Abstract
The goal of our study was to track changes in student understanding of the central dogma of molecular biology before and after taking a genetics course. Concept maps require the ability to synthesize new information into existing knowledge frameworks, and so the hypothesis guiding this study was that student performance on concept maps reveals specific central dogma misconceptions gained, lost, and retained by students. Students in a genetics course completed pre- and posttest concept mapping tasks using terms related to the central dogma. Student maps increased in complexity and validity, indicating learning gains in both content and complexity of understanding. Changes in each of the 351 possible connections in the mapping task were tracked for each student. Our students did not retain much about the central dogma from their introductory biology courses, but they did move to more advanced levels of understanding by the end of the genetics course. The information they retained from their introductory courses focused on structural components (e.g., protein is made of amino acids) and not on overall mechanistic components (e.g., DNA comes before RNA, the ribosome makes protein). Students made the greatest gains in connections related to transcription, and they resolved the most prior misconceptions about translation. These concept-mapping tasks revealed that students are able to correct prior misconceptions about the central dogma during an intermediate-level genetics course. From these results, educators can design new classroom interventions to target those aspects of this foundational principle with which students have the most trouble.
INTRODUCTION
Research shows that despite efforts by the higher education community to address and break down student misconceptions (6, 11, 13), focus courses on the fundamental enduring principles of biology (2), and shift classroom focus from content to concepts (24, 34), students still retain many misconceptions about basic principles after completing biology courses (26, 27). The central dogma of molecular biology, which describes the basic flow of genetic information inside a cell, is one of these fundamental principles, captured by the American Association for the Advancement of Science’s (AAAS’s) Vision and Change “Information Flow” category (2). Previous studies have shown that undergraduate students have many misconceptions about topics related to the central dogma (26, 37, 53). The results of these studies thus shift the questions biology educators can ask from “do students understand the Central Dogma?” to “how do students understand (or misunderstand) the Central Dogma?”
Understanding the flow of genetic information inside the cell is crucial to understanding more advanced topics such as inheritance, phenotypic expression, developmental biology, and evolution. Formally, the central dogma is the hypothesis put forward by Francis Crick in 1970 stating that “once information has been passed into protein it cannot get out again” (10). More commonly, the central dogma is portrayed as the linear progression from deoxyribonucleic acid (DNA) to ribonucleic acid (RNA) (via transcription) to protein (via translation) (Fig. 1A). This (largely) one-way sequential flow of genetic information forms the basis of such varied biological processes as signal transduction cascades, cell division, and maintenance of homeostasis in both unicellular and multicellular organisms. This linear model of gene expression is difficult for students to master, and a recent study showed that their difficulty stemmed from not being primed to think about what the arrows in the linear model (that refer to transcription and translation) really mean (53).
FIGURE 1.
Concept map assessment tool and implementation. Concept maps were used to assess student understanding of the central dogma of molecular biology (A). Concept maps are made of interconnected propositions, in which each proposition consists of two terms connected by a linking verb (B). Students were provided with a list of 27 terms (C) and were instructed to use those terms to create a concept map explaining the central dogma. These assessments were given before the first day of molecular biology content and again on the last day of class (D). DNA = deoxyribonucleic acid; RNA = ribonucleic acid.
In order to gauge how students’ understanding of this topic changes over the course of their undergraduate biology careers, it is important to first track the changes in their understanding before they arrive at college. Students’ misconceptions about the central dogma are established early and are maintained through at least introductory biology in college. Studies have shown that middle and high school students, regardless of age, have either no understanding or only a partial understanding of what DNA and genes are (28, 45, 48). The absence of association with grade level indicates that this lack of understanding is established early, does not improve with further instruction, and is persistent. Even after high school, a recent study concluded that undergraduate students in an introductory biology class struggled with the vocabulary of gene expression and made only small gains in their understanding of this topic (32).
These persistent errors in understanding are not altogether bad, as they represent important early stages in the construction of knowledge (46). Misconceptions are artifacts and indicators of prior learning, whether that learning happened informally in everyday experiences or formally in the classroom (8, 35). Moving from this novice understanding to more expert understanding involves refinement and reorganization of those misconceptions, rather than mere replacement of them, as articulated by the Constructivist Learning Theory (CLT) (39). Practically, this mechanism of learning means that as students encounter advanced topics in their mid- and upper-level biology courses, they must build any new, advanced information upon what they already know. And despite the thorough identification of the presence of misconceptions, we still do not fully understand how undergraduate students progress from their simple, unsophisticated, error-filled understanding of the central dogma to the more complex, sophisticated, and accurate understandings of this topic held by advanced undergraduates and experts in the field.
