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1.
This study explores biology undergraduates' misconceptions about genetic drift. We use qualitative and quantitative methods to describe students' definitions, identify common misconceptions, and examine differences before and after instruction on genetic drift. We identify and describe five overarching categories that include 16 distinct misconceptions about genetic drift. The accuracy of students' conceptions ranges considerably, from responses indicating only superficial, if any, knowledge of any aspect of evolution to responses indicating knowledge of genetic drift but confusion about the nuances of genetic drift. After instruction, a significantly greater number of responses indicate some knowledge of genetic drift (p = 0.005), but 74.6% of responses still contain at least one misconception. We conclude by presenting a framework that organizes how students' conceptions of genetic drift change with instruction. We also articulate three hypotheses regarding undergraduates' conceptions of evolution in general and genetic drift in particular. We propose that: 1) students begin with undeveloped conceptions of evolution that do not recognize different mechanisms of change; 2) students develop more complex, but still inaccurate, conceptual frameworks that reflect experience with vocabulary but still lack deep understanding; and 3) some new misconceptions about genetic drift emerge as students comprehend more about evolution.  相似文献   

2.
We are involved in a project to incorporate innovative assessments within a reform-based large-lecture biochemistry course for nonmajors. We not only assessed misconceptions but purposefully changed instruction throughout the semester to confront student ideas. Our research questions targeted student conceptions of deoxyribonucleic acid (DNA) along with understanding in what ways classroom discussions/activities influence student conceptions. Data sources included pre-/post-assessments, semi-structured interviews, and student work on exams/assessments. We found that students held misconceptions about the chemical nature of DNA, with 63 % of students claiming that DNA is alive prior to instruction. The chemical nature of DNA is an important fundamental concept in science fields. We confronted this misconception throughout the semester collecting data from several instructional interventions. Case studies of individual students revealed how various instructional strategies/assessments allowed students to construct and demonstrate the scientifically accepted understanding of the chemical nature of DNA. However, the post-assessment exposed that 40 % of students still held misconceptions about DNA, indicating the persistent nature of this misconception. Implications for teaching and learning are discussed.  相似文献   

3.
Geoscience instructors depend upon photos, diagrams, and other visualizations to depict geologic structures and processes that occur over a wide range of temporal and spatial scales. This proof-of-concept study tests click-on-diagram (COD) questions, administered using a classroom response system (CRS), as a research tool for identifying spatial misconceptions. First, we propose a categorization of spatial conceptions associated with geoscience concepts. Second, we implemented the COD questions in an undergraduate introductory geology course. Each question was implemented three times: pre-instruction, post-instruction, and at the end of the course to evaluate the stability of students’ conceptual understanding. We classified each instance as (1) a false belief that was easily remediated, (2) a flawed mental model that was not fully transformed, or (3) a robust misconception that persisted despite targeted instruction. Geographic Information System (GIS) software facilitated spatial analysis of students’ answers. The COD data confirmed known misconceptions about Earth’s structure, geologic time, and base level and revealed a novel robust misconception about hot spot formation. Questions with complex spatial attributes were less likely to change following instruction and more likely to be classified as a robust misconception. COD questions provided efficient access to students’ conceptual understanding. CRS-administered COD questions present an opportunity to gather spatial conceptions with large groups of students, immediately, building the knowledge base about students’ misconceptions and providing feedback to guide instruction.  相似文献   

4.
This study investigated the effectiveness of combining conceptual change text and discussion web strategies on students' understanding of photosynthesis and respiration in plants. Students' conceptual understanding of photosynthesis and respiration in plants was measured using the two-tier diagnostic test developed by Haslam and Treagust (1987, Journal of Biological Education 21: 203--211). The test was administered as pretest and posttest to a total of 233 eighth-grade students in six intact classes of the same school located in an urban area. The test of logical thinking was used to determine the reasoning ability of students. The experimental group was a class of 116 students received discussion web and conceptual change text instruction. A class of 117 students comprised the control group received a traditional instruction. After instruction, data were analyzed with two-way analysis of covariance (ANCOVA) using the Test of Logical Thinking and pretest scores as covariate. The conceptual change instruction, which explicitly dealt with students' misconceptions, produced significantly greater achievement in understanding of photosynthesis and respiration in plant concepts. Analysis also revealed a significant difference between performance of females and that of males in the favor of females, but the interaction of treatment with gender difference was not significant for learning the concepts.  相似文献   

