The Role of Form and Function in the Collegiate Biology Curriculum

AMER. ZOOL., 28:619-664 (1988)

The Role of Form and Function in theCollegiate Biology Curriculum

WILLIAM V. MAYER

Professor of Biology Emeritus, University of Colorado,Boulder, Colorado 80302

INTRODUCTION

Form and function are usually regardedas essential, but routine, items in a curric-ulum. They seem less important now thanbefore the rise in interest in molecular biol-ogy and ecology. Those of my age groupcan recall the morphological drudgery ofintroductory zoology that involved draw-ing, with a 4-H pencil, typical representa-tives of the various animal phyla and label-ing their parts with parallel guidelines andproperly printed names. The aim of sucha course seemed to be to produce theseillustrated sheets rather than to under-stand either the organisms or relationshipsamong them. I plodded through these ster-ile and boring assignments knowing thatsomewhere along the line, in later courses,I would be introduced to content that wouldsynthesize this mass of detail and lead to aconceptual understanding of morphologyand its application to the living world. LaterI was to find this a vain hope. Ultimately Ihad to make my own synthesis.

Fortunately the days of the dissect, look,draw, label and memorize type of labora-tory are drawing to a close. The formal-dehyde smell and the lanolin covered handsare less a requirement for biology than inthe past hastened, perhaps, by the obser-vation that formaldehyde is carcinogenic.As a graduate assistant in the formalde-hyde and shark era I found myself exposedseveral times a week to barrels of preservedspecimens in the atmosphere of isolationand privacy given the laboratories of dis-section in science halls. Changes in intro-

ductory courses have come about slowlyand largely independently in various col-leges and universities. This does not meanthat guidelines for improvement did notexist. It does mean they went largelyunheeded. To understand the climate forchange one needs to examine activities thathave been underway for close to a centurydesigned to improve the caliber of biologyprograms. To this end one must review thework of committees, commissions, andstudies that looked at the status quo andmade recommendations. The followingsection highlights the more significantefforts focused on the biology classroom.

A BRIEF REVIEW OF STUDIES ONINTRODUCTORY BIOLOGY

Many efforts have been made to placeobjectives in some kind of orderly pattern.Attempts to delineate cognitive and affec-tive objectives for biology can be traced tothe ancient Greeks, see Moore (p. 483).However, serious study of the subject inthe United States can be traced to about1890 according to Hurd (1961, p. 9).Hurd's work is a major, but little known,contribution to biological education, appli-cable to all levels from elementary schoolthrough college. Its value as a source ofgeneralizations about the content of a col-legiate biology course is due, in part, to theearly congruence of curricula in secondaryschools and undergraduate colleges. At theturn of the century almost every studentwho graduated from high school contin-ued education in a college or university,

619

620 WILLIAM V. MAYER

making the major objective of secondaryschools one of preparing students forhigher education. Prior to 1900 only 3.8%of the school population aged 14 to 17 yearswas enrolled in secondary schools and therewere about 2,500 high schools in the UnitedStates. By 1900 the number of schools hadincreased to 6,005 and 8.4% of the 14 to17 year old age group was enrolled in highschool, with enrollment of girls exceedingenrollment of boys by 25%. In New YorkState, between 1896 and 1900, 82.5% ofhigh schools taught botany, 70% physiol-ogy, 42.5% zoology and 10% biology, sothat a variety of opportunities in the bio-logical sciences were readily available tostudents. As high schools were essentiallycollege preparatory they reflected colle-giate biases in their curricula. Collegesthemselves were spared examination. Thesignificant early literature regarding intro-ductory collegiate courses varies from non-existent to sparse. However, what wasgoing on within the college of the time isreflected in the curricula of secondaryschools. It would not be unfair to note thatthe study of secondary school biology cur-ricula of the period is also a study of intro-ductory collegiate biology in the absenceof usable data concerning collegiate intro-ductory courses. The criticisms and sug-gestions for improvement focused on thesecondary schools were, by and large, asapplicable to the collegiate introductorycourse, if not also to the entire collegiatecurriculum.

Reports of the National Education Association

Concern about the quality of biologyeducation initiated a series of studies ofsecondary curricula that now span almosta century. The first significant study to con-cern itself with the life sciences was that in1893 when the National Education Asso-ciation formed a Committee on SecondarySchool Studies, also known as the Com-mittee of Ten. This was headed by CharlesW. Eliot, President of Harvard University.Subcommittees were formed to deal withspecific disciplines and, for the teaching ofzoology, the subcommittee emphasizedform and function. While the outline ofthe year's course was essentially phyletic,

the students were to examine the externalanatomy of animals. In addition to studyof the general form, regional parts andsymmetry were also to be stressed. Theapproach was basically comparative, withone animal compared to others of the samespecies to determine points of variation andcompatibility together with comparisonwith other types. Simple physiologicalexperiments were also to be a part of thecurriculum. Laboratory work was consid-ered an essential and students were to besubject to both a written and laboratorytest. The Subcommittee on Physiologysuggested a one semester course in each ofanatomy, physiology and hygiene with anemphasis on practical work that stressedthe mechanics of physics and chemistry ofthe body. This committee separated phys-iology from botany and zoology, which itregarded as sciences of description andobservation, and placed it more with chem-istry and physics as a science of experi-ment.

In 1896 the National Education Asso-ciation's Department of Natural ScienceInstruction was organized. The president,Charles E. Bessey, was concerned that sci-ence should be something more than accu-mulating facts. More attention was to begiven to the classification, arrangement andgeneralization from facts. In short, thedevelopment of what was termed a "judi-cial state of mind." This approach was con-firmed by a science committee sponsoredby the National Education Association in1898 under the Chairmanship of E. H.Hall of Harvard. This 1898 committeeexpressed the opinion that the minuteanatomy of plants or animals or specializedwork of any kind would be premature andout of place in a high school course of oneyear in length. Rather, the work shouldconfine itself to the elements of the subject,the principles and methods of thought.John M. Coulter, Chairman of the Sub-committee on Botany in Secondary Schools,severely criticized the common practice ofexamination and recitation on the grossstructure of flowering plants accompaniedby herbarium observations. He felt thesesuperficial and restricted and even an irrel-evant presentation of biological science. By

THE COLLEGIATE BIOLOGY CURRICULUM 621

extension, his recommendations couldapply to similar practices in the zoologyclass.

These studies at the secondary schoollevel represented an early attempt todevelop both cognitive and affective objec-tives for education in the biological sci-ences. Then, as now, there was little studyof science courses at the collegiate leveldue, in part, to the resistance on the partof collegiate content specialists to anyinterference with the way they interprettheir disciplines. However, collegiatefaculties then, as now, were expressing deepconcern regarding the inadequate prepa-ration of students entering college. In 1895the National Education Associationappointed a committee of 24, consisting of12 university scientists and 12 high schoolteachers, to consider college entrance stan-dards. The major objective of this com-mittee was to explore ways in which sec-ondary schools could do their legitimatework as schools of the people while, at thesame time, furnishing adequate prepara-tion to pupils intending to continue theireducation in colleges and universities. Thesubcommittee on zoology reported in 1899.Its members unanimously opposed thetextbook method of teaching zoology inwhich "a large amount of informationabout animals is acquired thereby in a lim-ited time, and a minimum of attainmentand preparation is demanded of theteacher." The subcommittee also opposedthe taxonomic approach as it gave the stu-dent an exaggerated notion of the impor-tance of structural parts for a limited groupof animals and failed to develop biologicalideas. The majority of the committeethought that external morphology, life his-tory, habits and the economic importanceof animals were of greater interest andvalue to secondary pupils than the system-atic and morphological approach then typ-ical of colleges.

The decade from 1890 to 1900 wasgreatly influenced by the mental disciplinetheory of psychological development. Lab-oratory work, for example, was seen as anideal procedure for the training and exer-cising of mental faculties devoted to obser-vation, will power and memory. While the

mental discipline approach to learning wasrejected by psychologists soon after the turnof the century, laboratory work in a sur-prising number of institutions still today isconducted for its value for developing"mental discipline." The last decade of the19th century also focused on a shift awayfrom a natural history approach to whatmight be called "pure" botany and zoologywhose major emphasis continued to bemorphological. One must distinguishbetween studies and implementation. Theassumption cannot be made that teachingpractices or course curricula immediatelyrespond to committee recommendations.Periodically, committees are formed toreport on the state of education and mostof these reports are read and filed, ratherthan acted upon.

Recommendations of theAmerican Society of Zoologists

The American Society of Zoologists in1906 made recommendations for improv-ing the teaching of zoology in the highschool. Among these recommendations wasthat a full year of zoology be taken by thestudent at secondary school and that it begiven for college credit for those continu-ing their education. The content outlinefor a year's work in high school zoology,as recommended by ASZ, was:

1. Natural history. Structure in relation toadaptation, life history, and geograph-ical range; the relation of plants to ani-mals and economic relations.

2. Classification of animals by phylum,major classes and, in the case of insectsand vertebrates, prominent orders.

3. General plan of external and internalstructure for at least one vertebrate (fishor frog) in comparison to that of thehuman body; an arthropod, an annelid,a coelenterate and a protozoon.

4. General physiology of" the above organ-isms and comparisons with human phys-iology and with the life processes inplants.

5. Reproduction of protozoa, hydroids andthe embryological development of thefish or frog.

6. Evidence of relationships suggesting


evolution and a few facts on adaptationand variation. This recommendationwas presented with the strange caveatthat "the factors of evolution and thediscussion of its theories should not beattempted."

7. History of biology presented as anoptional inclusion dealing with majordiscoveries and the careers of eminentnaturalists.

Both form and function were prominentin the recommendations of the AmericanSociety of Zoologists. Structure was to bepresented in relation to adaptation, clas-sification and evidences of relationships,with specific investigations of the structureof representative organisms coupled witha study of their general physiology. Repro-ductive physiology and anatomy were alsoto be investigated on the basis of represen-tative organisms so that form and functionwere pervasive throughout the six initiallyrecommended content groupings. ASZ alsostressed the need for laboratory facilitiesand, where other studies, such as that ofNEA in 1895, unanimously opposed thetextbook method of teaching, the ASZstressed the necessity for a good textbook.It is interesting to note that two-thirds ofthe course was recommended to consist oflaboratory and notebook work. The note-book, to be submitted at examination time,was to contain carefully labeled drawingsof the chief anatomical structures studied,thus placing a high emphasis on details ofform and on the drawings which wereessentially dull and repetitive exercisesbereft of intellectual stimulation.

Reactions to committee reports

In an attempt to measure the impact ofthe Committee of Ten, E. G. Dexter, in1906, examined 80 courses of study in biol-ogy prior to 1895 and 160 courses of studyin 1905. He found, in contrast to the Com-mittee of Ten's recommendations, thatphysiology courses in high school hadactually decreased 50%. In addition, whilemore high schools were teaching botanyand zoology, the courses were not beingoffered for a full year as had been rec-ommended and, most importantly for form

and function, biology teachers had reactedagainst the morphological approach sug-gested as desirable by the Committee ofTen.

Despite the fact that the members of theCommittee of Ten were well known sci-entists, that the membership of the com-mittee was the largest in the history of edu-cation at the time, that the report had beenwell advertised, had wide readership, andhad been the center of many educationaldiscussions, little was achieved by it. Thissituation is not much different from reac-tions to current reports recommendingchanges in content and approach for bio-logical education.

H. R. Linville (1910) in his article "Oldand New Ideals in Biology Teaching" madethe following cogent observation:

The teachers of morphological biologyin the schools brought with them fromthe colleges certain ideas of method.Possibly the lecture system never tookstrong hold in the schools, but the lab-oratory method of the college with muchof its paraphernalia, did. The conse-quence of this was that thousands ofyoung and untrained pupils wererequired to cut, section, examine, anddraw the parts of dead bodies of unknownand unheard of animals and plants andlater to reproduce in examination whatthey remembered of the facts they hadseen.

From separate courses to biology?

For the most part, physiology was treatedas a separate course from botany and zool-ogy and it experienced, as noted, a declinein enrollments. It was generally disliked bystudents and was regarded as difficult toteach. Oscar Riddle, writing in School Sci-ence and Mathematics in 1906 recommendedthat human physiology be incorporatedinto the zoology course with more empha-sis on physiology rather than morphology.His recommendations were followed bythose of Clifford Crosby in 1907 in an arti-cle entitled "Physiology, How and HowMuch." Crosby reported on several sur-veys he had made on the teaching of humanphysiology in high school and found a


strong negative feeling in students abouttheir physiology courses. Most of the stu-dents took physiology before they had hadzoology or botany and thus possessed littlebackground for appreciating physiology.He, too, recommended the developmentof a zoology course unified by a theme ofphysiology. With three separate coursesreduced to two in number the next logicalstep was to combine the two into a singlebiology course.

The editors of School Science and Mathe-matics in 1908 polled a number of univer-sity biologists who had been involved in theeducational as well as the academic aspectsof biology regarding the purpose and orga-nization of biology courses. There was aconsensus on three points. 1) That a biol-ogy course should be adapted to the major-ity of pupils. 2) That the course shouldstress general educational values and bepractical and focused on broadening ofpupil interests and the deepening of theirappreciation. 3) That the course should befocused more on the ideas and principlesof the discipline rather than on its details.This poll did not settle the issue of a singlebiology course incorporating botany, zool-ogy and human physiology. Instead, therewere still options for "sub-courses" in eachfield, either each field for a third of a yearor a year's work in each field.

Report of the Central Association ofScience and Mathematics Teachers

A Committee on Fundamentals wasestablished by the Central Association ofScience and Mathematics Teachers in 1910.The result of this committee's work incor-porated suggestions for greater emphasison reasoning rather than memorization,more attention given to developing prob-lem raising and problem solving attitudeson the part of students, greater emphasison the relationships of the subject to every-day life without commercialization orindustrialization of science, more emphasison the unfinished nature of science, includ-ing the great questions yet to be solved byinvestigators and, lastly, less attempts atcoverage. The course would progress nofurther than students can go with under-standing.

This comment concerning "coverage"appears in a number of reports as a partof an ongoing debate on breadth versusdepth in education. With the passage ofyears and the increase in the amount ofmaterial to be covered, critics of breadthnote an increasing superficiality, with con-sequent lack of understanding. While amonomolecular film of coverage may indi-cate an instantaneous exposure, it does notnecessarily follow that comprehension hasbeen achieved as well. Those critics ofdepth criticize what they regard asattempting an understanding of very fewbiological topics. However, most universitycurricula are organized on the principle ofdepth rather than breadth. The prolifer-ation of specialized topics has been ridi-culed by citing such progressions as fromcourses in morphology, to those in verte-brate morphology, to those in mammalianmorphology, to those in carnivore mor-phology, to those in canine morphology,to those in carnassial tooth morphology. Itis obvious that both the proponents of themonomolecular film of content spread overthe entire corpus of biology and thosewhose specialty is so narrow as to ignoreall but a single facet of the discipline arein error when their approach is applied toan introductory biology course. Such acourse it is clearly understood, cannot beall things to all persons. Content, then,becomes a matter of selection to illustratemajor concepts and principles with excur-sions in depth in a few selected areas.

The 1910 Central Association of Scienceand Mathematics Teachers report sug-gested great principles to which studentsshould be exposed. These were:

1. Growth and progressive development,both individual and racial.

2. Division of labor and differentiation forefficiency.

3. Sexual differentiation and its meaning.4. Economic dependence of man on other

organisms.5. The value of social combination and

service.6. The natural processes of the human

mind itself in passing from observationsto conclusions.


The role of form and function in illumi-nating these great principles would be leftto the individual instructor.

By 1910 general trends were apparent,in almost all recommendations regardingcurriculum content, as follows:

1. The teaching of biology should be ori-ented towards principles, ideas andinterrelationships.

2. More emphasis should be given to sci-entific methodology and the processesof science. (A recommendation beingrealized within the American Society ofZoologists through this Science As AWay Of Knowing program.)

3. The establishment of practical objec-tives for biology teaching.

4. Emphasis attached to capitalizing onstudent interests and experience and arejection of the mental discipline the-ory of learning.

Within the secondary schools the argu-ment of breadth versus depth had defi-nitely been settled in favor of breadth, asphysiology failed to become established asa separate course in the curriculum andwas combined in some fashion with theexisting zoology course. Morphology wasstill the study of preserved specimens, apractice deprecated by Oscar Riddle in1906 when he stated "And what objects doour students handle and how do they han-dle them? I answer that in the majority oflaboratories they use dead unyielding spec-imens which have centralized within them-selves all the rigidity that is within the powerof over-proof spirits to impart."

NEA Committee on Natural Sciences

The National Education Association in1913 appointed ten high school teachers,three university professors, three normalschool instructors and a physician to studythe secondary school curriculum. Remem-ber, that such a study also reflects on intro-ductory collegiate programs, as highschools were, and in some instances stillare, patterning their curricula upon thoseof colleges and universities in their imme-diate vicinities. Despite the fact that onlyabout half of current high school graduates

go on to college and of these smaller frac-tions concentrate in science and still smallerfractions in the biological sciences, the highschool curriculum in large measure stillremains a microcosm of collegiate intro-ductory work. For all intents and purposesthen, criticisms and recommendations forthe high school biology curriculum at thistime can equally well apply to collegiateintroductory programs.

A major recommendation of this 1913NEA Committee on Natural Sciences wasthat unity of subject matter in any coursein science was of prime importance. Onlyin this way could underlying principles beseen to apply over the broad spectrum ofthe discipline. Secondly, a recommenda-tion was made that biology should includeplants, animals and man as living organ-isms. By the 1930s and 40s, however,humans had almost disappeared from col-legiate biology courses. Storer's classictextbook, General Zoology, first published in1943, devotes 21 of its 832 pages to man-kind in a terminal chapter 33, which wasunlikely to be reached even by the mostardent proponents of coverage. Perhapsthe discarding of mankind as a suitable sub-ject of biological study was based on thedesire to shun anything that had practicalor applied values because of its potentialvocational trend. Abstract knowledge forits own sake was considered Aristotelianand proper. Applied knowledge was seg-regated in courses in human anatomy andphysiology of primary interest to nurses,premeds and others who proposed to makesome use of their course content.

