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Curricular Goals for the Near Future ELEMENTARY SCHOOL Time for Science Science knowledge about the natural world and the processes by which that knowledge is acquired is a basic subject. To pretend otherwise is to deceive, but we perpetuate the deception in our schools. To present science as a basic subject, we need to make some substantial changes, starting with the time that is allocated to science in elementary school. We believe that during those early years, students should receive science-related instruction. As much time should be spent on science as is spent on the other basics reading, writing, and mathematics. Wherever possible, the presentation of science should dissolve the historical boundaries between educational disciplines. Knowledge about the natural world should become integrated with reading, writing, and mathematics. Examples of written science materials that could be incorporated into the normal language- arts lessons include stories about nature and organisms, travel, and how the universe operates. Such reading materials should be written in an interesting style, be filled with visual accompaniments, and be conceptually accurate. Lists of resources of this nature are available, for example, The Museum of Science and Industry Basic List of Children's Science Books (Richter and Wenzel, 1986, 1987). But the suggestion of more time for science involves something much more important than reading and writing about science. The time should be used primarily and most importantly for hands-on exploration by the students. The emphasis should hinge on engagement with, observation of, and direct experience in the natural world. Instruction should not be narrowly focused; it 13

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4 FULFILLING THE PROMISE should not suggest at the start of the lesson that something unusual, esoteric, or difficult is about to be studied. The most important goal is to make science attractive and interesting to the students. Many organizations are currently working toward that end, as noted in Science for Children (NSRC, 1988), a compilation of curriculum materials, supplementary resources, and sources of information and assistance for elementary-school teachers. Many districts throughout the country are now developing hands-on science programs for elementary-school children. These districts find it necessary to support their teachers through a comprehensive inservice education program and a science-resource center that supplies modular science kits. At regular intervals, the kits which include a teachers guide, a set of student activity books, and a set of equipment for the classroom are circulated from one teacher to another after being checked and resupplied with disposable materials at the district level. Such kits are being designed at the national level in several places, including the Lawrence Hall of Science in Berkeley, California, and the Education Development Center in Newton, Massachusetts. The National Science Resources Center (NSRC) in Washington, D.C., is developing 24 kits of this type: four each for grades 1-6. The first three kits, scheduled for commercial availability in the spring of 1991, deal with plant growth, with electricity, and with microscopes. Natural History as One Focus The K-6 years are the appropriate years for developing an "intuitive" (rather than a formal, taxonomic) understanding of biological diversity and the relationships of living organisms. Students should be engaged in observing and caring for a wide range of organisms that can be housed in the classroom, with emphasis on local plants and animals. Many animals can be raised in terrariums or aquariums. Students should assist in feeding and rearing animals to understand their needs, their behavior, and their life histories. Because plants are especially easy to grow and care for, students at every grade level should be involved with gardening projects, using outside space, window boxes, or potted plants. Both domesticated and native plants should be grown and observed. The ecological and agricultural importance of plants should be a major point of emphasis. The historical importance of agriculture in the development of the human race provides an ideal opportunity to integrate the social and natural sciences. Students should visit both pristine and disturbed habitats often to observe and study the web of life and how it is influenced by natural and human-related factors. Local resources should be used, such as museums, natural areas, parks, the zoo, and any municipal facility where local talent can be tapped. Local school districts should work together with local resource people to develop appropriate field trips and study sites that can be used routinely by classes. The same sites should be visited periodically throughout the school year to follow the annual weather cycle, thereby stressing continuity and change over time. Every school should provide transportation to appropriate field sites. A reasonable pattern is two trips per month (on the average) away from the school