Concept mapping tasks are well suited to assessing such changes in understanding. Concept maps are visual representations of knowledge and are most often used to depict the connections between different concepts via directional arrows linked to action verbs (36). These individual connections are known as propositions, and together they form a concept map (Fig. 1B). Such mapping requires the use of higher-order cognitive skills (25) because it challenges students to assimilate new concepts into existing knowledge frameworks (3, 33), rather than relying on memorized definitions of terms. Research shows that knowledge has organizational properties to it that can, in fact, be structured and captured by these mapping activities. Concept mapping has therefore been implicated as a potential source of information about the content and organization of students’ knowledge. Because of the nature of the work required to construct a concept map, these tools have been extensively validated in the education literature as effective tools for assessing student learning (5, 9, 18, 20, 43, 49). Concept maps can be used to facilitate problem solving (4), identify gaps in knowledge (1), and identify sophistication of understanding (that is, that experts and successful learners create elaborate, highly integrated maps, as opposed to the linear, simple maps created by novices) (7, 29, 51). Concept maps can also be used to identify misconceptions (16, 21, 23, 42, 44), diagnose cognitive structures (14), reveal changes in learning structures (18), and distinguish meaningful versus rote learning (33). Concept maps are valid and reliable assessment tools because students’ maps change with expertise (29, 50) and with instruction on relevant content (30, 38). Researchers have successfully used concept maps to identify misconceptions about many topics in fields as divers as nursing (52), dentistry (19), and engineering (22).
In this study we used presemester and postsemester concept mapping tasks to track changes in undergraduate students’ understanding of the central dogma of molecular biology. We hypothesized that this pre/post concept map structure reveals shifts in students’ understandings of the central dogma, from novice to more expert types of understanding. Here we report the results of this tracking, and we discuss the types of changes in understanding that this tracking revealed. Students started the semester with many misconceptions about the central dogma, most of which were resolved at the end of the course. They dropped both accurate and inaccurate information in their resolution of those misconceptions, and the patterns of these changes reveal how they learned the central dogma, moving from novice-level to more advanced-level understanding of the topic. Understanding how students learn fundamental enduring principles of any discipline can inform our design and implementation of classroom interventions to facilitate learning both these basic principles as well as more advanced topics.
METHODS
Subjects
In the fall semester of 2012, 41 students enrolled in two sections of an intermediate level genetics course at Beloit College (BIOL289 Genetics). Demographic data, including class year and number of college biology courses previously completed, were collected from the students at the beginning of the semester via a survey. The students were in their second through fifth years of undergraduate work and included 18 females and 23 males. Thirty-six students were either biology or biochemistry majors, and the remaining students were majors in other disciplines. The number of prior biology courses taken varied from one to more than six other courses (mean = 2.9). BIOL289 was a semester-long, 16-week course that included three 65-minute class periods per week. These class periods included a combination of lecture, discussion, and group activities. There was also one three-hour inquiry-based molecular genetics laboratory each week, all of which were taught by A. Briggs. The prerequisites for this course were one introductory biology course and a biological statistics course (which could, alternatively, be taken concurrently with Genetics). The course content included five weeks each of molecular genetics, Mendelian genetics, and population genetics (Fig. 1D). This order of course content was informed by recent efforts to restructure undergraduate genetics curricula by placing greater emphasis on molecular and quantitative principles and devoting less time to classical Mendelian genetics (41).
Assessment structure and implementation
To assess students’ understanding of the central dogma, a concept-mapping task was used. Students were provided a list of 27 terms related to the central dogma of molecular biology (Fig. 1C) and instructed to create a concept map using all 27 terms (36). These 27 terms were chosen to include the basic monomers, polymers, regulators, enzymes, and other relevant terms associated with transcription and translation. Students were further instructed to write each term on a sticker and use a provided sheet of paper to construct their maps by creating linking verbs between different terms (see Appendix 1), with each linking verb being attached to an arrow that indicated the directionality of the association (Fig. 1B). This connection structure—term 1 connected to term 2 via an arrow and linking verb—is known as a proposition.
To measure changes in student understanding, the central dogma concept map assessments were given at the beginning and end of the semester. Figure 1D provides a schematic representation of the time points for the assessment. During the first laboratory session in the first week of class (before any content on molecular biology had been taught) students first completed a short exercise introducing them to concept maps, in which they created collaborative concept maps of the college curriculum requirements. Students were then given one hour to individually complete the central dogma concept-mapping task. One hour was chosen based upon previous work (31) showing that students usually took between 16 and 59 minutes to complete their maps. Concept maps were used as active learning tools throughout the course for topics such as evolution and DNA replication. During the final laboratory session of the semester, students again were given one hour to complete the concept-mapping task. These assessments were voluntary, were not graded for course credit, and were submitted with students’ identification (ID) numbers only.
Concept map scoring
To assess the overall depth and accuracy of students’ understanding of the central dogma, each pre- and post-concept map was scored using two methods. First, concept maps were scored for complexity (the total number of propositions used), regardless of propositional validity (31, 40, 54). The minimum complexity score would be 26 (each term connected to only one other), and the maximum possible complexity score would be 351 (each term connected to every other term). Second, concept maps were scored based on propositional validity (number of valid propositions/total number of propositions). Validity was determined based upon the factual correctness of each linking verb in connecting two concepts and the direction of the arrow between those two terms (for example, the linking verb “creates” would be invalid if used to link “DNA” and “RNA” but valid if used to link “RNA polymerase” and “RNA,” as long as the arrow pointed toward “RNA” and not “RNA polymerase”) (20, 31, 40). Representative examples of pre- and posttest concept maps are provided in Figure 2, demonstrating differences in propositional complexity between two students, one with a high starting complexity and validity (Fig. 2A) and the other with a low starting complexity and validity (Fig. 2B). Normalized learning gains were then calculated using the pre- and post- validity scores using the equation [100 × ((post - pre)/(100 - pre)] (17).
