Facilitating Conceptual Change in Students' Understanding of Ecological Concepts

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Journal of Science Education and Technology pp1149-jost-483384 March 19, 2004 17:14 Style file version June 20th, 2002

Journal of Science Education and Technology, Vol. 13, No. 1, March 2004 ( C© 2004)

Facilitating Conceptual Change in Students’Understanding of Ecological Concepts

Ozlem Ozkan,1 Ceren Tekkaya,2 and Omer Geban1,3

In this study, the effect of conceptual-change-texts-oriented instruction to seventh-grade stu-dents’ understanding of ecological concepts was investigated. Using information collectedthrough interviews and related literature, the Ecology Concept Test was developed and ad-ministered to 58 elementary students in two classes of an elementary school before and afterthe treatment. The experimental group received conceptual-change-texts-oriented instructionand the control group received traditional instruction. Results of independent t test analysisrevealed a statistically significant difference between the gain score means of the studentsin both groups with respect to ecological concepts in favor of experimental group after thetreatment.

KEY WORDS: ecological concepts; misconceptions; conceptual change text.

INTRODUCTION

Ecology has long been recognized as one ofthe most important and difficult-to-learn concepts ofthe biology curriculum (Johnstone and Mahmoud,1980). Although biology teachers rate the ecologicalconcepts as very important topic in school biology,they do not perceive these concepts to be particu-larly difficult (Finley et al., 1982). Despite its impor-tance, students have been reported to perform poorlyin ecology. Over the past few decades, research onteaching and learning of ecology has revealed that thestudents possess several ideas that are at variance withscientifically accepted knowledge even though ecol-ogy forms a predominant aspect of most biology cur-riculum (Adeniyi, 1985; Aubusson, 2002; Eilam, 2002;Gallegos et al., 1994; Griffiths and Grant, 1985; Hogan,2000; Manzanal et al., 1999; Munson, 1994; Musheno

1Department of Secondary Science and Mathematics Education,Faculty of Education, Middle East Technical University, 06531,Ankara, Turkey.

2Department of Elementary Education, Faculty of Education, Mid-dle East Technical University, Ankara, Turkey.

3To whom correspondence should be addressed; e-mail: [email protected]

and Lawson, 1999; Reiner and Eilam, 2001; Webb andBoltt, 1990). Briefly, these studies identified students’misconceptions and underlying beliefs as related totheir difficulties in understanding the concepts relatedto the respiration, photosynthesis, energy, material cy-cling, food web, and food chain. For example, Adeniyi(1985) reported that students hold several misconcep-tions about food chain, energy flow, pyramid of en-ergy, and the carbon cycle. Griffiths and Grant (1985)identified misconceptions of students concerning foodwebs. In a separate study Munson (1994) summarizedthe students’ misconceptions related to food web, eco-logical adaptation, carrying capacity, ecosystem, andniche concepts. Furthermore, studies of Gallegos et al.(1994), Reiner and Eilam, (2001), and Eilam, (2002)reported students’ ideas about food chains.

It is well documented that students’ misconcep-tions in science are pervasive, stable, and often resis-tant to change at least through traditional instruction(Fisher, 1985). The construction and reconstructionof meanings by learners requires that they activelyseek to integrate new knowledge with knowledgealready in their cognitive structure (Novak, 2002).Meaningful learning involves students in construct-ing integrated knowledge structures, which containtheir prior knowledge, experiences, new concepts, and

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96 Ozkan, Tekkaya, and Geban

other relevant knowledge (Tsai, 2000). Smith et al.(1993) criticized the research on student misconcep-tions in science and mathematics to express construc-tivist view of learning in which students conceptionsplay productive roles in the acquisition of scientificconceptions. The practical results of research on stu-dent misconceptions are accepted but the questionarises out of views of the character, origin, and growthof students’ conceptions. Smith et al. claimed that mis-conceptions researchers have often understood learn-ing science and mathematics as a process of removingmisconceptions and adding relevant expert concepts.Learning involves both the acquisition of expert con-cepts and the banishment of misconceptions. The as-sumption that removing misconceptions has no neg-ative consequences because they play no productiverole in expertise is implicit in the replacement view.Smith et al.’s central claim is that many of the asser-tions of misconceptions research are inconsistent withconstructivism. Research on misconceptions has em-phasized the flawed results of student learning. Con-structivism stresses the role of prior knowledge inlearning. Students interpret tasks and instructional ac-tivities involving new concepts in terms of their priorknowledge. Errors are characteristics of initial phasesof learning because students’ existence knowledge isinsufficient and supports only partial understanding.As their existing knowledge is recognized to be in-adequate to explain phenomena and solve problems,students learn by transforming and improving thatprior knowledge into more sophisticated forms. Smithet al. have emphasized student’s prior conceptionsas resources for cognitive growth within a complexsystems view of knowledge. This perspective stressesknowledge refinement, and reorganization, ratherthan replacement, and it supplies a framework forunderstanding misconceptions as both flawed andproductive.