5.
This study explored and documented the frequencies of conceptual difficulties confronted by college students seeking to understand the basic processes of cellular respiration. Using concept maps, clinical interviews and an open-ended instrument, viewpoints were elicited from 100 (novice) introductory biology students before and after relevant instruction in cellular respiration and from 100 (experienced) students enrolled in advanced biology courses. Chi-square analyses revealed significant differences among groups in the frequencies of scientifically acceptable and alternative conceptions. The findings suggest that novices harbor a wide range of conceptual difficulties that constrain their understanding of cellular respiration. Furthermore, many of these difficulties persist after instruction and new ones arise. Often these conceptual problems remain intact among experienced students despite well-planned, repeated instruction at advanced levels.  相似文献   

6.
This study involved the development and application of a two-tier diagnostic test measuring college biology students' understanding of diffusion and osmosis after a course of instruction. The development procedure had three general steps: defining the content boundaries of the test, collecting information on students' misconceptions, and instrument development. Misconception data were collected from interviews and multiple-choice questions with free response answers. The data were used to develop 12 two-tier multiple choice items in which the first tier examined content knowledge and the second examined understanding of that knowledge. The conceptual knowledge examined was the particulate and random nature of matter, concentration and tonicity, the influence of life forces on diffusion and osmosis, membranes, kinetic energy of matter, the process of diffusion, and the process of osmosis. The diagnostic instrument was administered to 240 students (123 non-biology majors and 117 biology majors) enrolled in a college freshman biology laboratory course. The students had completed a unit on diffusion and osmosis. The content taught was carefully defined by propositional knowledge statements, and was the same content that defined the content boundaries of the test. The split-half reliability was .74. Difficulty indices ranged from 0.23 to 0.95, and discrimination indices ranged from 0.21 to 0.65. Each item was analyzed to determine student understanding of, and identify misconceptions about, diffusion and osmosis.  相似文献   

7.
As biotechnology‐related scientific advances, such as stem cell research (SCR), are increasingly permeating the popular media, it has become ever more important to understand students’ ideas about this issue. Very few studies have investigated learners’ ideas about biotechnology. Our study was designed to understand the types of alternative conceptions students hold concerning SCR. The qualitative research design allowed us to examine college students’ understandings about stem cells and SCR. More specifically, we addressed the following questions: How can alternative conceptions about stem cell topics be categorized? What types of alternative conceptions are most common? Participants included 132 students enrolled in a biotechnology course that focused on the scientific background of biotechnology applications relevant to citizens. In this study, we used an inductive approach to develop a taxonomy of alternative ideas about SCR by analyzing student responses to multiple open‐ended data sources. We identified five categories of conceptions: alternative conceptions about what, alternative conceptions about how, alternative conceptions about medical potential, terminology confusion, and political and legal alternative conceptions. In order to improve instruction, it is important to understand students’ ideas when entering the classroom. Our findings highlight a need to teach how science can be applied to societal issues and improve science literacy and citizenship.  相似文献   

8.
This article explores the effectiveness of intervention discussion sections for a college general chemistry course designed to apply research on student preconceptions, knowledge integration, and student explanation. Two interventions, on bond energy and spontaneity, were tested and intervention student performance was compared with that of a control group that did not use the experimental pedagogy. Results indicate that this instruction, which identifies students' initial conceptions and integrates those ideas into class discussion, leads to enhanced conceptual understanding. The intervention group outperformed the control group on a written course midterm, the thermodynamics portion of a standardized American Chemical Society examination, and an in‐depth interview. In interviews, the intervention group students explained the energetics of bond breaking and formation at a more sophisticated level than did the control students. In contrast, control students were more tenuous in their thinking, tended to contradict themselves more when discussing bond energy, and harbored more misconceptions about spontaneity. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 464–496, 2002  相似文献   

9.

This study describes a lesson in which students engaged in inquiry in evolutionary biology in order to develop a better understanding of the concepts and reasoning skills necessary to support knowledge claims about changes in the genetic structure of populations, also known as microevolution. This paper describes how a software simulation called EVOLVE can be used to foster discussions about the conceptual knowledge used by advanced secondary or introductory college students when investigating the effects of natural selection on hypothetical populations over time. An experienced professor's use and rationale of a problem-based lesson using the simulation is examined. Examples of student misconceptions and naïve (incomplete) conceptions are described and an analysis of the procedural knowledge for experimenting with the computer model is provided. The results of this case study provide a model of how EVOLVE can be used to engage students in a complex problem-solving experience that encourages student meta-cognitive reflection about their understanding of evolution at the population level. Implications for teaching are provided and ways to improve student learning and problem solving in population genetics are suggested.  相似文献   

