Asia-Pacific Forum on Science Learning and Teaching, Volume 9, Issue 1, Article
11 (Jun., 2008)
Material and Methods
This research is in a testing model. The experimental group (CCT, CMI) in Table I, represents the group of students using the concept and the conceptual change text. The control group (TBI) represents the group using traditional teaching method (teacher-directed strategy), T1 shows the Biology Achievement Test (BAT).
Table I. The study’s research pattern
Groups Pre-test Treatment Post-test Experimental Group (CCT, CMI) T1 (CCT, CMI) T1 Control Group (TBI) T1 (TBI) T1
The Biology Achievement Test was applied on both of the groups before teaching about molecules carrying genetical information in order to see whether there is a considerable amount of difference between the groups. The first step of the study was to randomly choose 5 students to interview before taking the course. In accordance with the data acquired by the interview analyses and the dialogues conducted among teachers, a biology achievement test was formed. Before applying the concept maps on the experimental group, the students were informed about the concept map and conceptual change texts during the preceding unit. A researcher gave the classroom instruction for both groups. The researchers, in the course of study, prepared concept maps and the researchers again used them during the lesson. Also, the students prepared some concept maps during the teaching process. Conceptual change texts were prepared by the researchers and handed out to the students during the lesson. The questions and explanations, which took place in conceptual change texts, were discussed among the researchers and students. During the discussion, the misunderstood concepts were clarified and the correct usage of those concepts were explained to the students.
Sample The sample of study was randomly selected from 11th grade high school students in the province center of Konya, a big size city at the Central Anatolian Region of Turkey. The total number of students was 50 and was split into two equal classes (see Table II). The ages of students were between 16 and 17.
Table II. The groups involved in the study and the number of students
Groups No of students (N) Experimental Group (CCT, CMI) 25 Control Group (TBI) 25 Total 50
Instrument There was only one written instrument used in this study. This instrument was the Biology Achievement Test (BAT). The data acquired by this surveying instrument was transferred to the computer and assessed by using SPSS 10.00 package programme. This test, which was developed by the researchers, consisted of 30 multiple-choice questions. There was only one correct answer and 4 misleading answers for each question. While preparing the misleading answers, the misconceptions acquired by the students were taken into account. Test was examined by a group of experts in biology education, biology, measurement and evaluation regarding content validity, and format. The internal consistency reliability of this test was found to be 0.79. This test was applied to 11th grade high school students. During the analysis of the data, the “t” test was applied and percentage expressions were used. a = 0.05 was used as significance level. Treatment This study was conducted for 5 weeks in the second semester of 2003-2004 academic year. A total 50 students, from two different 11th grade classes attending biology lessons from the same teacher participated in the research. One of the classes was assigned as the experimental group, and the other was assigned as the control group. Two different practices were used in this study. While applying traditional biology teaching method on the control group; concept maps, given together with conceptual change texts, were applied on the experimental group. Biology lessons were given regularly three hours a week. The methods of teaching for the control group included teacher explanations and discussions in accordance with the course books. The control group received the traditional instruction involving lessons using lecture/discussion methods to teach concepts. Teaching strategies relied upon teacher explanation and textbooks, with no consideration of the students’ alternative conceptions. In this group, the teacher provided instruction through lecture and discussion methods to teach the concepts. The teacher structured the entire class as a unit, wrote notes on the chalkboard about the definition of concepts, and passed out worksheets for students to complete. The primary underlying principle was that knowledge as fact to students. After the teacher’s explanation, some concepts were discussed, prompted by teacher directed questions. Worksheets were specifically developed by the researchers for each lesson. They required written responses and reinforced the concepts presented in the classroom sessions. They were collected and corrected by the teacher. This classroom typically consisted of the teacher presenting the right way to solve problems. The majority of instruction time (70%) was devoted to instruction and engaging in discussion stemming from the teacher’s explanations and questions. This classrom typically consisted of the teacher presenting the ‘right way’ to solve problems. The researcher gave the classroom instruction for both groups. Students in the experimental group worked with conceptual change text and concept maps. Because of the complex process of making a concept map, some pre-arrangements were made for students in order to make a concept map. The students were given some examples of concept maps used in the preceding unit of the subject molecules carrying