An Integrated College Freshman Natural Science Curriculum A M R. Garafalo and Vlncenl C. LoPresti Massachusetts College of Pharmacy and Allied Health Sciences, Boston. MA 02115 The amount of factual information that students must assimilate in a modem science-based curriculum has risen t o overwhelming proportions ( I , 2).Yet, as the volume of factual knowledge has increased, so has the need for students to make unifying connections between the specific areas of knowledge in a given science. A recent report of a special committee of the National Academy of Sciences commenting in tbis instance on the amount of hiological information states, ". . . we seem to be a t a point in the history of biology where new generalizations are being approachedibut may f;e obscured hy the simple mass of data. . . " ( I ) . Ideallv. well-educated science students should be able t o make connections between different sciences as well. We live in a world that is becomine technoloeicallv more c o m ~ l e x and compartmentalized. c he sheer weiglit of knowledge compiled by the collective cultures of the modern world seems to be thrusting specialization upon young people a t an ever earlier age. Students have little time to develop . anypersonal perspective concerning the sciences as a whole. Consequently, we may be producing a generation of specialists withlittle ability or desire to put their specific endeavors into a broader framework. A major problem confronting educators in the sciences today is not only what to teach, since time constraints forbid covering all topics in a given discipline, but also how to teach the chosen topics (3). One way to help science students maintain as broad a perspective as possible is t o provide a more closely integrated presentation of the natural sciences. There are many areas of interdependence among chemistry, biology, and physics to which even the beginning student can have access in an integrated curriculum. I t is more often the case in each of these courses that material is introduced from another discipline solely for the purpose of developing a specific topic. For instance, discussions of the details of photosynthesis and cellular respiration often occur early in general hiology courses after a cursory treatment of the topic of energy transfer, storage and utilization by cells, and before the description of bond energy in standard chemistry curricula. Such approaches often leave students with no other choice than to memorize definitions. terms. and details in order to pass examinations, since cursory coverage rarely allows for the development of solid conceptual foundations. Thus students may emerge with a highly fragmented picture of Nature, a view cultured and reinforced bv the entirelv separate curricula to which they are exposed.-On the other hand, an integrated curriculum, if carefully planned, can provide students with the same information hut with the added benefit of developing in them a much improved ahility to see the interrelationships between diverse disciplines. If in addition to tbis reinforcement of unifying themes, qualitative oresentations of coucents can be made to nrecede quantitative ones by a reasonable amount of time, it is perhaps more likely that students will develop critical thinking skills necessary for true conceptual understanding, and less likely that thev will become strictlv. aleorithmic ~roblemsolvers (4-6). In this report, we present a detailed integrated curriculum outline for freshman biology and chemistry within the con-
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straints of our pharmacy baccalaureate program. Several preliminary steps within each discipline in our curriculum have been underway for some time, including areas of crossdisciplinary instruction within the individual biology, chemistry and physics courses, an abbreviated physical science presentation in the first two weeks of freshman biology, and an advanced interdisciplinary course in the natural sciences (7).Each instructor has been involved in an ongoing process of cross-disciplinary study. Specific examples include the fact that one of us (a chemist) bas taught a course in physics and the other (a biologist) has lectured on topics in chemistry. The current outline then represents a culmination of several years of work, and we are now in the process of final preparations to facilitate its implementation in the near future. A conceptual understanding of the process of energy flow is the foundation upon which we have developed the presentation of our chosen topics. The primacv of this concept pervades physics, chemistry and biology-and the idea of attributing fundamental significance to the relationships between things (i.e., processes) and a secondary importance to the individual things themselves has been suggested by several authors (8.9) .. . Our freshman chemistry curriculum contains a threequarter sequence of four credit courses, two of which include laboratory, while biology comprises a two-quarter sequence of five-credit courses, both with laboratories. Laboratories in both courses are coordinated as closely as possible to the lecture presentations. Quarter One integrated Curriculum The entire outline for quarter one is shown inTable 1with topics in both courses displayed chronologically and opposite one another. I t should be mentioned that this ouarter ~ has no