It is accepted that the methodology of instructionis the underlying factor that influences achievementand the textual information is an important part of in-struction. Learning textual information is a complexand dynamic process, which involves the mobilizationof existing knowledge to translate textual informationinto meaningful units that are integrated into existingmemory (Anderson and Botticelli, 1990). The mean-ing of the textual information is not derived whollyfrom the reading of the text, but from the interactionof the reader with the textual information. The con-struction of meaning occurs when the textual infor-mation is concerned with and modifies the students’existing knowledge. The modified prior knowledge is

then used to direct subsequent learning. To cause bet-ter acquisition of scientific conceptions, the textual in-formation should enable students to progress at theirown pace and force them to use their thinking ability.

Text-based conceptual features can supplementlecturer-presented classroom experiences. Texts de-signed to promote conceptual change can reinforcein-class instruction and help teachers teach in a waythat promotes conceptual change. Many specific in-structional strategies based on conceptual change ap-proach have been proposed to help students changetheir misconceptions. Supportive evidence for thisapproach comes from the literature on refutationaltext and conceptual change text (Alvermann andHynd, 1989; Hynd, 2001; Hynd et al., 1997; Palmer,2003). Alvermann and Hynd (1989) developed therefutational text approach upon the basis of Posneret al. (1982) conceptual change model. They definedrefutational text is a text that contrasts common alter-native conceptions with scientific conceptions. Refu-tational text presents the commonly associated alter-native conception, refutes it by explaining why it isnot a scientifically acceptable concept, and providesan explanation of the scientific conception. The majordifference between the refutational text and concep-tual change text involves whether students are askedexplicitly to make a prediction about a situation. Inthe refutational text model, common misconceptionsare contrasted to scientific conceptions, but the stu-dent is not asked first to make a prediction about acommon situation before the refutation is given. Inthe conceptual change text model, students are askedexplicitly to make a prediction what would happen ina situation before being presented with informationthat demonstrates the inconsistency between com-mon misconceptions and the scientific conceptions.Following the prediction phase, the students are pre-sented with common misconceptions along with theevidence countering these misconceptions.

Moreover, other techniques have been used tocause acquisition of scientific conceptions and elim-ination of misconceptions. For instance, Odom andKelly (2001) investigated the effectiveness of conceptsmapping, the learning cycle, expository instruction,and a combination of concept mapping and learn-ing cycle in promoting conceptual understanding ofdiffusion and osmosis. They found that the conceptmapping/learning cycle and concept mapping treat-ment groups significantly outperformed the exposi-tory treatment group in conceptual understanding ofdiffusion and osmosis. Besides, Hameed et al. (1993)used a computer-assisted instructional (CAI) package

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Ecological Concepts 97

based on the conceptual change model to challengestudent misconceptions of chemical equilibrium. Thedesign of the CAI package was based on the condi-tions (Posner et al., 1982) proposed for bringing aboutconceptual change. The package used simulations tocreate cognitive conflict in students and promote ac-commodation of their conceptions. It produced sig-nificant conceptual change in students.

This study examined the effect of conceptual-change-texts-oriented instruction on students’ un-derstanding of ecological concepts. The conceptualchange text strategy is designed to suggest conditionsin which alternative conceptions can be replaced intoscientific conceptions and new conceptions can beintegrated with existing conceptions. The text is de-signed in such a way that the students’ misconceptionsare acquired by disequilibrating their preconceptionswith scientific phenomenon through questions. Theteacher provides the discussion environment with dis-equilibrating questions. The text provides the condi-tion to test their preconceptions and notice their mis-conceptions in the concepts. The explanatory phaseof the text involves an explanation of the scientificallycorrect concept in the context of prediction questions.The final phase provides opportunities to apply thecorrect conception in different settings.