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CURRICULAR GOALS FOR THE NEAR FUTURE 15 site and frequent trips around the school grounds or local neighborhood. The self contained classroom model in place in most elementary schools lends itself nicely to scheduling half-day or all-day trips. In contrast, the departmentalized or rotating classroom model in place in most secondary schools makes the scheduling of field trips almost impossible. The enriching experience of the field trip is thus logically the domain of the elementary-school science curriculum. The Need to Explore The existing emphasis on learning facts derived primarily from reading is inadequate. It should be replaced by learner-centered lessons that allow students to observe nature directly and practice the skills of inquiry. By inquiry we mean several related processes. Students need to become actively engaged in thinking, asking, and problem-solving. The students' role should be to experience, discuss their experiences with each other, and write about the experiences. The teacher's role is to listen, encourage, ask questions, and lead, but not to act as a font of knowledge, pouring information into empty vessels. Lessons in science should develop skills in careful observation, comparison, measurement, questioning, and communication. As the next step, they should then engage the students in formulating interpretations, conclusions, and explanations. In short, they should reflect more accurately the processes by which science is done and scientific understanding achieved. Ideally, units of study should be designed as projects, rather than as isolated topics or chapters in a book. During each project, students can produce a tangible product related to the unit of study for display at school and presentation to their families. This approach of "discovery, project, and product" helps each student to develop skills in communication, promotes pride in creativity, engages family support, and develops a positive self-image. The products can include posters, models, photo essays, measurements and presentations of growth or seasonal changes, and the like. Emphasis should be on successful and creative completion of such projects and then on re-examination of results, rather than on worksheets or written examinations, which promote a competitive atmosphere that is detrimental to most young children. Projects also lend themselves well to integrating mathematics and social studies into the units of study. Achievement Tests The public's desire to see evidence of school improvement carries a danger. The danger lies not in the understandable wish to see improvement, but in the primitive measures available for assessing what students have learned. This subject is taken up in more detail later in the report (Chapter 4), but a word of caution is in order here. If education in science in elementary school is to improve, achievement tests must not be allowed to drive the curriculum in wrong directions. Tradition- ally, such tests have emphasized factual recall and have led teachers to design curricula that "teach to the tests." The tests seriously compromise curricula that

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16 FULFILLING THE PROMISE are devoted to teaching science as a participatory process and to developing skills in observation and inference. The California Assessment Program (CAP), an example of a testing pro- gram of a different sort, does not monitor specific students or even specific teachers, but attempts to monitor only the overall effectiveness of a schoolwide curriculum. The California Science Framework and Science Framework Adden- dum are statewide documents that attempt to define the educational approach and curricular emphases on which CAP testing is based (Science Curriculum Framework and Criteria Committee, 1984~. Since the institution of the eighth- grade science test in 1985-1986, test scores have improved each year (results provided by the California State Department of Education). Although the test- ing program still has far to go to meet the stated goals of an instrument that evaluates conceptual and process-oriented understanding, the attention currently focused on the CAP and a statewide emphasis on meeting the objectives in the State Science Framework are helping to fuel a reform of the science curriculum. Students should leave elementary school with a strong love for and appre- ciation of nature and for their own world around them and with the recognition that science is an important way to learn about the world. In elementary school, every student should feel successful in learning science and should look forward to additional instruction. Emphasis should therefore be placed on active partic- ipation in science activities, and not on highly competitive grading procedures. These objectives are far more important than either acquisition of the kind of knowledge that is measured by traditional examinations or attempts to identify and reward future scientists. If every student entering the middle-school years already had positive attitudes toward science, the lifelong curiosity about the natural world that would be in place could be exploited in later years. Science Education of Elementary-School Science Teachers Teachers of science in elementary school must be far better prepared than are most at present. To disguise their anxieties about science, most elementary- school science teachers have hidden behind textbook-centered lessons that stress vocabulary and memorization of facts. Given the minimal amount of science instruction taken in college by most elementary-school teachers, that attitude is understandable. But the situation must change to achieve quality science instruction in the elementary schools. Because of the breadth required to teach interdisciplinary science well, and because of the very poor science background of most elementary-school teachers, science specialists might be needed to introduce science instruction into most elementary schools. A science specialist should be trained and certified specifically for teaching science in elementary schools. Such training will require more than the conven- tional college-level courses in science. The specialist needs training as well in teaching elementary-school science with approaches that engage children in the excitement of the subject. Few programs for preparing teachers currently offer, let alone require, such training for future elementary-school teachers, even those who will teach science. If elementary schools were to rely primarily on science specialists for

