using ‘‘the organism’’ as a conceptual focus in an...

Using ‘‘The Organism’’ as a ConceptualFocus in an Introductory Biology Course

William J. Hoese Stephen Nowicki

Akey role of introductory biology in the collegecurriculum (similar to other introductory sci-ences) is to provide students with a founda-

tion of information on which they can build the restof their major. Too often, however, students (andsome faculty) view the introductory course as nothingmore than an overview of essential facts and concepts.This ‘‘baseline’’ approach to teaching introductorybiology is lamentable because it misses a uniqueopportunity to engage the students’ imagination earlyin their college careers and, in so doing, to teachthem that biology is more than just a collection offacts. Most students who enroll in introductory biol-ogy are just beginning to explore their interests inmore depth than was possible during secondaryschool, making the introductory course an ideal venuefor expanding their outlook and developing theircritical thinking skills; that is, improving the students’ability to ask good questions and to know how toanswer them. In our renovation of the introductorybiology program at Duke University, we developedan integrated series of exercises focused on ‘‘theorganism’’ that serve both as a way to nurture studentimagination and individual interests and also as away to teach students about the process of askingand answering questions in biology.

We chose ‘‘the organism’’ as a conceptual focusfor this series of exercises for several reasons. First,organisms are tangible. Many students are attractedto biology initially because of an interest in organisms(fostered, perhaps, by their exposure to the abundanceof nature programs on television if not their ownexperiences in nature). Even students who are notnature-lovers bring an intuitive feel for organismsto class. Thus, organisms provide a good startingpoint for grounding a student’s interests in biology.This point is supported by the growing number ofintroductory biology curricula that emphasize theintegrative and process-oriented nature of biology,as opposed to the more traditional approach of start-ing with chemistry and working up (Goodwin et al.

William J. Hoese is an Assistant Professor in the Departmentof Biological Sciences at California State University–Fullerton,Fullerton, CA 92834; e-mail: [email protected]. StephenNowicki is an Associate Professor in the Department of Biol-ogy at Duke University, Durham, NC 27708.

176 THE AMERICAN BIOLOGY TEACHER, VOLUME 63, NO. 3, MARCH 2001

1991; Chiras 1992; Ebert-May et al. 1997; Groh etal. 1997).

A second reason is that organisms represent aparticularly important level in the hierarchy of biolog-ical organization. While evolution occurs on the levelof populations, natural selection acts on organismsbecause, in general, this is the level at which differen-tial reproduction occurs. To the extent that most ofthe biological processes studied in introductory biol-ogy are in some sense or another adaptations resultingfrom natural selection, including phenomena occur-ring at the level of molecules through the level ofecosystems, these processes are best understood inthe context of the organisms within or among whichthey occur.

We designed this exercise to stimulate studentinterest in biology while helping students learn scien-tific methods. Recent curriculum reform recommen-dations emphasize the importance of actively involv-ing students as a way to engage students in biology(Project Kaleidoscope 1991; BSCS 1993; NRC 1996,1997; NSF 1996). Especially useful activities includeproblem-driven exercises that require student creativ-ity in order to achieve the specified goals (ProjectKaleidoscope 1991; Chiras 1992; NRC 1996). In ourproject, students choose an organism at the beginningof the semester and this organism becomes their ownpersonal focus for a series of exercises throughoutthe semester (as described below).

One key to the success of any exercise, however,is providing enough guidance to students so theydo not feel lost on an assignment, while leavingthem room for creativity in pursuing their goals.Therefore, instead of simply letting the students looseon the project, we meet with students in groups toensure that they make adequate progress throughoutthe semester. We do provide feedback to the students,but we do not tell them exactly how to proceedthrough each step of the project. In addition, weprovide students with handouts that have suggestionsand guidelines for the exercise [copies of these hand-outs are available from the corresponding author,WJH].