The 1913 NEA committee, however,recommended that constant referencesshould be made to applications of biologyto human welfare and convenience.Included in the objectives for such a coursewas the recommendation that each pupilbecome familiar with the structure, func-tion and care of his own body so that formand function of an applied nature becamea desideratum. The committee saw noth-ing wrong in a human biology. It also crit-icized many common teaching practicessuch as the use of laboratory work simplyto keep students busy or class work con-


fined to a single text within the four wallsof the classroom. Committee memberswere concerned that "The most importantconsideration is that the course should beconducted with a live teacher." Theemphasis on teaching of biology for itsimportance to human welfare made phys-iology come to mean human physiology andhygiene. By now space in the curriculumwas being found for topics such as ecologywhich were being included at the expenseof morphology.

Breakdown of collegiate/secondaryschool relationships

In the first two decades of this centurycollegiate and secondary school instructorsworked rather closely together. Researchbiologists were frequently involved in cur-riculum recommendations but, after about1920, high schools and colleges partedcompany, at least as regards such closecooperation. The high school was devel-oping its own identity and while it stilllooked, and still does look, to college cur-ricula for guidance, continued recommen-dations that biology become a more prac-tical course and criticism of the miniaturecollege course taught at the secondary levelgreatly affected the high school curriculumwhile having little, if any, effect upon thatat the collegiate level. This changing rela-tionship of the high school and the collegecommunities can be demonstrated byexamining the membership of two com-mittees on science teaching. In 1893 theCommittee of Ten consisted of five collegeor university professors and/or scientists,three high school teachers, one normalschool teacher and one superintendent ofschools. By 1920 the Committee on Reor-ganization of Science in Secondary Schools,which consisted of 47 members, included24 high school teachers or administrators,11 college or university professors and/orscientists, 6 normal school teachers, 5superintendents of schools, and 1 businessrepresentative, further demonstrating theincrease in involvement in the constructionof science courses on the part of publicschool personnel and the lessened poten-tial influence of representatives from col-

leges and universities, a disjunction thatwas not remedied until the establishmentof the Biological Sciences Curriculum Studyin 1958.

Not all educators and scientists foundthe emphasis on the practical and theapplied to be sound. John Dewey, address-ing the National Education Association inMarch of 1916, expressed a concern thatthe basic contribution of science would belost in the rising emphasis on practical andapplied content. He expressed this as fol-lows:

The entire cogency of their positiondepends on the identification of sciencewith a certain limited field of subjectmatter, ignoring the fact that science isprimarily the method of intelligence atwork in observation, in inquiry andexperimental testing; that, fundamen-tally, what science means and stands foris simply the best ways yet found out bywhich human intelligence can do thework it should do, ways that are contin-ually improved by the very process ofuse.

Recommendations of the North CentralAssociation of Colleges andSecondary Schools

Reports on the state of science educationaccumulated until they began to sound likea broken record. They focused largely onthe need for emphasis of principles andgeneralizations and the involvement of stu-dents with the application of biologicalprinciples to problematic situations.Emphasis shifted from the content imposedby the discipline to meeting the needs ofthe student and presenting principlesselected from those most important in theday-to-day life of citizens. The biologycommittee of the North Central Associa-tion of Colleges and Secondary Schools in1931 recommended six biological princi-ples to fill these needs as follows:

1. The adaptation of organisms to theirenvironment.

2. The germ theory of disease.3. The interdependence of organisms.


4. The cell as the structural and physio-logical unit of living things.

5. The theory of evolution.6. The distinctive characteristics of living

things.

While these recommendations did not spe-cifically isolate form and function as a majorprinciple, cellular structure and functionwas a desideratum and adaptation and thedistinctive characteristics of living thingsimplied knowledge of form and function.Morphology, per se, however, continuedto be deemphasized in a trend discernableas far back as the beginning of the century.

The committee was realistic in itsapproach, recognizing that, while princi-ples provided a sound and practical focusof biology teaching, acceptance of suchrecommendations was not guaranteed. Itexpressed concern that teachers were notinterested in spending the time necessaryto develop an understanding of a principle.Rather, they chose to have students mem-orize large masses of unorganized factswhich were easy to teach and simple toevaluate. Colleges were perceived as partof the problem, as their entrance exami-nations consisted primarily of questionsfocused on the recall of facts. The com-mittee observed that college science classeswere not taught from the point of view ofthe consumer of science and that, there-fore, teachers at the secondary level werenot prepared to make use of science as itapplies to problems encountered by stu-dents. Further, such emphasis could havenegative effect on college admissions andstudent's subsequent performance in classesdevoted to rote memory.

Office of Education "Instruction in Science"

The difference between promise and ful-fillment was underscored by a publicationof the Office of Education, United StatesDepartment of the Interior in 1933 enti-tled "Instruction in Science." An investi-gation of biology curriculum objectivesdemonstrated they were laudable butunfulfilled. The six major objectives mostfrequently listed included:

1. Acquiring knowledge that will producea better understanding of our environ-ment.

2. Presenting knowledge that will func-tion to achieve the cardinal principlesof secondary education as defined bythe Commission on the Reorganizationof Secondary Education (Caldwell,1920).

3. Developing an appreciation of natureand of individual responsibility in theworld.

4. Acquiring knowledge of the fundamen-tal principles of biology.

5. Developing an interest in nature.6. Developing the ability to think scientif-

ically.

Despite the enunciation of objectives reit-erating still earlier recommendations, vis-its to biology classes showed that teachersstill asked questions that could be answeredin one word and which were primarilyfocused on the parts of either plants oranimals. Details of morphology still dom-inated the curriculum and examinationsmeasured only the students ability toremember isolated facts. The biology lab-oratory work was also centered on detailand typically requested copying picturesfrom the textbook, a pointless and stulti-fying exercise.

The report of the National Society forthe Study of Education

In 1932, the National Society for theStudy of Education (NSSE) issued a 364page report entitled "A Program forTeaching Science." This committee waschaired by S. Ralph Powers and exploredquestions on science teaching at every levelfrom kindergarten to college. Course con-tent was to be selected in terms of its appli-cability and should illuminate the majorgeneralizations of science as well as relat-ing to the welfare of human beings. Thecommittee recognized that content shouldnot only have a practical value, but culturaland liberalizing values should be stressedas well. In terms of laboratory work, it, too,should be directed toward problem solving


and be focused on providing students withscience experiences, rather than on simplybeing illustrative or confirmatory of whathad already been presented in either lec-ture or textbook. Again, a series of biolog-ical principles was considered as funda-mental. This time nine such principles wereelucidated as follows:

1. Energy cannot be created or destroyedbut merely transformed from one formto another.

2. The ultimate source of energy for allliving things is sunlight.

3. Microorganisms are the immediatecause of some diseases.

4. All organisms must be adjusted to theirenvironmental factors in order to sur-vive in the struggle for existence.

5. All life comes from pre-existing life andreproduces its own kind.

6. Animals and plants are not distributeduniformly nor at random over the sur-faces of the earth, but are found in def-inite zones and in local populations.

7. Food, oxygen, optimal conditions oftemperature, moisture and light areessential to the life of most living things.

8. The cell is the structural and physio-logical unit in all organisms.

9. The more complex organisms have beenderived by natural processes from sim-pler ones. These, in turn, from still sim-pler and so on back to the first livingforms.

It can easily be seen that the NSSE pro-gram for teaching science had principlesthat paralleled those developed by theNorth Central Association for Colleges andSecondary Schools in 1931. Evolution andthe germ theory of disease are common toboth as are adaptation and the focus on thecell. Here again, form and function are notspecifically delineated except in relation tothe cell but are implicit in coverage of otherprinciples. Despite recommendations ofprestigious committees and commissions,science examinations continued to reflectemphasis on naming parts, giving func-tions, arranging in order, or defining terms,indicating that emphasis was still basicallyon the vocabulary of form and function

and the principles and concepts were leftfor students to derive from large masses ofunsifted data.

Union of American Biological SocietiesCommittee on the Teaching of Biology

The disparity between what was actuallydone in the classroom and the recommen-dation of "experts" in the field of scienceand science education is nowhere betterdemonstrated than by responses to theCommittee on the Teaching of Biology ofthe Union of American Biological Societiesquestionnaire published in 1942. Responsesto the questionnaire were received from3,186 biology teachers and two sets of dataare especially revealing. In the first, theteachers felt that the greatest classroomemphasis in general biology should be on(1) Health, disease, hygiene; (2) Physiol-ogy; (3) Heredity; (4) Conservation; (5)Structure. This confirmed the emphasis onform and function which was apparentlystill taking up some 40% of classroominstructional time. Secondly, that class-room practice differed from that recom-mended is clearly noted in the nature ofthe topics to which the teachers gave thelowest rating in terms of emphasis. Thesewere: (1) Eugenics; (2) Behavior; (3) Sci-entific method; (4) Photosynthesis; and (5)Biological principles. In short, the princi-ples approach so highly recommended bystudy groups was the least used in class-room presentations of any of the recom-mendations.

Cooperative Committee on Science Teaching

During World War II the CooperativeCommittee on Science Teaching was estab-lished. It included representatives of theAmerican Chemical Society, The Mathe-matical Association of America and theUnion of American Biological Societiesamong others. Despite its war time slanttoward practicality, it developed a series ofinstructional goals not too different fromthose recommended earlier. Theseincluded:

1. Structure, function, care, first aid andnutrition of the human body.


2. Bacteria and disease.3. Personal and public health.4. Use of plant products as food, medi-

cine, shelter, and clothing among otheruses.

5. Genetics as exemplified by plant andanimal breeding.

6. Conservation of soil, grasslands, forest,wild life and flood control.

7. Applied ecology.

In this report the study of structure andfunction was primarily related to the humanbody and such topics as evolution and thecell were only incidental.

Trends toward scientific literacy

When one examines the recommenda-tions made by the many committees andcommissions studying introductory sciencecourses two trends can be discerned. Rec-ommendations from committees com-posed primarily of scientists requested moretime be given to the social implications ofscience, supported a balanced program ofphysical and biological sciences, and sug-gested special attention be given to the tal-ented student and potential scientist. Inaddition, the scientists on these commit-tees recognized that the nature of science,its methods and place in the social and eco-nomic life of individual citizens was ofgrowing importance.

Those committees composed principallyof educators looked upon science as a meansfor meeting the "needs" of individuals.They spoke of making science functionalin the lives of young people. However, they,too, considered that the methods and tech-niques of the scientist were valuable pro-cedures for solving problems of daily livingand suggested that scientific attitudes wereworthy goals for all students at all levels.

In the 1930s, new ways of presentingintroductory collegiate biology were beingdeveloped in a few institutions. At the Uni-versity of Chicago, under the leadership ofRobert Maynard Hutchins, a general edu-cation program was developed that brokewith tradition to develop what was consid-ered a more meaningful introductorycourse. At Yale, George A. Baitsell alsodeveloped an innovative approach to anintroductory course emphasizing human

biology. It should be remembered thatbiology, per se, did not constitute an iden-tifiable discipline within colleges and uni-versities until the early 1920s when the firstcollege biology for general education wasoffered at Stanford University. Biologycourses were not common enough even topromote the preparation of texts in thesubject for use at the collegiate level. Exceptfor the experimental programs of the1930s, most universities introduced stu-dents to life sciences through either botanyor zoology. It was not really until the 1950sthat biology as a recognizable discipline wascommon enough to foster the productionof biology textbooks, one of the first ofwhich was Garrett Hardin's Biology, ItsHuman Implications(l952).

Every committee which studied biologycurricula supported, wholly or in part, theimportance of science in the maintenanceof a free society and democratic ideals. Allfelt such support would be accomplishedthrough the preparation of a citizenryinformed in science and by maintaining anadequate supply of scientific and technicalmanpower. However, despite good inten-tions, the expected widespread curriculumreforms in science curricula and improvedteaching procedures did not materialize.

Between 1950 and 1960 it was recog-nized that few of the major problems ofmodern civilization could be dealt with inthe absence of scientific literacy. The real-ization that an understanding of sciencewas imperative in the education of all peo-ple was beginning to be apparent, althoughhow this understanding should be com-municated was unclear.

Southeastern/North Central Conferences onBiology Teaching

The Southeastern Conference on Biol-ogy Teaching held during the summer of1954 brought together 85 high school andcollege teachers. Six biological scientistsprepared written summary statements ofhow their special fields could and shouldcontribute to the improvement of biolog-ical education. The six fields were:

1. Heredity and development.2. Evolution and paleontology.3. Morphology.


4. Taxonomy.5. Physiology and health.6. Ecology and conservation.

Morphology and physiology together con-stituted a third of the special fields consid-ered of value in biological education.

In 1955 at Cheboygan, Michigan theNorth Central Conference on BiologyTeaching involved 87 persons includinghigh school science teachers and collegebiology teachers. Its work closely paral-leled that of the Southeastern Conference,with research biologists invited to preparepapers as background resources. There wasa consensus that current scientific develop-ments and social trends should influencethe content of biology courses, that courseadjustments are needed to meet the prob-lems of urbanization, and that the wholebiology course needed to be upgraded interms of intellectual content.

NAS I NRC Committee on Educational PoliciesThe National Academy of Sciences

National Research Council (NAS/NRC)established, in 1954, a Committee on Edu-cational Policies which recognized a needfor agreement among educators and sci-entists as to what constituted biology incourses at high school, college and grad-uate levels. This committee also felt that abasic knowledge of biology should be thepart of everyone's education. Just as in thetime of Mondino (p. 643), the committeeexpressed concern about the extensivevocabulary found in biology courses andstated "One of the shortcomings of text-books and courses is often that the studentmay become so impressed with need forlearning a new vocabulary as to lose sightof larger objectives. Moreover, much con-fusion has arisen in use of terms and unitsin biology simply because of the way biol-ogy has grown. . . . Authors and teachers,meanwhile, have a special problem and aspecial responsibility in regard to termi-nology."

A Subcommittee on Instructional Mate-rials and Publications of this NAS-NRCcommittee concerned itself with the roleof the laboratory in introductory biologyand stated ". . . even in some colleges, thepressures of mounting enrollments and

inadequate facilities, the ineptitude and lackof enthusiasm of some teachers, the notionthat students learn as well from demon-strations and films as from laboratory workthey do themselves, have led to drasticreduction or even total abandonment oflaboratory and field study. Elsewhere,though 'laboratory' remains on schedule,what is offered is so pedestrian and un-imaginative, so unlikely to challenge thestudent's powers as to be almost worse thanno laboratory work at all." The latter partof this statement at least categorizes myown experience with introductory zoologylaboratories and it is distressing to find thistrend continuing into 1954 and beyond.

Source Book of Laboratory and FieldStudies in Biology

In an attempt to provide more challeng-ing laboratory opportunities a writing con-ference was held at Michigan State Uni-versity during the summer of 1957. Awriting team composed of ten biologistsfrom colleges and universities worked withtwenty high school biology teachers to pro-duce what was called the The Source Book ofLaboratory and Field Studies in Biology. Noneof the major eight outlined topics was con-cerned primarily with form and function,although both would play a part in themajor areas of investigation which weredesigned as follows:

1. Organisms living in their particularenvironments are the primary subjectsof biology.

2. The diversity of organisms.3. Some essential chemistry.4. The organism as a dynamic open sys-

tem: introduction to the basic organ-ismic functions.

5. Maintenance of the individual.6. Maintenance of the species.7. The organism in its ecological setting.8. Evolution of organisms and their envi-

ronments.

Physiology was stressed over morphology,with students learning to report observa-tions, experimental findings and interpre-tations as an important phase of laboratoryand fieldwork. Further, laboratory and fieldstudies were to be integrated with reading,


discussion, consultation with resource per-sons, and evaluative procedures so that theywere perceived as equivalent learning pro-cedures rather than isolated confirmatoryevents.

Still, the plethora of studies and rec-ommendations went largely unheeded, pri-marily because they acted as sheets ofinstructions on which others were sup-posed to take action. It became quiteapparent that continuing to produce rec-ommendations and expecting others toimplement them would be the same chanceproposition as having a baby and leavingit on someone else's doorstep to raiseaccording to the desires of the natural par-ents.

The Biological Sciences Curriculum Study

A turning point came in 1955 when theAmerican Institute of Biological Sciencesappointed an Education and ProfessionalRecruitment Committee which wascharged not with making recommenda-tions but with the development of a pro-gram of biological education at all levels.This was to be a comprehensive curricu-lum project involved with course content,laboratory manuals and teacher aids. Itwould produce films, film strips, charts andmodels. It would study in-service trainingof teachers and the possible production ofpamphlets, booklets and other publicationsto serve to increase the effectiveness of bio-logical education. Oswald Tippo was chair-man of the AIBS Education Committee anda Steering Committee, composed ofresearch biologists, high school biologyteachers, educators and school administra-tors, was appointed under the chairman-ship of H. Bentley Glass, then of JohnsHopkins University, and Arnold B. Grob-man of the Florida State Museum whoserved as Director of the Biological Sci-ences Curriculum Study (BSCS) whichbegan in 1958.

The emphasis on production of mate-rials rather than a specific course of studywas a departure from the previous effortsprimarily aimed at making recommenda-tions. Early on, the Biological SciencesCurriculum Study developed themes that

should be pervasive in any biology course.These themes, as valid today as when theywere elucidated in 1960, are as follows:

1. Change of living things through time,evolution.

2. Diversity of type and unity of patternamong living things.

3. Genetic continuity of life.4. Complementarity of organism and

environment.5. Biological roots of behavior.6. Complementarity of structure and

function.7. Regulation and homeostasis, the

maintenance of life in the face ofchange.

8. Growth and development in the indi-vidual's life.

9. Science as inquiry.10. Intellectual history of biological con-

cepts.

The BSCS themes reemphasized theimportance of form and function butrelated both to broader goals. Diversity oftype and unity of pattern focused both oncommonality of structure and adaptationsof it in diverse organisms. The comple-mentarity of structure and function relatedform and function as an operating unit andavoided morphology for morphology's sakeand physiology solely as the interpretationof experimental results. Regulation andhomeostasis and change of living thingsthrough time also imply a knowledge ofform and function both in terms of geo-logic time and within organisms facingenvironmental changes in today's world. Abiology course organized to deal with formand function in terms of principles of unityand diversity offered an alternative to rou-tinized memorization of structure and con-firmational experimental work in physiol-ogy (Mayer, 1986).

