Home > Contents of Proceedings > Volume 13

[Out of print]
Editor: Corey A. Goldman (University of Toronto)
Host: Jane M. Beiswenger

1. Testing Issues of Foraging and Flocking Behavior

Christopher C. Smith, Kansas State University  [abstract] [full text]

2. Studies in Protozoan Population Ecology

Jon C. Glase and Melvin C. Zimmerman, Cornell University  [abstract] [full text]

3. Responses by Stomata on Leaves to Microenvironmental Conditions

Carol A. Brewer, University of Wyoming  [abstract] [full text: pdf | html]

4. The Struggle for Existence: Competition Between Bacterial Strains

Beth A. D. Nichols, Linda B. Cholewiak, Princeton University, and Richard Condit, Smithsonian Tropical Research Institute  [abstract] [full text]

5. The Effects of Cattle Grazing on Vegetation in a Shortgrass Prairie Ecosystem

Ken L. Driese and Nancy L. Stanton, University of Wyoming  [abstract] [full text]

6. Enzyme Investigations for Introductory Courses

Ruthanne B. Pitkin, Shippensburg University  [abstract] [full text: pdf | html]

7. Stream and Pond Field Trip

Frank J. Rahel, University of Wyoming  [abstract] [full text]

8. Organelle Isolation and Marker Enzyme Assay

Harish Padh, University of Chicago  [abstract] [full text]

9. The Use of Fossils in Interpreting Past Environments

Brent H. Breithaupt, University of Wyoming  [abstract] [full text]

10. Developing Customized Instructional Software

Michael Parker, University of Wyoming  [abstract] [full text]

Appendix A: Abstracts of Mini Workshops

Appendix B: ABLE Membership List - March 1992

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Abstracts (Vol. 13)

1 -- Testing Issues of Foraging and Flocking Behavior
Christopher C. Smith  [full text]
Key Words: students simulate foraging, protective coloration, flocking, disruptive competition.
Students foraging for 100 pieces of macaroni in 100 square feet where the daily food requirement is 5 pieces of macaroni, days are 1 minute long, and winters are 12 days long provide data that simulate survival statistics for populations using nonrenewed resources. Food density, food color, habitat vegetation density, forager experience, and level of forager competition are changed to simulate other environmental variables. Different food for different foragers and a population of predators on the foragers are added to simulate selection for mixed-species foraging flocks.

2 -- Studies in Protozoan Population Ecology
Jon C. Glase and Melvin C. Zimmerman  [full text]
Key Words: population ecology, protozoa, competition, predation.
This 2-week investigative laboratory introduces students to the basic mathematical models describing exponential and logistic growth in populations of organisms. They consider two- species interactions, such as predation and competition, that may effect population growth. Student groups set up cultures of protistans in order to collect data on population growth and design and conduct an investigation of competition, predator-prey interactions, or some other factor that may limit growth of these organisms. These studies are completed during the second week and groups share their results and conclusions with the class.

3 -- Responses by Stomata on Leaves to Microenvironmental Conditions
Carol A. Brewer  [full text: pdf | html]
Key Words: stomatal aperture, leaf surface replica, ecophysiology, microenvironment.
Stomatal aperture provides much information about how leaves sense and respond to environmental conditions. Recent evidence suggests many species have nonuniform stomatal opening under both laboratory and field conditions, for example, different areas of the same leaf seem capable of responding independently to microenvironmental conditions. This exercise demonstrates how stomata respond to microenvironmental conditions by making casts of leaf surfaces and using them to evaluate stomatal opening and closing. It can be conducted in conjunction with discussions of photosynthesis and transpiration, as well as the implications of microenvironmental conditions to gas exchange.

4 -- The Struggle for Existence: Competition Between Bacterial Strains
Beth A. D. Nichols, Linda B. Cholewiak, and Richard Condit  [full text]
Key Words: bacteria, competition, lag phase, exponential growth phase, carrying capacity, Escherichia coli.
Two strains of Escherichia coli are grown in broth and plated out at intervals. A population growth curve is plotted for each strain. The two strains are then grown together for several days in different types of broth. Students from each day's laboratory plate out the mixed culture on selective media. Data are pooled. Population curves are plotted for the two strains in competition. With different conditions, it is possible to observe competitive displacement of one strain by another.