‘‘The organism’’ project gradually builds across thesemester, starting first with students asking questionsabout their organism, then developing testable

hypotheses and designing experimental tests focusedon their organism (Table 1). The project culminateswith each student preparing and delivering a 12-minute oral presentation in which he/she describesa research proposal for testing a hypothesis that hasemerged from his/her semester-long study of his/her organism. Students receive informal feedbackfrom their peers at each stage of the project, whichfosters communication and interest throughout thesemester. Furthermore, the graduate student teachingassistant (referred to as ‘‘TA-mentor’’ in our course)monitors students’ progress and provides formalfeedback across the semester.

One additional goal of ‘‘the organism’’ exercise isto actively involve students in reading and interpre-ting the scientific literature, activities that are com-pletely new to most students entering an introductorybiology course. As students progress through theexercise they learn how to navigate the library, start-ing first by using general references and secondaryliterature, then moving to primary literature. Thelevel of library research required increases as studentsprogress through the exercise. For example, studentsuse general references to identify their organism andask initial questions about their organism. As studentsdevelop their own hypotheses, they use the primaryliterature to investigate previous research in theirareas of interest.

The exercise has four main components (1) choosingorganisms, (2) asking questions, (3) developinghypotheses, and (4) delivering an oral research pro-posal. Each stage of the exercise builds on previouswork, and by the end of the semester students under-stand what it takes to design a research project.Students may focus their investigations at any levelof biological organization, not just the organismallevel; thus students have opportunities to identifyand develop their own interests in the context of‘‘the organism’’ project.

The Exercise

Choosing Organisms

During the first week of the semester, in seminar,we introduce students to the organism project. Ourcourse consists of three main components: lecture,laboratory section and seminar section. Each sectionis composed of 12 students and one ‘‘TA-mentor,’’with the same group of students meeting togetherfor lab and seminar. Small sections led by a singleTA-mentor allow us to have small-group learningexperiences embedded within a larger, 240-personintroductory course. In addition to learning contentin lecture and performing experiments in laboratory,students have an additional forum in seminar todiscuss biological material from new perspectives.

ORGANISMS IN INTRODUCTORY BIOLOGY 177

Table 1. Timetable and progression of organism projectthroughout semester.

TIMING ACTIVITYWeek 1 ● Introduction to organism project

● Students choose organismWeek 3 ● Identify organism using secondary

literature● Ask questions about organism● Discuss levels of organization in biology

Week 7 ● Propose testable hypothesis● Identify two primary references

pertaining to hypothesis● Begin developing tests for hypotheses

Week 13 ● Oral presentation on organism withoutline of proposed test for hypothesisand expected results

The seminar section meets once a week for an hourand provides opportunities to engage students inactive, inquiry-based learning.

We present students with a list of genera and eachstudent chooses one genus from the list. The list oforganisms consists of approximately 40 genera fromfour kingdoms (see Table 2 for examples). This listwas compiled and checked using Biological Abstracts,Medline and Agricola to confirm that each genus hadsufficient past research conducted on it to introducestudents to a wide variety of biological approaches.We avoided organisms for which the literature washard to follow for one reason or another. For example,we did not include the firefly genus Photuris becauseluciferase, originally derived from fireflies, is com-monly used as a photodetection assay in a widevariety of molecular investigations that are unrelatedto the genus Photuris. In addition, we avoided easilyrecognized genera such as Canis or Gorilla to preventstudents from vying for a subset of charismatic, well-known organisms.

Once a genus has been chosen from the list, it isno longer available to anyone else in that section.Thus, each student in a 12-person section has adifferent organism, but there are frequently severalstudents studying the same organism in our 240-person course. We encourage students to seek outthese other students and share information they havegathered. After choosing a genus, students are giventhe taxonomic hierarchy for their organism, but notits common name [a complete list of organism taxo-nomies used in this exercise is available from WJH].As part of their first assignment, students simply haveto figure out what kind of organism they have chosen,using taxonomic resources available in the library.

