These 2-3 hour workshops are hands-on, laboratory sessions during which presenters will share their innovative and successful undergraduate lab exercises with participants. View the abstracts below, organized by topic.
Ecology
The use of corn and sugarcane to produce ethanol biofuel
(Valerie Banschbach and Robert Letovsky)
The controversy over the use of food crops to produce fuel provides a new way to engage students in learning some important biological concepts. In this workshop, I will demonstrate a laboratory experiment in which students investigate the process of ethanol fuel production and then integrate their scientific analysis with a discussion of the economic and environmental impacts of ethanol as fuel. This exercise is suitable for interdisciplinary, college-level environmental studies, science and biology courses, as well as high school courses. Because the process of ethanol fuel production is based upon fermentation, this laboratory exercise represents a means of involving students in the study of a basic and important biological process by relating the use of that process to important current events.
Community Assembly in a Leaf Litter Invertebrate Community
(Christopher Beck)
In this exercise, students design and carry out an experiment to test among competing hypotheses for community assembly, using a leaf litter invertebrate community as a model system. By constructing mesh bags with leaf litter from which the invertebrates have been extracted with a Berlese funnel, students can begin the experiment with an open community. By sampling a subset of leaf litter bags at different time points over a 4-6 week time period, the degree to which community development is deterministic or random can be evaluated. Depending on the degree of statistical analysis of the resulting data, this experiment could be used in introductory courses for majors or upper-level capstone courses.
Substrate Size Selection by Bean Beetles
(Christopher Beck, Saphida Migabo, and Lawrence Blumer)
Live animal systems that are easily manipulated and permit rapid data collection would be ideal for teaching non-science majors and introductory-level majors the methods of science. In this study, we use the well-developed bean beetle, Callosobruchus maculatus, model system to guide students in the development and implementation of an experiment that is an authentic scientific study from which they can easily collect meaningful data. Bean beetles are agricultural pest insects of Africa and Asia. Females lay their eggs on the surface of beans (Family Fabaceae) and the entire pre-adult parts of the life cycle occur inside the host bean. In this study, students design and conduct experiments to evaluate whether female bean beetles discriminate between beans of different sizes within one bean species. We also will present an assessment strategy for student understanding of the scientific process.
The Role of Feeding Adaptations in Resource Competition between Invasive and Native Clams
(Doug Graber Neufeld and James Yoder)
This laboratory allows participants to investigate the feeding architecture of gills as an adaptation which may allow invasive clams to more successfully take advantage of food resources, and thereby displace native clams. Participants measure clearance rates in an invasive (such as Corbicula) and a native clam (a unionid species) for two potential food items–algae and bacteria. The ability of these clam species to clear relatively large (algae) and/or small (bacteria) items is correlated with the spacing between cirri on gills. In addition to gaining experience in carefully controlling experimental design, participants refine skills in pipettor operation, microscopy, and absorbance spectrophotometry.
Investigation of Escherichia coli in freshwater sources using membrane filtration and Rep-PCR DNA fingerprinting
(Joanna Klein)
Escherichia coli is a common indicator bacterium for fecal contamination and testing for E. coli levels is a measure of recreational freshwater quality. This workshop presents a multi-component laboratory activity for detection and identification of E. coli. Students use a membrane filtration protocol adapted from the EPA for detection and enumeration of E. coli from freshwater sources. Students then use standard biochemical methods to confirm isolates as E. coli. Finally, students use Rep-PCR DNA fingerprinting to determine the relatedness of E. coli isolates. Beginning with sample collection and proceeding to molecular analysis, students learn necessary skills and are exposed to the most current methodology used by government, industry and academic researchers for the analysis of microbial contamination of water, food and pharmaceuticals. This series of experiments has been used in an introductory microbiology summer enrichment course for high school and colleges students. To increase student engagement, the experiments have been done within two contexts, as a case study and as a service learning/research project. In this workshop, participants will complete key portions of the activity including the membrane filtration protocol and will run PCR reactions on a gel to compare strain relatedness. In addition, the use of this lab as a case study and service learning opportunity will be discussed.
