Time Efficiency, Written Feedback, and Student Achievement in Inquiry-Oriented Biology Labs

We examined how different styles of written feedback by graduate-student teaching assistants (GTAs) in college intro biology lab (USA) influenced student achievement and related the different styles to time efficiency. We quantified GTA feedback on formative lab reports and student achievement on two different types of assessments, a quiz in 2010 and a summative lab report in 2011. We evaluated the extent to which three categories of written feedback impacted student achievement (grade discrepancy between actual and ideal, short direct comments, and in-depth explanatory comments). Student achievement was best explained by both grade discrepancy and short direct comments in 2010 and grade discrepancy only in 2011. In-depth explanations were not part of the best-fit models in either year. Results also indicated that GTAs provided little encouraging feedback, most feedback was targeted and asked students to expand on explanations. Results are discussed in relation to relative time efficiency and GTA training

Motivation Strategies and Exiting Class by Students in Inquiry-Oriented Biology Labs

Experimental inquiry-oriented science labs can be designed to have students regulate their own learning and decide when they leave class or to have the teacher regulate student learning and determine when they leave class. In this study, grades were examined relative to student exit times in a student-regulated class design. Preliminary interviews revealed four motivation strategies likely to differentially influence exit times and grades: proficiency, grade-target-A, grade-target-C, and time-limited. Students were categorized into the four groups of motivation strategies with a survey. Twenty teaching assistants teaching three lab sections each taught the stand-alone lab class. Students recorded the time they left class each week. Grades were determined as the overall percentage of points a student received in class. Results of the survey showed that the four motivation strategies were well represented in the student population, and two additional strategies were also frequently seen: a hybrid-1 between proficiency and grade-target-A, and a hybrid-2 between time-limited and grade-target-C. Grades were significantly higher for grade-target-A and hybrid-1 students, followed by time-limited, proficiency, grade-target-C, and hybrid 2. Time spent in class was not significantly different among categories. Students who chose to stay in class longer had significantly higher grades. If a grade is the goal, these results support the idea of a teacher-controlled exit time for the students in these inquiry-oriented labs. Implications are discussed

Optimal central-place foraging by beavers: Tree-size selection in relation to defensive chemicals of quaking aspen

At a newly occupied pond, beavers preferentially felled aspen smaller than 7.5 cm in diameter and selected against larger size classes. After one year of cutting, 10% of the aspen had been cut and 14% of the living aspen exhibited the juvenile growth form. A phenolic compound which may act as a deterrent to beavers was found in low concentrations in aspen bark, and there was no significant regression of relative concentration of this compound on tree diameter. At a pond which had been intermittently occupied by beavers for over 20 years, beavers selected against aspen smaller than 4.5 cm in diameter, and selected in favor of aspen larger than 19.5 cm in diameter. After more than 28 years of cutting at this site, 51% of the aspen had been cut and 49% of the living aspen were juvenileform. The phenolic compound was found in significantly higher concentrations in aspen bark than at the newly occupied site, and there was a significant negative regression of relative concentration on tree diameter. The results of this study show that responses to browsing by trees place constraints on the predictive value of standard energy-based optimal foraging models, and limitations on the use of such models. Future models should attempt to account for inducible responses of plants to damage and increases in concentrations of secondary metabolites through time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47775/1/442_2004_Article_BF00379963.pd

Design of Inquiry-Oriented Science Labs: Impacts on Students\u27 Attitudes

I examined impacts of problem based (PB) vs. guided inquiry (GI) lab styles on students\u27 attitudes toward lab. In 2007 and 2008, I used a summative survey to assess students\u27 attitudes in General Biology. From 2007 to 2008, I modified two labs from GI to PB, one from PB to GI and I left two unaltered (controls). No significant differences in ratings were present for controls. Students\u27 rated GI significantly higher than PB in two treatments. For both, level of difficulty was significantly higher and time efficiency was significantly lower. No significant differences in ratings were present for the third treatment, but lecture help was significantly higher for the GI format. When attempting to improve students\u27 attitudes: GI appears better than PB, level of difficulty appears to have the strongest influence followed by time efficiency, and lecture help does not appear to substantially impact students\u27 attitudes towards lab