To aid students in identifying their organism aspart of their initial library search, we provide studentswith a list of useful, general taxonomically orientedreferences. For example, a student with Strongylocen-trotus as her organism might first look in an inverte-brate zoology resource text (e.g. Ruppert & Barnes

Table 2. Representative sample taxonomic hierarchies that students receive after choosing a genus from the organism list.Each of these representatives appears as an example in the accompanying text. The complete list (available from WJH)includes taxa from four kingdoms (Animalia, Fungi, Plantae, Protista).

Kingdom Plantae Kingdom PlantaeDivision DivisionAnthophyta AnthophytaClass ClassMagnoliopsida MagnoliopsidaOrder OrderSapindales FagalesFamily FamilyAceraceae FagaceaeGenus GenusAcer Quercus

Kingdom Animalia Kingdom PlantaePhylum DivisionMollusca AnthophytaClass ClassGastropoda MagnoliopsidaSubclass OrderOpisthobranchia CaryophyllalesOrder FamilyAnaspidea CaryophyllaceaeFamily GenusAplysiidae SileneGenus Aplysia

Kingdom Animalia Kingdom AnimaliaPhylum PhylumChordata EchinodermataClass ClassAmphibia EchinoideaOrder OrderCaudata EchinoidaFamily FamilyPlethodontidae StrongylocentrotidaeGenus GenusPlethodon Strongylocentrotus

1994) if she recognized that echinoderms were marineinvertebrates. If, however, with the student onlyrecognizes that Strongylocentrotus is an animal, then


she could start her search with a more general refer-ence (e.g. Grzimek 1972). This initial search for anorganism’s identity increases student ownership inthe project. In addition, students looking through thereference section of the library tend to help eachother during this initial phase of the exercise andhelp foster cooperation in seminar groups; both ofthese interactions stimulate interest in the project.

After identifying their organism at the generic level,students choose a focal species within the genus theyselected on which to concentrate the rest of theirinvestigations. Although students have a focal organ-ism, we make it clear that their exploration need notbe limited to the organismal level of biology. Instead,we encourage students to investigate their organismat any level of biological organization they findinteresting (from molecules to ecosystems). Allowingstudents the freedom to choose their own topic toinvestigate promotes general interest in biology andit also encourages students to identify their ownspecific interests.

Asking Questions About Organisms

During the third week of the semester studentsintroduce their organism to the rest of their seminarsection and present two or three questions theyhave developed from their initial readings. We findstudents’ questions vary from being fairly simple(e.g. ‘‘What does the sea slug, Aplysia, eat?’’) torelatively advanced (e.g. ‘‘How does Aplysia learn toavoid predators?’’). This discussion has three goals.First, it gives students the opportunity to identifylinks among different organisms within each section.

For example, one organism may be the prey foranother, or a number of organisms may occupy thesame trophic level within an ecosystem. Studentsenjoy discovering connections among organisms andadditional spontaneous discussions often evolve fromthese discoveries.

A second goal of this seminar exercise is to helpstudents recognize different levels of biological orga-nization and to gain some appreciation for howinteresting questions can be used to investigate eachlevel. The questions within a single section usuallyaddress multiple levels of biological organizationranging from cellular questions (e.g. ‘‘How do themuscles of the rat snake, Elaphe, contract and howstrong are they?’’), to metabolic questions (e.g. ‘‘Whathappens to the vital systems during hibernation inthe rat snake, Elaphe?’’), to questions about locomotion(e.g. ‘‘How does the sea urchin, Strongylocentrotus,move using tube feet and spines?’’), to questionsabout reproduction and speciation (e.g. ‘‘What arethe ecological conditions that have made the speciesof maple trees differ so greatly in Asia and theAmericas?’’). During this discussion we emphasizemultiple levels of biological organization as one wayto avoid biasing students from just asking questionson the organismal level. As students identify theirown interests we help them find ways to pursuethese interests as they develop hypotheses and experi-mental tests.

A final goal of this seminar session is to reinforcethe role of hypotheses and hypothesis testing inbiology. After students pose general questions abouttheir organisms we ask them how they might goabout answering some of their questions. Earlier inthe semester (in two different seminar exercises)students already will have discussed scientific meth-ods, how hypotheses lead to testable predictions,and how experiments can be designed to test thosepredictions. We re-introduce the role of hypothesesin biology during this session as a prelude to thestudents’ next assignment in which they consult theprimary literature and develop their own hypothesesabout their organism.