Forest Ecology: Point Pleasant Park Field Project
(Allison Schmidt and Christine Beauchamp)
On September 28, 2003, Hurricane Juan made landfall near Halifax, Nova Scotia, devastating Point Pleasant Park, the city’s 185 acre coastal urban forest. This recent ecological disturbance presented a unique opportunity to evaluate the effects of disturbance and document the physical and biological changes in the community over time. Several 20 x 20 m plots were established throughout the park in 2004. In successive years, students visit the plots to measure tree diameter, estimate the percent cover of ground vegetation using ten 1 x 1 m quadrats and make qualitative observations of the physical surroundings. The data is then used to reconstruct the pre-disturbance forest and assess regeneration in different areas of the park.
Owl Web: Using Owl Pellet Dissection as a Hands-On Introduction to Food Webs
(Katherine Thorington and Meghna Ostasiewski)
The goal of this laboratory exercise is to provide a hands-on introduction to food webs, nutrient cycles and energetics. Combining owl pellet dissection and a low stakes food web activity allows students to observe and handle tangible evidence of a food web before constructing a more complete picture. It also provides an opportunity for students to incorporate alternative food webs into their concept of energy flow through an ecosystem. This exercise is designed for students at multiple levels and to work at a range of class sizes.
Evolution
Origin of Species: Starting the Story with DNA
(Robert Ketcham)
This set of activities starts with a pop bead model of DNA, although the model is presented to students initially not as DNA but as necklaces worn by members of a tribe of humans. Students manipulate the necklaces according to customs of the tribe and discover the simple story of where new species come from: populations split and the resultant daughter populations diverge due to mutation. They also use the necklaces to learn about restriction enzymes and the production of phenotype from genotype via translation.
Evaluating the Effects of Natural Selection and Genetic Drift in Drosophila melanogaster
(Elizabeth Welsh)
This laboratory provides a “hands on” experimental approach to illustrate evolution in a semester long study using red-eye and white-eye phenotypes of Drosophila melanogaster. Students set up and maintain small and large fly populations for several generations to observe the effects of genetic drift and natural selection. They record the phenotypes, calculate allele frequencies and at the end of the semester, submit a formal laboratory report on this experiment which includes chi-square tests, and graphs of allele frequencies, heterozygosity and divergence (Fst) values. They gain valuable practical, analytical and writing experience from this experiment.
Genetics
Eggheads: An Alternative Classical Genetics Model Organism
(Janice Bonner)
Although numerous organisms can be used in a classical genetics laboratory exercise with non-majors or first-year students, many of them pose problems, most appreciably constraints imposed by the length of life cycles and the difficulty of examining traits. Eggheads, a teaching tool adapted from American Biology Teacher (Beals, 1994) present an alternative to standard Mendelian organisms. Because Eggheads can be specifically adapted to the conceptual understanding of students, they can be used in general education courses and in introductory courses for majors. In this model system, 100 Eggheads constitute the F1 generation of a single pair of Egghead parents. To prepare the F1 for a class of about 25 students, several bags of colored plastic Easter eggs are used. Various facial features are drawn on the eggs with opaque paint markers so that they represent numerous patterns of inheritance. Eggheads can be designed to show complete dominance, incomplete dominance, and codominance; sex-linked traits; interaction of gene pairs; linked genes and crossing over; and epistasis. The goal for students working with the Eggheads is to correctly explain the mode of inheritance shown by each character, while demonstrating familiarity with vocabulary words that are frequently confused (character and trait, gene and allele, for example). This workshop will be conducted as it would be with non-majors or with first-year students to provide participants with an opportunity to experience working with Eggheads. The workshop will also provide information for constructing a set of Eggheads.
Phagehunting with Introductory Biology Students
(Pamela Connerly and Deborah Jacobs-Sera)
There is growing interest in the scientific community about the genomic diversity of one of the most numerous biological entities on the planet: bacteriophages. These tiny (<0.2 um) viruses play a critical role in gene exchange between bacteria, which can influence pathogenicity. Luckily, this important area of active research is extremely accessible to introductory biology students of all ages. In our workshop we will lead you through the process of isolating novel bacteriophages from soil samples brought in by students. We will introduce you to our favorite host bacteria, Mycobacteria smegmatis and Acinetobacter baylyi, but the activity can be modified to suit other bacteria typically found in soil that can be grown in the lab. Students enjoy the possibility of finding a completely novel bacteriophage in their backyard and there are extensive follow-up opportunities for students interested in further phage purification, DNA isolation, DNA sequencing, and genome analysis of the newly identified phages. This lab provides an excellent way for faculty to link together pedagogical goals such as learning about the diversity of organisms and understanding gene structure and exchange with the research goal of extending our knowledge about the genome sequences of some of the >1031 bacteriophages that exist on Earth.
