We were estimating the diversity of two different prairie restoration sites at Prophetstown State Park. Week 1: critically evaluate the data in a published paper on the impacts of fire on tallgrass prairie plant communities - interpret graphs and figures, and create new graphs with the published data to facilitate different types of comparisons; Week 2: go into the field and do the same sample design that was implemented in the published paper, but at a different site with features that should lead to different patterns than was found in the published paper if the authors' underlying hypotheses about the mechanisms driving plant community structure were correct; Week 3: analyze their own data that they collected in Week 2, and compare their results to those in the paper examined in Week 1; Week 4: explore the implications of their results and the broader social and economic challenges associated with tallgrass prairie restoration and management.
This module is intended to refresh or introduce students to aspects of experimental design, enhance their understanding that the experiment design should support appropriate statistical analysis of the data, and promote the students’ recognition that there is often more than one possible way to design an experiment. This module is easily adaptable for students of any background or any education level. Instructions for presenting the module are included here, an associated power point is available for modification and use, and possible modification and extensions are indicated. This instructional teaching module was inspired and developed based upon the Experimental Design Assessment Tool (EDAT) developed by Karen Sirum from Bowling Green University and published in Bioscene: Journal of College Biology Teaching (2011). Sirum, K., and J. Humburg (2011). The Experimental Design Ability Test (EDAT). Bioscene: Journal of College Biology Teaching 37(1), 8-16.
How do organisms detect changes in their environment, and how do scientists and their instruments detect changes in experimental conditions, such as: How does a photoreceptor detect the presence of a photon? How does a doctor detect the presence of a tumor? How does a cell detect the presence of a chemical, such as a morphogen, a chemoattractant, or a nutrient?
The focus of the module is on interpreting figures from the scientific literature. To do this, students must differentiate between categorical and continuous variables, identify the dependent and independent variable, understand treatments, interpret visual presentation of variation and draw and evaluate conclusions from the data presented.
The major goals of the module are for students to a) be exposed to the overwhelming importance of size in an animal’s life; b) understand the relationships between surface area, volume, and size; and c) see how the relationship between surface area and its volume is fundamental to the operation of many animal systems. The module includes simple calculations of surface area, an introduction to the mathematical relationship between size and heat loss/metabolic rate, and a series of questions exploring the relationship between surface area and organ function. There is also an opportunity to students to extend this understanding to the cellular level in optional additional exercises.
This lesson is part of a sophomore level biochemistry course to introduce the concepts of experimental design. Students are provided with the description of an experiment designed to examine the effect of an electric field on bacterial growth. They are given initial observations from the experiment (inhibition of growth and an elongation phenotype for the bacteria) and asked to consider control experiments to evaluate whether the electric field is directly responsible for the effect. Students are prompted with questions then work in groups and share ideas. Ultimately it is revealed that platinum in the wires reacts to form cisplatin compounds that prevent cell division. Next the instructor explains that ciplatin reacts covalently with DNA and causes a bend or kink at the site of attachment. This led to the isolation of proteins that preferentially bind cisplatin modified DNA. Quantitative analysis of DNA-protein binding is presented to evaluate the affinity of proteins for unmodified and ciplatin modified DNA. Students are provided data from multiple binding trials and asked to evaluate the data. Students discuss and share ideas in class. Averages and standard deviations are discussed and calculated. Finally, data is presented from published studies that include averages and standard deviations. The lesson is designed to reinforce the concepts of control groups, quantitative analysis, statistical variation and display of data.
How does the volume of a cell, as measured by weight, change when placed in environments of varying tonicity?