chemistry laboratory. The more detailed description that follows focuses nrimarilv on ooints of inteeration and u their effects on sequencing in theindividual curricula, and does not treat all topics in Table 1in detail. I t is important to note that all instructors attend all lectures in both courses. The initial chemistrv lecture on fundamentals starts with the physical concepts-of distance and time and proceeds through those of velocity, acceleration, matter, mole, mass, inertia, momentum, and force. The fundamental forces of gravity and electromagnetism are compared and contrasted, and the field concept is presented. The following lecture introduces the abstract idea of energy. Gravitational and electrical potential energy are seen as due to the relationship between objects. Wave behavior as a manifestation of mechanical and electrical oscillations. and the idea of enerw "" dissipation are presented. Finally, the concept of the nuclear atom is introduced so that chemical and radiant enerw mav be described. A variety of carefully chosen examples-fn thfs lecture reinforces the central role of force in the descrintion of natural processes. In biology, we begin with a general discussion of fundamental concepts prefaced by mention of the uncertainty as to an exact definition of "alive", and a few suggestions as to where boundaries might be set. We discuss the properties normally associated with things alive, namely metabolism, ~
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growth, development, heredity, and especially the dynamic nature of all life-process parameters (homeostasis, hut we prefer homeodynamics). We now present the many different levels of organization a t which dewriptions of life processes can be rendered, from subcellular to ecosystem, taking care to emphasize that the new interdependence and integration present a t each higher level make a simple summation of a t anv level inadeauate t o describe the next. The .nronerties . first discussions of taxonomic systems of classification and of ecological principles occur a t this point. These are descriptive in a way that appeals to the student's experience of the natural world. Certain noniutuitive concepts are necessarily introduced here, such as those of unicellular, colonial and multicellular patterns of organization. The biology curriculum follows a fairly traditional course up to this point. Rather than pursuing topics in molecular and cellul& biology as is more>ustom&y,ke continue with the levels a t which this interdependent organization is most familiar to the student, namely that of community interactions within ecosystems. This approach continues t o emphasize that wholes have primacy, and that only with varying degrees of approximation can we analyze them into parts. This is made more nossible because the chemistrv curriculum begins by presenting carefully defined phykcal concepts which provide the student with an initial vocabulary
Table 1.
Quarter One T o ~ l cOutllneA
Chemistry Natural Sciences; Scientific MeUlod: Metric System Fundamental Phvsical Conceots Concept of Energy; The Nuclear Atom Cosmic Evolution; Stars: Element Formation Periodicity of Elements E ~ ~ l u t i oofnPlanets, Ewh; Compwnd Formation Physical Properties of Manw Types of Bonds; Lewls Strunures Oxidation States: Formal Charges
Energy Transformations in Biological SystemsC Types of Intermolecular Faces PTOpeRIes 01 Liquids and Solutions Bonding Theory: VSEPR Bonding Theory: Valence Bond (2 lectures) Bonding Thwry: MO (2 lectures)
Types ol Solids Svslematic Chemical Nomenclahne Systematic Chemical Nomenclalwe Systematic Chemical Nomenclatwe Stoichiometry (4 lectures) Main Ooup Descriptive Cheminry (9 lectures)
Biology Unilying Principles in Life Fmcesses Levels of BiOlOOicaI Ormnization Taxonomic Cle~~ilication Taxonomic Classification; Basic Ecological Principles Basic Ecological Principles Survey of Ecosystems
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Selection: Adaptive Radiation: Mcdem Evolutionary Theory Orioin of Life:. Earlv ~, Evolution E n e q Transformations/ Degradation in Pnysicat and Chemical Systemsn Energy Transformationsin Biological Systems Energy Transformationsin Biological Systems T, V D ~of S Biolwicai Molecules Solnmn Prapemes ol Brmolecules: Enzymes Ce I Ssuct~re.Cell Organelles (2 lectures) Osmosis; Cell Transport PTocesSes (2 lectures) Photosynthesis Photo~vnlhesis Giym ys S. Fermentation Aeroboc Respiration; Carbon Cycle Mitosis; Meiosis (2 lectures) Mendelian Genetics (3 IecMss) Molecular Genetics (3 lecturas)
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Structure.. Phvsiolwv . -. of Selected Oroanisms 17 lectured
