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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology subject areas that might be encountered in any such introductory course (see the following section). To formulate the course outline, the College Board sends a curriculum survey questionnaire every 5 years to several hundred colleges and universities that have a history of granting AP credit. In the most recent survey (ETS, personal communication, 1997), about 500 institutions were contacted, and only 56 responded. Of these 56, only about 6 are institutions that might generally be recognized as having first-rank biology programs (University of California at Berkeley, Carnegie-Mellon University, the University of Washington at Seattle, Cornell University, Dartmouth College, and Brandeis University), and 16–20 might be considered second-rank. Therefore, the AP curriculum has been based on a sample that is (1) very small and (2) not representative of the nation’s best colleges and universities. The recent report of the AP Commission (Commission on the Future of the Advanced Placement Program, 2001) recommends that the College Board change this approach to course development substantially as mentioned above, replacing the current survey-based curriculum with course outlines based on input from leaders in the biological disciplines, as well as pedagogy, “to ensure that current reforms and best practices are reflected in AP” (p. 12). This more proactive stance is intended to position AP as a lever for positive change in curriculum and instruction. The panel strongly endorses this change, which will undoubtedly help in addressing some of the concerns regarding AP that are discussed below. The IB curriculum is formulated by an international consortium and also revised on a 5-year cycle. The consortium consists primarily of experienced IB teachers, most of whom are present or past examiners or moderators. (IB does not publish the committee rosters.) As noted earlier, because the IB curriculum is not constrained by the need to prepare students in specific areas for an advanced placement exam, it tends to be less comprehensive and more flexible than its AP counterpart, with 12 percent of class time allocated for options and 25 percent mandated for laboratory work over a 2-year period. Keeping up to Date Biology is in an explosive phase of development. Almost every day there are articles in the newspaper about some new advance in biomedical knowledge. Four of the most exciting areas of biological research today are the following: Genomics. Sequencing of the complete genomic DNA of humans and other organisms is making it possible to count the number of genes required for control of development and physiology, and ultimately to determine the functions of all these genes. Mechanisms of development. This work is addressing how genes and their encoded proteins control the development of a fertilized egg into an adult organism. Cell signaling. Researchers are learning how cells talk to each other via signals from transmitting cells to receptors at the cell surfaces of receiving cells, as well as working out the pathways of interacting proteins that transduce a signal to the cytoskeleton and nucleus of the receiving cell to activate specific behaviors and changes in gene expression.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology Evolution and the relatedness of organisms at the molecular level. Researchers have come increasingly to realize that all organisms utilize not only similar molecules, but also entire homologous systems of signaling and response for the same purposes in development and physiology. Modern aspects of these topics are largely lacking from the AP and IB course syllabi. Although it can be argued that secondary-level courses do not need to be up to the minute to be educationally valuable, courses that omit these topics lose an opportunity to engage students with issues in biology that are related to their daily lives. Sample Suggestions The following are some suggestions for addressing the shortcomings noted above: Expand discussion of the fluid mosaic model of membranes (dating from the 1970s) to include ligands, receptors, and signal transduction. Extend Mendelian genetics and the concept of mapping to the nucleotide sequence level. Use the rapidly advancing knowledge of developmental mechanisms as a review and synthesis of everything students have learned previously about gene expression, cell motility, signaling, and so on. Introduce the concepts of protein databases, sequence comparisons of homologous proteins, and building of sequence-based evolutionary trees. In the IB course outline, almost all the material on evolution is in the optional curricular materials. Given that evolution provides the conceptual framework for most of modern biology, it is essential that evolution be taught as a core subject and a basis for practical problem solving in all advanced high school biology courses. As with any curricular reform, such changes are likely to pose challenges to the structuring of existing and time-honored courses. Difficult decisions will have to be made about how to accommodate these critical tenets of modern biology. By condensing and making greater attempts to integrate topics, however, many of these concepts can be introduced in ways that build upon other components of the courses and within the time allotted to teach them. Balance Table 3-1 compares the amount of time prescribed for three broad biological subject areas in the AP and IB curricula of 180 hours total (excluding the mandated 60 hours of laboratory in the IB course), and Table 3-2 shows time spent on more specific topics. Despite the explosive advances in MCD and evolutionary biology over the past 20 years, the overall distribution of time spent in the three major subject areas in Table 3-1 has not changed since the mid-1980s for the AP curriculum. In the AP course, 50 percent of class time is still spent on