Developing Hypotheses

By the seventh week of the semester the focus ofthe project shifts from the organisms themselves tohypothesis generation. Students with similar initialquestions end up developing very different hypothe-ses. For example, questions about how an organismeats have evolved into hypotheses focused on forag-ing behavior, prey capture, digestion, and metabolicpathways of ingested food. As students identify theirown interests they need additional information fromthe primary literature in order to make substantialprogress on their hypotheses.


When using library resources most students turnto Biological Abstracts or Medline to identify primaryreferences. By performing keyword searches combin-ing terms to include topics of interest and theirorganism name, students usually locate multiple rele-vant references. For example, a student interested insalamander nesting behavior performed a searchusing the following terms: ‘‘mating,’’ ‘‘nest,’’ ‘‘Pletho-don’’ and ‘‘nesting behavior.’’ From this search sheidentified eight sources that she thought would beuseful in developing her own hypothesis about sala-mander nesting behavior. Students supplement com-puter searches with additional referencing frompapers they identify from initial searches, so thattheir keyword search is often the beginning of theirinvestigation into their hypotheses.

Discussion of hypotheses during the seminar ses-sion works in the following way: Meeting in pairs,each student presents her/his hypothesis to anotherstudent. Meeting one-on-one in this way promotesstudent interaction and provides an opportunity tofor students to give specific feedback on each other’shypotheses. To facilitate individual explanations weprovide each listener with questions to ask and recordthe answers during discussion. Half-way through theseminar we reconvene and each student presents

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his/her partner’s hypothesis to the group as a whole.This format emphasizes the need for students to beclear and precise in what they are trying to say, andprovides informal feedback to each student on his/her hypothesis.

During this session we also discuss differentapproaches biologists use to test hypotheses. Moststudents already are familiar with the idea of experi-mentation, in which one or more variables are manip-ulated and compared to a control. Students are lessfamiliar with the use of observational tests, modeling,and the phylogenetic comparative method as alterna-tive approaches to investigating biology. In laboratorywe use each of these methods to investigate biologicalphenomena. For example, students create their ownphylogenetic hypotheses based on skull morphologiesin primates and compare their trees with publishedhypotheses. By the end of the semester studentshave had laboratory experience working with manyinvestigative methods and often use a combinationof approaches to address their hypotheses.

Oral Research Proposals

During the last week of the semester studentsdeliver 10- to 12-minute oral presentations in whichthey outline the research proposals they have devel-oped to test hypotheses about their organisms. The


hypothesis and how to test it are the main themesof the presentations. Students introduce their topicswith information sufficient to give the audience ageneral background to the problem and previousresearch in their area of interest. Students describetheir hypotheses in detail, including alternative hypoth-eses, and how the original hypotheses may be brokenup into subsidiary hypotheses. Students also explaintheir research plans, experimental designs, and howtheir proposed tests explicitly relate to their hypothe-ses. We encourage students to address assumptionsthat they make in their experimental designs. Finally,we ask students to discuss the predicted results oftheir proposed research and to interpret these resultsin light of their original hypotheses.

For many students, this is the first oral presentationthey have delivered to their peers, and the qualityof student talks varies greatly, depending on howcomfortable they feel about public speaking. Thus,TA-mentors emphasize clarity, knowledge and appro-priateness of a student’s research proposal for testingtheir hypotheses, while de-emphasizing the impor-tance of presentation mechanics (i.e. polish and audio-visuals). We ask students to prepare outlines of theirtalks and lists of references that not only make iteasier for other students to follow along, but alsoprovide the TA-mentor with an additional basis forevaluation that is independent of the delivery of thetalks. Therefore, we have a mechanism to addresshow a student is thinking about the material evenif that student has poor speaking skills.