necessary t o developing a precise description of phenomena in both courses. In particular, reinforcing the relational nature of energy is crucial to the biology curriculum a t this point. Concurrent with these lectures in biology, lectures in chemistry involve the origins of the elements via star formation and death, following logically from a discussion of the "Big Bang" theory. The strong force is introduced, and a comparison of nuclear and chemical processes is made. Planet formation and the evolution of the earth up to a point where prebiotic molecules formed provides a lead-in to evolution in hioloev. -. Evolutionarv theorv is first treated in the modem ecological context of habitat, niche, and resource availahilitv. I t is nossible durine this discussion t o introduce the ideas i f intra-and inter-species selection and present an overview of modern evolutionarv theories as anplied -. to present and recent past. Several examples of familiar agents of selection are available, and students can appreciate differ.. ential survival of a "type" in a given circumstance without a detailed knowledge of the notion of alleles and their inheritance. For instance, differential selection for color in English peppered moths (10)is a rather comprehensible example. Now we turn to the theories of the origin and early evolution of life on earth. The topic of compound formation in chemistry includes a simplified discussion of amino acids and nucleotides subseauent to the treatment of olanetarv evolution. ~lthouyhthe.studentswillnut as yet haie studied these molecules in detail. we feel that the interrated asuect of tying together planet& and biotic e v o l u ~ o nspanning the two cnrricula is important in immediatelv demonstrating the unity of physical principles as applied to living systems; conversely, the effect of the origin of life on the ohvsical system is likewise important to emphasize, given thaiwe have encountered students beyond the freshman vear who still believe that earth's atmosphere is relatively independent of life processes. Reference is of course made hack to these lectures when cells, their component molecules, and the molecular aspects of genetics are treated later in the auarter. The chemistry curriculum now introduces the different t v ~ e of s bonds but instead of develooine . different t .w.e s of boiding theory as is often done, we postpone this and instead discuss various types of energy transformations. As the topic outline indicates, this first lecture is given during biology class time bv a chemistrv facultv member and provides eibmp~esof ph;sical and chbmiral inergs transformations. The concepts of catalyA and entropy are also introduced. These roncepLq are developed for ihree more lectures in ecology, the first of rhese given during chemistry class time (iee Tahle 1 ) to maintain continuity and balance between the courses. We feel that this appronrh helps to emphasire the tuoicas a first nrincinle rather than its brine achieved hv the more traditional approach of first b u i l d i g hio-mollcules from chemical elements, and then organelles and cells from bio-molecules. These ecology lectures center on energy flow through the oreanismal com~onentsof ecosvstems. The description of producers, consukers, and decbmposers is now presented, and emphasis is placed on the mvriad of symbiotic relationships-between brganisms. ~ e t r i t u sand grazing food webs are described and the unpredictable effects of intervention into these intricate energy transfer systems are also explored. In all of these discussions, the equivalence of food, energy, and biomass is stressed. Chemistry now develops the topic of intermolecular forces so that the soluhilitv nronerties of various suhstances mav be investigated. ~ h i s ' s e kthe stage for the properties l f various hiomolecules in water. In biology, the structures and biological roles of the molecules is presented, with the discussion of enzvmes drawing from the idea of catalvsis introduced in chemistry and in the previous discussion of the Volume 63 Number 10 October 1986
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origins of life in biology. The properties of lipids as applied to cellular membranes also draws heavilv on the prior lectures on energy. For example, it is customary present phospholipid bilayers as the ".. .configuration with the lowest energy level.. . " (10). We suggest that in a more traditional biology curriculum, the significance of this point is more likely to be lost in the absence of an extensive prior discussion of energy. At this iuncture. both courses nursue a more "structural" approach;n that bonding t h e 0 6 builds molecules from atoms in chemistry coincident with the assembly of organelles and cells in biology. Again we feel that our prior groundwork outs these lectures into better ~ e r s ~ e c t i vIet .is more likelv. we hope, that cells will be viewed dynamically, and t h i t "machine" or "factory" analogies will he less likely taken literally. Lectures on cell transport processes benefit from the discussions of solutions in both courses. Students' first exposure to traditional stoichiometry comes late in this presentation. Up to this point, they have had some exposure to solving problems in recitation with respect to metric conversions. Delaying formal stoichiometry to this point has major benefits. In recent years, we have consistently observed that a significant fraction of our entering freshmen have a poor mathematics background, and they therefore take a basic college algebra course in the first quarter concurrently with chemistry and biology. The need to master many concepts and to simultaneously perform auantitative calculations often Droves too demandine for these students. The delayed exposure to stoichiometi allows all students to develop the qualitative conceptual framework first, while the poorer students can focus on develooing their mathematical skills in aleehra. I t can he argued that expertise in quantitative calc~lationsincreases a student's quality of understandinp in the phvsical