To date, several studies have reported the effec-tiveness of conceptual change texts on creating con-ceptual change and promoting meaningful learning instudents regarding many science concepts (Chambersand Andre, 1997; Hynd et al., 1994; Mikkila, 2001;Sungur et al., 2001; Wang and Andre, 1991). In thepresent study, a group of texts grounded in concep-tual change approach was used to promote concep-tual change in elementary students regarding ecolog-ical concepts. It can be said that the main differenceof the present study when compared to other stud-ies is due to the conceptual-change-text-oriented in-struction factor on the understanding of ecologicalconcepts.

PURPOSE

Considering the importance of ecology to stu-dents’ understanding of their environment, studentsshould learn ecological concepts in a meaningful man-ner. To promote meaningful learning, the identifica-tion of students’ misconceptions is just the first stepbut the elimination of these misconceptions is themost important task. For that reason, the purposesof this study were to identify the seventh-grade stu-

dents’ misconceptions concerning selected ecologi-cal concepts and to investigate the effectiveness ofconceptual-change-texts-oriented instruction in elim-inating these misconceptions.

Research Question and Hypothesis

The main research question in this study is“is there a significant difference between the effectof conceptual-change-texts-oriented instruction andthat of traditional instruction on seventh-grade stu-dents’ understanding of ecological concepts?” Thehypothesis was that there is no statistically signifi-cant difference between the posttests mean scores(gain scores) of the students taught with conceptualchange instruction and those taught with traditionalinstruction with respect to understanding of ecologi-cal concepts.

METHOD

Sample

Participants in this study included 58 seventh-grade students from two intact classes of an elemen-tary school located in an urban area. Both classeswere taught by the same science teacher and both re-ceived identical syllabus-prescribed learning content.The data were obtained from 28 students in the ex-perimental group utilizing conceptual-change-texts-oriented instruction, and 30 students in the controlgroup attending traditional instruction. The studentswere typical seventh graders, with a mean age of12 years. The socioeconomic status (SES) of the stu-dents in both groups was similar, with the majorityof the students coming from middle- to high-classfamilies.

Instrumentation

Data for this study were obtained through twomajor sources: (1) interviews with students and(2) Ecology Concept Test.

Interviews With Students

To assess students’ understanding of ecologicalconcepts, 10 eighth-grade students who had studied

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the ecology were interviewed. The interviews useda semistructured approach involving the asking ofstructured questions followed by clarifying unstruc-tured thought-provoking questions. The interviews,conducted at the beginning of the study, served as themain sources of data and addressed the students’ mis-conceptions concerning ecological concepts. Ten in-dividual interviews were held and each lasted about25 min. Interview questions covered basic ecologicalconcepts, such as producers, consumers, decomposers,ecosystem, notion of energy flow within the ecosys-tem, food chain, energy pyramid, and food web. All ofthe interviews were audiotaped and transcribed ver-batim by the researchers.

The Ecology Concept Test

A two-tier multiple-choice test including 21 itemswas developed by the researchers to determine stu-dents’ understanding of selected ecological concepts.Items present in the test were based on the two-tier multiple-choice format described by Haslam andTreagust (1987). The first tier of each item exam-ined the content knowledge with two or three alter-natives. The second tier consists of four reasons forthe first tier. These reasons include one scientificallyacceptable answer and three misconceptions identi-fied during the interviews and from the related lit-erature. A list of students’ misconceptions identifiedby the Ecology Concept Test is presented in Table I.Students need to have both the content choice and

Table I. A List of Student Misconceptions Related to Ecological Concepts

1. Environment is places where living things exist because it includes plants and animals in it2. Population is the number of people in a certain area, e.g., population of a city3. Ecosystem is the interaction among living things4. Decomposers eat dead plants and animals to keep environment clean5. Decomposers are not important because they are found on dead animals6. Decomposers have no effect on ecosystems because they are too small to be seen by naked eye7. The energy source for plants is soil because they grow in and feed on water and minerals found in the soil8. There is no relationship between plants and animals in terms of energy because both plants and animals have their own energy9. Energy does not pass from one organism to another because every living thing has its own energy