Using the Organism Exercise‘‘The organism’’ exercise easily can be incorporated

as an integrative theme running across the term ina wide range of biology courses. The exercise requiresfew supplemental materials other than access tolibrary resources, thus it is not costly to implement.It provides opportunities for students to teach eachother about biology, thereby increasing student inter-est and understanding (Trombulak 1995; Brewer &Ebert-May 1998; Lord 1998). In addition, the list oforganisms can be tailored to fit the structure andcontent of particular courses. For example, an intro-ductory zoology course might eliminate botanicalorganisms while expanding the list of zoologicalrepresentatives.

Anecdotal evidence suggests that ‘‘the organism’’exercise stimulates student interest in biology. Stu-dents who initially are not excited about their organ-ism often identify and develop interesting hypothesesand research proposals if they can get beyond theirearly reluctance. One student, for instance, struggledwith Quercus for much of the semester until sherealized that she was interested in community-levelinteractions among species. Her final presentation,

about which she was extremely enthusiastic, focusedon hypotheses of seed dispersal mechanisms byacorn-eating squirrels. A key to success with manystudents is to find ways of helping them identifytheir interests, and then connecting these interestswith some aspect of their organisms. One of thestrongest measures of success is that former studentsoften contact us to tell us that they saw ‘‘their’’organisms. Often they observe their organisms whiletravelling or while at home and they are excited tobe able to share background information and naturalhistory about their organisms with their familiesand friends. For example one student wrote us that‘‘meeting’’ her organism, Gigartina, while snorkelingwas like discovering a friend in a land of strangers.

Finally, students self-report on course evaluationsthat the organism project facilitated their learning,the oral presentation of their project facilitated theirlearning, and the project increased their understand-ing of scientific methods (Figure 1). We measuredstudent responses over three semesters. Our evalua-tion scale included the following six categories : (1)strongly disagree, (2) disagree, (3) somewhat disagree,(4) somewhat agree, (5) agree and (6) strongly agree.Most students felt that the project facilitated theirlearning (mean 4 4.0, n 4 456). Most studentsbelieved that their oral presentation facilitated theirlearning (mean 4 3.9, n 4 454). Finally, studentsfelt that their understanding of the scientific methodwas increased by this project (mean 4 4.0, n 4 458).While these results suggest that the organism exercisestimulates learning, it is important to recognize thatstudent perception of learning may not reflect actuallearning. In order to address how student perceptionrelates to performance we asked students to reporttheir satisfaction of (1) the content and (2) the organi-zation of their oral presentation. We measured stu-dent satisfaction in one semester after all students hadgiven their presentation but before their presentationgrade was returned; this controlled for the possibilitythat presentation grade could influence student satis-faction. Using linear regression we evaluated whethersatisfaction could predict the grade students receivedon their presentation. We find that student satisfactionof the content is positively related with presentationgrade (F 4 14.69, p 4 0.19 * 10-3, R2 4 0.09, n4

144). In addition, student satisfaction of presentationorganization was positively related with presentationgrade (F 4 12.21, p 4 0.63 * 10-3, R2 4 0.08, n 4

144). Students, therefore, have some understandingof how content and organization relate to their perfor-mance. Thus, by extension, it seems reasonable toconclude that student responses of the impact ofthe project on their learning are likely to reflectactual learning.


Figure 1. Student assessment of the organism exercise. Sum-mary of student evaluations from fall 1998, spring 1999 andfall 1999 semesters. Students responded on a 1 to 6 scale tothe following statements: A. The organism project facilitatedmy learning (mean response 4 4.0). B. The oral presentationof the organism project facilitated my learning (meanresponse 4 3.9). C. The organism project increased myunderstanding of the scientific method (mean response 44.0).

Acknowledgments

This project was supported by NSF RAIRE award9620019. Special thanks to M. Hughes, J. Rowden andN. Underwood for help in developing this exercise.S. Weiss assisted in data analysis. We thank S. Weiss,S. Patek, M. Beebee and two anonymous reviewersfor valuable suggestions.

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