It was never envisioned that these themeswould become headings for chapters thatwould encapsulate an idea which thenwould never again appear in the text. Thiswas the case with the infamous chapter on"the" scientific method which opened somany textbooks for so many decades. Itgave the student an apparent recipe for


scientific infallibility which never again wasreferred to in the text. The very conceptof themes implied that these major ideaswere to be interwoven throughout the textand emphasized wherever applicable so thatthe student would meet them again andagain and, by their ubiquitous nature,become familiar with them as basic recur-ring principles of biology with applicabilitythroughout the living world.

The time was right for a change. Biologycourses were woefully out of date and,through neglect, had become routine exer-cises in mediocrity. This was widely rec-ognized but no alternatives had been madeavailable. Except for those exceptionalinstructors who, on their own, strove toremedy defects as they saw them, the biol-ogy courses of the 1950s were scarcely dis-tinguishable from those of the 1930sexcept, that in some cases, a biochemicalterminology had been substituted for onedealing with gross morphology.

The BSCS produced materials focusedon the secondary school because this wasthe first time most students encounteredbiology as a discrete discipline. It was inter-esting to observe the effect new materialsat the secondary level had on the entireeducational continuum. It would beexpected that elementary schools wouldrespond to changes at the secondary levelbut, for the first time, the river began toflow backwards. Traditionally, high schooltextbooks were simply watered down col-legiate ones. A simpler vocabulary sufficedto turn an introductory college text intoone usable in a high school. In the case ofthe BSCS, however, the secondary schooltexts were so revolutionary that writers ofcollegiate texts had to take cognizance ofthem (BSCS Newsletter #42, 1971). Thus,college textbooks began to be written thatreflected the changes instituted at the sec-ondary level. It took a few years for BSCStrained high school students to reach col-lege and, when they did, they expresseddissatisfaction with courses that had beenunchanged for decades. Student unrest inthe 1960s and 70s has been almost exclu-sively ascribed as being political in naturebut, in part, it was also academic as students

appreciated that cut and dried, routinememorization neither reflected the worldas they saw it nor was it likely to be respon-sible for productive change.

Why was the BSCS successful? Why,practically from its inception, did it enterthe curricula of 50% of American schoolsdirectly and almost 100% indirectly as itsworks influenced curriculum content?Although Sputnik convinced many thatU.S. science was falling behind that of theSoviet Union, the primary answer has tobe that BSCS was a concerted activist effort.The first that attempted to change, on anationwide basis, the curriculum of sec-ondary schools. It capitalized on the studiesand reports that had gone before and itsaim was to produce materials that reflectedthe current state of the discipline of biol-ogy within a matrix of teachable pedagogy.It combined distinguished scientists withoutstanding biology teachers. The need wasconsidered so great that the BSCS attractedmany members of the National Academyof Sciences, a Nobel Prize winner, and out-standing research biologists representing abroad variety of fields who were willing towork to improve the biology curriculum.Further, because BSCS was a national effortit received national publicity not only injournals devoted to science such as Biosci-ence and those devoted to education suchas The American Biology Teacher, but also inthe public press as well, including Timemagazine.

This well publicized effort involved sci-entists and teachers from all over theUnited States in a task that sorely neededto be done (Mayer, 1978). Funding fromthe National Science Foundation made suchan effort possible and the success of thisproject in inducing classroom change is welldocumented (Shymansky, 1984).

The Commission on UndergraduateEducation in the Biological Sciences(CUEBS)

This was also a time of general educa-tional ferment in the sciences, with curric-ulum projects engaged in preparing mate-rials for chemistry, physics, earth sciences,and a variety of other disciplines at levels


from elementary through high school (K-12). In addition, the need was felt forchange in the collegiate introductorycourse. After all, the collegiate course hadprofoundly influenced courses offered atthe secondary level and criticisms of sec-ondary courses were implicating collegecourses as well. The Commission onUndergraduate Education in the Biologi-cal Sciences (CUEBS) was established tolook into the collegiate program. How-ever, during its seven year existenceCUEBS neither developed a textbook norpostulated specific content and emphasis.Because of the nature of education at thecollege and university level more generalrecommendations were made with outlinesof typical courses given as models.

Biology in a liberal education. T h e Com-mission on Undergraduate Education in theBiological Sciences produced a number ofpublications dealing with specific aspects ofcollege biology teaching. Publication #15,for example, edited by Jeffrey J. W. Baker,dealt with biology in a liberal educationand reported on a colloquium held at Stan-ford University 2-13 August 1965. Thisreport is of particular significance in rela-tion to the introductory collegiate biologycourse primarily designed as a contribu-tion to the liberal arts. It is interesting tonote that no agreement could be reachedon topics so fundamental that they shouldappear in any introductory biology course.However, analysis of course outlines sub-mitted at the colloquium noted that vir-tually all contained units on anatomy andphysiology, the nature of science, metab-olism, photosynthesis, genetics, develop-mental biology, evolution and ecology.

With one or two notable exceptions, fewprofessors attending the colloquium indi-cated satisfaction with the coverage of themajor plant and animal phyla. One solu-tion suggested was to eliminate the phyleticsurvey. Another was to de-emphasize ana-tomical and morphological detail and,instead, emphasize the experimentalaspects of biology, applying specific ana-tomical detail only where relevant. If mate-rials on plant and animal phyla weredeemed pertinent and were to be included,each phylum might be discussed in terms

of a specific organism used to attack cur-rent research problems. For example, thesquid might be discussed in terms of use ofits giant nerve fiber in neurophysiologicalresearch. A few participants felt that cov-ering certain biological principles such astransport in both plant and animal formssimultaneously was a great mistake. Instead,they felt it essential that such processes,initially at least, be treated on the level ofthe whole organism. All participants agreedthat subject matter should be included thatwould give the student an understandingof biology as an investigative science andthat such subject matter should make stu-dents aware of the vast scope of biology.

Further, all participants were aware ofthe changes taking place in biology. Someviewed emphasis on molecular biology asposing a threat to content concerned withmorphology, taxonomy, phylogeny, and soforth. Others, however, welcomed thenewer material. This skewed opinion aboutcontent was expressed by one participantas follows:

I think that the poor teaching of classicalbiology by molecular biologists is worsethan the poor teaching of molecularbiology by classically oriented biologists.

As regards the perennial questionwhether there should be one introductorycourse offered to majors and non-majorsalike, the initial attitude toward non-majorswas that they should receive an apprecia-tion of the scope of biology, its history andphilosophy, its current problems and prob-able future. It follows that such insights areprobably even more important to the biol-ogy major. Although this was not a primarytopic of discussion it was generally agreedthat the non-science major should not beexposed to the course traditionally givento the major but, rather, that both majorsand non-majors should receive a newlydesigned course that would impart an over-view of the field and its vast potential forintellectual growth and achievement inorder to provide continuing appreciationof the discipline for the non-major and theenrichment of participation on the part ofthe major.

Core curriculum for biology majors. In addi-


TABLE 1. Form and function topics in the core curriculum of four universities (Purdue, Stanford, Dartmouth, andNorth Carolina State).

Amylase and starch digestionThe nerve impulseSliding filament theory of muscle contractionCilia and flagellaCell organellesErythrocytesStructure of prokaryotesBacterial cell wallStructure and composition of a phageStructure and composition of the nucleusPlasma membrane (Robertson's Unit Structure)Growth and structure of the cell wallStructure and function of the Golgi apparatusEndoplasmic reticulumMitochondriaCytoplasmRole of the electron microscope in the study

of cell structureUse and care of the compound microscopeCyclosisElectron transportKrebs cycleEnergy yield and AT? balance in respirationProducts of energy metabolismGlycolytic pathway of Embden-MeyerofGlucose metabolismEnergy coupling of ATP synthesisRespiration ratesNeuron structureMuscle ultrastructure (the sarcomere)Leaf and stem structureStructure and physiology of ParameciumSeed and root structureFern gametophyte structureDiatom structure (Pinnularia)Volvox structure

Iodine test for starchMembrane permeabilityComposition of DNAStructure of proteinsStructure of ribosomal RNAStructure of starch, cellulose, glycogen, fats, phos-

pholipids and steroidsDNA replication (Meselson and Stahl experiments)RNA and protein synthesis (Nirenberg experiments)Amino acid activation and binding to sRNAmRNA binding to ribosomesRNA-AA complex binding to site on mRNA by base

pairingActivation energy and enzymesChlorophylls a and bLight reaction of photosynthesis (Van Niel's hypoth-

esis, Hill reaction)Electron excitation and splitting of the water moleculeOxidative phosphorylationStructure and reproduction of slime moldsChromosomal aberrationsCytokinesisMitosisProblems of synapsesHeterospory in Selaginella and EquisetumChiasma formation during meiosisCytological analysis of meiosisEgg differentiation in oogenesisAngiosperm gametogenesisLife cycle of NeurosporaNuclear role in egg developmentFactors influencing growthGrowth as synthesis of protoplasmCell division as an aspect of growthBacterial growth phases

tion to considering biology within the lib-eral arts, CUEBS also investigated, inpublication #18, the content of a corecurriculum in biology for majors (1967).The core curricula of four universities(Purdue, Stanford, North Carolina State,and Dartmouth) were closely investigated.Subject matter was broken down into cat-egories, topics, and subtopics. Table 1 liststhose topics which primarily related to formand function and which all four universi-ties included in their core.

Table 1 excludes many items relative togenetics and to plants, but of the total num-ber of topics listed in publication #18 onlya small fraction were included by all fourinstitutions surveyed. If one picks, instead,topics which three of the four institutionsincluded in their core, the list becomes

appreciably lengthened. However, thiswould be a poor way to pick course contentbecause of the way items were listed in thestudy. For example, Purdue and Dart-mouth were listed as the only two institu-tions providing a definition of life, butNorth Carolina included characteristics ofliving matter and systems and Stanfordpresented attributes and characteristics ofthe living organism. Perhaps all three top-ics are saying the same thing in differentways so that a detailed analysis dependingonly on specific combinations of words, mayconceal that the same topic is being cov-ered but simply being reported differently.

A major recommendation concerningthe content of the curriculum was coverageof fundamental biological concepts includ-ing, at all levels of biological complexity,


structure-function relationships, growthand development, the nature of hereditarytransmission, the molecular basis of ener-getics, synthesis and metabolic control, therelationship of organisms to one anotherand to their environment, the behavior ofpopulations in space and time, and evolu-tion. These generalized recommendationsshow a great deal of similarity to those madein earlier studies pertaining to the second-ary school, such as the BSCS themes. Thedifference, however, is that the core cur-riculum was designed to cover two years oftraining for majors while the introductorycourse would be for no more than a yearand could well be for majors and non-majors alike.

Modules in college biology teaching. CUEBSalso investigated the use of modules in col-lege biology teaching (Creager and Mur-ray, 1971). Modules can be considered toolsof instruction. They are self contained,independent units with primary focus on afew well defined objectives. Modules pro-vide opportunities for organizing experi-ences meeting the needs and interest ofteachers and/or students. The modularapproach provides a way of assessing stu-dent's learning progress, reduces routineaspects of instruction, allows for easyupdating of study material, relatively easilycan be developed by teachers and can beexchanged between institutions. Amongthe most well known of the modularapproaches to biology is the minicourseprogram developed at Purdue Universityby Sam N. Postlethwait.

The laboratory. CUEBS publication #33(Thornton, 1972) was entitled The Labo-ratory: A Place to Investigate. This work dealswith laboratories in introductory courses,advanced courses, field stations, and twoyear community colleges. It delineates thelaboratory curricula at Marquette Univer-sity and at MIT. In the investigative lab-oratory, activities parallel lectures and textsimultaneously to unearth content. Somelaboratory programs have been completelyuncoupled from introductory lecturecourses while others are closely integratedwith the lecture course. CUEBS deliber-ately set out to identify alternatives to tra-ditional undergraduate programs, par-

ticularly those for teaching the art ofinvestigation within an institutional envi-ronment whose usual practices are not sup-portive of this educational goal.

The context of collegiate biological education.The final CUEBS report, #34 (Cox andDavis, 1972) constituted a comprehensiveview of the then studied undergraduatebiological education which could be sub-sumed in one word "paternalism." CUEBSconcluded that the instructor still holds hisposition as the knowledge authority know-ing that what is being done is best for thestudent while, at the same time, chokingoff student opportunities for academicmaturity, educational self direction, andintellectual growth. This report, entitledThe Context of Biological Education: The Casefor Change, included many recommenda-tions and suggestions all based on pro-grams actually in existence in identifiedcollege biology departments. While theserecommendations would be anathema tothose who regard recall as the highest formof intellectual achievement and the collec-tion of unrelated facts a the goal of edu-cation, their announced goals of under-graduate biology education challenge thevoice of authority as being valued morethan independent judgment and questionwhether there is always a single unambig-uous right answer to a question.

The Transient Nature ofReform Efforts

One of the positive features of the BSCS,in contrast to CUEBS, is that it hasremained in existence since its inception in1958. All other similar programs dis-banded with the altruistic hope that theyhad done their work, made their impact,and further effort on their part was nolonger needed. The fates of these pro-grams have proven otherwise, for only ves-tiges of their work remains. Curriculumrevision at any level is not a one time pro-cess but, rather, one that requires contin-uous presence and effort. There is no waythat a series of widely spaced, unrelatedefforts at curriculum revision can producedesired changes during the decadesbetween such revisions. The gearing up forsuch individual efforts is a costly and time


TABLE 2.et al.

The fifteen most important science topics as ranked by secondary teachers of biology in a 1982 study by Finley

PhotosynthesisMitosis/meiosisCell theoryCellular respiration

„. Animal circulatory systems6. Mendelian genetics7. Chromosome theory of heredity8. Gene concept

9. Digestion in animals10. Hormonal control of reproduction11. Chemistry needed for biology12. Complementarity of structure/function13. Leaf structure and function14. Food chains and webs15. Respiratory systems in animals

consuming process which is not necessaryif there is a continuing entity designed tomonitor content and pedagogy, and tochange objectives in keeping with newknowledge in order to meet the needs ofa given population at a given time. Thatonly one of the NSF's sponsored curricu-lum studies remains intact from the num-ber begun in the late 50s and early 60s is,to some extent, a testament to futility. Justas one battle does not win a war, so onecurriculum effort does not ensure imple-mentation and change in subsequent timeperiods. The BSCS was initially eminentlysuccessful and continues to make contri-butions to the improvement of biologicaleducation, but a revival of the effort at thecollegiate level begun by CUEBS would bea welcome contribution to the improve-ment of introductory collegiate biology.

Importance vs. difficulty

Studies relative to biological educationstill continue. Many are concerned with thesame issues on which this paper has alreadyreported. Those concerned with biologicalcontent are ones of import to this presen-tation. In 1982, Finley, Stuart and Yarrochpolled 100 secondary teachers of biology,chemistry, physics and earth science. Theywere asked to rate the 15 most importantscience topics and 15 topics most difficultto teach. For biology, the 15 importanttopics ranked as shown in Table 2.

While the poll did not elicit answers ina way that could be easily quantified, threeof the top items of importance related tothe cell (2, 3, and 4) and of these mitosis/meiosis and cell theory are classical inclu-sions traceable to the development of the

cell theory by Schleiden and Schwann.Three of the important inclusions con-cerned genetics (6, 7, and 8) with 6 con-centrating on the work of Mendel and theother two presenting information at leastdecades old. DNA, per se, does not makethe list unless somehow it's hidden withinitems 7 and 8. Only two items relative toplants are considered of importance (1 and13) and here 13 is a rather pedestrian inclu-sion undoubtedly listed as necessary to pro-vide a place for photosynthesis to occur.Despite all of the publicity about pollutionand preservation of the environment onlyitem 14 concerning food chains and webs,can be considered ecological.

Form and function, however, constituteat least a third of the items considered ofimportance. One deals with a generalizedtopic of complementarity (12) and four aredirectly related to specific study of struc-ture and function of systems (5, 9, 10, and15). This gives evidence of the backgroundof teachers and their concern with the clas-sical. The coverage of structure and func-tion of specific organ systems indicates nonew synthesis of materials or its presenta-tion around organizing principles. Circu-lation and respiration are not combined aspart of an overall transport system nor aredigestion and respiration presented interms of energy. Hormonal control is dis-cussed primarily in terms of reproduction,but not as an overall part of a coordinatingmechanism involving the nervous system.Information listed as of importance is stillof the scrappy and uncoordinated naturecriticized by the Committee of Ten in 1893.Even a casual perusal of this list elicits con-cern about the items not regarded asimportant and gives an impression that a


TABLE 3.et al.

The ranking of fifteen topics secondary teachers thought most difficult as shown in the 1982 study by Finley

1. Cellular respiration2. Protein synthesis3. Mitosis/meiosis4. Chemistry necessary for biology5. Enzyme structure and function6. Photosynthesis7. Hormonal control of reproduction8. Multiple alleles

9. Chromosome theory of heredity10. Probability in genetics11. Mendelian genetics12. Taxonomy and classification13. Dihybrid crosses14. Homeostatic systems15. Population genetics

student of the 1930s would be very com-fortable 50 years later in one of these class-rooms whose work apparently still parallelsthe course outlines of half a century ago.

The 15 topics teachers thought most dif-ficult are ranked in Table 3. It is interest-ing to compare what teachers thought wasimportant with what they thought was dif-ficult and there seems to be a correlationbetween difficulty and importance, almostas if the interpretation were "if it's hard itmust be important." Almost half of theitems considered important were alsoconsidered difficult to present. Cellularrespiration, mitosis/meiosis, chemistrynecessary for biology, photosynthesis, hor-monal control of reproduction, the chro-mosome theory of heredity, and Mende-lian genetics appear on both lists.

Five items concerning physiology areconsidered difficult to present (1, 2, 5, 7,and 14). Six items concerned with geneticspresent difficulties (8, 9, 10, 11, 13, and15). Only one item relative to plants (pho-tosynthesis) seems both difficult and impor-tant. Taxonomy and classification are pre-sented as difficult when perhaps what isreally meant is they are dull or uninterest-ing to students who have no motivation fortheir study. Difficult subjects are usuallyconsidered to be dull or boring or unin-teresting either because they are not pre-sented properly or because they are per-ceived as leading nowhere. The difficulty,in short, may not be so much with the topicitself, but the way in which it is presented.The implied criticism may not be so muchdue to the subject matter but the pedagogyused to present it. It is interesting that noneof the structure-function topics listed asimportant (4, 5, 8, 9, 12, and 15) are listed

as being difficult to present. Hormonalcontrol of reproduction is the only itemconstrued as physiological which appearson both lists. Apparently, then, teachersfind form and function topics importantbut not difficult.

