STUDYING THE PROCESSES AND EFFECTS OF EVOLUTION WITH EVOLUTIONLAB

Judith T. Parmelee, Manchester Community College
Last revised: Thursday, February 22, 2001

INTRODUCTION

Teaching and learning about evolution has always been difficult because one cannot do an exercise showing natural selection over time or examine hypotheses prospectively. Labs usually last three hours, not 300 years!! As a result, beginning undergraduate education in this area has been necessarily limited to presentation of retrospective studies based on fossil records or review of long-term observational research done by others. With the capabilities of the modern computer, however, all this changes. A good program can extrapolate results into the future given parameters that are known to affect survival, hardiness and adaptations of a species. In our General and Introductory Biology course we have used EvolutionLab from BiologyLabs On-line by R. Desharnais, J. Bell and M. Palladino.

These labs are available by yearly subscription for a small fee that allows the student and the instructor unlimited access to the web site during the subscription period. The material in Evolution Lab includes a general introduction and definition of evolution presented in an understandable, scientifically accurate way, and it reviews the contributions of many scientists including Darwin and Wallace for whom the "islands" studied in the project are named. Although keyed to a particular Addison Wesley Longman text, the lab can be used with other Biology textbooks and incorporated and integrated with various laboratory schedule structures.

The site has assignments geared both to the biology major and non-major, with the scenario for the major most useful for our community college students. During our first year trial of this website and the EvolutionLab, in particular, both instructors and students alike were pleased and impressed with the information that could be gathered from these experiments, the level of enjoyment that learning in this manner achieved, and the critical thinking processes that were stimulated in forming hypotheses and interpreting results.

So let's go to the Galapagos Islands and see what our students are able to learn.



Galapagos Islands, 1997

PRINCIPLES AND LEARNING OBJECTIVES

The exercises in EvolutionLab are centered in small populations of finches on two different islands. Parameters that influence natural selection can be altered individually, and results compared between the two island groups. Changes in beak size and population numbers are the evolutionary results that may be measured over intervals of 100, 200, or 300 years. Parameters that can be altered are initial beak size, precipitation, island size, clutch size, trait variance and heritability.




Masked booby with clutch, Galapagos Islands, 1997

Students are given a brief review of the history and principles of natural selection before beginning the exercises, and they are referred both to a textbook and to outside readings before progressing with the lab activities. An online glossary is an added resource to aid in their learning.

Importantly, for each activity, students are instructed to develop an hypothesis, to test it with the experiment and to explain their results in terms of expected changes. This stimulates critical thinking and engages the student in the learning process and scientific method.


The stated objectives of the laboratory are to:


COMPUTER-ENHANCED TECHNIQUES

The real beauty of this lab is the flexibility that is built into the program which allows all manner of changing parameters, combining variables and looking at extremes or at very subtle changes. Students can not only follow the prescribed experiments, but also go on and try out their own ideas and combinations that may or may not affect outcomes.

Another real plus is that the program runs actual numbers, so identically designed experiments will have some variation when repeated several times. This is so much more like real research than some other programs where every student will get exactly the same result on every trial. Likewise, in some sessions, students test all three time runs of 100, 200 and then 300 years, and learn that in the shorter trial, changes in beak size or numbers may not be apparent, but become significant when evolution occurs over the 300 year time frame.

Results of the activities on beak size and population numbers are presented in several forms at the end of the run. These include line graphs, histograms and raw data; several of these can be exported and saved or printed. This allows the student to see both general trends and individual changes over short and long times.

The manipulation and combination of both environmental and genetic effects provide students with an appreciation for evolutionary results. There are several ways in which the key factors in extinction can be demonstrated with this program, and the dire results of small clutch size and narrow variance are especially striking over relatively short periods. The student guide and lab questions encourage both individual thought and group interactions and cooperation.

The website does provide a mechanism for trying these labs for a limited time (3 days) for those who want to test the EvolutionLab or any of the other exercises available from this site.

LESSONS LEARNED

In our course for biology majors, we have found very little down side to this lab. It is long and takes a full three-hour lab period, but the website directions are clear and the presentation and arrangement are easy to use. Most students proceed through the activities easily and there were few complaints regarding difficulty or confusion. Students enjoyed this and many students may want to continue to explore the variables and results after the lab is ended, but, of course, this is a positive and not a negative outcome.

The only caveat was expressed by a professor who tried this in a non-majors basic biology course. She found that the lab was far too complex for the understanding level of those students and the three-hour time requirement was much too long to keep this group engaged. She plans to try this again in the future, however, by using very selected portions of the lab that can be done in about an hour, and combining it with other lab activities to maintain student interest and enhance understanding of this important topic.

CONCLUSION

EvolutionLab at the biologylab website provides an enjoyable and valuable way to present the priniciples of natual selection to beginning biology majors. Its programs and graphics work well, are easy to handle, and have a low frustration factor. The flexibility of parameter input and speed of running 300-year simulations are very valuable. Computer generated results available from this product provide students with laboratory experiences in evolution that previously have not been possible in a standard low tech laboratory setting.

So if you can't take your students to the Galapagos to study the unusual island inhabitants, EvolutionLab may serve as an acceptable temporary substitute.


Giant tortoises of the Galapagos Islands

NOTES AND CONTACT INFORMATION

There are several references for students that are cited on the website.
This document was prepared with the assistance of Joanne Russell, Ph.D. and Wesley Klein, D.O., Biology Faculty at Manchester Community College who initially tried this lab with their students.

For more information:
Judith T. Parmelee, PhD.
Manchester Community College
PO Box 1046 MS #17
Manchester, CT 06045
Email: parmelee@neca.com



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