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CURRICULAR GOALS FOR THE NEAR FUTURE 17 science instruction, it could be a major change from the current practice of assigning one teacher to teach everything (except perhaps an occasional lesson on music or art). Such a use of science specialists, however, presents two dangers. First, it could preserve the place of science as a peripheral or supplementary subject, taught only when a specialist is available. Second, it could postpone the necessary preparation of other elementary-school teachers to teach science. Science specialists must therefore be used imaginatively and in ways that do not compromise other goals. One possibility is teaming assigning a team of two or three teachers with different strengths to teach two or three classrooms of students. Students need not change classrooms; members of the teaching team can move from one classroom to another. Successful models of teaming exist nationwide (see discussion, for example, in the report of the Carnegie Council on Adolescent Development, 1989, pp. 38-40~. With appropriate cooperation, science specialists' skills can complement those of other teachers on the team, making them more comfortable with science in the classroom. Furthermore, the skills and knowledge of science specialists can be used in inservice programs to assist their colleagues. We see a role for science specialists in the classroom as a short-term expedient. Preservice education of elementary-school teachers should prepare all teachers to present science with the other basics. Conclusions The last 20 years have seen the transformation of the United States into a society that is increasingly dependent on science and technology, but awareness of that reality has not yet permeated our system of education. Science must be treated as a first-priority subject, beginning in the crucially formative years of elementary school. Our general failure to treat it thus is a major reason why secondary-school students perform poorly and harbor negative attitudes about science. Substantially more time needs to be devoted to science in elementary schools. Biology should focus on natural history, be integrated with other subjects wherever possible, and emphasize observation, interpretation, and hands-on involvement, rather than memorization of facts. Recommendations The first three of the following recommendations are starkly worded. Each raises other issues, and each confronts us with numerous obstacles that will have to be overcome before it can be implemented. Most of the rest of this report deals in more detail with how the obstacles can be met and overcome. (In Chapter 8, which addresses the need for national leadership, we propose a means of monitoring and encouraging progress on many fronts.) State departments of education should not only make science a basic subject in elementary schools, but ensure that science instruction is

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18 FULFILLING THE PROMISE of adequate quality. This will require much more than token observance of new regulations. All programs for preparing elementary-school teachers should in- stitute preservice and inservice activities to assist teachers in presenting sci- ence to young children. Likewise, licensing and credentialing boards should require rigorous training of those who will seek to teach elementary-school science. All elementary-school teachers should become more familiar and comfortable with science, so that the subject can be truly integrated into the elementary-school curriculum. Statewide or district tests should be used only if they are consis- tent with the goals of a concept-oriented and hands-on elementary-school science curriculum. Achievement tests, when used, should stress concep- tual understanding and development of problem-solving skills, rather than acquisition of detailed factual knowledge for its own sake. Inclusion of performance-based exercises in any testing program is also desirable. Industry, government agencies, universities, professional societies, and other organizations should assist school personnel and cooperating local resource people in identifying field sites and appropriate field trips to be used by elementary schools. For example, many members of conservation groups and birding clubs have extensive knowledge of local natural history. Local groups could provide summer financial support to help develop programs of study that use those resources in conveying how science is related to the immediate world of the students. Attention should be given to the integration of "science stories" into language-arts lessons. Reading and writing about natural phenomena appropriate for the range of readers in elementary school should be an inte- gral part of language-arts and reading instruction. Readings could include stories and other narrative forms and introduce and increase expository science materials over the elementary-school years. Writing should give students opportunities to explain their observations and findings and to examine feelings about the natural environment. MIDDLE SCHOOL Human Biology as a Focus Science courses in middle schools must meet the specific needs and interests of early adolescent students. There are doubtless a number of ways to achieve that goal, but we conclude that the most appropriate formula for the life sciences is one that makes the student the object of study. Rather than perpetuating the life-science course as an anemic version of high-school biology or as a maze of discrete topics distributed throughout textbooks of general science, we would make human biology, broadly defined, the theme. This perspective should raise the student's level of motivation and thereby generate a continuing incentive to learn. In addition, it will provide an appropriate continuation of the science that we propose be taught in elementary schools.