It must be remembered that difficultyalso can be equated with degree of non-familiarity. This was adequately dem-onstrated by the molecular biologicalapproach introduced into secondaryschools by the BSCS in 1960. Almost uni-formly teachers decried the interpolationof molecular biology because of its diffi-culty—difficult because they had no back-ground or training in molecular biology.While all things are supposedly new to thestudent, what is new to the teacher becomesa learning experience that poses difficulty.However, because many of the topics listedabove as difficult are practically standardsin the biological repertoire—dihybridcrosses, taxonomy and classification, forexample—these cannot be difficult becausethe teacher is unfamiliar with them. Froma perusal of the list it appears that modernbiological concepts (post-DNA) may not bepart of the curriculum at all and thereforeescape categorization as either importantor difficult.

Recent recommendations

Berkheimer et al. (1984) delineate fourscience objectives for the non-specialist asfollows:

1. Overcoming the fear of science.2. Developing capacity for critical think-

ing.3. Finding and using reliable sources of

scientific data.


4. Gaining scientific and technical knowl-edge for professions and civic respon-sibilities in an increasingly technologi-cal society.

In different words, such recommendationshave been made before and there is noindication that these will be accepted andimplemented any more than have thosepreviously made. Koballa, undated, pre-sents an analysis that reveals that emphasison discrete knowledge is characteristic ofall the programs investigated, indicatinglittle or no improvement in a situationdeplored for almost a century.

Fortunately, there are attempts to mod-ify traditional approaches to biology.Flashpohler and Swords (1985) have devel-oped an introductory collegiate course thatdeals with issues in social biology such ashuman reproduction, genetics, trans-plants, immunology, hormones and drugeffects. Practicality and applicability char-acterize this type of presentation. Moll andAllen (1982) at West Virginia Universityhave organized a course around develop-ing critical thinking skills. Their introduc-tory program emphasizes the applicationof knowledge, the making of predictionsand the drawing of conclusions.

Concern for undergraduate collegiatebiology courses is not confined to theUnited States. The International Union ofBiological Sciences Commission for Bio-logical Education reflects global concernsin its A Strategy for Biology Courses for Under-graduate Non-Biology Majors (1987). Usinga curriculum hypothesis that does not startfrom scientific subjects but, rather, fromlife situations in which a student is likelyto become involved, the question is posedas to what kind of knowledge a citizen needsin order to master the most important sit-uations in life. It is maintained that thesesituations require a great variety of biolog-ical topics for their comprehension. Themajor objective of this approach is "tomotivate non-biologists to appreciate theimportance and usefulness of an under-standing of biological sciences in their livesand their roles in society."

Subsumed under this major objective isa comprehension of the functioning of a

healthy body and an appreciation of thegreat extent to which people are a part of,and dependent upon the natural environ-ment around them. Further, as in studiescited previously, the report notes:

It is important that non-biologists shouldbe led to appreciate the methodology ofscience, its scope and limitations, and toappreciate that science has a methodol-ogy, which combines rational processeswith intuition and ethical values in aunique way. Science is a mainly logicalprocess supported by repeatable, exper-imental evidence, developed by rigidtraining and practice.

Scientific methodology is envisioned ashaving applications beyond the realm ofscience. The report states "The method-ology of science can and should be appliedto social administration, business, and otherpublic activities which require reasoneddecision making, taking into account allrelevant constraints, but recognizing thatin public affairs moral and aesthetic con-siderations have to play an important role."This publication illustrates the apprecia-tion of global deficiencies in our approachto biological science and its applicability,particularly in terms of the education ofthose who are not destined to be scientists.

Many modern investigations are empha-sizing cognitive research findings andattempting to incorporate them intoinstruction. For example, Linn (1986)emphasizes need for increase in quantityof science instruction and on deeper cov-erage of topics that then result in betterlearning. Mestre (1987) deplores the lackof use of cognitive research data. He feelsthat, among the major obstacles to thechanges that cognitive research can direct,are changes in textbook design affectingclassroom performance by deemphasizingcoverage and rote learning, and changesin tests to reduce measurement of factualand quantitative material, and to provideincreasing opportunities for exercise ofcognitive ability.

The applications of cognitive researchare recent additions to our concerns aboutinstructional improvement. As a relativelyyoung addition, whose data and approaches


are still being debated, it shows promise.However, what data we have on cognitionare as unlikely to find immediate use in anintroductory biology program as have otherrecommendations. Without concertedeffort, and in the absence of motivation forchange, the introductory course is likely toproceed in slow Darwinian steps rather thanto experience a saltational jump or one dic-tated by rapid movement in a period ofpunctuation of equilibrium.

Once again, some colleges are engagedin the exploration of innovative introduc-tory biology programs. One example isafforded by Stanford University. Sup-ported by the Ford Foundation, Stanford,in 1969, initiated its Department of HumanBiology and developed a highly popularcourse in human biology at the introduc-tory level. The course brings togetherstudies on the human, previously scatteredthroughout numbers of university depart-ments, into one focused on the biology ofhumans broadly interpreted as involvingthe social sciences, psychology, and otherpertinent disciplines.

References to studies and recommen-dations regarding introductory biology:Armacost and Klinge (*1956), Baker(*1967), Beauchamp (1932), Berkheimeret al. (*1984), Bessey (1896), Bigelow(*1906), BSCS (1971), Breukelman andArmacost (*1955), Caldwell (1920),CUEBS (*1967), Cox and Davis (*1972),Creager and Murray (1971), Dewey (1916),Dexter (1906), Downing (1931), Finley etal. (1982), Fisher et al. (*1986), Flashpoh-ler and Swords (1985), Galloway (*1910),Grobman (*1969), Hall (*1898), Havi-ghurst et al. (1943), Hurd (*1961, 1978),IUBS/CBE (*1987), Koballa (undated),Linn (1986), Linville (* 1910), Maienschein(*1986), Mayer (1978, *1986), Mestre(•1987), Moll and Allen (1982), NEA(•1893), Peabody (1915), Powers (*1932),Riddle (1906), Shymansky (1984).

OBJECTIVES AND CONTENT OF ANINTRODUCTORY BIOLOGY COURSE

The importance of unlearningOne of the first problems in dealing with

any discipline involves not what needs to

be learned but what needs to be unlearned.Objectives and content of our introductorycourse must take cognizance of the factthat students come to classes with folk wis-dom and a variety of misunderstandingsgarnered from folklore which may be rein-forced by various media presentations.Sometimes the misrepresentations aremade by groups with which the studentmay have had contact and whose presen-tations they had uncritically internalizedwithout recognizing them as special inter-est pleadings designed to further a partic-ular dogma by thinly disguising it as havingscientific merit. In many cases, the misla-beled educational baggage a student bringsto a course is ignored, creating conflicts asa student is faced with new information atvariance with that already possessed, with-out any mechanisms offered for the eval-uation of what might, in the student's mind,be polar positions.

Kitcher (1984) takes cognizance of theknowledge a student may bring to the class-room as follows: "Our beliefs are a productof processes in which our early training,encounters with the world, and construc-tive thinking all have parts to play. Weobserve the lore of our community andcount ourselves justified as we modify thethings we are taught in the light of ourexperience." It is these beliefs that are fre-quently challenged when students areexposed to knowledge of which they hadbeen previously ignorant. Unfortunately,many times the student's preconceptionsare derided and dismissed without newinformation sufficiently convincingly pre-sented to take its place. This creates aquandary for the student as cherishedbeliefs are cast aside but not effectivelyreplaced or modified by the data that chal-lenge the preconception. In many cases thestudent is cut loose from a comforting, ifinaccurate, view of the world without beingprovided an adequate anchor for new con-ceptions that ultimately could prove evenmore personally satisfying.

Student misconceptions

Some student misconceptions result notfrom prior knowledge, or lack thereof, but


from misunderstanding the presentationof new material. In some cases it is safe tosay that a student may acquire more mis-information than information from anintroductory course. Fisher et al. (1986)dealt with problems of misconceptions ofcollege students. Misunderstandings aboutevolution frequently result from erro-neous prior knowledge as do misunder-standings of the role played by heredityand environment. For example, some stu-dents when polled felt that heredityaccounted for some 50 to 80% of physicalcharacteristics but, when questioned aboutmental characteristics, only 0 to 15% feltthat these were determined by heredity.Sometimes the bugbear of vocabularytransmits an unintended message. Theterm "dominant" in relation to genes wasinterpreted by students as that the domi-nant gene "turns off" the recessive which,in the student mind, was equated with itsbeing submissive. The dominant geneswere also felt by students to increase in apopulation, indicating that the Hardy-Weinberg principle had not been inter-nalized.

Students were found also to have prob-lems with terms such as "chromosome"which they applied to decondensed eukary-otic chromatin, to prokaryotic genomes,and to linkage maps. In the metaphase ofmitosis the replicated and condensed chro-mosome was still referred to as being a"pair" of chromosomes. When questionedabout DNA, students responded that DNAwas made up of amino acids, or that aminoacids were products of translocation.Somehow the student, by being exposed toDNA, amino acids and translocation,understood these terms to be related butdid not know how.

Such misunderstandings go unnoticedprimarily because they are not sought.Objective examinations fail to reveal themas the reasons why a student has missed aquestion. Instructors may perceive thattheir presentations have been internalizedby the student without ever recognizingthat such reception may be faulty and themessage garbled to the point of unintelli-gibility.

The nature of science

The sine qua non of the collegiate intro-ductory biology course is to communicatethe nature of science. The initial organi-zation of a liberal arts college, or a collegeof letters, arts and sciences, was episte-mological. The objective was to acquaintstudents with the ways in which humansknow about their world and the differentsystems for obtaining data concerning it.Students were to become acquainted withhow such diverse disciplines as history,social sciences, arts and the natural sci-ences viewed the world. Unfortunately, theliberal arts college strayed from this initialperspective of explicating ways of know-ing. Instead, it became enmeshed in detailand minutia in all of its divisions in muchthe same way as the Laocoon group becameenmeshed with serpents. Almost no liberalarts college retains its focus on how knowl-edge is organized, how various disciplinescollect their data, and how comparisonsbetween different systems of knowledge aremade. Instead, college divisions anddepartments have become more compart-mentalized and involved with internal soulsearching that results in concentrating onthe data but not the discipline. It is under-standable, therefore, why college gradu-ates cannot distinguish between data of thesocial sciences and data derived from thenatural sciences. Nor can an average col-lege graduate assign degrees of validity andcredibility to data derived through certainsystems. It is no small wonder, then, thatlocal school boards, state boards of edu-cation and state legislators show no abilityto distinguish between theological data, asderived from biblical revelation, and sci-entific data derived from observation andexperiment. Their inability to distinguishbetween different ways of knowing leadsthem, logically in their minds, to a struc-turally illogical conclusion that biblical rev-elation has a place in the science classroomto "balance" the presentation of evolution.This becomes particularly appealing as anti-evolutionists have developed the pseudo-science of creationism whose basis is theGenesis account of creation in the KingJames version of the Bible. Anti-evolution-


ists have dignified this biblical story byreferring to it as "creation science" readilyperceived as an oxymoron by those famil-iar with the data that support evolutionand the absolute lack of scientific data tosupport "creation science" (Kitcher, 1982).

This confusion is no trivial matter. Instates as diverse as California, Arkansas,Tennessee and Louisiana major court caseshave been initiated demanding the inclu-sion of "creation science" in public schoolclassrooms wherever and whenever evo-lution is discussed. In every court, at everylevel, the anti-evolutionists have beenrebuffed and their position recognized bythe courts as a religious one fostered byhyperorthodox Christian fundamentalists.The latest of these cases was decided bythe U.S. Supreme Court in 1987 whichruled against Louisiana's "equal time" law.This decision, however, will not serve toterminate the efforts of the anti-evolution-ists who prosper from preying on the sci-entifically naive or illiterate. This scientif-ically naive population is not an ignorantone and, while it contains relatively fewreputable biologists, it has attracted engi-neers, educators and college graduatesfrom non-science disciplines.

The fact that a purportedly educatedpopulation exists incapable of distinguish-ing science from other ways of knowingand able to confuse science and religionindicates that colleges and universities doa very poor job of delineating ways ofknowing, defining science, clarifying itsboundaries and assigning credibility to itsdata. Any science course that does not dothese things is failing to achieve the objec-tive for which science was made an under-graduate requirement in the first place. Asa humbling exercise, include a question onthe biology final examination asking thestudents to define science. Reading theanswers, unless one is satisfied with acanned, meaningless definition such as"Science is a body of organized knowl-edge," will give an insight as to whetherthe year has clarified in the student's mindscience as a way of knowing. Any coursethat does not give students an understand-ing of science as a discipline, including thosethings science can explicate well and those

to which it cannot contribute, does stu-dents of the liberal arts no service.

We seem to be in an age of anti-intellec-tualism, and the National Science Foun-dation has categorized us as a nation ofscientific illiterates. It would be too muchto expect that changes in the presentationof biology in an introductory course wouldturn this situation around. An impact canbe made, however, on the population seg-ment addressed if effort is made to orientthe course to explicate the nature of sci-ence and emphasize rational approaches toproblem solving. Many students haveinherited from their cultures "anti" biases.It is rare to find that someone actively anti-intellectual is enrolled in college, but anti-scientism is relatively easy to find. The pop-ular image of a mad scientist creatingmonsters has been replaced by the madscientist unleashing viruses or mutants uponan unsuspecting population. The fetteringof scientific investigation by ignorancebecomes more and more common. Nega-tive community reactions to geneticallyengineered organisms is but one example.Those who deprecate animal experimen-tation and march under the outmodedbanner of antivivisectionism have their ownstereotype of science, but I know of noscientist who has sadistic impulses towardanimals that are played out in a researchlaboratory. "Creation science" becomes thebanner under which many anti-evolution-ists march and rising interest in the occultis fostered by its presentation with a sci-entific patina.

References to the nature of science:Achinstein (*1968), Ayala and Dobzhan-sky (*1974), Blake et al. (*1960), Braith-waite (1953), Brody (1970), Gallie (* 1957),Harre (*1970), Kockelmans (1968), Kuhn(*1970), Madden (*1960), Nash (1963),Northrop (1947), Poincare (*1952), Stauf-fer (* 1949), Suppe (1977), Suppes (* 1969),Toulmin (*1953), Wiener (*1953),Woodger (1937).

Science and pseudoscience

Confusion exists in the student mind notonly between science and religion—sup-posedly easily definable realms—but alsoin relation to systems masquerading as sci-


ence. So many attempts are made to givea degree of respectability to nonsense byclaiming a scientific base for it that it is nowonder students cannot clearly identify ascientific statement from a non-scientificone. An introductory course must clarifythis distinction between science and pseu-doscience.

Even college bookstores do not seem tobe able to distinguish between science andpseudoscience. On the science shelves canbe found such works as those by Velikovskyand Tompkins and Bird, whose Secret Lifeof Plants indicated that conversation raisesplant spirits. On many shelves Von Danikinstands side by side with Sagan. What areour introductory science courses doing todistinguish science from pseudoscience?How can a student evaluate the science ina popular work such as The Double Helixand contrast it to the sheer speculationpresent in The Chariot of the Gods} Scienceis not only a way of knowing but it is a wayof evaluating. The analytical and evalua-tive capacities of students are seldom calledupon in an average introductory programin which cognizance should be taken notonly of what students do not know, butwhat they know in error. If all studentswere blank slates on which one could writefor the first time, education would be aneasier endeavor. But seldom is attentionpaid to the fact that education is not simplya matter of being exposed to somethingnew, but being exposed to something dif-ferent and many times contradictory torandomly accreted knowledge accumu-lated as a part of a student's cultural back-ground.

Health and nutrition

Among the varieties of folk wisdombrought to class by entering college stu-dents perhaps none is more common orinsidious than folk prophecies concerninghealth and nutrition. Some of this infor-mation is handed down through a familyoral tradition. It has tended to take on apseudoscientific patina, moving awayfrom the sulfur, molasses and mustard plas-ters of grandmothers to over-the-counterpills and syrups coupled with exercise andbehavior regimens designed to ameliorate

whatever condition one seems to have.Television ads hawk nostrums of all kinds.Magazines contain advertisements designedto promote medication and mechanisms forweight loss, body building, retarding aging,building breasts and enhancing romance.Patrons of supermarkets are assailed bycheckout counter magazines and newspa-pers, each outdoing the other in pushingunsubstantiated claims designed to provideeasy solutions to complex problems. Quacknostrums are touted as a panacea for every-thing from cancer to AIDS and charlatansbecome rich because of gullibility enhancedby desperation to try anything that prom-ises relief.

Markets and specialty stores offer expen-sive foods and potions whose major con-tribution to the unwary seems to be hope.Expensive and excessive vitamin prepara-tions, foods high in calcium, low in sodium,high in iron, or low in cholesterol dot theshelves. These are welcome, indeed, topersons with such conditions as high bloodpressure or osteoporosis on good medicalgrounds. However, quack "nutritionists"or "dietitians" take advantage of real find-ings to improve their own fiscal well being.Organic foods and dietary items are afavorite of charlatans as are vegetables andfruit grown "organically" that supposedlywill bring roses back to sallow cheeks.

And what has this to do with the contentof an introductory biology course and whatpart does form and function play in rela-tion to what many would feel is consumerscience and not real biology? The point issimply this, the large number of gullibleand naive individuals influenced by adver-tisements for items touted as the results ofscientific breakthroughs are themselvesproducts of ineffectual backgrounds in sci-ence. Do students understand the term"organic" in relation to nutritionalrequirements of plants and do they haveany comprehension that plants are unableto distinguish sources of nitrogen, forexample? To the plant, nitrogen is nitro-gen, whether it comes from DOW Chem-ical or horse manure. How does the way ascientist use the term "organic" differ fromthe way in which the term is used by selfstyled nutritionists? What are the nutri-


tional consequences of an exclusively veg-etable diet or a macrobiotic one? How canall the varied nutritional patterns availablein diet books be valid when they contradictone another? What are the essentials ofgood nutrition and what are the conse-quences of following fads and fancies? Dostudents in a biology course understandenough about the functioning of the bodyto ensure an intake of basic requirementsand a rejection of advertising foolishness?At the very least, our presentations of formand function should indicate performancelimits and the inability of metabolism toprofit by many of the recommendationsmade in popular literature.