FIGURE 2.
Example student concept maps. Representative examples of high- (A) and low- (B) complexity student-generated concept maps created at the beginning of the course (upper panels) and at the end of the course (lower panels) from two students enrolled in Section 2 of BIOL289: Genetics. Validity (number of valid propositions/total number of propositions) and complexity (number of propositions) scores are provided for comparison.
To detect specific changes in student understanding of the central dogma, we developed a three-part method for quantifying propositional changes over time. Each of the 351 possible unique propositions could change in nine ways: on the pretest, that particular proposition could be valid, invalid, or absent, and again on the posttest, that same proposition could be valid, invalid, or absent (Fig. 3A). First, all maps for which both pre- and post- versions were completed (n = 36) were converted into 27 × 27 matrices (Fig. 3C), in which each column and row represented a particular term on the concept map (such as “Ribosome” or “Uracil”) (Fig. 3B). These pre- and post- matrices were generated using a numerical code to indicate the absence or presence (and the validity of those present) of each of the 351 possible unique propositions. This numerical code was: 1 = proposition absent, 3 = proposition present and valid, and 7 = proposition present and invalid (Fig. 3A). The second step in our analysis was to identify the type of changes in each student’s pair of maps, and so a third matrix was then generated, for each student, that summarized the changes in each proposition from pre- to post- map. The formula [(pre code + post code) × pre code] allowed for the generation of nine unique values (referred to here as change codes) to identify the nine possible types of change (Fig. 3A): absent to absent, absent to invalid, absent to valid, valid to absent, valid to invalid, valid to valid, invalid to absent, invalid to invalid, and invalid to valid. Thirdly, to quantify the frequency of changes of each of the 351 possible propositions across the entire participant population, the number of occurrences of each possible change code for each matrix cell was calculated.
FIGURE 3.
Matrix scoring method. To track changes in propositions from pre- to post- maps, each proposition on each individual student map was given a code (1 = absent, 3 = valid, 7 = invalid) and then the formula [(post + pre) × pre] (A) was used to generate nine unique values indicating the nine possible types of changes. Each student’s separate pre- and post- map (B) was then converted into a single 27 × 27 matrix containing these change codes (C). DNA = deoxyribonucleic acid; RNA = ribonucleic acid.
To assess the degree of novice and expert understanding in each concept map, four biology faculty members (experts) completed the same concept-mapping task (see Appendix 2). These expert concept maps were scored for complexity and validity. These maps were then compared with the student-generated maps to identify propositions made only by experts, those made by novices and experts alike, those made by novices only, and those never made by anyone.
Statistical analysis
All statistical analyses were performed using JMP. Multivariate correlation analysis was used to determine the correlations between concept map complexity scores, validity scores, learning gains, and demographic data. One-factor ANOVA was used to compare pretest and posttest scores for the different concept map scoring methods.
Informed consent and data handling
All participant data were collected and analyzed with protocols approved by Beloit College’s Institutional Review Board for human subjects research. Identifying information (such as student ID numbers) on surveys and concept maps was stripped from the data and replaced with random numbers before analysis. All students in the course consented to the study.
RESULTS
To track changes in student understanding of the central dogma over time, student knowledge and misconceptions were analyzed prior to and after taking a semester-long genetics course. The data collected and analyzed included: (a) concept map complexity scores, (b) validity scores, (c) complexity and validity gains, and (d) propositional changes.
Overall student learning gains about the central dogma
Student concept maps increased in both validity and complexity. A comparison of pre- and posttest scores revealed a statistically significant increase in complexity (*p < 0.05 vs. pretest t = 3.00, degrees of freedom (DF) = 36) and validity (*p < 0.0001 vs. pretest t = 6.06, DF = 36) (Fig. 4). These results indicate that students developed more accurate and more intricate and complex understandings of the central dogma, and that students’ expertise and content knowledge increased.
FIGURE 4.
Overall complexity and validity gains (n = 38). Concept maps were graded using two methods: (A) validity (percent valid propositions) and (B) complexity (total number of propositions made). *p < 0.05 one-way ANOVA versus pretest.
Multivariate correlation analyses were used to determine whether concept map validity and complexity were correlated (Fig. 5 and Table 1). When pre-, post-, and gains scores for concept map complexity and validity were compared, there were no significant correlations between complexity gains and validity gains (Fig. 5E) or between validity and complexity posttest scores (Fig. 5B), but there were significant correlations between complexity and validity pre- scores (Fig. 5A), validity pre- and post- scores (Fig. 5C), and complexity pre- and post- scores (Fig. 5D).
FIGURE 5.
Tests of correlation between concept map validity and complexity. Multivariate analysis was used to determine correlations between concept map complexity (number of connections made) and validity on pretests (A; Spearman correlation coefficient R2 = 0.38, p = 0.0342) and posttests (B; R2 = 0.3234, p = 0.0751), and between complexity gains and normalized validity gains, (E; R2 = −0.210, p = 0.2567). Correlations were also determined for pretest and posttest scores for validity (C; R2 = 0.62, p = 0.0002) and complexity (D; R2 = 0.55, p = 0.0014).