10.
ABSTRACT

Graduate students regularly teach undergraduate STEM courses and can positively impact students’ understanding of science. Yet little research examines graduate students’ knowledge about nature of science (NOS) or instructional strategies for teaching graduate students about NOS. This exploratory study sought to understand how a 1-credit Teaching in Higher Education course that utilised an explicit, reflective, and mixed-context approach to NOS instruction impacted STEM graduate students’ NOS conceptions and teaching intentions. Participants included 13 graduate students. Data sources included the Views of Nature of Science (VNOS-Form C) questionnaire administered pre- and post-instruction, semi-structured interviews with a subset of participants, and a NOS-related course project. Prior to instruction participants held many alternative NOS conceptions. Post-instruction, participants’ NOS conceptions improved substantially, particularly in their understandings of theories and laws and the tentative nature of scientific knowledge. All 12 participants planning to teach NOS intended to use explicit instructional approaches. A majority of participants also integrated novel ideas to their intended NOS instruction. These results suggest that a teaching methods course for graduate students with embedded NOS instruction can address alternative NOS conceptions and facilitate intended use of effective NOS instruction. Future research understanding graduate students' NOS understandings and actual NOS instruction is warranted.  相似文献   

11.

The goal of this study was to understand how six college biology students complete the tasks of a traditional paper and pencil instrument designed to detect alternative conceptions about photosynthesis. Participants responded to relevant items in a two-tier diagnostic instrument in a think-aloud task. Responses to the traditional content question (first tier) were correct more often than reasons (second tier). However the participants' verbal data indicated that they relied upon test-taking strategies, not retrieval from memory, to choose their reasons. Some distractors caused participants to accept incorrect propositions being considered for the first time (rather than eliciting a misconception from extant knowledge). They also considered relevant exceptions and subtle language cues that justified their choices of incorrect reasons. Participants voiced concerns about the conscientiousness with which students complete such instruments. These findings raise concerns about the validity of using such instruments for diagnosing alternative conceptions.  相似文献   

12.
This case study is part of a larger study of teachers' use of curriculum materials in planning and teaching fifth-grade science. This case study focuses on one of the nine teachers observed teaching an activity-based unit on plant growth and photosynthesis. Although the teacher became aware that her students held certain misconceptions about plant growth, she was unsuccessful in helping them replace their misconceptions with the scientific conceptions she wanted them to learn. The analysis revealed several factors that contributed to this disappointing result. The teacher and the curriculum developers held different views about learning and the nature of science, and several problems surfaced about the content and organization of the teacher's guide.  相似文献   

13.
Students often hold misconceptions about natural phenomena. To overcome misconceptions students must become aware of the scientific conceptions, the evidence that bears on the validity of their misconceptions and the scientific conceptions, and they must be able to generate the logical relationships among the evidence and alternative conceptions. Because formal operational reasoning patterns are necessary to generate these logical relationships, it was predicted that, following instruction, formal operational students would hold significantly fewer misconceptions than their concrete operational classmates. To test this hypothesis 131 seventh-grade students were administered an essay test on principles of genetics and natural selection following instruction. Responses were categorized in terms of the number of misconceptions present. The number of misconceptions was compared to reasoning ability (concrete, transitional, formal), mental capacity (<6, 6, 7), verbal intelligence (low, medium, high), and cognitive style (field dependent, intermediate, field independent). The only student variable consistently and significantly related to the number of misconceptions was reasoning ability; thus, support for the major hypothesis of the study was obtained.  相似文献   

14.
College-level biology courses contain many complex processes that are often taught and learned as detailed narratives. These processes can be better understood by perceiving them as dynamic systems that are governed by common fundamental principles. Conservation of matter is such a principle, and thus tracing matter is an essential step in learning to reason about biological processes. We present here multiple-choice questions that measure students' ability and inclination to trace matter through photosynthesis and cellular respiration. Data associated with each question come from students in a large undergraduate biology course that was undergoing a shift in instructional strategy toward making fundamental principles (such as tracing matter) a central theme. We also present findings from interviews with students in the course. Our data indicate that 1) many students are not using tracing matter as a tool to reason about biological processes, 2) students have particular difficulties tracing matter between systems and have a persistent tendency to interconvert matter and energy, and 3) instructional changes seem to be effective in promoting application of the tracing matter principle. Using these items as diagnostic tools allows instructors to be proactive in addressing students' misconceptions and ineffective reasoning.  相似文献   