References to health and nutrition:Brown and Goldstein (1984), Eaton andKonner (*1985), Goodhart and Shils(*1980), Kolata (1986), Monmaney (1986),Rechcigl (*1977), Tver and Russell(*1981).

Form and function

While the prime purpose of an intro-ductory science course at the collegiate levelis to impart an understanding of science,including both its strengths and weak-nesses, the role of form and function insuch a course may be less obvious. Fromthe latter half of the 19th century to thepresent we have accumulated a century ofopinions on the role to be played by formand function. From its initial primacy,occupying the majority of time and effortwithin the introductory course, the empha-sis on form and function has waxed andwaned but it still occupies a position ofimportance in almost every introductorycourse. It would be inconceivable toattempt to explain the living world withoutreference to form and function which areubiquitous from the inorganic worldthrough the organic and within the latterfrom monerans through the most complexof animals at the organ/system level.

One can deal with form and function atthe molecular level. In terms of informa-tion transfer, one can speculate whether acell is simply DNA's way of creating moreDNA in the same way that there used tobe speculation as to whether a hen is simplyan egg's way of creating another egg. Suchspeculations constitute attractive asides but

may miss the main point that DNA bearsthe instructions for what an organism willlook like and how it will function and, thus,constitutes a blue print for form and func-tion with the blue print, itself, conformingto a specific structural pattern that followsfunctional principles.

Form and function can be dealt with ata number of other levels as well. Recog-nition of form, for example, seems almostan innate property of the natural world.Chemical elements have form recognitionof sorts as they bond with one another.Complex compounds, likewise, exhibit aform recognition as the structure ofenzymes fits specific portions of complexmolecules. Guanine fits cytosine, ade-nine—thiamine on the basis of form. Inthe world of organisms, predators recog-nize prey by sight and some, such as bats,can even recognize their prey by echolo-cation. Mimicry in certain organisms emu-lates the form of other species less likelyto be preyed upon. Form, then, is a per-vasive element within our universe, exist-ing from the atomic to the organismal leveland pervading both organic and inorganicrealms.

Both form and function display two verycontradictory principles. Systematic ar-rangement of organisms implies a unity ofpattern among living things while, at thesame time, depending on diversity of type.Aristotle (Moore, p. 489), for example, wasable to separate crustaceans from otherarthropods but, nonetheless, recognizedsimilarities between both groups. He wasalso able to do so when separating cepha-lopods from other mollusks while still rec-ognizing similarities just as he did when heseparated cetaceans from the other mam-mals while still recognizing them as mam-mals. He recognized unity of pattern whenhe noted that oviparity united fishes,amphibians, reptiles and birds but he alsoseparated fishes from the other groups bydiversity of type noting that they had whathe called "imperfect" eggs. A unity of pat-tern was recognized when Aristotle com-bined both oviparous and viviparous ani-mals because they had red blood. As morebecame known about structure and func-tion, principles of diversity of type and unityof pattern were reinforced.


Knowledge of form and function isessential to our understanding of the livingworld. However, too few organizing prin-ciples incorporate form and function intothe average introductory course. Diversityof type and unity of pattern is just oneprinciple that can be used to synthesize whatis too frequently presented as a mass ofunrelated and disorganized data. Vocab-ulary, a stumbling block for students ofform, continues to be a pervasive elementin teaching biology. The selection oforganizing principles, however, is in partconditioned byjust what it is that the intro-ductory course is designed to accomplish.Knowing this, content and areas of empha-sis then can be chosen to further the goalsof the course. The content of an introduc-tory course is ultimately always a compro-mise. With an almost infinite amount ofinformation to be covered in a finiteamount of time, a course outline can onlybe a selection of what is considered mostimportant at a given point. To the ancients(Moore, p. 500) the four humors were basicto the understanding of the living worldbut today they are of only historical inter-est.

What should be included in an intro-ductory course today? What are the bigideas of biology? What are those facets ofthe discipline of greatest applicability tothe lives of all citizens? What concepts arelikely to be retained and prove useful? Whatsubject matter is most likely to develop anunderstanding of and a sympathy for thebiological sciences? What is the role of formand function within the chosen objectives?The answers to these questions form amatrix within which overall objectives ofeducation are subsumed. Never have Iheard it expressed that the objective ofeducation is to cram a student with thegreatest number of isolated factual detailsthat can be transmitted in a given periodof time. Instead, the objectives most likelycorrespond to high blown platitudes suchas teaching the skills of analysis, synthesisand evaluation, developing a critical think-ing capacity, demonstrating to students howto learn on their own, and inculcating asense of the value of knowledge, bothabstract and applied.

Vocabulary

Objectives to the contrary, however, thefact remains that form and function, par-ticularly morphology, are detail and vocab-ulary laden. After almost a century of rec-ommendations to the contrary, vocabularystill dominates the content of many courses.The number of italicized or bold face typewords on a typical textbook page bears thisout. In just one 17 line paragraph dealingwith skeletal muscle a popular and widelyused collegiate text confronts the begin-ning student with a dozen words in boldface type. Guess which of the followingtwelve will be on the next examination?Antagonistic pairs, flexor, triceps, exten-sor, adductors, abductors, levators, depres-sors, pronators, supinators, sphincters,dilators. Another seven line paragraphconsiders the following five significantenough to appear in bold face: epineph-rine, norepinephrine, tyrosine, chromaffincells, and neurotransmitter.

Vocabulary has been a stumbling blockin the study of form since the 14th centurywhen Mondino de 'Luzzi taught at Bologna.Mondino dissected both animals andhuman bodies primarily to verify the Latinanatomical works that had been translatedfrom the Arabic. In doing so, Mondinocame across a problem that continues tobedevil teachers and students of anatomy.The many terms for organs, structures orprocesses made Mondino's students asunhappy as they make students today.Despite the fact that the terminology savestime and space, the proliferation of words,words, words frequently focuses attentionon the name rather than the object andsaddles students with the burden of mem-orizing a vast vocabulary of form and func-tion without the necessity of understand-ing either. As Mondino was reintroducingthe study of the form and function of thebody to the Western world he needed newwords and these he took mostly from Ara-bic and Hebrew, transmuting the namesinto Latin forms. Thus, the students ofform and function in the 13th and 14thcenturies faced vocabulary as a demandingritual of memory, as is still sadly the casein many anatomy and physiology coursestoday.


Mondino's terminology, however, wasmuch more complicated than that of today,suffering not only from involved construc-tion, but debased Latin combined withconfusing nomenclature which makes hisbook extremely hard to read. For manyparts he has several names. The sacrum,for example, is variously called alchatim,allannis, and alhavius. Conversely, the samename is often used for several parts. Anchae,for example, could mean the hips or thepelvic skeleton or the acetabulum or eventhe corpora quadrigemina.

Many of the Arabic terms employed byMondino were in common usage until therevival of the Greek language in the 15thand 16th centuries. Mondino's now obso-lete terms included such as mirach for theanterior abdominal wall, siphac for theanterior layer of peritoneum, and zirbus forthe great omentum. In his works Mondinoalso included terms of classical origin thathad been in use through the Dark and earlyMiddle Ages, such as longaon for rectum.For many of these classical words Mondinosupplied false etymologies. He attributescolon, for example, to the medieval Latinword cola (cellule) when, in fact, it was aGreek word meaning primarily an organ,although both Aristotle and Pliny used itin its present meaning.

Fortunately, today we are spared the bat-tle of vocabularies and our anatomical syn-onyms are mercifully few. Specific namesfor specific structures or parts of structureshave become codified and simplified andhave practically universal comprehensionamong students of form, except in thosecountries where nationalism has so affectedtheir language that special words are coinedwith no prior meaning within the countryof use and no applicability beyond its bor-ders. The creation of scientific terms inHindi and in Tagalog, a major source ofthe manufactured language of the Philip-pines, are examples of this trend. In Francea Secretary of State for Francophone affairsand a General Association for the Users ofthe French Language are concerned withthe linguistic purity of the French lan-guage. In the fields of science, commerce,and high technology new French words arecreated to replace terms that are not Frenchin derivation.

If this trend continues we may some daysee a return to the type of warfare wagedin the past on behalf of Latin and Greekagainst Arabic anatomical terms during the16th century. Then words became symbolsof two cultures, the Arabist and theHumanist. As the Humanists were gainingthe upper hand, new experimental anat-omy was being developed and the expo-nents of this new science exhibited the samevirulence against the Humanists as theHumanists had shown against the Arabists.Although the furor over anatomical ter-minology can well be regarded as a tempestin a teapot, there are those who regard itas a sine qua non of anatomy. Historically,however, without the Arabists Western sci-ence would not have been preservedthroughout the Dark Ages. Without theHumanists, 16th century anatomists wouldhave had to start from ground zero, or atleast a much lower level than that at whichthey were able to begin.

Anatomical vocabulary still has not beenfully purged of Arabic terms. Numbers ofthem still exist but so Latinized or Grae-cized as to be hardly recognizable. Singer(1957) considered this a case of protectivemimicry in the world of words. Basilica,cephalica, retina, saphena and sesamoid (theopen sesame of the Ali Baba story) are suchArabic words still extant in our anatomicalvocabulary. To the Arabs we must alsocredit clavicle, true and false ribs, iris, piamater, dura mater, matrix and mesentery.

Tracing the words employed in the studyof form can be an illuminating experienceshowing relationships of Greek, Latin, andArabic vocabularies that have formed thebody of today's anatomical nomenclature.Single, specific words now exist for singlespecific structures. The beginning studentmay perceive this nomenclature as nothingmore than a plethora of detail. But it issimplicity itself when compared to themurky, indefinite applications of vocabu-lary from a variety of" sources applied in aquixotic fashion that characterized earlymorphology. Several names for a singlestructure or worse, a single name for sev-eral structures are no longer the problemsthey were. The present-day problem is notprecision of nomenclature but, rather, theplethora of detailed terminology whose


memorization occasionally passes for com-prehension of anatomical concepts.

It has been estimated that toward theend of the 19th century about 50,000 ana-tomical names were in use for some 5,000structures in the human body. Such avocabulary load retarded the study of anat-omy. But, by 1895, a list of about 4,500terms was accepted at the Basle Confer-ence. This system of nomenclature is knownas the Basle Nomina Anatomica, usuallyabbreviated B.N.A. and is in Latin. Sub-sequent revisions have occurred, with thatundertaken in Britain as the BirminghamRevision or B.R. in 1933 being the bestsource of translations of Latin terms intoEnglish. In Paris, in 1955, internationalagreement was reached on a Latin systemof nomenclature based largely on theB.N.A. This Nomina Anatomica, was sub-sequently amended in New York in 1960and translated into English. The principlesinvolved in the new N.A. are (1) that, withvery few exceptions, each structure shallbe designated by one term only, (2) thatevery term in the official list shall be inLatin with the option that each country isat liberty to translate the official Latin termsinto its own vernacular for teaching pur-poses (an option that has resulted in prob-lems of intercountry communication), (3)that the terms shall be primarily memorysigns with preferably some informative ordescriptive value and (4) that eponyms shallnot be used. This latter principle removesthe use of personal names for structures.They are used quite haphazardly and giveno clue as to the type of structure involved.In addition, they are frequently misleadinghistorically because, in many instances, theperson commemorated was, by no means,the first to describe the structure. Forexample, what was called Wirsung's ductwas referred to by Mondino some 300 yearsbefore Wirsung. If there were persistencein the use of eponyms, red blood corpuscleswould be called Swammerdam cells; thecollecting tubules of the kidney—Bellinitubules, mast cells—Ehrlich cells, and soon.

The question may well be asked con-cerning the amount of vocabulary that theaverage student not destined for medicalschool or for further study of structure

should know. In terms of the skeletal sys-tem, for example, the names of the majorbones of the body would seem appropriateas it makes a difference whether one is talk-ing about a fractured humerus or a frac-tured femur, but it would be difficult torationalize, in dealing with the femur, thata student should also be familiar with suchterms as greater trochanter, lesser tro-chanter and intertrochanteric crest. Simi-larly, location and function of major mus-cle groups might provide both valuable anduseful knowledge to understand how thebody moves in terms of extensors and flex-ors, adductors and abductors. But, hereagain, mindless learning of origin, inser-tion and action of each muscle in the humanbody is such a pedantic exercise that eventhose whose field is myology are sometimescaught referring to reference works torefresh their own memories prior to theday's lecture on muscles.

Centuries have been devoted to descrip-tive morphology, from the time of Neo-lithic observations of gross external andinternal anatomy. Closer and closer obser-vation with magnifying lens and micro-scope revealed more structural detail fromorgans to tissues to cells and intracellularcontent. Each new discovery was worthy ofbeing named. It is understandable in termsof discoveries of structure that the names,themselves, should become an end ratherthan simply a means of communicatinginformation.

Only in the last few decades has therebeen a noticeable deemphasis on vocabu-lary and more emphasis on concept andprinciple. We have come full circle to ask-ing larger, rather than smaller, caliberquestions as Moore (p. 493) has noted wassomething Aristotle did—seek answers tobig questions.

For those of us who have had to gothrough life with a head cluttered with use-less terminology, one wishes this vocabu-lary deemphasis had started earlier. As aprofessional biologist for more than 40years I've never had one occasion in myentire career to use such a term as "adam-bulacral ossicles" (the bumps on the uppersurface of starfish) in any substantive way,although it may have currency among thosewho study echinoderms. Similarly, the only


use I've ever had for protopodite, endopo-dite, and exopodite has been to show offat a lobster dinner at a seafood restaurant.Somehow, Huxley's serial homology andthe differentiation of a simple biramousappendage became lost in a welter of detailthat sometimes included, not only thenames of the three basic parts of the appen-dage, but the names applied to each jointedsegment of each appendage.

Unfortunately, this is not an extreme orunusual example, and it accurately exem-plifies the loss of the forest among the trees.Mercifully, physiology has been sparedmuch of the climate of minutia so commonto morphology due, in part, to its being amore experimental discipline in contrast tothe observational nature which, initially atleast, characterized morphology. In phys-iology an experimental result is the desid-eratum, in contrast to locating and nam-ing a particular line, eminence, duct orpore. Descriptive morphology relied onnames, experimental physiology on results.As Moore (p. 567) has pointed out, formand function developed as contemporaries.Once an organ was identified, questioningbecame focused on its function and its placeamong other organs. Form did not existwithout function nor, obviously, functionwithout form, but both became obscuredby a fog of verbiage.

References to vocabulary: Effler (1935),Field and Harrison (* 1957), Nomina ana-tomica (*1961), Singer (1957), Skinner(*1961), Wain (*1958).

DIVERSITY OF TYPE/UNITY OFPATTERN AS AN ORGANIZING PRINCIPLEOF AN INTRODUCTORY BIOLOGY COURSE

This paper has discussed themes, objec-tives, principles and content recommendedfor inclusion in an introductory biologycourse. Just as the entire course needs majorobjectives that permeate all of its aspects,so subtopics need organizing principles. Forform and function, diversity of type andunity of pattern tie seemingly unrelatedobservations and conclusions together andcan serve as an organizing principle.

In organizing a presentation of form andfunction there are many pathways that canbe followed. However, there appear to be

basic elements that should be common toall. The following pages present types ofcoverage that emphasize basic ideas andserve to tie seemingly unrelated data intoa meaningful whole. By no means are theseto be taken as a course outline. They areto serve merely as examples of how formand function topics can be made moremeaningful to an introductory student bygrouping data into related clusters undera unifying concept.

Prokaryotes I eukaryotesThe primary organismic dichotomy,

prokaryotes vs. eukaryotes (Fig. 1), is basedon observation of structure and function.Both in structure and in biochemistryeukaryotes and prokaryotes differ by farmore than the presence or absence of amembrane bounded nucleus. Table 4, fromMargulis and Schwartz (1982), presents thestructural and functional features of thisdivision which has been characterized byStanier et al. (1963) as "this basic diver-gence in cellular structure which separatesthe bacteria and the blue green algae fromall other cellular organisms, probably rep-resents the greatest single evolutionary dis-continuity to be found in the present dayworld." Although the division was pro-posed in 1937 by Edouard Chatton, aFrench marine biologist, this dichotomy hasyet to find its way into some introductorybiology programs. There are still some forwhom the primary division of organisms isinto plants and animals as when one playedthe game Animal, Vegetable or Mineral,in which all the planet's objects could becategorized under one of these three head-ings. The Margulis (1982) use of five king-doms is today scarcely enough. Margulisrecognized only a single kingdom of pro-karyotes, the Monera, with the other fourkingdoms (the Protoctista, Fungi, Plantsand Animals) comprising the eukaryotekingdoms. Current researches willundoubtedly lead to the creation of otherkingdoms. Current researches will un-doubtedly lead to the creation of otherterms much in the same fashion as the king-doms of eukaryotes are defined. Such tax-onomy exemplifies diversity of type andunity of pattern at a basic level and uses


MitochondriaGolgi body

Plastid/ Jhylakoids

/ — i

Noncellulosiccell wall

Cell membrane !f*',"; >•

Nucleoid-

Small ribosomes^

Flagellum- Chromatin^

Kinelosome

Plastidinner membrane

Plastidouter membrane

Nucleus

Nucleolus

Nuclear membrane

Cell membrane

Cell wallKmetochores (cellulose or chitin)

Undulipodium

Cell membrane

PROKARYOTE

EUKARYOTE

FIG. 1. The primary dichotomy of living organisms is represented by their division into prokaryotes (left)and eukaryotes (right). These cell drawings are based on electron microscopy. Every prokaryotic or eukaryoticcell does not display all the features shown here. Unity of pattern and diversity of type is represented at thecellular level in this very early separation of organisms based on cell type. (Margulis, 1982, p. 9.)

knowledge of both form and function toaccount for organismic similarities and dif-ferences.