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CURRICULAR GOALS FOR THE NEAR FUTURE 19 Adolescents at the middle-school level are especially curious about them- selves, so links should be forged between the middle-school health-science course and the life-science course. That will necessitate extensive change in the format of both courses. Properly taught, human biology provides a cross- disciplinary perspective on the nature of humankind and what it means to be human. For students, human biology should be learning to know oneself, un- derstanding other human beings, and appreciating their relationships to all other forms of life and to the biosphere. For the teacher, teaching biology means providing a curriculum that not only focuses on understanding oneself, but also increases human potential by developing responsible attitudes about the health of self and others, by reducing maladjustive behaviors (e.g., unhealthy eating and drinking, smoking, and the use of illegal drugs), and by fostering respect for the environment and for the need to sustain a biosphere favorable for the survival of life. Course Structure A human-biology course for a middle-school life-science program could be designed as a 2-year sequence that would fill the curricular time slots now occupied by life-science and health-science courses. The subject matter would have both a biological and a cultural and social dimension. The course should include conceptual strands to reinforce ideas of relationships, community, ethics, one's place in the universe, and understanding of self. State requirements regarding teaching about topics related to health and safety should be integrated into the presentation. Investigative activities should be designed in which students are most often the objects of study for example, examining human cells, studying genetic and physical diversity in a class population, and studying the local environment. We must not underestimate the effort that will be necessary to effect the suggested change in the middle-school life-science program, because it cannot be achieved by tinkering. The subject matter for a curriculum in human biology needs to be drawn from several disparate fields of scholarship, and that will require the efforts of others besides biologists. Fortunately, some models are already being developed. One such program is the Carnegie-Stanford human life-science curriculum that is being formulated by researchers from the Stanford University departments of biology, sociology, psychology, and anthropology; the school of medicine (including departments of general practice, psychiatry, and pediatrics); and the Families Study Center (Hurd, 1989a). Representatives of those fields all have teaching assignments in Stanford's Program in Human Biology. Other groups are in the preliminary stages of developing middle-school science curricula that focus on the development of the early adolescent and the inclusion of science-technology-society (STS) themes (NSF, 1988; BSCS, 1989~. Another group, the National Science Teachers Association (NSTA), has initiated the Scope, Sequence and Coordination project that addresses science teaching in grades 7-12 (Aldridge, 1989~. Creation of a syllabus is only the start. Courses need to be field-tested, appropriate textbooks must be written, new modes of examination need to be

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20 FULFILLING THE PROMISE developed, models for preservice and inservice training must be created and tested, and the relationship with health courses and with teachers responsible for that component of the middle-school curriculum must be redefined. (For example, persons not trained in science should not teach science.) The necessary changes are not matters that can be dealt with by casual administrative fiat; they require extensive cooperative ventures by many people who must make the necessary commitment of time and energy, and every school district in the nation will have to be willing to reexamine cherished practices. Many of the potential barriers to implementing curricular change are discussed at greater length in Chapters 4 and 5. Conclusions The middle-school life-science course needs drastic revamping. An ori- entation to human biology holds great promise for both sustaining students' interest in science and addressing a variety of educational goals important to society at large. Recommendations Several models of refashioned middle-school life-science curricula are being developed. Therefore, the greatest need is not to undertake new initiatives, but to create a process by which programs can be tested, monitored, and evaluated in the science and education communities. As new programs enter the classroom, we will need to know what is working for which socioeconomic, ethnic, and cultural groups; whether a given program has paid sufficient attention to long-term aspects, such as inservice training, and to the development of appropriate testing materials; and what is needed to ensure not only high scientific quality in individual programs, but wide dissemination of the most successful ones. Unfortunately, the argument that good educational programs necessarily push out bad ones rings hollow. Therefore, in Chapter 8 we propose a mechanism for the continuous evaluation and monitoring of science education in the nation's schools. HIGH SCHOOL When this committee began its deliberations, we found ourselves wrestling with the content of the high-school biology course what it was and what we thought it ought to be. The more we discussed the details of the curriculum, however, the more we saw that we could not convey our vision of the future with yet another syllabus. We fully expect some readers to pick up this document with the hope of finding an outline for the perfect course. They will be disappointed, for our message is vastly more complex than can be conveyed in a syllabus. The high-school biology course, like the other high-school science courses, requires fundamental changes.