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology organismic biology and ecology and 32 percent on the structure of plants and animals (Table 3-2). This distribution does not reflect the current balance of emphasis in either biological research, the best instruction at the college level, or future career options for students. It is out of date and does not leave adequate time for teaching of cell and molecular biology. TABLE 3-1 Distribution of Class Time in Major Biological Subject Areas in IB and AP Courses IBa Subject Area APb 22% Molecules and Cells 25% 31% Heredity and Evolution 25% 35% Structure of plants and animals, ecology 50% 12% Optional Topics 0% a Based on information from International Baccalaureate Organisation (1996) (see Table 3-2). Figures in this column are percentages of nonlaboratory class time (75% = 181 hours); they do not include laboratory periods, which are mandated to be 25% of total time (59 hours; see Table 3-2). The evolution component (12%) of heredity and evolution is an optional topic. b From Educational Testing Service (1999)], pp. 3–5. Percentages of total class time, including laboratory. BREADTH VERSUS DEPTH A major problem with the AP course is that pressure to cover all of biology in less than a year precludes in-depth study and leads to superficial knowledge. In contrast, the IB program allows time for some in-depth study by subdividing the curriculum into core and options and by allowing 2 years for the Higher Level (HL) course. The AP course needs to include more options, both in the curriculum and on the tests, to make its breadth manageable. One solution would be to have two AP courses—one emphasizing EPO and the other MCD biology—both with significant evolutionary emphasis. Coverage of Topics in the AP and IB Courses As noted above, because of the importance of scores on the comprehensive AP examination, AP instructors are under pressure to cover all of biology within a year, necessitating a fairly superficial treatment. Little time is available to explore any topics in depth. Although the ETS maintains that students do not need to know all topics well to be successful on the exam, many instructors, especially those who are less experienced, feel they must cover all the material. In contrast, the IB curriculum builds in considerably more flexibility. First, there is a distinction between Subject Specific Core (SSC) and Additional Higher Level (AHL) material. Even together, these two categories do not cover all topics on the course outline and do not occupy the full instructional time, which also includes 12 percent set aside for optional topics to
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology be chosen by the teacher. The range of optional curricular material (Table 3-2) allows IB instructors some level of control over the composition of their courses and the relative weights given to different areas of biology. TABLE 3-2 Percentages and Hours of Class Time Spent on Various Subareas of Biology in IB and AP Courses Total Teaching Time Percent of IB Teaching Time Specified for a Concept (total hours 240) Prescribed Teaching Hours IB Curriculum Topics (1:, etc.) That Correspond to AP Concepts AP Teaching Concepts Percent of AP Teaching Time Specified for a Concept (total hours 180) 5 12 2: chemistry of life (12 hr) Chemistry 7 5 12 1: cells (8) 7: cells (4) Cells 10 6 15 4.2: photosynthesis and respiration (5), 9: cell respiration and photosynthesis (10) Energy 8 9 22 3: genetics (11), 10: genetics (11) Heredity 8 5 12 2.7: genetic engineering, DNA fingerprinting, gene therapy (3) 8: nucleic acids and proteins (9) Molecular Genetics 9 9 22 Option D: evolutiona Evolution 8
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology 3 7 13: classification and diversity (7) Diversity 8 4 10 16: plant science Structure of Plants and Animals 32 16 38 5: human health and physiology (17), 11: human reproduction (5), 12: immune system (6), 14: nerves and muscles (6), 15: excretion (4) Human Physiology 0b 4 9 4: ecology (9) Ecology 10 9 22 (evolution counted above) E: neurobiology/ behavior; F: applied plant/animal science, G: ecology and conservation Optionsc 0 Total: 75 181 100 Laboratory Percent IB Time in Labs (240 hours) Prescribed Laboratory Hour Laboratory Program Percent AP Time in Labs (180 hours) 4 10 Group 4 Interdisciplinary Inquiry Lab Project 0
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology 7 16 Options laboratory work 14 33 6: investigations (15), 17: investigations (18) Laboratory Program 12 prescribed labs Total: 25 59 0d a From IB optional topics. Note that teaching evolution is an option in the IB program. b Covered under the concept “Structure of Plants and Animals,” which includes discussion of functions. c IB options can be used to create flexibility and modify emphasis in the curriculum. For example, basic human health and physiology is built into the core IB curriculum, but the optional topics include considerably more material on human physiology, physiology of exercise, and human nutrition. Good coverage of cell biology exists in the core curriculum, but additional material on cell biology and cell physiology is provided in the optional curricular materials. Basic nerve and muscle biology is covered in the core curriculum, but an additional unit of neurobiology and behavior is optionally available. The same two-tier system exists for ecology. d Laboratory time not specified (see the discussion later in this chapter). The IB program further alleviates the breadth versus depth problem