10. Food chain is a kind of feeding relation including different food materials such as proteins and vitamins11. In a food chain including plant, insect, chicken and man, energy flows through man to plant because man has the greatest

amount of energy12. In a food chain including grass, sheep and man, man has the greatest amount of energy because he gets his energy both from

grass and sheep13. In a food chain including grass, sheep and man, man has the greatest amount of energy because he is stronger and has more energy14. Among lion, rabbit and man, lion is the primary consumer because it is carnivore, wild and strong15. Among lion, rabbit and man, man is the primary consumer because he consumes everything16. A change in one population only affects another population if the two populations are related as predator and prey17. A population located higher on a given food chain within a food web is a predator of all populations located below18. If the size of one population in a food web is altered, all other populations in the web will be altered in the same way

the reason (combination) correct to be awarded 1.Content validity of each item in the test was deter-mined by a group of experts in science, science edu-cation, measurement, and evaluation. The classroomteacher also analyzed the relatedness of the test itemsto the instructional objectives. The reliability coeffi-cient computed by Cronbach’s alpha estimates of in-ternal consistency of this test was found to be 0.77,when both parts of the items were analyzed.

The test was administered to both experimentaland control groups as a pretest before the treatmentand as a posttest after the treatment.

The development of multiple-choice instrumentsis an alternative method to identify students’ mis-conceptions. Multiple-choice test can be easily ad-ministered and interpreted but it has the limitationthat it does not give information about the reasoningof the students. Students may give correct answersfor wrong reasons. To get students’ reasoning behindtheir choices, Haslam and Treagust (1987), Odom andBarrow (1995), and Rollnick and Mahoana (1999)have recommended the use of two-tier multiple-choice instrument that focuses on helping studentsreason and detecting common misconceptions. In thispresent study, two-tier multiple-choice instrumentwas developed to determine seventh-grade students’misconceptions concerning ecological concepts (seethe Appendix). The focus of this type of instrumentis to help students reason and to detect common mis-conceptions. This type of assessment sends studentsthe message that reasoning and/or thinking are im-portant. Typical multiple-choice items usually require

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students to recall specific content. No reasoning is re-quired. This type of assessment sends the message tothe students that memorization of content is impor-tant. Reasoning is not required. Multiple-choice testshave been used to evaluate students’ content knowl-edge, but they had limitations with the determiningstudents’ reasoning behind their choices (Odom andBarrow, 1995).

Treatment

This study was conducted over a period of 5weeks. A total of 58 students from two intact sci-ence classes were involved in the study. The same sci-ence teacher gave the classroom instruction for bothgroups. One of the classes was assigned as the experi-mental group and other as the control group. Instruc-tion in both classes was observed by the first authorto control for the teacher effect and bias and also toverify the treatment. The topics related to ecologywere covered as part of regular classroom curricu-lum in the science course. Students in both groupswere exposed to same content for the same duration.Duration of the lessons was four 40-min periods perweek.

Students in the control group were taught uniton ecology by the teacher upon the basis of a lec-ture/discussions methods. The teacher explained thefacts on the blackboard and students took notesthrough the lesson. The teacher made frequent useof the chalkboard to illustrate the various conceptsof the ecology and described their function. Theteacher has designed and photocopied worksheetsand information sheets and printed a series of bookson science topics relevant to the ecology concepts.The teacher defined and described each conceptin order in which it appeared in the passage. Thestudents read each passage and then the major con-cepts were written on the board. The teacher de-scribed and defined the concepts and after teacherexplanation, the concepts were discussed (in smallgroups), motivated by teacher-directed questions. Themajority of instruction time was devoted to instruc-tion and engaging in discussions stemming from theteacher’s explanation and questions. In the controlgroup, teaching strategies relied on teacher explana-tion, classic textbooks, and worksheet study withina discussion environment with no consideration ofthe students’ misconceptions. But in the experimentalgroup, teaching strategies relied on teacher explana-tion, questions, and discussion of conceptual change

texts with students, taking into account the students’misconceptions.