TABLE 1.
Multivariate analysis of concept map pre-, post-, and gains scores.
| Variable | By Variable | Spearman R2 | p |
|---|---|---|---|
| complexity gains | complexity post | 0.4275 | 0.0165* |
| complexity gains | complexity pre | −0.4253 | 0.0171* |
| complexity post | complexity pre | 0.5477 | 0.0014* |
| normalized validity gain | complexity gains | −0.2101 | 0.2567 |
| normalized validity gain | complexity post | −0.2822 | 0.124 |
| normalized validity gain | complexity pre | 0.0767 | 0.6817 |
| validity post | complexity gains | 0.0306 | 0.8701 |
| validity post | complexity post | 0.3243 | 0.0751 |
| validity post | complexity pre | 0.2516 | 0.1721 |
| validity post | normalized validity gains | 0.2825 | 0.1236 |
| validity pre | complexity gains | −0.2981 | 0.1034 |
| validity pre | complexity post | 0.2405 | 0.1925 |
| validity pre | complexity pre | 0.3816 | 0.0342* |
| validity pre | normalized validity gains | 0.2381 | 0.1971 |
| validity pre | validity post | 0.6204 | 0.0002* |
p < 0.05.
Other factors affecting concept-mapping performance
To investigate other variables that affected concept map scores, multivariate correlation analysis was performed. Class year, number of biology courses, and genetics course grade were compared with pre-, post- and gains scores for concept map complexity and validity, and the correlations between these variables are shown in Table 2. The only statistically significant correlations were between number of biology courses taken and both complexity pre- scores and validity pre- scores, and between class year and complexity pre- scores.
TABLE 2.
Multivariate analysis of concept map performance vs. other effects.
| Variable | By Variable | Spearman R2 | p |
|---|---|---|---|
| # bio courses | complexity gains | −0.2382 | 0.205 |
| # bio courses | complexity post | 0.24 | 0.2014 |
| # bio courses | complexity pre | 0.4769 | *0.0077 |
| # bio courses | validity post | 0.3043 | 0.1021 |
| # bio courses | validity pre | 0.3778 | *0.0396 |
| # bio courses | normalized validity gains | 0.1135 | 0.5502 |
| class year | complexity gains | −0.3344 | 0.0709 |
| class year | complexity post | 0.0267 | 0.8886 |
| class year | complexity pre | 0.3685 | *0.0451 |
| class year | validity post | 0.1182 | 0.5338 |
| class year | validity pre | 0.126 | 0.5071 |
| class year | normalized validity gains | 0.0255 | 0.8937 |
| course grade | complexity gains | 0.0241 | 0.8995 |
| course grade | complexity post | 0.1498 | 0.4296 |
| course grade | complexity pre | 0.1061 | 0.5768 |
| course grade | validity post | 0.2474 | 0.1875 |
| course grade | validity pre | 0.0097 | 0.9596 |
| course grade | normalized validity gains | 0.2676 | 0.1528 |
p < 0.05.
Quantifying changes in student concept maps
To quantify the changes in student understanding of the central dogma over time, we tracked the changes in concept map propositions. An overview of how the class, as a cohort, shifted their thinking about the central dogma is seen in the frequencies of the nine possible types of proposition changes (Fig. 3A). Out of the 1,415 total propositional changes made by the students in the class, most fell into only four of the change types: none to valid (33%), valid to valid (24%), valid to none (22%), and invalid to none (9%) (Fig. 6). The other five categories made up the remaining 12% of changes. As the students learned more, they discarded both valid and invalid propositions to construct more complex maps with new valid propositions. This analysis of proposition changes also shows that students had very few new misconceptions and retained very few old misconceptions by the end of the course. The category of invalid to invalid occurred in only 1% of all propositions, and none to invalid occurred in only 6% of propositions.
FIGURE 6.
Analysis of most common propositional changes. The frequency with which each proposition changed between each student’s pre- and post- maps in each pre/post change category (see Table 1) was quantified (A, B; n = 1,415 total proposition changes). The most common propositions within each change category are shown.
The central dogma is comprised of two different processes, transcription and translation. To identify where in this gene expression pathway students were making changes to their understanding, the frequency with which particular pairs of terms were used in each propositional change category was determined (Fig. 6A). For example, of all the students that made propositions in the “none” to “valid” category (that is, two terms never connected on the pretest and then validly connected on the posttest), 43% included the terms “Transcription” and “Promoter,” and 37% included the terms “Transcription” and “RNA polymerase.” Two other groups of propositions are noteworthy. In the “valid to valid” category, the most common pairings of terms included “Base (nucleotide)” paired with “A/T/C/G” (67% of students) and “Protein” paired with “Amino acid” (53% of students). And in the “valid to none” category, the most common pairings were “Transcription” with “DNA” (37% of students), “Gene” with “Genetic Code” (33% of students), and “Gene” with “DNA” (27% of students).