by extending the IB Biology HL course over 2 years, thereby allowing more time for in-depth study of at least selected topics. Even for the 1-year AP course, less comprehensiveness should be acceptable if all entering students have had a previous survey course in introductory high school biology. The panel is pleased to note that a nonscientific survey of students taking the AP exams indicated that about 78 percent had had a full 2 years of biology, implying that they had taken a comprehensive biology course before taking the AP course.2 As noted in Chapter 2, the panel believes this figure should be increased toward 100 percent. Finally, the IB course outline prescribes in some detail the degree of depth that should be achieved, whereas the AP course outline does not, although the same degree of depth knowledge may be demanded on the exams (see the examples in Appendix B). As noted earlier, one approach to decreasing comprehensiveness and allowing more time for in-depth learning in the AP program would be to offer two separate courses—one emphasizing MCD and the other EPO biology (with evolution included in both). The panel finds the need for decreased breadth more compelling than the arguments against separation put forward previously by the College Board (AP Biology Teachers Guide, 1995, p. 16). Some consequences of separation would be as follows: Increased costs to a school system if staffing, teacher training, and laboratory resources had to be provided for both courses. While this would probably not pose a significant problem for larger schools that already offer multiple sections of AP 2 In an ETS questionnaire administered with the 1999 AP Biology exam, 61,952/79,212 students reported that they had taken biology for 2 years or more in grades 9–12, including their current courses. These data are limited in value as they are self-reported and were not verified, and students were not able to receive clarification of questions they did not understand.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology Biology, it could be a significant burden for smaller school systems. However, the latter schools could choose to offer only one of the two courses. The need to develop separate AP tests for the two areas. Most significant, and representing the major stumbling block to any proposal for reform of the AP curriculum, scores on such restricted tests could no longer be considered as qualification to place out of a more comprehensive college introductory course. In fact, however, many of the better college biology programs have realized the impossibility of teaching a meaningful comprehensive introductory course, and are instead offering alternative courses that are restricted along just these lines, or further (see Chapter 5). The “Less Is More” Paradox The study of biology is of necessity broad; biology encompasses a huge variety of organisms and can be studied at many different levels of organization. In this regard, two pedagogical implications of the breadth versus depth issue are specific to biology. First, the study of evolution depends on the use of comparative methodologies and analysis across broad phylogenetic spectra. Synthesis and integration depend upon inferring robust generalizations from diverse samples. This approach is applicable at many levels, from multiple sequence alignments in bioinformatics and molecular evolution to the use of morphological, behavioral, and ecological characters in phylogenetic classification. Second, biologists are deeply committed to preserving and appreciating biodiversity. If students are not able to understand the valuable contributions of diverse plants for food, clothing, fiber, housing materials, and pharmaceutically active drugs, not to mention their aesthetic and historical importance for art, culture, and landscape, we will be missing a critical opportunity for environmental education. On the other hand, recent research on learning indicates that often “less is more”; in other words, more real learning takes place if students spend more time going into greater depth on fewer topics, allowing them to experience problem solving, controversies, and the subtleties of scholarly investigation. More is not always better from other perspectives as well; for example, Shenk(1997) describes how we are being buried by information overload. Students need to learn critical data mining skills so they can find relevant information and distinguish meaningful from irrelevant data. Until they understand enough biology to focus on the key concepts in new material, they are likely to be swamped by details and unable to experience science as a process of creative thinking and problem solving. The panel therefore recommends that more curricular flexibility be built into the IB and particularly the AP programs so that students can experience sustained, in-depth study of fewer areas. This study should be built around “big ideas” (as discussed below) and an understanding of the experimental method. It should be tightly integrated with similarly focused, in depth, inquiry-based laboratory experiences (also discussed below). Students need to be encouraged to think about the interrelatedness of the various disciplines of biology and the importance of interdisciplinary approaches to solving scientific problems. Emphasis should be placed on students’ ability to incorporate material they are learning into a meaningful conceptual framework.