Students in the experimental group worked withconceptual change texts. Conceptual change textswere prepared by the researchers by using infor-mation obtained from related literature and inter-views. Conceptual change texts were written con-cerning the following topics: ecosystem, population,producer, consumer, decomposer, food chain, foodweb, and energy pyramid. In each of these texts, stu-dents were introduced with questions and their pos-sible answers that may include misconceptions heldby the students. Each possible answer was then dis-cussed in the texts. In this way students were aimedto be dissatisfied with their current conceptions. Thenscientifically acceptable explanations that were moreplausible and intelligible were mentioned. Also, ex-amples and figures were included in the texts for fur-ther helping students understand the scientific con-cept and realize the limitations of their own ideas.For example, in the conceptual change text related toenergy pyramid, students were asked about the en-ergy transfer within living things and the directionof energy flow in the food chain including plant, in-sect, chicken, and man. From the interviews and thepretest, it was found that students had a misconcep-tion that energy cannot pass from one living thing toanother. These students believed that every livingthing has its own energy. In the conceptual changetext, students were first informed with this miscon-ception and then the text explained why these stu-dents think wrongly. It was reminded in the text thatproducers capture sunlight energy first and they useit to produce food. Thus, the flow of energy in a foodchain begins with producers. It was also mentionedthat role of producer in a food chain was related tomaterial cycles in ecosystems, light energy, and itsutilization by several organisms. The producer wasintroduced as the converter of sunlight into chemi-cal energy, in turn be eaten by other organisms. An-other misconception is related to the notion of theenergy flow in the ecosystems. In the text, it was men-tioned that most of the students thought that man hadthe greatest energy in a food chain including grass,sheep, and man, because he got his energy from bothgrass and sheep. To correct this misconception, thefigure of energy pyramid was presented in the textand the notion of energy flow was explained in ascientific manner. It was mentioned that no transferof energy is completely efficient and that some en-ergy is always lost as heat during any transfer. Withinan ecosystem, progressively less energy is therefore

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available at each tropic level. For this reason, the num-ber of tropic levels is limited to about six to sevenlevels.

The following excerpt is a part of the conceptualchange text used in this study:

. . .Some students define the food chain as a two-wayrelationship occurred when an animal eats a plant.When it is asked these students to give an exampleto food chain, they respond like this “sheep eats thegrass.” When it is asked who eats the sheep, their an-swer is the “man,” However, they failed to realizethat in a food chain plants are eaten by some ani-mals which in turn be eaten by other animals. Someanimals eat both plant and animal material. At eachstage of consumption, there is a transfer of storedenergy.

Let’s try to find out the deficiencies in the ideas ofthese students.

In order to understand the food chain concept bet-ter, let’s examine the following example. “Grass→sheep→man” is an example of a simple food chain.Here, the energy stored in the grass is passed fromgrass through man. Producers harness sunlight en-ergy and convert it to forms that they and the otherorganisms in the ecosystems can use. In other words,the energy stored in the form of food in plantsis passed from producers to consumers in a foodchain. . . .

Prior to the study, the teacher was informedabout the use of conceptual change texts in two1-h training sessions. During the study, several meet-ings with the teacher were conducted to facilitatethe proper use of conceptual change texts. The textswere given to students to be read 3 or 4 days beforethe class hour when the related topic would be cov-ered. The teacher discussed the conceptual changetexts with the students during the lesson. First, stu-dents read the texts silently, and teacher providedstudents with wait-time to think about the questions.Then, the teacher emphasized misconceptions in stu-dents’ answers by providing opportunities for stu-dents to be involved in discussions while studyingconceptual change texts. During this period, for ex-ample, students examined a model of energy pyra-mid that had been prepared and colored by the re-searchers. Then, students were asked to constructtheir own energy pyramid. Similarly, while discussingconcepts of food chain and food web, they con-structed their own food chains and food webs. Bythis way, teacher–student and student–student inter-actions were maximized. Thus, students in the ex-perimental group played an active role during theinstruction.

RESULTS

Interviews With Students

Qualitative data composed of students’ re-sponses to semistructured interview questions. Tenindividual interviews with eight-grade students wereconducted. The purpose of interview was to tease outthe students’ meaningful understanding of ecologicalconcept. The schedule was left flexible to allow stu-dents to express themselves in relative freedom andto enable the interviewer to ask followed-up ques-tions. Interview questions covered basic ecologicalconcepts, such as producers, consumers, decomposers,ecosystem, notion of energy flow within the ecosys-tem, food chain, energy pyramid, and food web. Se-lected examples of excerpts from interviews are asfollows:

Interviewer: How can you define environment? Whatkind of things can we find in the environment?

Student1: It is a place where all living thingsexist . . .plants, animals, people . . .Non-livingthings may be harmful for the environment forexample plastics, so we should not include theminto the definition of environment.

Students 6: We can find living things in the environ-ment

Interviewer: What about nonliving things.Students 6: Yes, of course, for example, buildings, cars,

etc.

Interviewer: What is population? Can you give anexample?

Student 3: Population is the number of people forexample population of a city.

Student 1: . . . , flowers and animals in a garden is anexample of population.

Interviewer: When I say ecosystem, what do youunderstand?