The cell

Basic structure and function permeatebiology. Every student should understandVirchow's doctrine that cells come frompreexisting cells. The cell theory of Schlei-den and Schwann provides a diversity oftype pervading the organic world. Tounderstand a cell is to understand anorganism and to understand a single cell isto understand trillions of cells. The celltheory is basic to biology and practicallyall biological phenomena can be elucidated

from a single cell. Just as Huxley used thecrayfish as a model animal, one can use thecell to illustrate biological principles.

If one considers the cell as a basic unitof structure and function and as an exam-ple of diversity of type (Fig. 2), one mustalso consider unity of pattern exemplifiedat the cellular level. If there is such a thingas a standard cell, its ability to exist in amyriad of forms and to specialize for allliving functions demonstrates the plasticityof living material. Too frequently studentsthink in terms of fixity of form and func-tion and ascribe an unchanging structureto an epithelial or to a muscle cell, forexample. The ability to clone an entireorganism from one of these "fixed" epi-


TABLE 4. Major differences between prokaryotes and eukaryotes (Margulis, 1982, p. 7).

Prokaryotes Eukaryotes

Mostly small cells (1-10 /mi). All are microbes.

DNA in nucleoid, not membrane-bounded. Nochromosomes.

Cell division direct, mostly by binary fission. Nocentrioles, mitotic spindle, or microtubules.

Sexual systems rare; when sex does take place,genetic material is transferred from donor torecipient.

Multicellular forms rare. No tissue development.

Many strict anaerobes (which are killed by oxy-gen), facultatively anaerobic, microaerophilic,and aerobic forms.

Enormous variations in the metabolic patterns ofthe group as a whole.

Mitochondria absent; enzymes for oxidation oforganic molecules bound to cell membranes (notpackaged separately).

Simple bacterial Hagella, composed of flagellinprotein.

In photosynthetic species, enzymes for photosyn-thesis are bound as chromatophores to cellmembrane, not packaged separately. Variouspatterns of anaerobic and aerobic photosynthe-sis, including the formation of end productssuch as sulfur, sulfate and oxygen.

Mostly large cells (10-100 jim). Some are microbes;most are large organisms.

Membrane-bounded nucleus containing chromo-somes made of DNA, RNA, and proteins.

Cell division by various forms of mitosis; mitoticspindles (or at least some arrangement of microtu-bules).

Sexual systems common; equal participation of bothpartners (male and female) in fertilization. Alter-nation of diploid and haploid forms by meiosis andfertilization.

Multicellular organisms show extensive developmentof tissues.

Almost all are aerobic (they need oxygen to live);exceptions are clearly secondary modifications.

Same metabolic patterns of oxidation within thegroup (Embden-Meyerhof glucose metabolism,Krebs-cycle oxidations, cytochrome electron trans-port chains).

Enzymes for oxidation of 3-carbon organic acids arepackaged within mitochondria.

Complex 9 + 2 undulipodia composed of tubulinand many other proteins.

In photosynthetic species, enzymes for photosynthe-sis are packaged in membrane-bounded plastids.All photosynthetic species have oxygen-eliminatingphotosynthesis.

thelial cells, however, adequately demon-strates their potential. The plasticity of cellsis reflected in entire organisms. For a stu-dent to be able to watch an aquatic, gilled,legless herbivore turn into a terrestrial,lung breathing, four legged carnivore ashappens when a tadpole turns into a frog,provides a simulated window throughwhich one can observe changes in form andfunction as a characteristic of the livingworld.

References to the cell: The field of cel-lular biology is advancing so rapidly thatany book over one year old is out-of-datein terms of recent advances. While stan-dard texts cover the basic cell adequately,only journals can keep up with day-to-dayadvances. Among the journals covering thevarious cell studies are:

Cell (biweekly)—Cell Editorial Offices, 50Church St.', Cambridge, MA 02138.

Cell Biology International Reports—Aca-demic Press (London) Ltd., High Street,Foots Cray, Sidcup, Kent DA 145HP,England.

Cell Differentiation—Elsevier ScientificPublishers Ireland Ltd., P.O. Box 85,Limerick, Ireland.

Cell Structure and Function—dist. byElsevier Scientific Publishers, P.O. Box211, 1000AE, Amsterdam, The Neth-erlands.

Cell and Tissue Kinetics (bimonthly)—Blackwell Publications Ltd., Osney Mead,Oxford OX2 0EL, England.

Cell and Tissue Research—Springer-Ver-lag, 44 Hartz Way, Secaucus, NJ 07094.

Analogy I homology

The concept of analogy and homologyis pervasive in the study of form. Thebeginning biology student is, by and large,


Animal cell Plant cell

Cell wallCell membrane

Centrosomewith centriole

NucleusNucleoliNuclearmembraneGolgi bodiesMitochondria

VacuoleChloroplasts

FIG. 2. Eukaryotic cells demonstrate a unity of pattern by means of the many structures they hold in common,but among cells, diversity of type is demonstrable. In the above illustration plant cells display cell walls, acentral vacuole, and chloroplasts not seen in the animal cell. In contrast, the animal cell has a centriole in itscentrosome, neither of which appears in the plant cell. Beyond these simple diagrams one develops diversityof type during examination of specialized cells such as those of striated muscle and neurons. (BSCS, 1963, p.58.)

incapable of differentiating between struc-tures that have a superficial resemblanceand those displaying more meaningfulrelationships. In this view of the world, afish and a porpoise appear far more closelyrelated than a porpoise and a buffalo. Legsare legs. The leg of an insect and that ofa cat are locomotor appendages that canbe seen to perform the same function forboth organisms. Butterflies, bats and birdsall have wings and, here again, in the stu-dent mind, there must be some relation-ship among them. It is an interestingassignment to have students pursue theselines of thought. Have them list all theorganisms with wings that they can and listall those with legs but without wings on aseparate sheet. Other than wings or legs,what do these organisms have in common?Do they form natural groups or do theyonly possess one prominent characteristicin common?

From such an assignment concepts ofhomology and analogy can be developed.It becomes readily apparent, for example,

that bird wings and insect wings have littlestructural commonality. The support sys-tem of both is different. They are moveddifferently. A chicken wing, for example,demonstrates some intrinsic musculature.The musculature of a butterfly wing is basi-cally extrinsic. One is covered by feathers,the other by scales. Continuing these com-parisons results in a conclusion that this isa relationship of function but not of struc-ture. Similarly, an analysis of an insect legand a vertebrate one leads to the same con-clusion. Exoskeleton versus endoskeletonand muscular placement in relationship toparts of the body are differences that showvariations in structure even though thelocomotor function is common to both.

The student can be led to an under-standing of functional similarities—anunderstanding that selection has operatedseveral times to produce legs or wingsdesigned for the function of walking orflying—which have come superficially toresemble one another simply because oftheir selection for a similar function.


FIG. 3. Unity of pattern is indicated through this series of forelimbs of seven vertebrates. From left to right,frog, whale, horse, lion, man, bat and bird. Despite differences of function, each limb has the same basicskeletal structure. The diversity of type arises through the differences in proportion of the skeletal elementsin each. Forelimbs, compared to hindlimbs of the same vertebrates, show a serial homology in which the samebasic skeletal elements are displayed. (BSCS, 1963, p. 363.)

Among invertebrates, insects display avariety of wing types. Among vertebrates,fossil reptiles, birds and mammals dem-onstrate flight by means of wings that havemore in common with one another thanthey do with the wings of insects. The prin-ciple of analogy involves superficial struc-tural similarities in organs performing asimilar function. A student who might havebegun thinking that a wing is a wing or aleg a leg wherever it is found, begins to seehow natural selection operates to result inthe provision of legs as prime terrestriallocomotor organs or wings as a basis forflight through structures that are func-tionally but not structurally similar.

It is unlikely that students will select wingsof bats, birds and extinct reptiles as beingclosely related in terms of their structure.When presented with a panoply of verte-brate appendages including the flipper ofa whale, the leg of a horse, a wing of a bat,and a human arm (Fig. 3), students are, atfirst, normally incapable of delineating anybasic relationships among them. However,closer examination of skeletal elementsleads to an appreciation of a basic patternof resemblance. Students see the same 1:2pattern in all of the vertebrate limbs theyexamine. The basic proximal element maybe elongated, as in the horse, or com-pacted, as in the whale, but nonetheless, itis a single element varying primarily in pro-

portion. This is followed by two distal ele-ments, again of varying size but, nonethe-less, readily apparent. Further distallycomparable bones may be absent orreduced, compacted, as in the whale flip-per, or greatly elongated, as in the bat wing.There is, therefore, a basic endoskeletalresemblance in which numbers resultingfrom fusions and deletions may change aswell as proportions, but in which there isa basic structural similarity. This basicstructural similarity, coupled with com-mon embryological origin and similar rela-tionship to the parts of the body, as theforelimbs of all vertebrates demonstrate bytheir relationship to the pectoral girdle,constitutes homology which has been usedas an indicator of relationship. It is thestudy of these homologues that is a centralprinciple within comparative anatomy. Thebasic patterns demonstrated by homo-logues illustrate that structures of similarorigin may be radically modified to per-form special functions. Huxley demon-strated this with the crayfish, showing themodifications possible to a simple, singlebiramous appendage. The existence ofserial homology, resemblance amongappendages on adjacent segments, showson one organism what takes many to dem-onstrate using different classes and orders.

A study of homologous structures leadsto the conclusion that evolution is a con-


servative process modifying what alreadyexists by changing proportions and posi-tions of previously existing elements in aprocess of adaptation to a new function.Structures that are greatly reduced areconsidered vestigial as are the "splintbones" of the leg of the horse. Others havebeen selected to perform different func-tions than those originally undertaken. Themodification of salivary glands into poisonglands in some reptiles, the reorganizationand migration of elements of the jaw toform bones of the middle ear, the trans-formation of sweat glands into milk glands,and the complex relocation of functions ofthe blood vessels in the transition from gillsto lungs are examples of such selection.Thus, basic structural plans demonstratean adaptability that allows them to be mod-ified by a process of selection to performfunctions as diverse as swimming or flying,mastication or hearing. The concept ofhomology and analogy is a basic principlefor a comprehension of form and functionas altered by adaptation.

Convergence

Study of homologous structures leads oneto begin with a diversity of type and extendit though unity of pattern as organismsbecome specialized to life in air or wateror land. The tendency is to emphasize thisdivergence but not that the processes ofadaptation result in many instances of con-vergence, in which diversities are reduced.The structural and functional parallelismbetween families of marsupials and ordersof placentals well demonstrates this con-vergence. Students need understand thatthe past history of an organism both deter-mines and limits its future directions ofstructural and functional change. Histori-cal analysis of form is based on the assump-tion that organisms possess features capa-ble of being ordered into nested sets (acladogram or phylogenetic tree), and thatthis pattern reflects a historical process ofdescent with modification (Fig. 4).

Dollo's Law

Correlated with this assumption is thestatement that evolution is irreversible, as

encapsulated in Dollo's Law which hasbecome, unfortunately, misunderstood.When we derive from Dollo's Law eitherthe inevitability of progress or a violationof the Second Law of Thermodynamics wehave derived nonsense. Dollo's Law is pri-marily a statement about the statisticalimprobability of following an identical evo-lutionary pathway again in either direc-tion. While it is easy to understand thereversal of a single mutation, difficultiesare multiplied for larger numbers of muta-tions, and probabilities become increas-ingly unlikely for exact repetition of a givenevolutionary pathway as the number ofgenes in a sequence becomes larger. Whalesmay again return to land, but not by revers-ing the gene path that led them into thesea in the first place. Their form and func-tion might still be demonstrating unity ofpattern, but the diversity of type will followa different path than that initially takenfrom land to sea.

The comparative approach

Morphology presented through thestructure of a single organism, even whileconcentrating on it as an example of unityof pattern, does not well explicate diversityof type. The study of human anatomy, forexample, concerned primarily with thedetailed structure of one organism, mayoffer only a casual sentence or two con-cerning the derivation of a structure or itscomparison with similar structures in otherorganisms. The malleus, incus, and stapesof the middle ear are frequently consid-ered as if they were de novo mammalianstructures without reference to their der-ivation from jaw bones of lower forms(SAAWOK—I, pp. 32-33). To under-stand diversity of type and unity of patterna comparative approach is necessary.

The tendency to select a type organismexemplifying the characteristics of a phy-lum (hydra, starfish, planarian, clam, cray-fish, etc.) tends to emphasize unity, wheneach organism is considered in isolation,and to ignore diversity. In order that unityof pattern and diversity of type can beincorporated to further an understandingof form and function, animals need be stud-ied as related both in structure and func-


I c_

FIG. 4. In order to test hypotheses about the trans-formation of design, nested sets of similarities (A) areordered into the most parsimonious cladogram (B).Congruent characters c and d are recognized as hom-ologues for the taxa they define, "b" is the incon-gruent character and represents a convergence. (C)represents a corroborated cladogram, that is ahypothesis of the phylogenetic relationships of taxaA and D. HT represents transformational hypotheses,HR relational hypotheses involving correlationsbetween aspects of the primitive network (Z) and mor-phological diversity. (Hildebrand et al., 1985, p. 371.)

tion. To speak of chordates, for example,without emphasis on the three character-istics that they have in common (Fig. 5), isto fail to appreciate the unifying structuresthat relate the members of this phylum(SAAWOK—I, p. 36). While the noto-chord may be a prominent part of theexposition of the structure of amphioxus,there is doubt that it is homologous to thenotochords of vertebrates. Morphologicalstudies of the cat or human may make nomention of the notochord unless embryo-logical development is included, at whichtime its relation to the vertebral columnmay be pointed out. But all chordates havea notochord. Even if only fragments mayremain in the adult, it nonetheless formsan embryological focus for vertebral col-umn development.

The significance of the presence of adorsal hollow nerve cord is lost if one stud-ies only human anatomy. Because of theupright human posture and a bipedalstance, the dorsal position of the nerve cordis obscured, and so many other features of

the nervous system need be covered thatits location as an example of unity of pat-tern is frequently ignored.

The pharyngeal breathing device (gillsor lungs) characteristic of chordates is oftenmisinterpreted. There is ample evidencethat this region performs no respiratoryfunction in protochordates where its pur-pose is filter feeding. Properly gills arefound only in vertebrates. Frequently it isstated that presence of gill "slits" sometimein the individual's life history is a chordatecharacteristic. While pharyngeal pouchesor furrows do appear in embryonic devel-opment, in birds and mammals they arequite rudimentary, existing only tempo-rarily and normally not perforating to forman actual slit. The presence of a notochord,dorsal hollow nerve cord, and pharyngealbreathing device is a unifying conceptdescribing a chordate pattern. The modi-fications of these structures provide ampleevidence of diversity of type. To emphasizeone without the other is to conceal a basicconceptual pattern that should ratherreveal relationships and adaptations. Thisunity of pattern and diversity of type isrevealed only through employing a com-parative approach to form and function.

Aortic arches

Structure sometimes seems unduly com-plex and inefficient as in the complex tan-gle of veins and arteries immediately enter-ing or leaving the heart. To explain to astudent what is there does not clarify whythe vessel pattern is as observed. The evo-lution of the aortic arches shows unity ofpattern and diversity of type from theprimitive condition of six aortic archesthrough a successive series of losses in ananterior-posterior gradient to mammals(Fig. 6). The first aortic arch is missing infish. In urodeles, the first and second archesare not present, the fifth is variable. Inreptiles, the fourth aortic arch is symetri-cal. In birds, it persists on the right sideonly and in mammals it persists on the leftside only. SAAWOK—I (pp. 33-35) illu-minates these relationships in more detail.The aortic arches illustrate that a compar-ative approach shows evolution as a basi-cally conservative process, saving from thepast what can be used in the present and


B | EndostyleBrain" vesicle

Gill basket

cNerve ganglion J.

Neural gland —fr/--

FIG. 5. The free swimming larva (A) of a solitary tunicate displays the notochord, the dorsal hollow nervecord, and the pharyngeal breathing device characteristic of all chordates. The plasticity of living tissue isillustrated in the metamorphosis of this free swimming larva, which attaches itself to a substrate (B) afterwhich the tail degenerates and most "somatic" structures, except for a notochord remnant, also disappear.In this methamorphosed form (C) the student seldom recognizes that a tunicate is an animal, let alone thatit is a chordate. The connection between tunicate and vertebrate through the larva's possession of the threebasic chordate characteristics illustrates unity of pattern. The adult demonstrates diversity of type. (Romer,1962, p. 19.)

modifying a pattern initially designed tosupply venous blood to gills. The vesselpattern in an adult mammal is made expli-cable through knowing the vessel patternin a fish. Presented as independent systemsthey seem so at variance, one from another,that no unity of pattern is even looked for.Once a pathway of relationship is shown,however, there is created a unifying pat-tern to the arterial circulation amongorganisms as diverse as fish, reptiles, and

mammals. The aortic arches constitute abasic unity of pattern capable of beingmodified into a diversity of types.

It is not lost on students that the appear-ance of the subclavian and iliac arteries iscorrelated with the appearance of pairedfins. They remain the limb supply throughthe tetrapod series up to, and including,man whose arms and legs are supplied withblood through subclavian and iliac vessels.Puimonary arteries make their debut in


FIG. 6. Unity of pattern and diversity of type, as illustrated by aortic arches and their derived vessels, viewedlaterally. A, hypothetical ancestor of jawed vertebrates with six unspecialized aortic arches; B, the typical fishcondition illustrated by the shark; C, Protoplerus, the lung fish; D, a teleost; E, terrestrial salamander; F, lizard;G, bird; H, mammal. The aortic arches are numbered in Roman numerals, the gill slits in Arabic numerals.s, spiracle, cd, carotid duct, da, ductus arteriosus. ec, external carotid artery, ic, internal carotid artery. L,lung. Diversity of type is illustrated by the carotid duct shown in the lizard, which is absent in other reptiles.In turtles, the carotids arise from a separate stem directly from the heart. In the mammal, the embryonicarterial duct, that bypasses the lung, is shown by a broken line. The essentially conservative nature of theevolutionary process is well illustrated by both the ontogeny and phylogeny of the aortic arches. (Romer,1962, p. 427.)

recent animals in the Dipnoi as branchesof the sixth pair of aortic arches. They sup-ply the new lungs emerging from air blad-ders. This connection of the pulmonaryarteries with lungs persists throughout thevertebrate series.