sriences. However, we feel that too many ciiculatioiai problems presented too soon to students with less-than-ideal mathematical backgrounds results in confusion and discouragement. There are ample topics that can be developed intuitively and oualitativelv& this earlv staee and such i n anoroachshould help most students. In biolow. the details of ~hotosvnthesisand of anaerobic and aerobriketabolic are now treated. These topics draw from the ~ r i o lectures r in chemistw in which concepts such as the effect of light absorption on electron energy states is introduced. Bondine theory immediatelv precedes discussions of electron transport in biology, and they thereby complement one another. We present the details of photosynthesis and respiration as representing another important level of information about energy input by the sun and energy transformation hy organismic metaholism, respectively. Finally, the reaction equations of the processes can be used as examples of balancing exercises during the presentation of stoichiometry in chemistry. At the end of the auarter. each course returns to a descriDtive mode; descriptive chemistry of the main group elements oarallels a svstematic descri~tionof selected oreanismal examples in biology, and a t the same time reinfokes the carbon and nitroeen cvcles. This occurs subseauent to a treatment of reproduction and heredity in biology, the molecular genetics discussion being slightlv abbreviated given its detailed treatment in biochem&r;, a required course in our pharmacy curriculum.
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Quarter Two and Three Curricula
Curriculum revisions in the first quarter of chemistry and biology also carry over into the second quarter where several additional ~ o i n t of s integration are Dossible. In hioloev. the structure or our curricul~mis such t i a t the second quarter is a survev of human eross and microsco~icanatomv with basic physiology and some comparison wirh other animal phyla. Much of the anatomical detail is reinforced in the hiology 856
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laboratory. Students in our pharmacy program then take a rigorous course in human physiology in their third year. The first group of lectures on terminology, tissues, organs, and organ systems in biology is followed by apresentation of Newton's Laws and of Statics (Table 2). We review the fundamental idea of mechanical force and demonstrate how thisideacan heapplied approximately toihemusculo-skeletal system, and how it is possible to validate auanritativelv the reasons for certain "iommon know1edge";deas such the advisibility of lifting heavy weights with bent knees. I t also sets the stage for the treatment of these topics in the second year of our curriculum, thus estahlishing connections in the minds of students who often are heard to complain about the irrelevance of various topics in physics. I t should he noted that there are several other important points of possible integration of this type (11) (e.g., frictional kinetic energy losses in blood flow through more or less constricted blood vessels) that are briefly mentioned, and that are prime candidates for future integration efforts. Currently these biological applications of physics are treated as much as is possible during physics lectures. In chemistry, a single lecture on the fundamentals of electrochemistry hased on electrical potential energy can suffice to lay the foundation for the application of these principles Table 2.
Quarter Two Toplc Outllnea
Chemistry Concentration Units Concentration Units Colllgative Properties
... Calllgative Properties Acids, Bases and Salts (2 lectures)
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Normality Titration ComplexationlPrecipnation Reactions
... Fundamentals ol Elechochemisby Balancing Redox Equations (2 lectures)
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Redox Titrations Transition Metals (2 lectures)
Tran~itionMetals Gas Laws (2 lectures)
... Gas Laws (2 lechnes) Thermodynamics: First Law Calculations
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Enthalpy. Ewopy Free Energy Calculations (2 lectures) Kinetics
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Kinetics
Biology Anatomical Terminology Tissue Types: Organs: Organ Systems Tissue Types: Organs: Organ Systems Newton's Laws lntrcduction to Statics Levers and Mechanical Advantage Skeletal Systems (2 lectures) Muscle Contraction Types of Movement: Motor Unlh Muscles: Statics Applled to Movements Types, CharacteriRiCsol Neurons Resting Potential Action Potential; Synaptic Transmission (2 lectures) Human Nervous System Human Nervous System Human Nervous System (2 lectures) Hormone Actlon: Endocrine systems Endocrine System BIWd: Composition: Gas. Nutrient Transport (2 lectures) H e m and Blwd Vessel Anatomy Cardiac Cycle; Blwd Pressure Regulation (2 lectures) Respiratory Anatomy; Ga6 Exchange Respiratory Anatomy; Gas Exchange Digestive Anatomy Digestion: Absorption; Metabolism Review Water Balance; Nltragen Exnetion Urinary Anatomy: Urlne Formation 12 iecturesl MalelFemaleRewcductive Systems (2 lectures) Menstrual Cycle: Fertilizet on:
Di8~rwncie in~me number of btal hours mr earn creflea dinerenoes in me number of exams anddiffering me of a weekly (nanaedit) rscltatlon seotlon by dlnwsnt Insvuaas, as well aa one 1-3 lecture per week ln ohemlsrm.