5 -- The Effects of Cattle Grazing on Vegetation in a Shortgrass Prairie Ecosystem
Ken L. Driese and Nancy L. Stanton  [full text]
Key Words: grazing, vegetation, shortgrass prairie, diversity.
Grazing by large herbivores has profound effects on both the structure and function of shortgrass prairie ecosystems. In this exercise a grazed section of prairie on a working cattle ranch is compared to a less grazed section on an adjacent wildlife refuge. The Daubenmire canopy-coverage method is used to measure percent cover by plant species and bare ground. Vegetation within the Daubenmire quadrat frame is clipped and weighed to assess biomass by species. In addition, relative soil compaction and cowpie frequency are measured to characterize grazing intensity. Calculations of plant biomass diversity are made using the Shannon-Wiener Diversity Index (H). Sampling methods and hypothesis testing are introduced.

6 -- Enzyme Investigations for Introductory Courses
Ruthanne B. Pitkin  [full text: pdf | html]
Key Words: enzyme kinetics, scientific method, investigative lab, introductory biology.
This laboratory is in a problem-posing format and was adapted from a traditional enzyme kinetics laboratory in order to help students do science. Students investigate how changing enzyme concentrations, substrate concentrations, temperature, pH, and an inhibitor influence the reaction rate of turnip peroxidase. The peroxidase in turnip extract prepared with a blender, is very stable, and can be kept at room temperature for several hours. Students use the following skills: planning experiments, pipetting, using a spectrophotometer, graphing data, and calculating reaction rates.

7 -- Stream and Pond Field Trip
Frank J. Rahel  [full text]
Key Words: aquatic ecology, fish, benthos, zooplankton, streams, ponds.
Streams and ponds offer good opportunities for comparative studies of biological communities. This exercise describes techniques for sampling aquatic organisms and quantifying habitat features that influence the kinds of organisms found in aquatic habitats. Inexpensive home-made alternatives to commercially-made sampling gear are described. Methods of analyzing community patterns and relating them to abiotic factors are discussed. The comparative approach can be used to contrast various aquatic environments; for example, polluted versus unpolluted streams, ephemeral versus permanent streams, headwater versus downstream reaches, pools versus riffles within a reach, shallow versus deep ponds, or surface versus bottom waters within a stratified lake.

8 -- Organelle Isolation and Marker Enzyme Assay
Harish Padh  [full text]
Key Words: organelles, marker enzymes, Dictyostelium discoideum, enzyme assays, mitochondria, lysosomes, contractile vacuoles.
Cells contain many specialized structures known as organelles which perform a variety of specific functions. To obtain precise information about the structure and functions of subcellular organelles, it is imperative to isolate them free from contaminating organelles. Marker enzymes are known to be localized exclusively in specific organelles and are used to monitor the separation of these organelles. In this exercise the homogenate of Dictyostelium discoideum will be fractionated by differential centrifugation to separate mitochondria, lysosomes, and contractile vacuoles. The fractions will be assayed for their marker enzymes: acid phosphatase for lysosomes, succinate dehydrogenase for mitochondria, and alkaline phosphodiesterase for the contractile vacuoles. This exercise presents two fundamental concepts to the students: organelle isolation and enzyme assays.

9 -- The Use of Fossils in Interpreting Past Environments
Brent H. Breithaupt  [full text]
Key Words: paleontology, fossils, ancient environments, casts, molds.
The earth's environment has changed dramatically over the past 4.5 billion years. A comparison of the remains of fossilized and recent organisms, associated with an understanding of geological processes (both past and present), allows scientists to interpret what ancient environments were like. This exercise was developed to help students understand (1) how past environments are determined and (2) how paleontological specimens illustrate such concepts as evolution, extinction, adaptation, paleobehavior, paleodiets, and paleoecology. Instructions for making molds and casts of specimens are included.

10 -- Developing Customized Instructional Software
Michael Parker  [full text]
Key Words: computer-assisted instruction, authoring software, critical thinking.
Costs to faculty in time and costs for the purchase of software help inhibit widespread instructional computing. mpAuthor is an expensive program for DOS/IBM microcomputers; anyone able to use a word processor producing ASCII files can create menu-driven exercises. Several examples of its use are presented, including some to improve thinking and problem- solving skills. Strengths of the program include: minimal computer skills required (have students create exercises instead of a term paper or as a project); works with virtually any DOS microcomputer (students can study anywhere); and easily exchange exercises with colleagues, and customize their exercises for your courses.

Mini Workshops  

• Chances' Choices: An Interactive Module to Study Human Genetics (Roberta Williams)
• AIDS Testing: A Demonstration/Problem (Rosamond Potter)
• The Use of Humor to Help Promote Critical Thinking in a General Biology Classroom (Nancy L. Goodyear)
• Use of Chives for the Study of Meiosis (Albert D. Robinson)
• A Training Program for Graduate Assistants Who Are Non-Native Speakers of English (Janet C. Constantinides)