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology Thus although some degree of breadth is necessary and desirable as argued above, it should be defined by the degree of integration among different topics, not the number of topics covered. If students understand the process of science and the hierarchy of interrelationships among topics they have studied in depth, learning new biological knowledge is easy because it fits into a conceptual framework that is already in place. Consequently, the selection of particular topics covered in a course is less important than activities designed to build understanding of science processes and a conceptual hierarchy, and courses need not strive for comprehensiveness of subject matter. Eliminating the use of AP and IB exam scores for automatic placement out of specific college courses, as recommended in Chapter 6, would allow advanced secondary-level courses, particularly AP, to evolve in this direction. We argued in the preceding section that new and current subject matter should be introduced into the AP and IB Biology curricula, while we have maintained in this section that these programs attempt to cover too many topics already. This is the paradox that makes curriculum design difficult, particularly for biology courses. We would resolve it by urging that currently exciting subject matter relevant to students’ everyday lives be included in the choice of recommended topics for consideration by teachers, but that teachers be encouraged to apply the “less is more” principal and choose those areas for in-depth study that will create the most meaningful learning experience for students. THEMES AND CONCEPTS Both the AP and IB programs have stated themes around which the courses are theoretically organized. The eight themes of the AP curriculum mix philosophy and content, with some redundancy in the content themes, but appear adequate for their stated purpose. In the IB curriculum, there are only four stated themes, which surprisingly do not include two that appear to be essential—energy transfer and heredity. Themes in both courses are intended to provide integration of different topics, but the extent to which they are followed in presenting subject matter depends on the individual teacher. Particularly in AP courses, better integration of topics is needed. Table 3-3 compares the stated themes of the AP Biology course, the IB Biology course, and the NSES Life Sciences content standards for grades 9–12. Equivalent or related themes are listed in the same row to the extent possible (heredity in the AP themes is subsumed under continuity and change). As seen from the disparities, these lists are somewhat arbitrary. The IB list appears to have two glaring omissions, mentioned above. On the other hand, it could be argued that the AP list includes too many themes. There is some redundancy in the AP themes (e.g., between evolution, and continuity and change), and some of their applications to the three major subject areas appear contrived.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology TABLE 3-3 Comparison of Stated Themes from AP and IB Biology Courses and the NSES AP IB NSESa Science as a process Understanding scientific inquiry Evolution Evolution Biological evolution Energy transfer Matter, energy, and organization in living systems Relationship of structure to function Structure and function Continuity and change Molecular basis of heredity Regulation Equilibrium within systemsb The cell Interdependence in nature Universality vs. diversity Interdependence of organisms Behavior of organisms Science, technology, and society Science and technology in local, national, and global challenges a This list includes the six Life Sciences content standards, as well as one from Science as Inquiry and one from Science in Personal and Social Perspectives, all for grades 9–12 (National Research Council, 1996). b Equilibrium is apparently used by the IB program (misleadingly) to mean steady state or homeostasis. More important than the specific themes listed is the way they are used. Recent research on learning (National Research Council, 1999) has documented the common-sense realization that experts in a given field have their knowledge organized into a hierarchical conceptual structure, with key concepts (“big ideas”) at the top, derivative ideas and topical knowledge below, and common themes connecting the concepts. An expert learning new knowledge can fit it into the appropriate place within the structure. To become expert learners, students must construct their own hierarchy, organizing topical knowledge under the appropriate concepts. Their instructors and instructional materials, therefore, need to emphasize the themes and big ideas and distinguish them from related topical knowledge. The AP Biology course description is introduced with a helpful definition of themes, concepts, and topics and how they are related in building a conceptual structure [Educational Testing Service, 1999, pp. 2–3). It points out the importance of emphasizing key concepts over specific topical information and the way recurrent themes can be used to provide connections in the study of different topic areas. It claims that “increasingly, the AP Biology Examination will emphasize the concepts and themes of biology and will place less weight on specific facts.” The panel hopes this is the case, and that teachers will be encouraged to use themes to integrate diverse topics in the course. At present, however, there is little emphasis on such integration in the AP course outlines, recommended laboratories, and teacher preparation materials (see Chapter 4), so that integration depends on the initiative of the individual teacher. In particular, while the process of science is a stated AP theme, it appears clear from the outline that most AP laboratories are not inquiry based, so that students have little chance to experience this process (see the next section). Several of the same comments apply to the IB themes. The term “equilibrium” is used misleadingly to mean steady state or homeostasis. The rubric of themes and topics presented in