Linking Genotype to Phenotype in Drosophila melanogaster: PCR Genotyping the White-one Eye Mutation
(Oney Smith and Kathy Falkenstein)
The purpose of this workshop is to instruct teachers on the use of a DNA-based learning activity that will add educational value to a classical lab on Drosophila genetics. At Hood College, our sophomore-level cell biology and genetics course includes a multi-week lab exercise that uses Drosophila to investigate the classic sex-linked inheritance pattern of “white eyes” discovered by Thomas Hunt Morgan in the early nineteenth century. In this workshop, we will demonstrate how the polymerase chain reaction (PCR) method can be used to DNA fingerprint (genotype) wild type (red-eyed) and mutated (white-eyed) flies. The use of this genotyping exercise as a component of a classical Drosophila laboratory experience will provide students “hands-on” experience establishing the link between genotype and phenotype. In addition, this lab-based learning activity will introduce students to common techniques used in molecular genetics, including the extraction of DNA, PCR, and agarose gel electrophoresis.
Genotyping SNPs Associated With Dyslexia
(Ann Yezerski)
This multi-week laboratory exercise is based on the research on the genetics of dyslexia that we have been conducting. In fact, data collected by the students in this exercise are compiled with our research data in order to expand our database. The exercise is designed to teach every aspect of a genotyping project from using Bioinformatics to create the molecular protocol, through data collection using their own DNA, to comparison of populations using the tenets of the Hardy-Weinberg theorem and statistical comparison to the HapMap database. In the wet lab portion of the exercise, students extract DNA from their own cheek swab and then set-up subsequent PCR reactions followed by a restriction digest in order to obtain their personal genotype for a SNP in the KIAA0319 gene, known to be strongly associated with dyslexia. Concurrent exercises demonstrate how a genotyping protocol is designed using Bioinformatics computer software as well as how a SNP can lead to a phenotypic difference. The result is a comprehensive exercise that demonstrates a complete, ongoing research project that now includes the student not only on an intellectual, but also a personal level.
Molecular Biology
Does Race Exist? Alu Transposable Elements and Ancestry DNA
(Peggy Brickman and Jim Burnette)
Alu transposable elements are useful as DNA markers for human population studies. For example, one of the 5000-7000 new Aluinsertions into the human genome since our ancestors split from a common ancestor with chimpanzees exists in human populations as 4 different polymorphisms (Kass, Jamison, Mayberry, & Tecle, 2007). Interesting variations in the presence of the different alleles in sampled populations from Africa, South America, Europe, and Asia can be used to elucidate human ancestry. But does this mean there are large genetic differences between human populations? In this lab, students read an article about the genetic basis of race and consider how much genetic variability exists between human populations. They relate this knowledge to the issue of whether or not society should or should not be concerned about gathering data based on race (at least for medical studies). Students also experience the excitement of extracting and analyzing their own DNA, performing PCR, restriction enzyme digestion, and gel electrophoresis. The lab can be accomplished in 3 2-hour laboratory meetings but can also be modified for 3 2-hour meetings. In addition to learning about transposons, polymorphisms, and DNA technology, this lab includes inquiry activities such as predicting results, analyzing data, and communicating understanding in writing.
Instructional Methods
Conversion Immersion: Clicker Question Edition
(Mark Walvoord and Mariëlle Hoefnagels)
Clickers (aka Personal, Audience, or Classroom Response Systems—PRS, ARS, or CRS) have received attention because they bring technology into the classroom, allow students to interact with each other and with course material, allow quick assessment of student understanding, can improve learning, and allow quick roll call and grading in large lecture classes. Though much of the research in higher education clicker usage focuses on large, lecture courses, the use of clickers in smaller settings (laboratories, small classes) is also warranted. One of the authors successfully uses clickers in her introductory biology laboratory by following some basic principles of good practice and by using well-written questions. In classrooms of any size, one challenge confronting instructors who adopt clickers is learning to compose effective questions, which may require different construction than test or homework questions. Proper pedagogy is necessary to maximize the benefits of clickers. During this workshop, we will present a brief summary of research on clicker pedagogy; participants will then work in small groups to convert existing clicker questions into ones that promote interaction and learning. Current clicker users and the “clicker curious” are welcome.