in a discussion of the resting potential and action potential in neurons. These tooics are treated in a hasic fashion. hut students can see how-the regulation of ionic is essential to the functionina of excitable memhranes. and how the physio-chemical dkscription of such phenomena correlates t o varying degrees with observed biological phenomena. Next, the lectures on transition metals in chemistry include examples of the importance of several of these elements in the functioning of biological molecules, thus also referring back to enzymecofactorsh the first quarter. These lectures occur so as just t o precede those on blood in biology, and enhance the discussion of normal hemoglobin functiin as well as the effect of poisons such as cyanide. Similarly, the placement of the aas laws in chemistrv is such that i t nrecedes by a few lectires the discussion oigas exchange b i t h e respiratory system. Finally, a brief qualitative treatment of the rates of drug absorption and metaholism in biology are reinforced shortly thereafter by a quantitative treatment of kinetics of simpler systems in chemistry. Quarter three in chemistry continues with two more lectures on kinetics, three on phase equilibria, 11on solution equilibria (including hydrolysis and soluhility-product constants), three on nuclear processes, and finally a sixlecture introduction to organic chemistry. Wherever appropriate, reference is made to relevant biological systems. Dlscusslon
The time spent introducing physical concepts in the early lectures in chemistry is well worth the effort. I t has been shown (12) that students who have had a hiah school phvsics rvurse usually perform hetter in freshman chemist& ihan students who have not. We lay a somewhat more extensive qualitative framework than is presented in most freshman chemistry texts since the concepts and vocabulary introduced here are ahsolutely essential to clear understanding of and the ability t o verbalize or write about essentially all topics that follow. Continual reference t o this material as each topic is introduced will hopefully lead students to an intuitive feel for energy flow regardless of the particulars of the system. The justification for presenting stoichiometry so late in our first chemistry course may be unique t o our curriculum since laboratory does not come until quarter two of this outline. Most institutions on the semester system have chemistry laboratory in hoth semesters. Postponing stoidhiometry for such long time in the two-semester c&riculum is clearly a problem if students are to perform laboratory calculations. This topiccan he presentedat an earlier time and many of the integrating features between the courses can still be maintained. Indeed, many different points and types of integration can be envisioned depending upon the maior focus of a oarticular deoartment or institution. For insiance, a more detailed treatment of electrochemistry with the usual development ofthe Nernst equation rould precede the discussion of membrane potentiais thus permitting a more quantitative treatment in biology. There are time constraints in our curriculum which prevent this. Our rather brief treatment reflects the more dominant focus on acidbase rhemistry, which 1s ot'paramount importance to pharmacy students, who constitute the majority of the freshmen taking these courses. The gas laws are traditionally placed a t the beginning of most chemistry courses where students are introduced to the physicallawsdescrihingsimplesystems. Presentationof this material in o!ir integrated curriculum not only serves as a prelude to lectures on gas exchange in humans, but also immediatelv precedes quantitative discussion of thermodvnamics where examples frequently employ gases. ~ i m i l a r i ~ , we postpone quantitative discussion of colliaative prooerties . . which also traditionally comes early in a chemistry course so that a qualitatir.erliscussion of intermolecular forces mnv be
a