15.
Conceptual change is a gradual process that occurs as students integrate new information into their existing conceptions. Throughout this process, assessing learning requires measures to diagnose misconceptions and understand how knowledge is changing. We developed three measures of misconceptions to assess students' knowledge early in instruction on decimals that measured the: 1) prevalence of misconception errors based on response patterns, 2) existence of misconceptions in a more abstract context, and 3) strength of misconceptions using confidence ratings. Students ages 9–11 (N = 297) completed the assessment at three time points. These measures revealed that whole number and role of zero misconceptions decreased and fraction misconceptions increased over time. The current measures also differentiated between weaker misconceptions that were changed after brief instruction and strongly held misconceptions. The current measures can create a more complete picture of knowledge than only measuring students' accuracy, providing a window into the conceptual change process.  相似文献   

16.
The researchers designed the study to achieve two goals: (1) determine the affect of peer collaboration on high school biology students' acquisition of concepts related to photosynthesis and (2) examine interactions in a collaborative peer group situation to determine how these interactions relate to the developpment of concepts associated with photosynthesis. Using quantitative and qualitative data analysis techniques, the researchers concluded that students working in peer collaborative groups developed more scientifically correct conceptions of photosynthesis than did students working alone. However, not all group-generated views were internalized by group members when assessed individually. Based on qualitative data, a functional relationship exists between prior knowledge and concept development. Two types of peer interaction, consonant and dissonant, were identified as enhancing concept development. When peer group roles are not assigned, roles fluctuate depending on group members' expertise or perceived expertise displaying a bidirectional zone of proximal development. This zone allows for enhanced concept development. Based on the above conclusions, the researchers recommend that (1) peer collaboration be used to help students overcome scientific misconceptions; (2) peer collaborative tasks be designed to engage students in consonant and dissonant interactions; and (3) cognitive group roles, as opposed to traditionl managerial cooperative group roles, be used.  相似文献   

17.
Do students from small high schools show fewer understandings and more misconceptions of biology concepts than students attending large high schools? Fifty students attending large high schools (enrollments exceeding 900 students) and fifty students attending small high schools (enrollments less than 150 students) were randomly selected and than evaluated on their understandings and misunderstandings of four biology concepts: diffusion, homeostasis, food production in plants, and classification of animals and plants. Students attending small high schools showed less instances of understanding and more instances of misunderstanding the concepts of diffusion and homeostasis. These differences could be related to a higher percentage of students in large schools capable of formal operations; sound understanding of diffusion and homeostasis required students to use formal operations. No difference was observed between the large and small school samples for the concepts of food production in plants and classification of plants and animals. Students in the small school sample lived in agricultural communities and their daily experiences allowed them to develop some understanding of food production in plants and prevented instances of misunderstandings from being developed. Classification of animals and plants required concrete operations to understand; therefore, students in small schools were capable of developing sound understanding as well as students from large schools.  相似文献   

18.
19.
The purpose of this research was to investigate students' understanding of electrochemistry following a course of instruction. A list of conceptual and propositional knowledge statements was formulated to identify the knowledge base necessary for students to understand electric circuits and oxidation-reduction equations. The conceptual and propositional knowledge statements provided the framework for the development of a semistructured interview protocol which was administered to 32 students in their final year of high school chemistry. The interview questions about electric circuits revealed that several students in the sample were confused about the nature of electric current both in metallic conductors and in electrolytes. Students studying both physics and chemistry were more confused about current flow in metallic conductors than students who were only studying chemistry. In the section of the interview which focused on oxidation and reduction, many students experienced problems in identifying oxidation-reduction equations. Several misconceptions relating to the inappropriate use of definitions of oxidation and reduction were identified. The data illustrate how students attempted to make sense of the concepts of electrochemistry with the knowledge they had already developed or constructed. The implications of the research are that teachers, curriculum developers, and textbook writers, if they are to minimize potential misconceptions, need to be cognizant of the relationship between physics and chemistry teaching, of the need to test for erroneous preconceptions about current before teaching about electrochemical (galvanic) and electrolytic cells, and of the difficulties experienced by students when using more than one model to explain scientific phenomena.  相似文献   

20.
We used both student interviews and diagnostic testing to reveal students’ misconceptions about number representations in computing systems. This article reveals that students who have passed an undergraduate level computer organization course still possess surprising misconceptions about positional notations, two's complement representation, and overflow. Contrary to common opinion, these misconceptions are widespread and reveal the need for instruction that specifically targets these misconceptions. In addition, these misconceptions will serve as the basis for the creation of a standard assessment tool called the digital logic concept inventory. This concept inventory will provide a rigorous and quantitative metric to assess the effectiveness of new teaching methods.  相似文献   

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