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology the program description (National Commission on Mathematics and Science Teaching for the 21st Century, 2000, pp. 7–14) again appears somewhat contrived in spots, and again the extent to which teachers use the themes in presenting subject matter is unclear. Nevertheless, with its more detailed course outline, the IB course appears to do a better job of integration, which is further enhanced by the Group 4 interdisciplinary project and the interdisciplinary thinking that pervades the IB program (as discussed later in this chapter). The NSES content standards include topical areas as well as themes and therefore are not directly comparable, but there is nevertheless considerable overlap with AP and IB. One AP teacher who met with the panel gave her students the interesting assignment of comparing and trying to relate the AP themes and NSES standards as a way to understand them more clearly. The above comments point to the need for more detailed guidance and development for AP Biology teachers. This is a theme to which we return in subsequent sections. LABORATORY WORK AND VARIETY OF LEARNING EXPERIENCES Meaningful learning in biology must involve inquiry-based laboratory experiences that require students not simply to carry out a technique or learn a laboratory skill, but also to pose questions, formulate hypotheses, design experiments to test those hypotheses, collaborate to make experiments work, analyze data, draw conclusions, and present their analyses and conclusions to their peers (National Research Council, 1996). One of the major differences between the AP and IB programs is the extent to which they meet these ideals. The AP laboratory exercises tend to be “cookbook” rather than inquiry based. They are not emphasized or tested adequately on the exam, and hence may be neglected. Written assignments that could integrate laboratories with the curriculum are not required. Schools are not evaluated by the College Board for adequate laboratory facilities. Although the IB laboratories are also largely not inquiry based, 25 percent of time in laboratories is mandated, portfolios describing students’ laboratory work are an integral part of the basis for evaluation, an extended writing assignment is required, and schools applying for IB status are initially reviewed and certified as having adequate laboratory resources and facilities. Yet both programs need more inquiry-based laboratory work. Learning experiences should be aligned with those set forth in the NSES. Although including laboratory performance in the AP exam is probably impractical, a portfolio of laboratory work should be made part of a student’s record, and universities should be encouraged to evaluate portfolios in advanced placement decisions. AP should certify that school facilities and resources can support college-level laboratory instruction before allowing courses to be designated as AP. The initial evaluation and continued surveillance of student work carried out by the IB program (see below) provide an appropriate model for implementing this recommendation. The AP manual suggests that “since one-fourth to one-third of the credit in comparable college courses is derived from laboratory work, AP courses should likewise emphasize
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology laboratory work.” However, there are several problems with the 12 recommended AP laboratories: They are highly prescribed, not inquiry based. The required laboratory write-ups involve filling in data tables or blanks, along with some “short” more extended responses. A sample AP laboratory is described in Appendix C. It is extremely directed; a student could work through it without gaining any understanding of what has occurred at the molecular level and its significance. Although the AP Biology course outline specifies that all 12 laboratories should be carried out, there is no check on whether the laboratories are completed. Questions dealing with laboratory material comprise only a small proportion of the exam. Moreover, many questions assess content knowledge related to the laboratory rather than protocol and process skills, so that the information can be obtained from reading or lecture without conducting the laboratory. (A few questions are better; for example, there should be more questions like those dealing with the photosynthesis laboratory.) Videos of the laboratories being carried out by others are available to familiarize students with protocols. Therefore, it is impossible to tell from AP test results whether students have actually performed laboratory exercises. The panel heard various anecdotal evidence that teachers wishing to maximize preparation time for the exam minimize the laboratories and may skip some altogether. Therefore, meaningful laboratory experiences are not guaranteed by the AP program, but rather depend on the skill and initiative of individual teachers. The 12 laboratories for which information is provided to teachers are an unnecessarily restricted set. Teachers who would like to use alternative laboratories may have neither a ready source for the necessary equipment and protocols nor the experience to use them. The limited teacher development available (see Chapter 4) is restricted to the 12 recommended laboratories. The AP program has no mechanism for certifying that teachers are competent to teach the laboratories or, just as important, that a school has the resources to support them with the required equipment and supplies. Consequently, students in poorer schools may be limited to learning about laboratories through videotapes and the textbook. In contrast, the IB laboratories are much less prescribed, and