Comparing student and expert concept maps
Student concept maps were also evaluated on the basis of expertise, or sophistication. Biology faculty members’ concept maps (Appendix 2) were compared with student pre- and post- maps. Average complexity values for student pre- and post- maps were 28.8 ± 0.85 standard error of the mean (SEM) and 32.1 ± 0.75 SEM propositions per map, respectively (Fig. 4B), compared with an average of 43.3 ± 1.75 SEM propositions per faculty map. Despite the increased number of connections, there were only a few propositions that faculty members used that not a single student used (Table 3). These propositions fell into three categories: those that connected base complementarity with the ribosome or genetic code, those that connected the genome with the three types of RNA, and those that connected RNA with the three nucleotide bases shared with DNA (A, C, and G).
TABLE 3.
Propositions used by faculty members that were never used by students.
| Genetic code – base complementarity |
| Ribosome – base complementarity |
| Ribosome – genetic code |
| RNA – A/C/G |
| Genome – rRNA |
| Genome – tRNA |
| Genome – mRNA |
rRNA = ribosomal ribonucleic acid; tRNA = transfer ribonucleic acid; mRNA = messenger ribonucleic acid.
DISCUSSION
The goal of this research project was to uncover students’ prior and new knowledge about the central dogma of molecular biology in an effort to understand whether and why students retain misconceptions about this fundamental principle. We saw a need for such a study based upon personal observations and evidence from the literature (26) suggesting that despite students’ demonstrated mastery of intermediate and advanced course material, they retain fundamental misconceptions about basic biology concepts such as the central dogma. We hope that this analysis will provide insights that will inform new curricular innovations to target those areas of greatest difficulty for our students.
We first quantified concept map validity and complexity to measure overall learning gains. Concept map validity (pre- scores only) correlated only with number of biology courses taken, suggesting that our concept-mapping task was measuring their knowledge of central dogma (since presumably the more biology courses a student has had, the more that student has learned about gene expression). Complexity pre- scores also correlated with class year and number of biology courses taken, which supports the observed phenomenon that more advanced students and experts generate more complex maps. This correlation means the complexity scoring method was in fact detecting more advanced types of thinking (7, 38, 51). Neither of the post- scores correlated with any of the tested external variables, which suggests that map complexity and validity after taking genetics reflects the learning students did over the course of the semester, regardless of their prior experience (Table 2).
Secondly, we developed a matrix-based visualization method for comparing propositional changes to uncover retained, lost, and gained misconceptions. Our analysis revealed evidence that students did understand more about the central dogma after taking genetics. Of all the propositional changes, 33% were in the none-to-valid category, indicating valid knowledge gained. Most of this new knowledge involved the regulation of transcription (promoter, transcription, and RNA polymerase), and the mechanics of translation (amino acid, tRNA, translation, ribosome, and rRNA) (Fig. 6A). Twenty-two percent of the proposition changes were in the valid-to-none category (that is, students did not include valid information on their post- maps that they included on their pre- maps), and the most common pairings in this category may indicate that students no longer found the connections between gene, DNA, and genetic code to be meaningful or useful in their descriptions of gene expression, perhaps because these pairings are too obvious.
This study revealed evidence that students were not developing new misconceptions and that they lost almost all the misconceptions that they had when they started the course (Fig. 6B). The invalid-to-invalid, none-to-invalid, and valid-to-invalid changes together only equaled 8% of the total proposition changes. The pairings in the invalid-to-none category (incorrect propositions on the pre- maps that were absent from the post- maps) accounted for 9% of propositions, and most of these propositions connected RNA with terms related to translation. Previous studies have shown the difficulties students have with translation (15, 47), but our results showed that students better understood the relationship between translation and RNA after taking genetics. This result complements the result in the none-to-valid category, which also heavily featured propositions related to translation.
Students already understood some of the basics of the central dogma, and they retained those basics after taking genetics. Twenty-four percent of proposition changes were in the valid-to-valid category (correct propositions made on both pre- and post- maps), and the most common pairings reveal the type of information students had retained related to central dogma from their introductory biology courses: that the nucleotide bases are called A/C/T/G, and that proteins are made of amino acids. These pairings were very common, suggesting that one reason students may not seem to understand central dogma even after we teach it in introductory courses is that they have focused on the building block aspects of each individual step of this pathway to the exclusion of both the bigger picture (DNA → RNA → protein) and any other components of the reactions. These results are consistent with Bloom’s taxonomy of cognition (12, 25), since incorporation of facts (memorization) is easier than filling in the big picture of a topic (synthesis, understanding).
The matrix map method used in this study could be suitable for large-scale use, as there are a number of software programs available for map analysis, such as text2mindmap (http://www.text2mindmap.com) and cmap (cmap.ihmc.us). The purpose of this study, however, was not to develop a novel assessment for detecting misconceptions and changes in learning, but rather to use those tools already established as capable of detecting learning gains to understand just what students do and do not understand about the central dogma. The results of this study suggest that students may be doing better than we as educators suspected—very few misconceptions were retained, and even fewer new misconceptions arose during their semester in genetics. Long-term retention, however, is not addressed by this study. Examining students’ misconceptions about fundamental enduring principles one and five years after graduation would uncover whether the gains observed in this study are long-term.