Physiology
Osmolarity and Tonicity: an Inquiry Laboratory Using Plant Material
(Dee Silverthorn)
Osmolarity and tonicity are very difficult concepts for students to understand and often for faculty to teach. The coverage of tonicity in most introductory biology textbooks is perfunctory at best and inaccurate or misleading at worst. Yet a clear understanding of the difference between the osmolarity of a solution and its tonicity is essential for pre-health professions students because tonicity is the basis for the appropriate selection of intravenous fluid therapy. One classic student laboratory experiment for studying osmolarity has students placing potato plugs into varying concentrations of NaCl to see what happens to their volume. That experiment demonstrates the osmotic movement of water but does not allow students to differentiate between solutions that are hyperosmotic/hypertonic and hyperosmotic/hypotonic. We adapted the techniques from the potato plug lab to create an inquiry laboratory using assorted plant materials that requires students to design two experiments. Their first task is to determine the internal osmolarity of their plant material. The second task is to determine whether a particular solute is a penetrating solute for plant cells. The tasks in the most independent format require students to make their own solutions, and design a controlled experiment for task 2. For student populations who need more guidance, the amount of independent work can be adjusted by the instructor. In this workshop we will discuss the fundamentals of osmolarity and tonicity and run the experiment using seasonally available plant material.
Exploring Animal Photoreceptors and Eyes
(Kathy Winnett-Murray and Lori Hertel)
In this exercise, students examine a diverse array of invertebrates and vertebrates to explore structure-function relationships in the Animal Kingdom, using photoreception and vision as a context for their comparisons. This lab exercise was developed to provide a “wet lab” experience to accompany a physics-based “bio-optics” lab (see ABLE: Tested Studies for Laboratory Teaching Vol. 30) in which students model the physical relationships achieved by different structural types of “eyes”, including pinhole, mirror and lens mechanisms for focusing light on photoreceptors. In addition to reinforcing the physical aspects of vision previously investigated, this exercise is intended to build in a biodiversity component, such that students will better appreciate the range of vision types exhibited in the animal kingdom, as well as gaining exposure to a wider array of animals. During the exercise, students examine simple eyespots (Dugesia), a variety of eyes that use “pinholes” to channel light rays, the eyes of scallops (Pecten), which include reflective “mirror” surfaces, they use microscopic slide preparations to examine structure-function relationships in insect compound eyes and among the retinas of various vertebrates, and they dissect a representative mammalian eye (Bos), having both lens and pinhole structures. Finally, students collect data from human individuals (Homo) on campus to test a working hypothesis about the relationship between age and accommodation. Students plot and analyze data from individuals with and without corrective lenses; the results of this comparison reinforce what they have learned about physical structure-function relationships important in vision
Biochemistry
Understanding Solution Chemistry the “Southern Way” with Sweet Tea
(Robyn Puffenbarger)
Solution chemistry is one of the most important and most confusing aspects of biology. In many labs outside academia, understanding concentration units such as M, % and X is critical. While students usually have made M calculations many times, especially in chemistry labs, the knowledge often does not “translate” to biology labs. In addition, biologists are often confronted with %, as in Ringers or 0.9% saline, and X, stock solutions that come 50X, etc. Thus, students need the ability to manage several different ways to think about and calculate solution concentrations. In the first lab in biochemistry (Biology/Chemistry 405 at Bridgewater College), we discuss a number of topics including solution chemistry. In order to put solution chemistry in “context” for the students, we discuss how they might have used X concentration when making juice from frozen concentrate without even realizing that they were making a solution! As we move through the lab exercise, each student must make a different M solution of tea with sucrose, i.e. sweet tea. We then do a blind taste test to see at what concentration “humans” cease to taste sweet. Students practice a number of thought processes and skills in this lab experience including: 1) review of solution chemistry; 2) dilutions; 3) making solutions; 4) writing a hypothesis; 5) writing lab methods; and 6) excel graphing. Informally, students have reported that this lab is fun while making them work on solution chemistry, a topic they have dreaded in the past.