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CURRICULAR GOALS FOR TlIE NEAR FUTURE 21 Teachers have no shortage of lists and skeletal outlines of topics to be presented in their courses. Those forms of guidance are in fact part of the problem. Putting down yet another bare-bones description of a course will send just the wrong message, for it will invite teachers and publishers alike to look for the topics that they "cover" and, on finding them, to conclude that they must be doing the right thing. Furthermore, academics will complain if their favorite corner of biology is not mentioned. We discuss textbooks in Chapter 4. We have argued that students who reach the high-school course in biology should already have experienced 9 or 10 years of formal exposure to science. Specifically, we have suggested that the biology to which they were exposed in elementary school should have focused on natural history and that middle school should have helped them to understand themselves as living organisms. By the time they reach high school, teachers should be able to build successfully on that foundation. We can indicate what the high-school course should be doing by contrasting it with the present version. The explosion of scientific knowledge in the twentieth century confronts us with the need to choose carefully the material to be presented at every level. In making these choices, we must be clear in our own minds about the criteria we are using. All too often, selection is driven by the calendar: If a fact was unearthed last year it must be important. Or if we understand something in great detail, we should teach that detail. The notion of punctuated equilibrium might be but a ripple on the surface of evolutionary theory; because it is current, it has received considerable attention. We know an enormous amount about the molecular details of intermediary metabolism, but to whom are those details important? Certainly not to students with no previous formal exposure to chemistry. We need a much leaner biology course that is constructed from a small number of general principles that can serve as scaffolding on which students will be able to build further knowledge. Further knowledge can come from reading the newspaper or from course work, but the scaffolding should include an understanding of basic concepts in cell and molecular biology, evolution, energy and metabolism, heredity, development and reproduction, and ecology. Concepts must be mastered through inquiry, not memorization of words. The number of new words introduced must be kept to an absolute minimum. Examples of What Is Needed A high-school course with the above aim embodies a substantial departure from the current course. Several examples drawn from different topics will help to convey our intent. Development and Reproduction The present course is so burdened with terminology that concepts are lost. For example, the emphasis on naming structures permeates the biology course from molecules to organisms. Consider the process by which the chromosome

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22 FULFILLING THE PROMISE number is reduced so that each sperm or egg receives a single copy of each chromosome. Many teachers and most textbooks today present the details of meiosis I and II, the specific structures of chromosomes in meiosis I, and the details of meiotic recombination by introducing as many as 20 terms. The names and details of the events during pairing and synapsis are not important in teaching that the process of meiosis halves the number of chromosomes. Students should learn that some chromosomal breakage and rejoining occur and that they increase genetic diversity, but the details can obscure the main function of meiosis genetic recombination and preparation for fertilization. The teacher could enrich the topic for some students by posing the question of how chromosomes find each other to pair. The students could make their own predictions, inasmuch as the answer is not yet known. Energy and Metabolism Many high-school textbooks handle energy superficially. Students must develop an intuitive grasp of the meaning of energy, its different forms, its conservation, and its relation to order and organization of matter in the world of their personal experience before an exploration of energy as the universal requirement for self-sustenance will hold any meaning. The capture and use of energy constitute a common theme that is encountered at the levels of cells, organisms, and ecosystems, but the theme is seldom well developed in the classroom. Much is known about the details of intermediary metabolism, but ninth- and tenth-grade students need not be burdened with structural formulas of organic molecules and the details of the Krebs cycle. The role of cellular respiration should be developed by focusing on the essential chemistry, involving the stepwise oxidation of organic molecules to form CO2 and the concomitant reduction reactions in mitochondria in effect, the charging of a battery that in turn forms adenosine triphosphate (ATP). Expenditure (hydrolysis) of ATP is then coupled to the manifold activities of cells that require energy: making muscles work, building proteins and other molecules, pumping ions out of cells, and so forth. Finding imaginative analogues in the world of the students' experience and interest is essential. For example, comparison with an engine is instructive, because both boys and girls at this age are developing strong (if superficial) interests in automobiles. Because enzymes enable the reactions to proceed at room temperature, less energy is wasted as heat, and the efficiency of energy conversion to work is high, compared with that in an engine. The formal and reciprocal relationship of cellular respiration with photosynthesis can be developed from the same small number of principles, and green plants lead naturally into the realm of ecology and the Earth's energy and food balance. The latter issues are now usually treated separately, if they are mentioned at all. Cell and Molecular Biology Today's students are presented with generalized diagrams of a cell and required to memorize the names of all the subcellular structures, associating each