they require that students play a more active, investigative role (see Appendix C). Laboratory portfolios are used for formative assessment throughout the course in documenting understanding of laboratory practices and student accomplishment. There are many laboratories from which to choose, and the teacher is given considerable latitude in their selection. Schools and teachers must be initially certified before they are allowed to offer an IB Biology course, and their ongoing performance is assessed through sample laboratory reports that must be submitted periodically to IB international headquarters. The IB laboratories offered may differ from school to school, depending on teacher preparation and availability of resources. However, the initial evaluation process demands that each school plan an acceptable series of laboratories commensurate with its resources before certification is granted.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology To address the above problems, the panel makes the following recommendations: Both programs should move toward including more inquiry-based laboratory work in accordance with the NSES. Laboratory work should involve students in the active learning of science by doing science. The AP laboratories in particular should include more activities that engage students in analysis of complex data, modeling, data mining, generation of hypotheses and experimental designs, and statistical analysis. There should be built-in opportunities for reflection and peer review of work, as well as collaborations among students, faculty, and experts from the community. The College Board should assess courses and schools directly rather than only through the performance of their students on the AP exam. The AP program should include a certification mechanism to ensure that teachers of AP Biology are qualified and that schools have the resources to support planned laboratory investigations. Because meaningful laboratory teaching is almost impossible in a single class period, schools wishing to offer AP Biology should be strongly urged to schedule at least one uninterrupted 2-hour period per week for laboratory work. The AP exam should include more questions that assess student understanding of laboratory protocols and processes, understanding that can be gained only by actually carrying out experiments. In addition, the AP exam should include assessment of a portfolio of laboratory work by the ETS in addition to the summative exam. Extensions to the 12 recommended AP laboratories should be provided so that students and teachers can go beyond the basic exercises if they have the time and resources to do so. The AP program should provide or accept many more alternative well-tested laboratories, which could be distributed via CDs and the Internet, to give teachers a choice in the laboratories they present. Teachers should be encouraged not to limit themselves to the 12 currently provided AP laboratories. The Web is already an important source of laboratory exercises through sites such as those of Access Excellence (Genentech Corp.), CIBT (Cornell Institute for Biology Teachers), ABLE (Association of Biology Laboratory Educators), and ACUBE (Association of College and University Biology educators). Access information for these Web sites is provided in Appendix D. Alternative laboratories could be grouped into categories and teachers asked to conduct a certain minimum number of laboratories from each category. In addition to AP and IB teachers and students, college and university scientists should be involved in the development of additional appropriate laboratories, including laboratory and field exercises. Both ethics and environmental responsibility should be addressed in laboratory work. It would be useful to consider the development of laboratory blocks in which a group of progressive laboratory exercises is built around a model organism suitable for molecular genetic analysis, such as yeast, the alga Chlamydomonas, the nematode C. elegans, or the fruit fly Drosophila. These organisms have many advantages for use in advanced high school biology laboratories, including that (1) they are inexpensive to grow and maintain, (2) they are convenient for genetic experiments, and (3) there are national genetic stock centers from which a variety of mutants is available without charge.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology The AP program should provide or certify more teacher development and ongoing support in relation to laboratory teaching for both the 12 AP laboratories and alternatives. The IBO, which already provides considerable support for IB laboratories through its 3-day teacher training workshops, should consider expanding that support. The best mechanism for doing so may be university-based weeklong workshops. All prospective AP teachers should be required to attend at least one weeklong workshop before being allowed to commence teaching AP Biology. The CIBT program at Cornell University is a model. Such programs often are able to provide loan equipment, supplies, and reagents in addition to teacher training. The AP and IB programs should evaluate and certify such college- and university-based workshops for their teachers. INTERDISCIPLINARY EMPHASIS There is little evidence of interdisciplinary emphasis in the AP course outline. In contrast, the entire IB program, including its biology course, rests on the importance of interdisciplinary connections in learning. The IB program is exemplary and far superior in this regard. The AP program should consider changes that would promote interdisciplinary learning. Interdisciplinary activities in the IB program include an extended essay and a course required of all students on the Theory of Knowledge, which