addressed and then employed in biolom. men.. Q.ualitative . tion of colligative propeiti& is introdured at various points in the first quarter biology curriculum in a way that appeals to students' experience of the manifestation of these properties in the biosphere. The major alteration which occurs in the first quarter of biology in the integrated curriculum is the delay in explicitly treating the structure and properties of biological molecules and of cells. This is the result of an extended period where the focus is primarily on whole organisms, namely their classification, continual evolution, interactions within ecosystems and esoeciallv the patterns of enerev flow amone them. These topics ark thus-treated before detailed discussions of bioenergetics a t the cellularand subcellular levels, or details of cellul& and organismic reproduction and heredity. I t might he argued that this deprives the student of the mechanisms required truly to understand the origin of life, evolution and ecology. On the contrary, we believe that the moundwork established in chemistrv will allow students ~ ~to ~grasp the intricate nature of biologic& interactions a t a more intuitive level, and will make the subsequent treatment of cellular and molecular mechanisms more meaningful. For instance, several aood descri~tionsof the oriein of life are available which do not depend on the details gf nucleic acid and protein structure (13. 14). and such a ~ ~ r o a c h have es been~successfullyartempted before ( 1 5 ) . A I Z ~it, is possible to offer several striking and often familiar examples of svmbioses, with more obscure examples delayed toward theknd of the quarter when the structure and physiology of various organisms are discussed. If students tend to develop misconceptions in areas where direct experiential knowledge is lacking or not possible (16,17), then perhaps i t is wise to root college freshmen firmly by first focusing on subject areas that are within the realm of common sensorv exoerience and in a fashion that better prepares them for t60sebthatare not. We feel that this combination of more accessible topics covered more slowly might perhaps reduce the tendency toward information overload in our freshman students at the heginning of their college experience (18). Our experience concerning the focus of much of our freshman population as they first enter college is reminiscent of sentiments expressed by Green (19),who quoting from author John Fowles speaks t o the ". . . loss of man's ability to see Nature as rich and symbiotic systems, wild and interlocking wholes without neatly defined boundaries." In a description of his own course in environmental chemistry, Green notes that he recalled no instances as an underzraduate where natural phenomena and chemical theory were used together in illustrative fashion. We feel that our integrated &rriculum begins to address both these issues. Our abbreviated attempt at presenting physical science concepts in the first two weeks of hiology was well received by students. In anonymous course evaluations. 77% of students agreed that thi presentation was a worthwhile learning experience while 71% encouraged us to implement the full version of the curriculum. Optional written comments included the following: "The idea never dawned on me (that) life is a balance-of everything. Everything depends on everything else." In conclusion, we should mention that we exuect that this integration effort will continue to evolve both' in form and content. For instance. i t is foreseeable that more flexibilitv might develop with respect to distribution of biology an2 chemistry lecture time over the total hours allotted for hoth courses. w e also feel that an integrated approach a t this level of detail may be attemoted in the lareer universitv environment where the interaction between v k o u s depart"ments is usually less than in smaller institutions. I t necessitatesmuch interdepartmental communication, but theoverall rewards for the student as well as the faculty are, we feel, worth the effort. ~
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Literature Clted ( 1 ) Holden, C. Science 1985.228.1412, (2) Lagorski, J. J. J . Chhm. Educ. 1985.62.273. ( 3 ) J0urnet.A. J.Coll.Sei. Teach. 1985.14.236, ( 4 ) Gsbe1.D. L.;Shemoal,R. D.;Enochs, L. J.R.8. S C ~Teach. . 1984,21,221. ( 5 ) Cardulh,F..IChem.Edur. 1984,61,151. ( 6 ) Nssh. L. J . Chrm. Edue. 1916.53,607. (7) Loprosti, V. C.; Gausfdo. A. R., submitted for publication. ( 8 ) Bohm, D. "Wholeness and the Implicate Order": Ark: Bmtan, 1983. ( 9 ) dlEspagnat, B.Sci. Arner. 1979.241 (51,158.
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(10) stan,
c.: art, R. " B ~ o I ~~~ Yh unity .* and Divemitv 01 ~
(18) R o w , M. B.J . c h r i E d u c . 1983,60.954.' (19) Gmon, W . J.J. Chom.Educ. 1982.59.296.
i w wadsuorth: : B~I-