genetical information, and the researcher made some explanations. In the course of this process; the steps to be performed in order to form a concept map were listed as follows: Concepts of the teaching subject were listed. The most general concept was written on the heading of the page. Concepts were written in a box. Correlation of the concepts, generalizations and principles were listed apart from the concept list. Two boxes were linked to each other through a line and the type of the relation was named. Concept maps of subunits were prepared. These concept maps were the sample maps prepared by the students. The students were charged with preparing concept maps for the subjects taking place in the unit. In the beginning, in order to help students for prepare their first concept map, a concept list was given to students. Then, the necessary steps to make a concept map were explained. The experimental group used conceptual change texts together with the concept maps. Conceptual change texts (13 conceptual change texts) were prepared by the researchers in order to focus on and correct the students’ misconceptions about the subject of molecules carrying genetical information. In the conceptual change texts prepared after the interviews with the students, these subjects were taken into account: the importance of nucleic acids, the types and functions of nucleic acids, their placements according to cell types; the functions of DNA and RNA, their similarities and differences; the crucial functions of DNA and RNA; DNA’s pairing and the following processes; the transfer of genetic characters from generation to generation; the types and functions of DNA and RNA; the fulfilment stages of protein synthesis; the structures and functions of ribosomes; amino acids forming the structure of proteins; the reasons for the differences between living creatures; genetic code; data flow in the cells. Then conceptual change texts were handed out to the students regularly in their lesson hours every week. Most of the concepts taking place in conceptual change texts were explained to the students. The aim of preparing the conceptual change texts was to replace misconceptions with the correct concepts. The texts offered a set of guidelines to help students gain experience in grasping the concepts. These guidelines provided a special learning environment, such as identifying common alternative conceptions, activating students’ alternative conceptions by presenting examples and questions, presenting descriptive evidence in the text that the typical alternative conceptions were incorrect, and providing a scientifically correct explanation of the situation. The teacher provided opportunities for students to be involved in discussion and question and answer sessions while studying the conceptual change text. In the conceptual change text, students were asked explicitly to predict what would happen in a situation before being presented with information that demonstrated the inconsistency betwen common alternative conceptions and the correct scientific conceptions. In each of the texts, the topics were introduced with questions, and students’ possible answers that were scientifically unaccepted were mentioned directly. Then scientifically acceptable explanations that are more plausable and intelligible were described. Also, examples and figures were included in the texts with the intention of further helping students understand the scientic concept and realize the limitations of their own ideas.
In this section, some misconceptions of students about the unit called “Molecules Carrying Genetic Information” were defined.
Question: How many types of nucleic acids are there in living creatures? Student 1:3 types Question: Can you tell me their names?
Student 1: DNA, RNA, ATP
Question: Do all the living creatures have to have their own DNA? Student 5: No, they don’t. Because only human beings and animals have DNA.
Student 5: Because the others don’t have cell-cores. Question: Can you give me the examples of living creatures without cell-cores?
Student 5: Plants, single-celled organisms, fungus.
Question: In which ways do DNA replications emerge? Student 5: DNA replicates itself before the cell dichotomy and protein synthesis.
Question: Well, is it necessary to have DNA replication in order to have protein synthesis?
Student 5: Yes. Question: Why?
Student 5: Because, by matching itself, DNA transfers the genetic information to m-RNA and to the new cells. Question: Is there any difference between adenine nucleotide molecule of DNA and adenine nucleotide molecule of RNA?
Student 1: No, there isn’t. They’re the same. Question: Do all living creatures make protein synthesis? Student 1: Some of them don’t make it. For example, parasites and decomposers. Question: Why? Student 1: Because they get all of their nutrients, including protein, from their environment.
Question: The permutation of metionine amino acid in human beings is AUG. Can we say that it is the same in mice?
Student 1: No, we can’t. Question: Why? Student 1: Because they are totally different living creatures.
Question: How many genetic codes does a DNA molecule contain in order to encode 20 types of amino acids taking place in the nature?
Student 2: It contains 20 types of code countering 20 types of amino acids.
Question: When a protein, consisting of 100 amino acid is synthesised, how many peptide core and H2O molecule do emerge?
Student 1: 200 Peptide bond and 99 H2O molecules emerge.
Student 3: 100 peptide bond against 100 H2O molecules.
Copyright (C) 2008 HKIEd APFSLT. Volume 9, Issue 1, Article 11 (Jun., 2008). All Rights Reserved.