The presence of five pharyngeal pouchesand six visceral arches alternating withthem in humans reinforces unity of patternand diversity of type that finds its only rea-sonable explanation in evolutionary the-ory. From the pharyngeal region of fish,skeletal elements have been converted intoear bones, attachment for the tongue and

support for the larynx. Three of the aorticarches persist and the pharyngeal deriva-tives of the gill pouches include such endo-crine glands as the thyroid, parathyroid,thymus and the ultimobranchial bodies(Fig. 7). From the second pair of pharyn-geal pouches come the palatine tonsils, anexample of diversity of type most childrenwould prefer not to have to contend with.

The eyeThe eye is frequently cited as an organ

so complex that the mind boggles whenasked to accept that evolutionary processes


FIG. 7. The gill pouches of the left side of the phar-ynx in A, shark; B, urodele; C, lizard; D, mammal;s = spiracle, the remaining pouches are numbered.The broken outline indicates variable thymus deriv-atives; vertical hatching, the thymus; horizontalhatching, the parathyroid; the solid black, the ulti-mobrachial body. Again, unity of pattern and diver-sity of type are exemplified, together with the con-servative nature of evolution and the plasticity of livingtissue. (Romer, 1962, p. 339.)

have led to its present state. By discreditingthe ability of complex structures to arisethrough evolution, anti-evolutionists feelthat they are strengthening their case fora designer. The 18th century theologianWilliam Paley first published his NaturalTheology—or Evidences of the Existence andAttributes of the Deity Collected From theAppearances of Nature in 1802. It is a classicexposition of the argument from design.In it, Paley compares the eye with a tele-scope and concludes that the eye must havehad a designer just as had the telescope. Ifone were to assume that the eye appearedthrough natural causes de novo, Paley mighthave a point or even if it developed througha series of smaller steps by random pro-cesses. However, the de novo eye from nat-ural causes would be as unsubstantiated asis the concept that the eye was created denovo by supernatural ones.

One hundred eighty years later, how-ever, Paley's argument appears in the Neckof the Giraffe (Hitching, 1982). Except thathis book has received a degree of credi-bility by being published and distributedby a reputable publishing firm, Hitching'sthesis is on a par with that in religious tractsof the anti-evolutionists. Hitching makesthe error so frequently made by propo-nents of design when he says "The eyeeither functions as a whole, or not at all.So how did it come to evolve by slow, steady,

infinitesimally small Darwinian improve-ments?" To amplify his case, Hitching givesas examples that if the cornea is fuzzy (sic),or the pupil fails to dilate, or the lensbecomes opaque, or the focusing goeswrong, then a recognizable image is notformed and, therefore, the eye is useless.It is obvious that a fuzzy image is betterthan no image at all. An image that is toodim, or clouded, or not properly focused,nonetheless, conveys to its possessor anadvantage over an organism incapable ofperceiving light. Further, Hitching asks"What survival value can there be in aneye that doesn't see?" In the country of theblind, the one-eyed man is king and, amongorganisms that lack any visual perception,so is an organism that has the ability todistinguish light from dark, or movement,or the fuzzy outlines of a predator. Suchan eye, while admittedly not perfect, offersdecided survival value.

Hitching makes a case for visual perfec-tion, but almost 50% of the Europeanhuman population wears glasses or contactlenses. When they are removed, a recog-nizable image may not form. About one intwelve males is color blind, others areastigmatic. No one with these various visualimperfections would agree that the eyefunctions either in a state of complete per-fection or not at all. Further, the rationalefor the all-or-none eye seems to be basedon the forging of an absolutely randomchain of events, each step apparently start-ing from ground zero. Instead, evolutionis a sequence of gradual step by stepchanges, each one building on the onebefore. Any change that improves survivalchances is quite likely to be beneficial. Thus,an animal with an eye spot capable of dis-tinguishing between light and dark has anadvantage over one that does not possessthat ability.

In protists, and throughout the animalkingdom, one finds that sensitivity to lightis widespread. An ameba, for example, willnot enter strong light. Sea anemones reactto light although they have no specializedphotoreceptors. All phototropic flagellateshave a red pigment spot like that of euglena.In multicellular animals, only those cellsrespond to light which contain some suchpigment as visual purple capable of being


FIG. 8. Median sections through the eyes of a vertebrate and a cuttlefish. In many basics the two eyesresemble one another. However, the retina of the vertebrate eye is inverted, while that of the cuttlefish hasthe light sensitive cells facing the lens. Light sensitive organs are found throughout the animal kingdom butthis parallelism between an invertebrate and vertebrate eye is unique. (Neal and Rand, 1936, p. 581.)

altered by light. The eye spots of coelen-terates are pigment cells which respond tochanges in light intensity. Many medusaehave light sensitive cells on the margin ofthe umbrella and the jellyfish Nausithoe hasa lens associated with each of its pigmentspots. The pigment spots of many flat-worms are light sensitive and, in somespecies, clusters of pigmented cells sur-round terminations of sensory nerves.

Even if we regard true vision as limitedto animals in which photoreceptors areaggregated into eyes capable of formingan image on a retina, one still sees the for-mation of eyes independently in a varietyof organisms. Some free swimming anne-lids have "beaker" eyes, so named fromtheir shape, with spherical lenses and a layerof retinal cells connected by nerve fiberswith the brain. In some, the beaker-likeeyes are associated with the epidermis. Inothers, the eye sinks below the skin level.Nereis worms have a liquid-filled cavityaround which photoreceptors are arrangedto form a vesicular eye. In mollusks, thereare sometimes beaker eyes, sometimesvesicular eyes with a lens. On the edge ofthe mantle of the pecten are found com-plex vesicular eyes, each partly surroundedby a layer of opaque pigmented epitheliumwhich, in front of the eye, becomes a trans-lucent cornea. Beneath the cornea andadherent to it is a biconvex lens. The eyeof pecten has a retina consisting of twolayers of photoreceptors, each connectedwith a nerve fiber, and the retina is backedwith an inner layer of pigmented epithe-

lium. Other mollusks have eyes that aresimilar to those of vertebrates, particularlySepia and Loligo. If anything, the cephalo-pod eye represents an advancement overthat of humans as the retina is not inverted,as in vertebrates, but rather the light sen-sitive cells face toward the source of light(Fig. 8).

In chordates the retina is derived fromthe ependymal layer of the neurocoel.Ependymal cells are light sensitive in allchordates from amphioxus to mammals,providing a unity of function within a vari-ety of morphological settings. The pairedeyes of all vertebrates are essentially sim-ilar. Unity of pattern with little diversityof type. The cyclostome eye and that of amammal, except for size, are basically thesame. The human eye serves as a modelfor all vertebrate eyes. It is not fair to saythat there exists a graded series of lightsensitive structures from ameba to man,nor is the claim made for eye spots ofeuglena and those of planaria being phy-letic precursors of the human eye. How-ever, perception of light is a common char-acteristic of living matter and the varietyof light sensitive cells and the functionsthey perform show a wide diversity of type.What unity there may be is functionalrather than morphological. The ability ofan ameba to detect light gives it an advan-tage. The ability of the human eye to forman image gives it a far greater advantage.But between these two extremes are a vari-ety of light sensitive structures which, whilethey do not form an integrated phyletic


sequence, nonetheless serve to illustrate aunity of function if not of structure.

Integumentary system

Practically every organ and system hasphylogenetic antecedents that illuminateits structure and function. Perhaps one ofthe most neglected in the classroom is theintegumentary system. The integumentprovides many examples of unity of pat-tern and diversity of type. Its position allowsit to be observed closely without dissectionand on intact, live organisms. Just as onecan trace light sensitivity throughoutorganisms from protists to vertebrates, acovering, separating cytoplasm from theenvironment, exists in unicellular organ-isms. A multicellular covering appears insponges and coelenterates, the latter exem-plified by the ectodermal layer of the hydra.Even in such a simple epithelium there issome differentiation. One can see the epi-thelial covering cells among which aregland cells and some of these, in turn,secrete lime salts. Among other inverte-brates the epidermis may be ciliated andthe cells also may be involved in secretingan external cuticle. From a simple epithe-lium to a stratified one, so characteristic ofterrestrial organisms, the difference seemsto be a change in direction of cleavageplanes during cell multiplication.

There are gland cells in a simple epi-dermis, but in mammals we find a greatvariety of integumentary glands—sweatglands, sebaceous glands, the lacrimalglands of the eye, the meibomian glandsof the eyelids, the wax glands of the audi-tory meatus, and a variety of others includ-ing preputial, vaginal, anal and mammaryglands. The luminous organs or photo-phores of some deep sea fishes are alsoglandular derivatives complete with con-densing lens and a reflecting membrane.Their light is produced by the oxidationof luciferin secreted by the gland with nocarbonic acid and little heat evolved in theprocess.

The presence of finger prints on thepalms and soles of all primates are readilyobservable and well known as sources ofidentification. The function of these fric-tion ridges is supposedly adhesion—to pro-

vide a surface less likely to slip. From theepidermis also are derived the horny scalesor scutes of reptiles which are not homol-ogous with the bony dermal scales of fishes(Fig. 9). It should be noted that epidermalderivatives are a product of reciprocalinduction. The dermal papilla is a neces-sary adjunct to structures originating fromepidermal cells. Scales persist on the legsof birds and the legs and tails of a varietyof mammals such as rodents, insectivores,and marsupials. The Old World pangolinis a mammal that has redeveloped a com-plete body covering of large horny scales.Bills or beaks are also epidermal structurespresent in those amniotes in which teethare reduced or absent. The skin on the jawmargins cornifies to form bills or beaks inbirds as well as in turtles and a few mam-mals such as the monotremes.

Hoofs, nails and claws are other exam-ples of the diversity of type of keratinizedepidermal structures (Fig. 10). They tip thedigits of amniotes. Horns and horn-likestructures are widespread in distribution,particularly among mammals, but manyhorn-like structures, such as the antlers ofdeer, are not homologous to the keratincovered bony cores of cattle so that theseare functional analogues rather than struc-tures with a unity of pattern. An investi-gation of the so-called "horns" of mam-mals shows a wide variety of structures andpatterns of shedding from the prong buck,which sheds the horny sheath covering itsbony core, to the giraffe whose "horns"are simply bony ossicles permanently cov-ered by skin and hair, or the horn of therhinoceros, which is but a fused mass oflong, modified hairs. The feathers of birdsare homologues of epidermal, reptilianscales with a mesodermal component seenduring development. Hair is purely epi-dermal, however. Hairs are not modifica-tions of horny scales and hairs can be con-sidered a mammalian analogue to the avianfeather because of their service as an insu-lating device. In mammals with scales, fre-quently hairs are found growing betweenthe scales, indicative of the fact that one isnot derivative of the other. Integumentarychromatophores account for the variedcolors and patterns of animals and play an


STRATUM CCRMIMkTIVUM

A. EVOLUTION OF PLACOID

SCALE

B. EVOU/TION OF HORNYSCALE

C. EVOLUTION OfFEATHER

EVOLUTION OFHAIR

FIG. 9. Hypothetical stages in the phylogenesis of integumentary appendages of vertebrates derived froman undifferentiated epidermis. Unity of type of the placoid scale (A); epidermal (horny) scale (B); feather (C);and hair (D) illustrate the relationships of structures whose functions vary from protection to thermoregulation.(Neal and Rand, 1936, p. 177.)

important role in camouflage, warning,mating and attraction. The color of hairand feathers are mainly responsible forsurface coloration in birds and most mam-mals but in lower vertebrates it is the chro-matophores that give the skin its specialcolor.

The wide variety of dermal and epider-mal integumentary derivatives providesample evidence for unity of pattern anddiversity of type within the integumentarysystem. In addition, the integument mayplay an active physiological role by absorp-tion or elimination of materials throughmoist skin membranes or glandular struc-tures. The integument functions forbreathing in many forms and may also serveas an accessory excretory organ. Embryo-logically, the nervous system still arises inconjunction with the ectoderm and the skinretains abundant sensory structures,although the vertebrate nervous tissueshave primarily withdrawn from the sur-face.

Too little attention has been given theintegumentary system in studies of formand function. It offers a wide variety of

adaptive structures and performs a multi-tude of functions. Both its structure andfunction are readily observable. It servesto demonstrate unity of pattern and diver-sity of type and offers both homologousand analogous structures for study.

The digestive system

Unity of pattern and diversity of type isclearly delineated in the study of the diges-tive system. First, one may divide the func-tions of the gut as (1) transportation, (2)physical treatment, (3) chemical treatment,and (4) absorption. In organisms above theflatworm level the gut is essentially a hol-low tube from mouth to anus. Food ismoved along by the muscular contractionsof peristalsis which, in turn, may be affectedby the autonomic nervous system or byhormones even though the gut musclesoperate independently of central controlthrough being stimulated by the contrac-tion of adjacent fibers or through a localnerve net.

Physical treatment. Some animals reducethe size of food taken in through the mouth


FIG. 10. Epidermal derivatives. (A) nail; (B) claw; (C) hoof; e, unmodified epidermis; u, unguis; s, subunguis.Claws first appear in urodele amphibia and are found in reptiles, birds and mammals. In mammals claws andnails form an integrated series. Hoofs develop on those mammals that run on their toes but the hoof constitutesmerely an enlarged and modified claw. In attempting to divide mammals as to whether they are hoofed orclawed, one encounters Hyrax, which has both. (Neal and Rand, 1936, p. 172.)

by chewing it into smaller and smallerpieces. Examining the structures for thispurpose, the teeth, gives the ability to thebiologist who understands Cuvier's dictumof correlation of parts to appear like Sher-lock Holmes deducing from meager evi-dences. From a single fossil tooth, forexample, the food preferences of an organ-ism can be deduced and from this, in turn,the type of digestive system, feet, habitat,and behavioral pattern can be correlatedwith that of a prototype herbivore. Here,unity is brought into play due to the basicpatterns held in common by all herbivores.Physical breakdown of food increases thesurface to volume ratio and thus facilitatessubsequent chemical breakdown. In organ-isms without the ability to comminute foodin the oral cavity, organs such as the giz-zard of birds serve as an alternative to mas-tication. Ingested pebbles serve within thegizzard to facilitate the breaking of foodparticles into smaller and smaller bits.

Chemical treatment. Water, vitamins, andnecessary salts are readily absorbed throughthe gut wall. Larger molecules such as poly-saccharids, fat and proteins require chem-ical breakdown facilitated by digestiveenzymes and accessory secretions thatreduce organic materials to molecules thatcan pass through the cells lining the intes-tine and enter the circulation.

Absorption. Absorption is a function oftime and surface. While in amphioxus andcyclostomes the post-pharyngeal gut is pri-marily a single tube, most vertebrates havea demarcation between the stomach and

intestine in the form of the pylorus (Fig.11). In those fish in which the pylorus ispoorly marked, the bile duct from the liveraids in establishing a line of demarcation.A stomach is absent in amphioxus, cyclo-stomes and in certain elasmobranchs andteleosts. When present, the stomach servesas a place for storage of food and for itsphysical treatment as well as its initialchemical treatment, particularly of pro-tein. The absence of a stomach is explic-able in the so-called "food strainers" inwhich food particles are small and col-lected more or less continuously. They canbe passed directly to the intestine withoutthe necessity of either storage or prelimi-nary treatment. This differs from the sit-uation in a shark, for example, in whichfood intake is only periodic, at which timea large quantity may be taken in so thatstorage is a necessity until the food can bepassed to the intestine. The stomach variesgreatly in shape and size among animalsand dissection rarely reveals its actual shapeafter preservation. Incidentally, it needs tobe noted that while students are perfectlywilling to accept external variation in aspecies from their own observations, theyare frequently incapable of recognizing thatsimilar variations occur internally. Thenumber of times that a laboratory dissec-tion elicits from students that something is"wrong" with their frog or shark becauseit does not match the pictures and direc-tions in the laboratory manual, confirmsthat diversity of type as a biological concepthas not been internalized. The variety of


Nosol opting EsoOwjus StomxnRectal glond

Perca

FIG. 11. Digestive tracts of A, lamprey; B, shark; C, chimaera; D, lung fish; E, sturgeon; and F, perch showingdiversity of type within unity of pattern. The digestive tract of the lamprey is essentially a straight and onlyslightly differentiated tube. The spiral valve of the shark greatly increases absorptive surface and a spiralvalve is found in the chimaera, lung fish and sturgeon. In the perch, the spiral valve is absent and compensatedfor by increased intestinal length. The absence of a stomach in chimaera and lung fish is made possible bythe feeding habits of both, wherein the food is cut into bits before swallowing, making the need for a stomachas storage area less necessary. (Romer, 1962, p. 347.)

stomachs from non-existent to the special-ization of that of the ruminants illustratesunity of pattern and diversity of type whilerecognizing that the function remainsessentially the same regardless of struc-tural adaptation (Fig. 12).

The intestine functions chiefly for ab-sorption which, in turn, is a function ofsurface area and time. The spiral valve inthe intestine of a shark increases surfaceand slows passage to maximize absorptivecapacity and makes meaningless the terms

"small" and "large" intestine as applied tomammals and, particularly, to man. Thelong intestine of herbivores can be con-trasted to the relatively short intestine ofcarnivores. The large functional caecum insuch a form as the guinea pig is in contrastto the reduced caecum in such a form asthe cat. Accessory organs such as liver andpancreas also vary but functionally they aresimilar in organisms in which they appear.

One may approach the presentation ofthe digestive system in terms of its function


and show the various patterns designed tofacilitate the treatment and absorption ofthe molecules necessary for continuedmetabolism. An alternative is to emphasizeunity of pattern and diversity of type asfacilitating the basic four functions of thedigestive system through a series of adap-tive patterns that can be utilized to inter-pret the life style of the organism whosedigestive system is being investigated. Asimple exercise designed to measureunderstanding of these correlations is topresent students with various gut patternsand ask them to describe structure, habitatand behavior of the organisms in whichthey would be mostly likely to be found.

References: unity of type/diversity ofpattern: Ballard (*1964), Eaton (1960),Hildebrand et al. (*1985), Montagna(1959), Murray (1936), Polyak (*1957),Prince (1956), Prosser (*1973), Radinsky(*1987), Romer (*1962), Russell (*1982),Shipman and Bichell (*1985), Wake(*1979).