Student 3: I suppose, it is something related to ecology.Student 10: It means ecology and so it is something

related to nature.

Student 2: Interaction between living things, for ex-ample the interaction between producer and con-sumers is the ecosystem. By eating producers, con-sumers keep continuity of ecosystem.

Interviewer: What is the main energy source for allecosystems?

Student 6: Sun.Interviewer: Then, how can living things use this

energy?

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Student 6: We cannot use sun energy directly, sun gen-erates heat and we use this heat to survive.

Student 9: Sun can be the main energy source. . .bothplants and people use sun energy. Plants use this en-ergy directly but I can’t remember how, but peopleuse this energy through indirect ways for exampleby eating plants.

Interviewer: Do you think that, is there a relationshipbetween plants and animals?

Student 1: No, because both plants and animals havetheir own energy.

Student 9: No, because animals are stronger thanplants, and therefore have their own energy.

Student 4: Yes, animals eat plants and get their energy.

Interviewer: How can you describe food chain?Student 1: It is something related to who eats whom.Student 2: It exists when an animal eats a plant.Student 3: I do not know exactly but it includes differ-

ent animals.Student 10: It must be a kind of feeding relation,

including different materials such as vitamin,proteins, etc.

Interviewer: What is the direction of energy flow ina food chain including plant, insect, chicken andman?

Student 1: Energy flows through plant to man becauseman has the greatest energy and he gets his energyfrom plant and chicken . . . thus energy accumulatesin the man.

Student 10: Energy flows through man to plant be-cause man has the greatest energy. . . so energyflows from high to low.

Student 4: Energy does not pass from one organ-isms to another because every organism has its ownenergy.

Interviewer: Do you know what energy pyramid is?Student 3: As I remember, it looks like a triangle where

producers and consumers are placed.Student 4: It is same as food chain but in the shape of

triangle.Interviewer: What about decomposer?Students 3: I do not know where I can put them in

the pyramid exactly. But I think that they should beat the top of it, because they eat dead animals andplant. So they come after all other organisms.

Student 4: There is no need to include decomposersbecause they are too small to be seen by naked eye.They are just found on dead animals.

Interview results revealed students misconceptionsconcerning basic ecological concepts.

Responses to Ecology Concept Test

Independent t test analysis showed that therewas no statistically significant difference between themean scores of the experimental and the controlgroups with respect to their prior knowledge in sci-ence (t = 0.595, df = 56, p > .05) and their under-standing of ecological concepts (t = 0.395, df = 56,p > .05) before the treatment. The students’ gradein a science course in the previous year was used asan indication of their previous learning in science.Because students’ prior knowledge is important inthe integration and construction of new knowledgeinto their existing cognitive structure, carrying out thisstep was crucial. These results demonstrated that thestudents in both groups were equivalent concerningthose variables prior to treatment. Paired sample t teststatistics showed that there was a statistical signifi-cant difference between the pre- and posttest meanscores of the experimental group (t = 13.98, df = 27,p < .05) and control group (t = 7.58, df=29, p < .05)with respect to achievement in ecological concept.The experimental and control groups each indicateda significant improvement. But, after the treatment,independent t test analysis revealed a statistically sig-nificant difference between the experimental and con-trol groups’ mean scores on the Ecology Concept Testin favor of the experimental group (t = 2.395, df =56, p < .05). The descriptive measures were given inTable II. The students in the experimental group whowere engaged in conceptual-change-text-oriented in-struction demonstrated better performance over thecontrol group students who were engaged in tradi-tional instruction. Also, the results indicated a statis-tically significant difference between the gain scoremeans (pre–post test difference) of the experimentaland control groups with respect to ecological conceptsin favor of the experimental group (t = 2.530, df= 56,p < .05).

Average percentages of students in both ex-perimental and control groups selecting the desiredcontent choice and reason (combination) were eval-uated for both pre–post ecological concept tests. Be-fore the treatment, the average percent of the correct

