No abstract

Concept inventories are often used to assess current student understanding although conceptual change models are problematic. Due to controversies with conceptual change models and the realities of student assessment, it is important that concept inventories are evaluated using a variety of theoretical models to improve quality. This study used a modified item response theory model to determine university nonmajor biology students' levels of understanding of natural selection (n= 1,192). Using Conceptual Inventory of Natural Selection, we have reported how we applied Bock's modified nominal item response theory model and the distracter test item analysis. We found that the use of this model can define student levels of understanding and identify problematic distracters.

Hands-on learning is at the heart of science learning. This study examined increased changes of student content knowledge in biology, particularly biotechnology, after a hands-on biotechnology intervention was implemented into a secondary school. A traditional learning school was selected for a control. Both teachers had participated in a biotechnology professional development program called Project Crawfish. Students from both schools took the same assessment before and after their respective units (biotechnology intervention and genetics unit), and the classroom was the unit of analysis (n=5, n=6, respectively). The assessment was compared as a whole and then divided into five components, eight questions each: DNA extraction/gel electrophoresis, polymerase chain reaction (PCR), DNA sequencing, bioinformatics, and phylogenetics. The pre-tests were compared to establish a baseline between the two schools. The biotechnology intervention school began with a higher pre-test raw score than the traditional learning school. After adjusting for the pre-test scores, each school was analyzed for increases in student content knowledge and then compared to each other for any significant increases between the two schools. When the entire assessment was analyzed, each school had statistically significant increases in student content knowledge (<0.0001 for the biotechnology intervention school and 0.0481 for the traditional learning school). When the schools were compared to each other, a p-value of 0.0543 provided a suggestive relationship that the biotechnology intervention school had a larger increase in student content knowledge. When the assessment was divided into the five components, the traditional learning school had statistically significant increases in student content knowledge in the PCR and DNA sequencing components (0.0459, 0.0043, respectively). The biotechnology intervention school had statistically significant increases in student content knowledge in all five components. However, there were no significant differences in learning between the two schools. Implementing biotechnology through hands-on teaching methods should be considered by secondary science teachers. Further research would scale up this study to include more classrooms.

This study examines how student practice of scientiWc argumentation using socioscientiWc bioethics issues aVects both teacher expectations of students' general performance and student conWdence in their own work. When teachers use bioethical issues in the classroom students can gain not only biology content knowledge but also important decision-making skills. Learning bioethics through scientiWc argumentation gives students opportunities to express their ideas, formulate educated opinions and value others' viewpoints. Research has shown that science teachers' expectations of student success and knowledge directly inXuence student achievement and conWdence levels. Our study analyzes pre-course and post-course surveys completed by students enrolled in a university level bioethics course (n = 111) and by faculty in the College of Biology and Agriculture faculty (n = 34) based on their perceptions of student conWdence. Additionally, student data were collected from classroom observations and interviews. Data analysis showed a disconnect between faculty and students perceptions of conWdence for both knowledge and the use of science argumentation. Student reports of their conWdence levels regarding various bioethical issues were higher than faculty reports. A further disconnect showed up between students' preferred learning styles and the general faculty's common teaching methods; students learned more by practicing scientiWc argumentation than listening to traditional lectures. Students who completed a bioethics course that included practice in scientiWc argumentation, signiWcantly increased their conWdence levels. This study suggests that professors' expectations and teaching styles inXuence student conWdence levels in both knowledge and scientiWc argumentation.

Science is a dynamic discipline, representative of the nature of science. Yet, young science students continue to think everything is already discovered. In this study, we examine why students are not actively doing science. From professional development to student engagement, how are classrooms and students changing as we increase teachers' content knowledge? Teaching practices modeled in professional development can change what occurs in the classroom. Our study was designed to probe differences in two different types of professional development programs both focused on content knowledge. We found that what is modeled by the professional developers has a profound effect on the direction of the classroom. This matched controlled study found that teachers reflect the teaching practice modeled by professional developers through their individual classroom teaching practices. A significant difference was found in cognitive activities and questioning skills between teachers in a professional development program modeling authentic inquiry versus the teachers in a professional development modeling simulated inquiry. While both groups increased the amount of overall inquiry used in the classroom, students whose teachers were in authentic inquiry professional development were engaged in higher cognitive activities and questioning skills. If students are engaged in dynamic classrooms, searching for answers to students' questions, perhaps they will understand that science is a dynamic discipline.