ties together all six groups of courses in the curriculum (International Baccalaureate Organisation, 1996). Another particularly desirable interdisciplinary requirement is the Group 4 laboratory project, in which students from several different advanced courses (e.g., biology, chemistry, physics) work together as a group to solve an experimental problem, often a local one involving the environment or the community (see the brief description in Appendix C). While restructuring the AP program in the near future along more interdisciplinary lines may not be practical, small steps could easily be taken in this direction, such as: Combining advanced biology and chemistry into a 2-year course team-taught by a biology and a chemistry teacher. Involving students from two or more AP science courses in joint interdisciplinary, community-oriented problem-solving laboratories. ASSESSMENT With regard to mastery of content knowledge, concepts, and applications (see the charge to the panel in Appendix A), both the AP and IB exams test primarily rote learning.3 In the IB assessment process, evaluation of a portfolio, laboratory notebooks, and other work provides more perspective. The AP exam should include more free-response questions and evaluation of laboratory work, and both should test more concept knowledge. With regard to application of knowledge to other courses and situations, the AP exam is limited by a lack of interdisciplinary 3 Based on reports of teachers interviewed and the panel’s inspection of recent AP and IB exams.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology emphasis, while the IB assessments include such applications. As recommended above, the AP course and exam would benefit from more interdisciplinary emphasis. Excessive use of multiple-choice and fill-in-the-blank questions assessing factual details on both AP and IB examinations encourages the rote learning of many facts at the expense of understanding larger concepts. It is encouraging to note that the AP Biology exam was redesigned in the mid-1990s to include more free-response or essay questions and fewer short-answer questions, and that there are plans to increasingly emphasize concepts and themes and deemphasize retention of specific facts (Commission on the Future of the Advanced Placement Program, 2001, p. 3). Both exams should move in this direction. Additional improvements could include the following: More questions that assess laboratory skills, e.g., scenario questions requiring analysis of datasets, quantitative analysis, and testing of multiple working hypotheses. For AP exams, document-based questions (already used in IB exams) requiring students to read a brief biological article and write about it. Open-ended questions with no prescribed answers, asking students to discuss a currently exciting topic they have studied. Questions of this type would promote study of such topics in the AP course. However, the panel’s primary recommendation is that assessment in the AP program should be extended to include formative evaluations of laboratory notebooks, presentations to peers, and other activities during the course in addition to the final high-stakes summative examination. Finally, as pointed out above, there is a great need in the AP program for assessment not only of students, but also of teachers and schools that offer AP Biology courses to ensure minimum standards of quality.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology 4 Teachers and Teaching IS CURRENT KNOWLEDGE OF LEARNING AND PEDAGOGY BEING APPLIED? The AP and to a lesser extent the IB Biology courses are taught inconsistently with current knowledge in several ways, some touched on above and more discussed below. Inconsistencies include rapid-fire course coverage at the expense of depth of understanding; continued reliance on the traditional learner-passive, transmission–reception model of learning; failure to specifically target common known misconceptions; limited use of history as a route to understanding in the context of people and society; failure to keep pace with new technological and instrumentation opportunities, such as learning through computer modeling of biological systems and hand-held data collection and analysis equipment for field work; overreliance on multiple-choice and fill-in-the-blank test questions; limited experiential and inquiry-based learning in the laboratory, including the “persuasion of peers” phase crucial to the scientific process; and in general, lack of an overall research-based learning theory that can drive the design of instruction and assessment. Classroom practice should be driven by research on learning and teaching. Following are key findings from How People Learn: Bridging Research and Practice (HPL2) (National Research Council, 2000b, pp. 10–15): Teachers need to probe students’ prior knowledge and engage it in their teaching. To develop confidence in an area of inquiry, students need to build a sound conceptual framework and structure it in ways that facilitate retrieval and application. Students need to learn how to monitor their own understanding (metacognition) and take an active role in their own learning. These findings have concomitant implications for teaching (HPL2, pp. 15–19): Teachers must be aware of students’ prior and evolving knowledge. Therefore, more emphasis should be placed on formative assessment. Fewer topics must be taught, but in greater depth and with more examples, in order to yield a sound conceptual foundation. Teaching of metacognitive skills should be integrated with discipline-based instruction.