Table II. Descriptive Measures

Pretest Posttest

N M SD M SD tpost p

Experimental 28 6.71 2.05 13.3 2.45 2.395 0.020group

Control group 30 7.00 2.27 11.6 2.58

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responses of the students who selected desired com-bination was 31.9% in the experimental group and32.7% in the control group. After the treatment,63.8% of the students in the experimental group se-lected the desired combination while 55.2% of the stu-dents in the control group selected the desired combi-nation. When the proportion of correct responses andmisconceptions determined by the item analysis forthe experimental and control groups was examined,striking differences between the two groups in favorof the experimental group on several items were indi-cated. For example, before the treatment, for an itemdealing with the definition of the food chain, 42.9% ofthe students in the experimental group and 40.7% ofthe students in the control group selected the desiredcombination, which was “food chain is the transfer ofenergy from one organism to another, because the en-ergy stored by producers is passed through the organ-isms in a food chain.” After the treatment, the major-ity of the students in the experimental group (96.4%)and 66.7% of the students in the control group se-lected the desired combination. Similarly, in anotheritem students were asked to determine the organismthat has the greatest amount of energy in the follow-ing food chain: grass → sheep → man. Before thetreatment, only 14.3% of the students in the experi-mental group and 13.3% of the students in the con-trol group selected the desired combination, whichwas “grass has the greatest amount of energy, becausethe first tropic level belongs to the producers.” Afterthe treatment, while the percentage of the studentswho selected the desired combination in the experi-mental group increased to 82.1%, the percentage ofthe students who selected the desired combinationin the control group increased to 43.3%. These re-sults showed that the students in the experimentalgroup who were taught with conceptual-change-texts-oriented instruction had better acquisition of scientificconceptions than those in the control group who weretaught by traditional instruction.

The misconceptions included in the distractorsof the Ecology Concept Test are the common mis-conceptions held by the students in ecological con-cepts. For instance, in one of the items students wereasked to determine the direction of energy flow in thefollowing food chain: grass → insect → chicken →man. The most common misconception found in thisconcept was that “energy flows through grass to manbecause man does not give energy to any other or-ganism.” Before the treatment, the percentage of thestudents who had that misconception was 17.9% in theexperimental and 16.7% in the control group. After

the treatment, while 16.7% of the students in the con-trol group who engaged in traditional instruction stillhad the same misconception; none of the students inthe experimental group who engaged in conceptual-change-texts-oriented instruction had that miscon-ception. Similarly, before the treatment, 14% of thestudents in the experimental group and 12% of thestudents in the control group thought, “food chain is akind of feeding relations including different food ma-terials such as proteins and vitamins.” After the treat-ment, the percentage of students in the control groupwho had that misconception was 10%. On the otherhand, none of the students in the experimental groupheld that misconception after the treatment. Anothercommon misconception found in this study was aboutthe population concept. Before the treatment, 18%of the students in the experimental group and 17%of the students in the control group defined the pop-ulation as “the group of people in a given area” andthey gave “the number of people in a city” as an ex-ample of population. After the treatment, while 13%of the students in the control group still had that mis-conception; none of the students in the experimentalgroup kept that misconception. The common miscon-ceptions identified by the Ecology Concept Test arepresented in Table I.

DISCUSSION

The main purposes of this study were to iden-tify seventh-grade students’ misconceptions concern-ing ecological concepts with two-tier multiple-choicetest and to investigate the effectiveness of conceptual-change-texts-oriented instruction in eliminating stu-dents’ misconceptions. The results of this studyshowed that the development of two-tier multiple-choice test to evaluate commonly held misconcep-tions regarding ecological concepts provided onestarting point for helping the teacher to improvestudents’ learning of these concepts. Teachers arenot generally critical of students’ answers, which re-veal misconceptions. Such multiple-choice tests canhelp the teacher to address existing students’ concep-tions that are not compatible with scientific concep-tions and to determine students’ reasoning behindtheir choice. Students may give correct answers forwrong reasons. Once misconceptions are identified, ateacher can more easily help students acquire the sci-entifically acceptable conception by developing alter-native teaching approaches, which address students’misconceptions.