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CURRICULAR GOALS FOR THE NEAR FUTURE 23 with a function, such as inheritance, secretion, energy production, or digestion. Instead of viewing the cell as a complex of independent factories, it would be more sensible to adopt a functional perspective in which various structures- such as the endoplasmic reticulum, lysosomes, and Golgi apparatus-can be thought of as part of an extra-cytoplasmic region involved in shifting proteins from one compartment to another and out of the cell. In the nucleus, the main concept is that the synthesis of RNA on a DNA template is physically separated from the synthesis of proteins, because the RNA has to pass through the nuclear membrane before it can be translated into proteins. The nucleolus (a prominent structure inside the nucleus with an unfortunate name) is not of special importance functionally for tenth-grade biology students. Other morphological terms, such as centromere and centriole, are merely confusing. Students need to know only that during mitosis the duplicated chromosomes split apart and are moved by the spindle structures to opposite spindle poles. Students need not memorize the names of the various stages of mitosis. Cells communicate with other cells by a few mechanisms. This important topic is not covered at all in high-school classes, yet it forms a scientific basis for understanding many biological problems, including the action of brain- altering drugs. In many kinds of cell-cell communication, signals must be interpreted by a cell, which then responds in specific ways. These responses occur during signal transmission from nerve cell to nerve cell and from nerve cells to muscles and glands. Other examples are response to light in the retina, response to signaling by hormones, response to artificial drugs (such as opiates), and the response of an egg to a sperm. Although these responses seem very different, they involve a few common mechanisms that start with the binding of molecules outside the cell (the signal) to proteins embedded in the cell's plasma membrane. The cytoplasmic tails of the receptors (the part inside the cell) respond to these external signals by inducing one of a few types of chemical response. In general, chemical responses follow a unified pattern of signal transmission and reception over a time scale from milliseconds in the brain to months in hormonal control of pregnancy. The general pattern is important, but the biochemical details of the chemical responses are varied, often complex, and totally unnecessary to memorize for a student to understand the general . ~ slgnlncance. Evolution The current handling of evolution is egregious. The meaning of the word "theory" has been so corrupted as to spread confusion about the process of science throughout the biology course. As Lerner and Bennetta (1988) have documented, not only do textbooks use "theory" synonymously with myth, legend, or any idea that might pop into the head, but the word is also used as an antonym of "fact." How can a student understand what is meant by "cell theory" or "kinetic theory" when assaulted by such nonsense? Evolution must be taught as a natural process, as a process that is as fundamental and important in the living world as any basic concept of physics one can name. The evidence that supports evolution-physical measurements of the age of the earth, the fossil record, patterns of similarity in body plans, the

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24 FULFILLING THE PROMISE records left in the primary structures of nucleic acids and proteins should all be examined, and students should be led to see how such disparate knowledge knits together to form an elegant and coherent whole. The existence of evolution should be distinguished from the mechanism by which it occurs; Darwin's contribution was enormous, but its nature should be made clear. Students should understand that natural selection is the principal, but not the only, factor that leads to evolutionary change; they should learn something about the concepts of populations and species; and they should understand the differences between changes that take place in an individual during development and changes that take place in a lineage as a result of evolution. Evolution is a process and should not be confused with classification, which is a static way of organizing information about organismic diversity. The study of evolution as a process will be most successful if students have acquired some feeling for biological diversity in earlier years through the study of natural history. The study of evolution does not require an extensive knowledge of classification, but knowledge of the evolutionary process provides a framework in which information about systematics will appeal to students. Conversely, dry taxonomic detail by itself is as appealing to learn as the table of organization of a large corporation. Consequently, systematics should appear in the biology course only to the extent necessary to illustrate the process of evolution and satisfy curiosity about the organisms with which most students are familiar. The amount and type of systematic information appropriate might therefore vary, depending on the location of the school and the backgrounds of the students. Our proposals for injecting a great deal of natural history into the earlier years should free much time that is now devoted to systematics in the high-school course. Ecology Ecology is often slighted in school; by one estimate, only about 20% of biology teachers find time to treat the subject at all in their courses. The section on ecology often comes at the end of a long text, and classes commonly do not get that far. Ecology involves connections between organisms and between organisms and their environments and students need to develop a feeling for this inter- relatedness as part of their high-school course. We have concern, however, about the effectiveness of the present curriculum with its pervasive emphasis on names and terms. For example, rather than have students memorize lists of every conceivable biotic and abiotic factor on the globe, how much better it would be to engage students in field observations! Rather than have students learn the conventional descriptions of various biomes, we could engage them more productively in analyzing local communities with which they are already familiar. The measurement of microclimatic factors and diversity could serve as the base for studying first-hand the effects of perturbation in similar nearby habitats. Concepts developed from that sort of direct experience will have lasting meaning when they are generalized to the unfamiliar.