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology HPL2 stresses that “a benefit of focusing on how people learn is that it helps bring order to a seeming cacophony of choices” (p.18). It continues with a variety of recommendations that are updated in Inquiry and the National Science Education Standards (INSES) (National Research Council, 2000a). For example, INSES suggests that inquiry is simultaneously a way of teaching and learning, a way of answering questions, and intrinsic to scientific investigation. Thus, learners should (pp. 13, 25): Be engaged by scientifically appropriate questions. Use evidence to build explanations. Weigh alternative scientific explanations. Communicate and justify their explanations. The AP and IB programs need to move toward reflecting this transformation from curricula that are directed by the teacher (as transmitter and corrector), the text, exams, and material to curricula that are learner-directed. Doing so will involve attention to (1) student knowledge construction based on investigation, analysis, and problem solving; (2) peer review and collaboration to continuously monitor student knowledge; and (3) efforts to address real problems of the local community and ecosystem. On average during a calendar year, students spend less than one-seventh of their time in school. During waking hours, they spend four times as much time in their homes and communities than in school (including more time watching television than in school; see HPL2, p. 23). Thus, “a focus only on the hours that students currently spend in school overlooks the many opportunities for guided learning in other settings.” TEACHER PREPARATION AND PROGRAM QUALITY Many teachers at the secondary level are unprepared with regard to content knowledge to teach college-level biology, and many schools that offer AP programs do not have the resources to support adequate laboratory instruction. The College Board should evaluate and certify AP schools and teachers in some manner similar to that in which the IBO initially evaluates and certifies its schools and teachers. Some of these issues have been addressed in Chapters 2 and 3. Through its application and interview process, the IBO ensures that new IB schools are qualified and that schools have the necessary resources for the program’s required laboratory activities. Once an IB school has been certified, the IBO monitors teachers through its internal assessment program. For AP schools, however, these issues represent basic concerns, including the following: Teachers who have not been certified to teach an AP course except by a local school system and may not even have a B.A.-level education in biology are teaching courses that can receive college credit. (Data are not currently available on what proportion of AP Biology teachers do not hold a B.A. degree in biology. The panel strongly urges the College Board to obtain these data and make them available.) An inexperienced teacher can be assigned to an AP course at the last minute, with no laboratory experience and no preparation beyond the “Acorn Book” (Educational Testing Service, 1999) and a set of previous exam questions.
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Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High Schools - Report of the Content Panel for Biology These concerns should be addressed by: Mandatory evaluation. While some teachers with a B.A. degree in biology and some experience are undoubtedly capable of teaching college freshman–level biology, others may not be. An M.A. degree in biology, involving some experience with research, would clearly be preferable for teaching the kinds of inquiry-based laboratories that would conform to the NSES and INSES. However, rather than mandating a certain level of preparation, the panel reiterates its recommendation that the AP program institute an assessment process, including teacher interviews, that teachers and schools would have to undergo before offering an AP Biology course for the first time. Mandatory teacher preparation. The panel reiterates that no teacher should be assigned or certified as above to teach an AP Biology course without having had the opportunity to participate in at least a 1-week summer workshop focused primarily on laboratory activities. TEACHER DEVELOPMENT AND SUPPORT More in-service teacher preparation and support are needed, and more attention should be paid to pedagogy in manuals and workshops, particularly for AP teachers. Neither the IB nor AP program requires or offers much in the way of continuous professional development of teachers as a prerequisite for participating and remaining in the program.4 According to anecdotal evidence gathered by the panel, most teachers have little opportunity to collaborate with one another in developing adaptations and implementations of more progressive curricular approaches. The AP workshops currently offered by the College Board are 1-day or half-day meetings that focus primarily on recent developments in the AP examination and how to prepare students for the exam. Both programs need: More instruction in and discussion of inquiry-based learning and pedagogy in general in the materials prepared for teachers, following the guidelines of the NSES and INSES (see the preceding section). More frequent workshops that include discussion of recent developments in biology and pedagogy. More training and ideas for laboratory activities, including the recommended or alternative laboratories, disseminated through workshops, CDs, or Internet sources (see Chapter 3). More involvement of the programs in establishing peer support groups for teachers in the same locale, and perhaps via the Internet for geographically isolated teachers. (IB already does this to some extent via the IBO Online Curriculum Center.) 4 Based on teacher interviews and review of AP and IB materials by the panel.
Representative terms from entire chapter: