Moyer MST: Understanding of stem cells

Jon Moyer
A comparative study of how high school students understand stem cells
Unpublished M.S.T. thesis, May 2007

In Spring 2004 an inquiry-based unit on stem cells was developed from chromatin dynamics research at the Jackson Laboratory in Bar Harbor, Maine. The unit was developed according to the backwards design model of curriculum development and implemented in Bangor area high schools in April 2005 and June 2005. With slight modifications, the stem cell unit was re-implemented in June 2006 and tested against a traditional, lecture-based unit.

Open response pre- and post-tests were used to capture initial student conceptions and measure learning gains. Pre-instruction interviews were conducted in order to gain a deeper understanding of pre-test answers. In addition, a two-tailed matched-pair analysis of post-test answers was performed in order to determine the effectiveness of inquiry- based instruction versus lecture-based instruction.

Comparison of pre- and post-tests shows relatively large learning gains after instruction. Analysis of pre-test responses and interview transcripts reveals many misconceptions, such as a fairly widespread belief that abortions are done specifically to obtain stem cells and beliefs that the amount of genetic information of stem cells is different from differentiated cells. Other findings include how students use a variety of terms to describe differentiation and the belief that stem cells are more prevalent early in life and “used up” during development.

The results of the two-tailed, matched-pair analysis for the most part do not indicate statistically significant differences between inquiry- and lecture-based instruction. However, results for a question on controversial aspects of stem cell research imply that the lecture-based instruction was more effective than the inquiry-based instruction at helping students understand the controversy. This result suggests that, given the limited time span of the unit, inquiry-based methods by themselves may not be the most appropriate pedagogy for teaching about controversies in stem cell research. A combination of lecture and inquiry, where the instructor gives a small series of initial lectures before assigning students a genuine inquiry activity, may be a better approach.

Pratt MST: Zebrafish teratogenesis and an inquiry curriculum

Jon Pratt
Zebrafish teratogenesis as a secondary-level science inquiry curriculum
Unpublished M.S.T. thesis, December 2006

A secondary-level zebrafish science education curriculum was designed and implemented with the Upward Bound Math Science program at the University of Maine in the summer of 2003. The six-week curriculum was designed to increase student scientific literacy in a program that integrates math and science education using inquiry- based methods. Scientific literacy is defined as knowledge of the nature of science, its concepts, and its human context: “A scientifically literate person is one who not only possesses a knowledge about these various aspects of science but also makes use of them in his or her ethical decision making and social participation in civic life” (NBPTS, 1997/2001). The zebrafish, Danio rerio, was chosen because it is a model organism in modern professional biological research. The zebrafish curriculum focused on biological development as a process that is influenced by both genetic and environmental factors, and the zebrafish development time of approximately 72 hours made it possible to conduct student designed experiment within a weekday-oriented education schedule. The students in the curriculum had completed their 10th, 11th, or 12th grade years in high school, and some had up to two years of prior experience in UBMS. The students were grouped so that all experience levels were represented, and groups developed, defended, implemented, and analyzed data collected in zebrafish development experiments using various environmental teratogens. The defense of the experimental protocol took place in front of a panel of experts, requiring students to justify the ethical fitness of their self- designed research because it involved the use of a vertebrate organism. Students used statistical tools to test the data they collected, and developed scientific explanatory models to interpret the results. Facilitators worked closely with small groups to promote participation in all aspects of the curriculum from all students.

Student learning in the curriculum was measured using formative and summative techniques that collected both qualitative and quantitative data. Formative assessment helped to fine-tune the curriculum while being implemented and summative assessment gave insight into student development via facilitator observations, student writing samples, and pre-post test score statistical analysis. The results of student learning were used to determine whether or not the zebrafish curriculum succeeded in increasing student scientific literacy, and the zebrafish curriculum was evaluated even further by comparing its fit with selected elements of the National Science Education Standards (NAS, 1995).

Analysis of student groups’ writing samples, group facilitator student evaluations, and of fitness with the NSES demonstrated that the zebrafish curriculum had a significant effect on the improvement of scientific literacy and a good fit with research based standards intended to guide the development of inquiry based science curricula. Statistical analysis of pre-post test data with students grouped by years of experience shows that the number of years of experience in UBMS also had a statistically significant effect on performance on the pre-post test. Suggestions are given for future iterations of the zebrafish curriculum, with emphasis on the importance of setting on the potential for success in raising student scientific literacy.