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CURRICULAR GOALS FOR THE NEAR FUTURE 25 Conclusions and Recommendations: The Scope of Change The several examples presented here do not constitute a course. They are offered solely to suggest how the teaching of biology needs to change. Skillful teachers will recognize the formula, and many will be able to offer more and better examples. For the most part, however, our schools have little experience in teaching scientific concepts, reasoning, and learning through inquiry; for a teaching force accustomed to lecturing, the demands are imposing: Verbal inculcation, however lucid, has very little effect in enhancing reasoning and concept formation. This is not to disparage clear explanation and presentation; it would be foolish to advocate unclear explanation or none at all. Too many teachers, however, labor under the illusion that clear explanation is all that is necessary, and this illusion is a significant source of student failure in development of understanding. Not only is hands-on experience essential, but students must be led to articulate explanations and lines of reasoning in their own words. They must interpret their own hands- on experience, and they must be able to define new terms through appeal to shared experience and simpler words having prior definition [Arons, 1989]. In that brief passage, we have before us the scope of change: In designing a course, we must identify the central concepts and principles that every high-school student should know and pare from the curriculum everything that does not explicate and illuminate these relatively few concepts. The concepts must be presented in such a manner that they are related to the world that students understand in a language that is familiar. They must be taught by a process that engages all the students in examining why they believe what they believe. That requires building slowly, with ample time for discussion with peers and with the teacher. In science, it also means observation and experimentation, not as an exercise in following recipes, but to confront the essence of the material. We are concerned as much with how science is taught as with the substance of what is taught, and we have considerable doubt about the success of any "reform" that fails to address both parts of the problem. Some will be nervous with this approach, having memories of open classrooms and other educational promises that stumbled. Reform that is perceived as a fad generates disquiet, if not resistance. In such a climate, the slogan "back to basics" might capture the imagination, for its ring of directness and simplicity makes it appealing. But in teaching biology, the conventional promise of "back to basics" is without hope, importance, or meaning. Consider first what is taught the content. Neither much of the biology of today nor the culture in which it has relevance existed in previous generations, so there is no solid core of basics to which we can be seeking a return. As for how it is taught, it is true that the methods of teaching high-school science have not changed much in the last century; but, as we have explained, there is little cause for pride in that record.

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26 FULFILLING THE PROMISE The high-school biology course should instill in students a recognition that science is a process that gives us ways of knowing about the natural world. Students should engage in that process themselves, learning by first-hand experience the skills of measuring and the limits of measurements, becoming acquainted with the practice of reasoning from observation and with the meaning of causation, developing a feeling for scales of size and time that lie beyond direct human sensory experience, and understanding the role of chance in natural phenomena. They should come to see that, although scientific understanding represents our best available analysis and is always subject to revision on the basis of new information, some knowledge is in fact secure and unlikely to change fundamentally, whereas other knowledge is tentative and certain to be refined in the near future. These goals are more simply stated than accomplished. Inspiring textbooks and skillful teaching are works of art. Like a virtuoso performance on a mu- sical instrument, they require- in various proportions time, training, practice, encouragement, and inspiration. In Chapters 4 and 5, we turn to the substantial obstacles that must be overcome before we can achieve the desired goals in a majority of the nation's biology classrooms. We examine there what teachers are taught and how they are taught to teach, how we assess educational success through testing, how textbooks are produced, and what research scientists and university teachers contribute both to the problem and to its solution.