Based on the results of this study, we have a number of recommendations for classroom interventions. Our results demonstrated that, despite our introductory biology courses including transcription and translation, our students did not retain much about the central dogma from these introductory courses, but that they did in fact move to more advanced levels of understanding by the end of a genetics course. What little information they did retain from their introductory biology courses was very focused on the structural components that require low-order cognition (such as memorization) (e.g., nucleotides make up DNA, and amino acids make up proteins) and very light on the overall mechanistic components that require higher order cognition (such as understanding) (e.g., DNA comes before RNA, the ribosome makes protein). These results demonstrate that when we teach introductory biology, we may want to spend considerably less class time on the monomer/polymer aspects of information flow and more on the pathway as a whole. Using multiple strategies, such as skits and strip sequences, to expose students to the temporal aspects of the central dogma may help them understand the mechanisms involved. Students could also create tables that compare and contrast the templates, products, and “actors” (proteins) of each of the processes involved: transcription, translation, and replication. The Biology in Bloom tool could serve as a guide for helping instructors design such interventions (12). And then in genetics and other intermediate and advanced courses, instructors may want to again not focus too much on the monomer/polymer parts (because students have already memorized those components) and instead focus on regulation, enzymes, ordering, and the overall pathway (areas where students have the most room to gain new knowledge). Having students brainstorm and share their own strategies for differentiating transcription from translation, or DNA from RNA, could help them articulate the gaps in their own understanding.
Comparing student concept maps with biology faculty concept maps provided further insight into student understandings of the central dogma. Students made more complex maps at the end of the course (average = 32 propositions), indicating a shift toward deeper and more sophisticated thinking about the topic, but they still made fewer connections than biology faculty (average = 42 connections). By comparing concept maps longitudinally over time, we have captured a moment partway through students’ undergraduate careers where they have attained an understanding of a fundamental enduring principle that lies somewhere between those of novices and experts.
SUPPLEMENTAL MATERIALS
Appendix 1: Concept map classroom handout
Appendix 2: Faculty concept maps
ACKNOWLEDGMENTS
Amy Briggs would like to thank the American Society for Microbiology’s Biology Scholars Program (NSF Grant # 1022542) for helping her develop her research ideas and for valuable feedback on this manuscript. Thanks also go to Ken Yasukawa and Yaffa Grossman for consultation on statistical analyses.
Dr. Briggs was a participant in the ASM Biology Scholars Transitions Residency and received editorial help from Dr. Marcy Kelly, JMBE Research Editor. To avoid a conflict of interest, Dr. Kelly did not review the subsequent submission of the manuscript to JMBE or any other part of the peer review process; all editorial duties were assigned to Dr. Samantha Elliott, JMBE Editor-in-Chief. The remaining authors declare that there are no conflicts of interest.
Footnotes
Supplemental materials available at http://asmscience.org/jmbe
REFERENCES
- 1.Adamczyk P, Willson M. Using concept maps with trainee physics teachers. Phys Educ. 1996;31:374. doi: 10.1088/0031-9120/31/6/018. [DOI] [Google Scholar]
- 2.American Association for the Advancement of Science. Vision and change in undergraduate biology education: a call to action: a summary of recommendations made at a national conference organized by the American Association for the Advancement of Science; July 15–17, 2009; Washington, DC. 2011. [Google Scholar]
- 3.Ausubel DP, Novak JD, Hanesian H. Educational psychology: a cognitive view. Holt, Rinehart, and Winston; New York, NY: 1978. [Google Scholar]
- 4.Baxter GP, Glaser R. Investigating the cognitive complexity of science assessments. Educ Meas Issues Pract. 1998;17:37–45. doi: 10.1111/j.1745-3992.1998.tb00627.x. [DOI] [Google Scholar]
- 5.BouJaoude S, Attieh M. The effect of using concept maps as study tools on achievement in chemistry. Eurasia J Math Sci Technol Educ. 2008;4:233–246. [Google Scholar]
- 6.Brewer CA. Near real-time assessment of student learning and understanding in biology courses. BioScience. 2004;54:1034–1039. doi: 10.1641/0006-3568(2004)054[1034:NRAOSL]2.0.CO;2. [DOI] [Google Scholar]
