noted one instance where the logic of the control treatment was carefully explained (Freeman 2002, p. 917) and one instance where alternative hypotheses yielded different predictions, one of which was supported (Purves et al. 2001, p. 947). The books mention results from many experiments and leave it to enterprising instructors to spell out the process of science. Often, I fear, the main instructor leaves this to the lab assistants (who may be beginning graduate students). Students in introductory biology get the structural message that the process of science is secondary to wrestling with long lists of terms and categories. The treatment of animal behavior in introductory textbooks illustrates that our practices of teaching science do not match our practices of doing science in the laboratory or the field. Acknowledgments I thank John Alcock, Lindsey Gish, Jill Pernicano, Erin Radloff, Cara Shillington, and Sheri Snavely for helpful comments on previous versions of this work. I received examination copies of all of the textbooks, have taught using current or previous versions of five of the textbooks utilized here, and was paid small honoraria for reviewing chapters of two of the textbooks. References cited Alcock J Animal Behavior: An Evolutionary Approach. 7th ed. Sunderland (MA): Sinauer A textbook history of animal behaviour. Animal Behaviour 65: Alters S Biology: Understanding Life. 3rd ed. Sudbury (MA): Jones and Bartlett. Audesirk T, Audesirk G, Byers BE Biology: Life on Earth. 6th ed. Upper Saddle River (NJ): Prentice Hall. Bednekoff PA, Lima SL. 1998a. Randomness, chaos and confusion in the study of anti-predator vigilance. Trends in Ecology and Evolution 13: b. Re-examining safety in numbers: Interactions between risk dilution and collective detection depend upon predator targetting behavior. Proceedings of the Royal Society of London, B: 265: Campbell NA, Reece JB Biology. 6th ed. San Francisco: Benjamin Cummings. Freeman S Biological Science. Upper Saddle River (NJ): Prentice Hall. Krogh D Biology: A Guide to the Natural World. 2nd ed. Upper Saddle River (NJ): Prentice Hall. Lewis R, Gaffin D, Hoefnagels M, Parker B Life. 4th ed. Boston: McGraw-Hill. Mader SS Biology. 7th ed. Boston (MA): McGraw-Hill. Purves WK, Sadava D, Orians GH, Heller HC Life: The Science of Biology. 6th ed. Sunderland (MA): Sinauer. Raven PH, Johnson GB Biology. 6th ed. Boston: McGraw-Hill. Solomon EP, Berg LR, Martin DW Biology. 6th ed. Belmont (CA): Brooks/Cole Thomson Learning. Starr C, Taggart R Biology: The Unity and Diversity of Life. 10th ed. Belmont (CA): Brooks/Cole Thomson Learning. 448 BioScience May 2005 / Vol. 55 No. 5