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In this study, the experimental group receivedinstruction using conceptual change texts, while thecontrol group received traditional instruction follow-ing the logical presentation of concepts seen in text-books. The results showed that both groups wereequal in terms of achievement related to ecologi-cal concepts and previous learning in science be-fore the treatment. Both groups showed gains withrespect to understanding of ecological concepts af-ter treatment. Of more interest than the changeswithin each treatment group are the relative changesbetween them. The experimental group had higherimprovement than did the control group after thetreatment. The conceptual-change-text-oriented in-struction caused a significantly better acquisition ofscientific conceptions than the traditional instruction.The conceptual-change-texts-oriented instruction ex-plicitly dealt with students’ misconceptions while thetraditional instruction did not. The method of dealingwith these misconceptions was to use strategies of con-ceptual change designed to promote the acquisition ofnew conceptions as consequences of the exchange anddifferentiation of the existing concepts and integra-tion of new concepts with existing ones. The concep-tual change texts included a set of guidelines provid-ing special learning environments such as identifyingcommon misconceptions, activating students’ miscon-ceptions by presenting simple examples, presentingdescriptive evidence that the typical misconceptionsare incorrect, and giving students the opportunity topractice the scientific explanation by using questions.These properties of conceptual change approach mayhave caused a better understanding of ecological con-cepts when compared to the traditional instruction.Teachers can use many different instructional strate-gies to eliminate misconceptions and promote con-ceptual change. The results of this study showed thatthere were still some misconceptions in both groupsafter treatment. The students in both groups have notabsolutely mastered certain concepts related to de-composers and food web. For example, after instruc-tion many students still thought that decomposerswere important for ecosystems because they helped tokeep environment clean by eating dead animals andplants. Actually, during the interviews it was revealedthat most students had a wrong definition for decom-posers in their mind that was “decomposers were thesweepers of the nature.” Previously acquired knowl-edge is highly resistant to change, and the change mayoccur if the students find their existing conceptionsinadequate or unsatisfactory (Webb and Boltt, 1990).Fellows (1994) claimed that conceptual change and/or

knowledge restructuring is a developmental processthat takes a long time, even with good instructionalstrategies. Moreover, many students in both groupshad difficulty in determining the effect of a changein numbers of one population on another populationwhen the effect was transmitted along more than oneroute. During the interviews, students tended to selectone of the several pathways without explaining whythey chose that particular route. Griffiths and Grant(1985) proposed that misconceptions might occur ifstudents consider a food web to be functionally likea network of individual food chains. Moreover, themost common misconception in the food web con-cept was based on the proximity of populations inthe food web. Students believed that a change in onepopulation would only affect another population iftwo populations were directly related as predator andprey. When asked to determine the effect of a changein one population on a second population in anotherpart of the web, students’ responses included “thereis no effect as the populations are too far apart” and“the two populations are not really closely linked.”

In summary, the conceptual-change-text-oriented instruction caused a statistically betteracquisition of ecological concepts and eliminationof misconceptions related to these concepts thanthe traditional instruction in the seventh-gradeelementary students. This result is consistent with theresults presented by Wang and Andre (1991), Hyndet al. (1994), and Chambers and Andre (1997). On theother hand, this study was limited to 58 seventh-gradeelementary students in two intact classrooms. Forfurther study, similar researches can be constructedfor different grade levels of elementary educationand larger sample size.

APPENDIX: EXAMPLES OF THEITEMS PRESENTED IN THE TEST

1. Population is the

a) All living things in a city.b) Number of people in living in a city.c) Anchovies in the Black Sea.

The scientific reason of my answer is that

a) Population is a group of living things in acertain area.

b) Population is the group of human beings ina certain area.

c) Population corresponds to the number ofinhabitants.

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d) Population is the group of individuals of aparticular kind.

2. Ecosystem is

a) The relationship between producers andconsumers.

b) A continual change in the way of lives ofthe living things in nature.

c) An interacting system of living things andtheir nonliving environment.


a) The consumers eat the producers to main-tain the continuity of an ecosystem.

b) It involves the living and nonliving thingsand their interaction in a certain area.

c) The livings have a continuous interactionwith each other.

d) An ecosystem involves the living things thatexist in a certain area.

3. Decomposers are

a) Necessary for the ecosystem.b) Not necessary for the ecosystem.c) Have no effect on ecosystem.


a) They convert organic materials into inor-ganic ones.

b) They are too small to be seen by naked eyes.c) They live on dead body.d) They keep environment clean by consum-

ing dead body.

4. In a Food chain including plant, insect, chickenand man.

a) Energy flows through plant to man.b) Energy flows through man to plant.c) Energy can not pas through from one living

thing to another.


a) Every organism has its own energy.b) Man has the greatest amounts of energy.c) Man does not give energy to any other or-

ganisms.d) Energy enter food chain through prod-

ucers.

5. In an energy pyramid.

a) Producers occupies the base.b) Consumers occupies the base.c) Man occupies the base.


a) Available energy decreases as one pro-gresses from producers to consumers.

b) Number of producers are higher than thatof consumers.

c) Man consumes both plants and animals.d) Consumers are stronger and larger in size.

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Facilitating Conceptual Change in Students' Understanding of Ecological Concepts

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