- 7.Chi MT, Glaser R, Farr MJ, editors. The nature of expertise. Lawrence Erlbaum Associates; Hillsdale, NJ: 1988. pp. 448–451. [Google Scholar]
- 8.Clement J. Algebra word problem solutions: thought processes underlying a common misconception. J Res Math Educ. 1982;13:16–30. doi: 10.2307/748434. [DOI] [Google Scholar]
- 9.Cohen D. The use of concept maps to represent unique thought processes: toward more meaningful learning. J Curric Superv. 1987;2:285–289. [Google Scholar]
- 10.Crick F, et al. Central dogma of molecular biology. Nature. 1970;227:561–563. doi: 10.1038/227561a0. [DOI] [PubMed] [Google Scholar]
- 11.Cross KP, Angelo TA. A handbook for faculty. National Center for Research to Improve Postsecondary Teaching and Learning; Ann Arbor, MI: 1988. Classroom assessment techniques. [Google Scholar]
- 12.Crowe A, Dirks C, Wenderoth MP. Biology in bloom: implementing Bloom’s taxonomy to enhance student learning in biology. CBE Life Sci Educ. 2008;7:368–381. doi: 10.1187/cbe.08-05-0024. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Ebert-May D, Hodder J, Williams K, Luckie D. Pathways to scientific teaching. Front Ecol Environ. 2004;2:323–323. doi: 10.1890/1540-9295(2004)002[0323:PTST]2.0.CO;2. [DOI] [Google Scholar]
- 14.Edwards J, Fraser K. Concept maps as reflectors of conceptual understanding. Res Sci Educ. 1983;13:19–26. doi: 10.1007/BF02356689. [DOI] [Google Scholar]
- 15.Fisher M. A misconception in biology: amino acids and translation. J Res Sci Teach. 1985;22:53–62. doi: 10.1002/tea.3660220105. [DOI] [Google Scholar]
- 16.González FM. Diagnosis of Spanish primary school students’ common alternative science conceptions. Sch Sci Math. 1997;97:68–74. doi: 10.1111/j.1949-8594.1997.tb17345.x. [DOI] [Google Scholar]
- 17.Hake RR. Interactive engagement versus traditional methods in mechanics instruction. Am J Phys. 1998;66:64–74. doi: 10.1119/1.18809. [DOI] [Google Scholar]
- 18.Hay D, Kinchin I, Lygo-Baker S. Making learning visible: the role of concept mapping in higher education. Stud High Educ. 2008;33:295–311. doi: 10.1080/03075070802049251. [DOI] [Google Scholar]
- 19.Hay DB, Tan PL, Whaites E. Non-traditional learners in higher education: comparison of a traditional MCQ examination with concept mapping to assess learning in a dental radiological science course. Assess Eval High Educ. 2010;35:577–595. doi: 10.1080/02602931003782525. [DOI] [Google Scholar]
- 20.Herl HE, O’Neil HJ, Jr, Chung G, Schacter J. Reliability and validity of a computer-based knowledge mapping system to measure content understanding. Comput Hum Behav. 1999;15:315–333. doi: 10.1016/S0747-5632(99)00026-6. [DOI] [Google Scholar]
- 21.Hoz R, Bowman D, Kozminsky E. The differential effects of prior knowledge on learning: a study of two consecutive courses in earth sciences. Instr Sci. 2001;29:187–211. doi: 10.1023/A:1017528513130. [DOI] [Google Scholar]
- 22.Huang G, Taddese N, Walter E. Entry and persistence of women and minorities in college science and engineering education. Educ Stat Q. 2000;2:59–60. [Google Scholar]
- 23.Kinchin IM, Hay DB, Adams A. How a qualitative approach to concept map analysis can be used to aid learning by illustrating patterns of conceptual development. Educ Res. 2000;42:43–57. doi: 10.1080/001318800363908. [DOI] [Google Scholar]
- 24.Knight JK, Wood WB. Teaching more by lecturing less. Cell Biol Educ. 2005;4:298–310. doi: 10.1187/05-06-0082. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Krathwohl DR. A revision of Bloom’s taxonomy: an overview. Theory Pract. 2002;41:212–218. doi: 10.1207/s15430421tip4104_2. [DOI] [Google Scholar]
- 26.Lewis J, Leach J, Wood-Robinson C. What’s in a cell?—Young people’s understanding of the genetic relationship between cells, within an individual. J Biol Educ. 2000;34:129–132. doi: 10.1080/00219266.2000.9655702. [DOI] [Google Scholar]
- 27.Marbach-Ad G, et al. A model for using a concept inventory as a tool for students’ assessment and faculty professional development. CBE Life Sci Educ. 2010;9:408–416. doi: 10.1187/cbe.10-05-0069. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Marbach-Ad G. Attempting to break the code in student comprehension of genetic concepts. J Biol Educ. 2001;35:183–189. doi: 10.1080/00219266.2001.9655775. [DOI] [Google Scholar]
- 29.Markham KM, Mintzes JJ, Jones MG. The concept map as a research and evaluation tool: further evidence of validity. J Res Sci Teach. 1994;31:91–101. doi: 10.1002/tea.3660310109. [DOI] [Google Scholar]
- 30.Martin BL, Mintzes JJ, Clavijo IE. Restructuring knowledge in biology: cognitive processes and metacognitive reflections. Int J Sci Educ. 2000;22:303–323. doi: 10.1080/095006900289895. [DOI] [Google Scholar]
- 31.McClure JR, Sonak B, Suen HK. Concept map assessment of classroom learning: reliability, validity, and logistical practicality. J Res Sci Teach. 1999;36:475–492. doi: 10.1002/(SICI)1098-2736(199904)36:4<475::AID-TEA5>3.0.CO;2-O. [DOI] [Google Scholar]