CONCLUSIONS

Content of an introductory collegiatebiology course constitutes an ad hoc deter-mination by the individual instructor. Evenin rare cases where a course outline hasbeen provided by the department, itsdegree of implementation is erratic andunsupervised. In general, college coursesare immune from study and data based rec-ommendations. Prior to 1920 biology pro-grams in secondary schools and introduc-tory courses at the collegiate level wereroughly parallel in content and emphasisso that a study of the secondary school ofthis period is, by inference, a study of thecollegiate introductory program. Subse-quent to 1920 secondary school programsbegan to be designed to meet the needs ofstudents and collegiate programs designedto meet the desires of the faculty, eventhough it is common to find secondary pro-grams still aping those at the collegiatelevel. Some changes at the secondaryschool, particularly those of the BSCS, haveaffected presentations of biology at the col-legiate level.

Despite almost a century of studies and

A,Squolus B.Anguilk) C,Triton D.Tholassochelys E,Povo

F, Homo G,Lepus H.Spermophilus I, Hyrox

K, Macropus L, Bos

FIG. 12. Stomachs, which serve for storage anddigestion, vary greatly among vertebrates. A, shark;B, teleost; C, salamander; D, turtle; E, bird; F, man;G, hare; H, ground squirrel; I, coney; J, whale; K,kangaroo; and L, cow. 1, esophageal epithelium (cil-iated in C) which may extend into the stomach par-ticularly in mammals; 2, cardiac epithelium found onlyin some mammals; 3, fundus epithelium; and 4, pyloricepithelium. The darkened area in the bird representsthe thickened wall of the gizzard. Unity of patternand diversity of type varies throughout the vertebrateseries with many specialized mammalian stomach types(F-L). Variation in stomach structure is difficult toascertain through the dissection of preserved speci-mens. (Romer, 1962, p. 351.)

recommendations by prestigious commit-tees and commissions the fundamentalconcepts on which collegiate biology pro-grams can be based are yet to be identifiedand agreed upon. Few action programshave been implemented and fewer stilladopted beyond the boundaries of a singleinstitution. The need for more studies isnot indicated, but rather, a need for actionrelative to already initiated investigations.

The study of form and function has beenan integral part of introductory biologysince its identification as a discipline. Tra-ditionally, heavy emphasis has been placedon morphological detail and the vocabu-lary attendant thereunto. The data inci-dent to form and function are usually pre-sented as isolated, unrelated pieces offactual information. The need is for ameaningful synthesis based on unifying


principles. The chief of these is unity ofpattern and diversity of type, which servesto explicate both relationship and adap-tation. Use of the comparative approachand stress on such concepts as analogy andhomology, convergence and divergence,and the use of specific systems and struc-tures in such a manner as to illuminate thecommon threads of structure and functionand ways in which they have been modi-fied, serve to make the study of form andfunction more comprehensible and mean-ingful.

Improvements in introductory biologycourses are not made by the simple substi-tution of a biochemical terminology for amorphological one to "bring the subjectup to date." Rather improvement entailsa difference in emphasis, switching fromdetail to inculcating the ability to analyze,synthesize and evaluate data by use of prin-ciples designed to provide a coherent pre-sentation of structure and function. Hurd(1978) looked at future courses for biolog-ical education and emphasized the neces-sity for change. Choices for improvementabound. What is now needed is implemen-tation of selected recommendations withinthe current framework of courses in col-leges.

REFERENCES

Achinstein, Peter. 1968. Concepts of science. JohnsHopkins Press, Baltimore.

Armacost, R. and P. Klinge (eds.) 1956. Report ofthe North Central Conference on biology teach-ing. The American Biology Teacher 18:4—72.

Ayala, Francisco J. and T. Dobzhansky (eds.) 1974.Studies in the philosophy of biology. Macmillan, Lon-don.

Baker, Jeffrey J. W. (ed.) 1967. Biology in a liberaleducation. CUEBS Publ. #15. Amer. Inst. Biol.Sci., Washington, D.C.

Ballard, William W. 1964. Comparative anatomy andembryology. Ronald Press Co., New York.

Beauchamp, W. L. 1932. Instruction in Science Bul-letin 1932, No. 17. National Survey of SecondaryEducation. Monograph No. 22. Washington, D.C.

Berkheimer, G. D., R. Edmonds, R. W. Hill, L. R.Krupka, H. C. Rudman, and G. A. Smith. 1984.Recommendations for science education. Journalof College Science Teaching xiv:174-180.

Bessey, C. E. 1896. Science and culture. Addressesand Proceedings, National Education Associa-tion. Washington, D.C. 35:939-942.

Bigelow, M. A. (chairman) 1906. Committeeappointed at the request of the American Society

of Zoologists 1906. College entrance option inzoology. School Science and Mathematics 6:63-66.

Biological Sciences Curriculum Study. 1971. Theimpact of BSCS biology on college curricula. BSCSNewsletter #42:1-8. February.

Blake, Ralph M., C. J. Ducasse, and E. Madden. 1960.Theories of scientific method. University of Wash-ington Press, Seattle, Wash.

Braithwaite, Richard B. 1953. Scientific explanation.Harper Torchbooks, New York.

Breukelmman, J. and R. Armacost (co-chairmen)1955. Publications committee 1955. Report ofthe Southeastern Conference on biology teach-ing. The American Biology Teacher 17:4-55.

Brody, Baruch A. 1970. Readings in the philosophy ofscience. Prentice Hall, Englewood Cliffs, N.J.

Brown, M. S. andj . L. Goldstein. 1984. How LDLreceptors influence cholesterol and atheroscle-rosis. Scientific American 251:58-66.

BSCS. 1963. Biological science: An inquiry into life. Har-court, Brace and World, New York.

Caldwell, O. W. (chairman) 1920. Reorganization ofscience in secondary schools. Commission onReorganization of Secondary Education Bull.1920, No. 26. Department of Interior, Bureauof Education, Washington, D.C.

Commission on Undergraduate Education in the Bio-logical Sciences. 1967. Content of core curriculumin biology. Report oj the panel on undergraduate majorcurricula. Publ. #18. Amer. Inst. Biol. Sci., Wash-ington, D.C.

Conference on Biological Education. 10 March 1953.National Academy of Sciences-National ResearchCouncil, (mimeo) Division of Biology and Agri-culture, Washington, D.C.

Cox, Donald D. and L. V. Davis. 1972. The context ofbiological education: The case for change. CUEBSPubl. #34. Amer. Inst. Biol. Sci., Washington,D.C.

Creager.Joan G. and D. L. Murray. 1971. The use ofmodules in college biology teaching. CUEBS Publ.#31. Amer. Inst. Biol. Sci., Washington, D.C.

Crosby, C. 1907. Physiology, how and how much.School Science and Mathematics 7:733-744.

Dewey,J. 1916. Method in science teaching. GeneralScience Quarterly 1:3.

Dexter, E.G. 1906. Ten years'influence of the reportof the Committee of Ten. The School Review14:254-269.

Downing, E. R. (chairman) 1931. The teaching ofbiology. North Central Association Quarterly 5:395-398.

Eaton, S. B. and M. Konner. 1985. Paleolithic nutri-tion: A consideration of its nature and currentimplications. New England Journal of Medicine31; 312(5):283-289.

Eaton, Theodore W. 1960. Comparative anatomy of thevertebrates. 2nd ed. Harper, New York.

Effler, Louis E. 1935. The eponyms of anatomy.McManus-Troup Co., Toledo, Ohio.

Field, Ephraim J. and R. J. Harrison. 1957. Anatom-ical terms: Their origin and derivation. 2nd ed. Hef-fer, Cambridge.

Finley, F. N., J. Stewart, and W. L. Yarroch. 1982.


Teachers' perceptions of important and difficultscience content. Science Education 66:631-638.

Fisher, K. M.J. I. Lipson, A. C. Hildebrand, L. Miguel,N. Schoenberg, and N. Porter. 1986. Studentmisconceptions and teacher assumptions in col-lege biology. Journal of College Science Teach-ing xv:276-280.

Flaspohler, R. J. and M. D. Swords. 1985. A generaleducation biology course that works. Journal ofCollege Science Teaching xv:l 17-119.

Gallie, W. B. 1957. What makes a subject scientific?British Journal for the Philosophy of Science 8:118-139.

Galloway, T. W. (chairman) 1910. Report of thecommittee on fundamentals of the Central Asso-ciation of Science and Mathematics Teachers.School Science and Mathematics 10:801-813.

Goodhart, Robert S. and M. E. Shils. 1980. Modernnutrition in health and disease. 6th ed. Lea andFebiger, Philadelphia, Pa.

Grobman, Arnold. 1969. The changing classroom: Therole of the Biological Sciences Curriculum Study. Dou-bleday, New York.

Hall, E. H. and Committee. 1898. Memorandumconcerning report of Committee of Sixty.Addresses and Proceedings, National EducationAssociation, Washington, D.C. 37:964-965.

Hardin, Garrett. 1952. Biology, its human implications.W. H. Freeman, San Francisco.

Harre, Romano. 1970. The principles of scientific think-ing. University of Chicago Press, Chicago. 111.

Havighurst, R.J. etal. 1943. High school science andmathematics in relation to the manpower prob-lem. School Science and Mathematics 43:138-141.

Hildebrand, Milton, D. M. Bramble, K. F. Liem, andD. B. Wake. 1985. Functional vertebrate morphol-ogy. Belknap, Harvard Univ. Press, Cambridge,Mass.

Hitching, Francis. 1982. The neck of the giraffe whereDarwin went wrong. Ticknor and Fields, New York.

Hurd, P. De Hart. 1961. Biological education in Amer-ican secondary schools 1890—1960. American Insti-tute of Biological Sciences, Washington, D.C.

Hurd, P. De Hart. 1978. A glimpse into the future.In W. V. Mayer (ed.), Biology teachers handbook,pp. 565-568. John Wiley, New York.

Huxley, Thomas H. 1880. The crayfish, an introductionto the study of zoology. Kegan Paul, Trench, Trub-ner and Co., London.

International Union of Biological Sciences. Commis-sion for Biological Education. 1987. A strategyfor biology courses for undergraduate non-biology stu-dents. IUBS/CBE, Hamburg, Germany.

Kitcher, Philip. 1982. Abusing science: The case againstcreationism. MIT Press, Cambridge.

Kitcher, Philip. 1984. Good science, bad science,dreadful science and pseudoscience. Journal ofCollege Science Teaching xiv:168-173.

Koballa, Thomas R. Undated. Goals of science edu-cation. In Research within reach: Science education.National Science Teachers Association, Wash-ington, D.C.

Kockelmans.JosephJ. (ed.) 1968. Philosophy of science:The historical background. Free Press, New York.

Kolata, G. 1986. How important is dietary calciumin preventing osteoporosis? Science 233:519-520.

Kuhn, Thomas S. 1970. The structure of scientific revo-lutions. Enlarged ed. University of Chicago Press,Chicago, 111.

Lawson, Chester A. (Conference director) 1957.Committee on Educatonal Policies, Division ofBiology and Agriculture 1957. Laboratory andfield studies in biology: A sourcebook for secondaryschools. Preliminary Edition, National Academyof Sciences-National Research Council, Wash-ington, D.C.

Linn, Marcia C. 1986. Science. In Ronna F. Dillon,Cognition and instruction. Academic Press, NewYork.

Linville, H. R. 1910. Old and new ideals in biologyteaching. School Science and Mathematics 10:210-216.

Madden, Edward H. (ed.) 1960. The structure of sci-entific thought. Houghton Mifflin, Boston, Mass.

Maienschein, Jane (ed.) 1986. Defining biology. Har-vard Univ. Press, Cambridge, Mass.

Margulis, Lynn and K. V. Schwartz. 1982. Five king-doms An illustrated guide to the phyla of life on earth.W. H. Freeman, San Francisco.

Mayer, William V. (ed.) 1978. Biology teacher's hand-book. 3rd ed. John Wiley, New York.

Mayer, William V. 1986. Biology education in theUnited States during the twentieth century.Quarterly Rev. of Biology 61:481-507.

Mestre, J. 1987. Why should mathematics and sci-ence teachers be interested in cognitive researchfindings? Academic Connections—Office of Aca-demic Affairs—The College Board. Summer:3—11.

Moll, M. B. and R. D. Allen. 1982. Developing crit-ical thinking skills in biology. Journal of CollegeScience Teaching xii:95-98.

Monmaney, T. 1986. Vitamins: Much ado about mil-ligrams. Science 86, 7(Jan./Feb.):10-l 1.

Montagna, William. 1959. Comparative anatomy. JohnWiley, New York.

Moore, J. A. 1988. Understanding nature—Formand function. Amer. Zool. 28:449-584.

Murray, Patrick D. F. 1936. Bones. Cambridge Uni-versity Press, Cambridge.

Nash, Leonard K. 1963. The nature of the naturalsciences. Little, Brown, Boston, Mass.

National Academy of Sciences—National ResearchCouncil. 1955. Division of Biology and Agri-culture. Biology Council. Committee on Educa-tional Policies. Proceedings of the Sixth Meeting.5 September 1955 (mimeo).

National Education Association. U.S. Bureau of Edu-cation. 1893. Report of the committee on sec-ondary school studies—Report of the Committeeof the Ten. Washington, D.C.

Neal, Herbert V. and H.W. Rand. 1936. Comparativeanatomy. Blakiston, Philadelphia.

Nightingale, A. F. (chairman) 1899. Report of thecommittee on college entrance requirements.Addresses and Proceedings, National EducationAssociation, Washington, D.C. 38:625-630.

Nomina anatomica. 1961. Excerpta Medica Founda-tion, Amsterdam.


Northrop, Filmer S. C. 1947. The logic of the sciencesand humanities. Macmillan, New York.

Paley, William. 1828. Natural theology—Or evidencesof the existence and attributes of the deity collected fromthe appearances of nature. 2nd ed. J. Vincent,Oxford.

Peabody.J. E. (chairman) 1915. Preliminary reportof the biology subcommittee on the reorganiza-tion of secondary education. National EducationAssociation, School Science and Mathematics 15:44-53.

Poincafe, Henri. 1952. Science and method. Dover,New York.

Polyak, Stephen. 1957. The vertebrate visual system.University of Chicago Press, Chicago, 111.

Powers, S. R. (chairman) 1932. A program for teach-ing science. The Thirty-First Yearbook of theNational Society for the Study of Education, PartI. Public School Publishing Co., Bloomington, 111.

Prince, Jack H. 1956. Comparative anatomy of the eye.Thomas, Springfield, 111.

Prosser, Clifford L. (ed.) 1973. Comparative animalphysiology. 3rd ed. Saunders, Philadelphia.

Radinsky, Leonard B. 1987. The evaluation of verte-brate design. Univ. of Chicago Press, Chicago.

Rechcigl, Milostav.Jr. (ed.) 1977. CRC handbook seriesin nutrition and food. CRC Press, Cleveland, Ohio.

Riddle, O. 1906. What and how much can be donein ecological and physiological zoology in sec-ondary schools. School Science and Mathematics6:212-216, 247-254.

Riddle, O. (ed.) 1942. The teaching of biology insecondary schools of the United States. Union ofAmerican Biological Societies.

Romer, Alfred S. 1962. The vertebrate body. Saunders,Philadelphia.

Romer, Alfred S. and T. S. Parsons. 1986. The ver-tebrate body. 6th ed. Saunders, Philadelphia.

Russell, Edward S. 1982. Form and function a contri-bution to the history of animal morphology. Univ. ofChicago Press, Chicago.

Shipman, Pat, A. Walker and D. Bichell. 1985. Thehuman skeleton. Harvard Univ. Press, Cambridge,Mass.

Shymansky.J. 1984. BSCS programs:Just how effec-tive were they? Amer. Biol. Teacher 46:54-56.

Simpson, George G. 1976. The meaning of evolution.Rev. ed. Yale Univ. Press, New Haven.

Singer, C. 1957. A short history of anatomy from theGreeks to Harvey. Dover, N.Y. Reprint of The evo-lution of anatomy.

Skinner, Henry A. 1961. The origin of medical terms.2nd ed. Williams & Wilkins, Baltimore.

Stanier, Roger Y., E. A. Adelberg, and M. Doudoroff.1963. The microbial world. 3rd ed. Prentice-Hall,Englewood Cliffs, N.J.

Stauffer, Robert C. (ed.) 1949. Science and civilization.University of Wisconsin Press, Madison, Wis.

Storer, Tracy I. 1951. General zoology. McGraw-Hill,New York.

Suppe, Frederick. 1977. The structure of scientific the-ories. University of Illinois Press, Urbana, 111.

Suppes, Patrick. 1969. Studies in the methodology andfoundations of science. Reidel, Dordrecht, Holland.

Supreme Court of the United States. 1987. EdwinW. Edwards, Etc., et al. Appellants v. Don Aguil-lardetal. No. 85-1513 June 19, 1987. (The deci-sion in the Louisiana "balanced treatment" case.)

Symposium on the function and organization of thebiological sciences in education. 1908. SchoolScience and Mathematics 8:536—551.

Thornton, John W. (ed.) 1972. The laboratory: A placeto investigate. CUEBS Publ. #33. Amer. Inst. Biol.Sci., Washington, D.C.

Tompkins, Peter and C. Bird. 1984. Secret life of plants.Harper & Row, New York.

Toulmin, Stephen. 1953. The philosophy of science: Anintroduction. Hutchinson, London.

Tver, David F. and P. Russell. 1981. Nutrition andhealth encyclopedia. Van Nostrand Reinhold Co.,New York.

Velikovsky, Immanuel. 1950. Worlds in collision.Pocket Books, New York.

Von Daniken, Erich. 1971. Chariot ofthe gods. BantamBooks, New York.

Wain, Harry. 1958. The story behind the word. Thomas,Springfield, 111.

Wake, Marvalee H. (ed.) 1979. Hyman's comparativevertebrate anatomy. Univ. of Chicago Press, Chi-cago.

Wiener, Philip P. (ed.) 1953. Readings in the philosophyof science. Scribners, New York.

Woodger, Joseph H. 1937. The axiomatic method inbiology. Cambridge University Press, Cambridge.

The Role of Form and Function in the Collegiate Biology Curriculum

Documents

Transcript of The Role of Form and Function in the Collegiate Biology Curriculum