- 32.McDonald K, Gomes J. Evaluating student preparedness and conceptual change in introductory biology students studying gene expression. J Transform Leadersh Policy Stud. 2013;3:21. [Google Scholar]
- 33.Mintzes JJ. Concept mapping in college science. In: Mintzes JJ, Leonard WH, editors. Handbook of College Science Teaching. NSTA press; Arlington, VA: 2006. pp. 67–75. [Google Scholar]
- 34.Momsen JL, Long TM, Wyse SA, Ebert-May D. Just the facts? Introductory undergraduate biology courses focus on low-level cognitive skills. CBE Life Sci Educ. 2010;9:435–440. doi: 10.1187/cbe.10-01-0001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Nesher P. Towards an instructional theory: the role of student’s misconceptions. Learn Math. 1987:33–40. [Google Scholar]
- 36.Novak JD. Learning, creating, and using knowledge: concept maps as facilitative tools in schools and corporations. Earlbaum Associates; Mahwah, NJ: 1998. [Google Scholar]
- 37.Pashley M. A chromosome model. J Biol Educ. 1994;28:157–161. doi: 10.1080/00219266.1994.9655385. [DOI] [Google Scholar]
- 38.Pearsall NR, Skipper JEJ, Mintzes JJ. Knowledge restructuring in the life sciences: a longitudinal study of conceptual change in biology. Sci Educ. 1997;81:193–215. doi: 10.1002/(SICI)1098-237X(199704)81:2<193::AID-SCE5>3.0.CO;2-A. [DOI] [Google Scholar]
- 39.Piaget J. Le structuralisme. Presses Universitaires de France; Paris, France: 1968. [Google Scholar]
- 40.Rebich S, Gautier C. Concept mapping to reveal prior knowledge and conceptual change in a mock summit course on global climate change. J Geosci Educ. 2005;53:355. doi: 10.5408/1089-9995-53.4.355. [DOI] [Google Scholar]
- 41.Redfield RJ. “Why do we have to learn this stuff?”—a new genetics for 21st century students. PLoS Biol. 2012;10:e10001356. doi: 10.1371/journal.pbio.1001356. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 42.Regis A, Albertazzi PG, Roletto E. Concept maps in chemistry education. J Chem Educ. 1996;73:1084. doi: 10.1021/ed073p1084. [DOI] [Google Scholar]
- 43.Ruiz-Primo MA, Schultz SE, Li M, Shavelson RJ. Comparison of the reliability and validity of scores from two concept-mapping techniques. J Res Sci Teach. 2001;38:260–278. doi: 10.1002/1098-2736(200102)38:2<260::AID-TEA1005>3.0.CO;2-F. [DOI] [Google Scholar]
- 44.Salmon D, Kelly M. Exploring what concept maps reveal about knowledge integration in teacher learning. Int J Learn. 2008;15:13–22. [Google Scholar]
- 45.Shaka FL, Bitner BL. Construction and validation of a rubric for scoring concept maps. Paper presented at the annual meeting of the Association for the Education of Teachers of Science; Seattle, WA. 1996. [Google Scholar]
- 46.Smith JP, III, diSessa AA, Roschelle J. Misconceptions reconceived: a constructivist analysis of knowledge in transition. J Learn Sci. 1993;3(2):115–163. doi: 10.1207/s15327809jls0302_1. [DOI] [Google Scholar]
- 47.Southard K, Wince T, Meddleton S, Bolger MS. Features of knowledge building in biology: understanding undergraduate students’ ideas about molecular mechanisms. CBE Life Sci Educ. 2016;15:1016. doi: 10.1187/cbe.15-05-0114. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 48.Venville G, Gribble SJ, Donovan J. An exploration of young children’s understandings of genetics concepts from ontological and epistemological perspectives. Sci Educ. 2005;89:614–633. doi: 10.1002/sce.20061. [DOI] [Google Scholar]
- 49.Walker JM, King PH. Concept mapping as a form of student assessment and instruction in the domain of bioengineering. J Eng Educ. 2003;92:167–178. doi: 10.1002/j.2168-9830.2003.tb00755.x. [DOI] [Google Scholar]
- 50.West DC, Park JK, Pomeroy JR, Sandoval J. Concept mapping assessment in medical education: a comparison of two scoring systems. Med Educ. 2002;36:820–826. doi: 10.1046/j.1365-2923.2002.01292.x. [DOI] [PubMed] [Google Scholar]
- 51.West DC, Pomeroy JR, Park JK, Gerstenberger EA, Sandoval J. Critical thinking in graduate medical education: a role for concept mapping assessment? JAMA. 2000;284:1105–1110. doi: 10.1001/jama.284.9.1105. [DOI] [PubMed] [Google Scholar]
- 52.Williams M. Concept mapping—a strategy for assessment. Nurs Stand. 2004;19:33–38. doi: 10.7748/ns2004.11.19.9.33.c3754. [DOI] [PubMed] [Google Scholar]
- 53.Wright LK, Fisk JN, Newman DL. DNA → RNA: what do students think the arrow means? CBE Life Sci Educ. 2014;13:338–348. doi: 10.1187/cbe.CBE-13-09-0188. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 54.Yin Y, Vanides J, Ruiz-Primo MA, Ayala CC, Shavelson RJ. Comparison of two concept-mapping techniques: implications for scoring, interpretation, and use. J Res Sci Teach. 2005;42:166–184. doi: 10.1002/tea.20049. [DOI] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Appendix 1: Concept map classroom handout
Appendix 2: Faculty concept maps






