The Virtual Fetal Pig Dissection

Chapter 39. The Virtual Fetal Pig Dissection
Earl W. Fleck,
Department of Biology
Whitman College*
Walla Walla, WA
With few exceptions, biologists are persuaded that the only way to learn the structure of an organism is to dissect it, accompanied by a well-written laboratory guide and a patient, observant instructor. However, owing to the resistance of some students to animal dissections and the need of others to have review material, I became convinced that I must provide my students with substitute or supplementary material for these dissections. Thus, as an initial effort to test this conviction, I created an animated program that presents a Virtual Fetal Pig Dissection. We call it VPD.

I started this project with a senior biology major, who is highly skilled in computers, and a local retired physician. Later, another senior biology major and a multimedia specialist from our computer center joined the team. The talents brought to bear on the project has allowed a far more sophisticated and appropriate approach than what I might have done on my own. The physician has a depth of anatomical knowledge far superior to mine while the multimedia specialist brings sophisticated and dedicated computer animation talent. Moreover, the two seniors who performed the dissection in lab only a few years ago bring a studentís perspective to bear as well as fine computer and photography skills. The Howard Hughes Medical Institute funded this effort.

IDEAS BEHIND THE DESIGN. My introductory biological principles course covers material typical of any introductory college-level biology course. Students receive a rigorous introduction to the molecular, cellular, and physiological processes of life. I use a three-week series of labs on the fetal pig as a supplement to the lecture discussions of whole animal physiology. On my class evaluations, students cite this section of the lab as the most interesting and exciting exercise. However, each year I have several students who refuse to participate owing to ethical or moral qualms; they have a strong aversion to performing any dissection on an animal, especially one that looks so much like a human. Various antivivisection agencies provide educational material as substitutes for a dissection. For example, videos of a fetal pig dissection and molded plastic models of pigs are available at modest costs. Unfortunately, my students and I find these substitutes inadequate; the videos are of poor quality and lack interactivity, and the molded models lack detail. Hence, those students who refuse to do the dissection miss a valuable learning experience. Further, the students who perform the dissection in lab complain that they lack a way of reviewing the material once they complete their dissection and prepare for the lab practical exam. Clearly, here are opportunities to enhance the education of my students using electronic multimedia tools and provide a measure of interactivity.

COMPUTER-ENHANCED TECHNIQUES. When I initially started the Virtual Pig Dissection (VPD) project about three years ago, I intended on using html format for the project--a rather crude technical conception. However, when Macromedia Shockwave became available a few years ago, I decided to use Macromedia Director as the basis for the interactive animations. Director provides the software tools to create animations, while the Shockwave plug-in allows a browser to play Director animations over the web. Using Director and Shockwave allows much more sophisticated and dynamic interaction between simulation and user. The drawback is that Director, especially higher level use, demands quite high technical expertise.

Initially, my team spent much of a summer preparing high-quality 35-mm photos of a fetal pig dissection. The following fall and spring we organized the photos, scanned appropriate images, formatted the images using Adobe Photoshop, and completed a few more dissections to fill in gaps in the coverage. More recently, we have switched from a 35-mm camera to a digital camera. This allowed us to upload images directly to our computer. Unfortunately, the image quality of our Kodak DC120 Zoom Digital Camera is less than that of the images taken with our 35-mm SLR camera. I am unsure whether this represents the poorer quality of a digital camera or our inexperience in its use.

After we took most of the photos, we embarked on the next and most important step---we prepared a storyboard for the first module. A storyboard is a simple method of mocking up the animation and making organizational decisions using static frames. We prepared rough drawings of the dissection photos we wished to use. To these images, we appended labels, text, and descriptions of the transitions from one panel to the next. We worked on this storyboard until we were satisfied that it represented the content we thought essential in the order that was appropriate for the students.

Once we finalized the storyboard, we began integrating the images into the animations for our first module. This required gaining command of the Director programming language, Lingo. After we created an animation that roughly represented the storyboard, we played through the animation and operated the interactive elements. Often, we markedly changed text, enhanced labels and highlights, and changed the order of presentation after viewing our efforts. One beneficial aspect of Lingo script in Macromedia Director is the ease of moving elements of the animation once you construct them.

I decided to reduce our task into modules that roughly correspond to the main physiological systems; for example, the digestive, respiratory, and excretory systems. At this time, we have four modules of about ten completed with three more in the final stages of completion. Each of these modules has high-quality images of the dissection coupled with appropriate text and links to further information or additional dissection views. We will complete the remaining modules by the end of the 1998/1999 academic year.

Mated with each module is a student self-assessment activity. Most of the questions are objective, but all make use of graphics from our pig dissection image file. For example, in one exercise on anatomical reference terms, students view an image of a pig and apply correct orientation labels. In another exercise on the digestive system, students match a series of definitions with the appropriate structures. Although this sounds like a simple matching quiz, there is immediate feedback. In a third exercise, on the circulatory system, students place the names of structures in an appropriate loop on a schematic diagram representing the pattern of circulatory flow.

MEASURED OUTCOMES. Although the project remains incomplete, we uploaded each module when finished and provided access to our students. We now have four semesters of experience using these modules in my introductory biology principles lab. On a supplemental student evaluation form that contains specific queries on the course, I ask students to indicate which of the half dozen computer-enhanced learning opportunities they consider most beneficial. Although exact percentages vary from semester to semester, students rank this enhancement as the best computer learning aid available. These survey results are supported by an analysis of the hits to the VPD web page, information that is available from our computer center. Our VPD site sustains a large number of hits from college sites outside my teaching lab.

Although I envisioned student use only for those withdrawing from the dissection exercise and for review just prior to the lab final, surprisingly, I find that students make extensive use of the animation during the lab period. Students preview the dissection on the computer before they actually perform the incisions. They tell me that they find the interplay between the actual dissection and the computer dissection very helpful as they embark on their first serious dissection.

LESSONS LEARNED. First, the students who opt out of the dissection are grateful for the chance to view quality images with matching labels and text. Although the animation is markedly inferior to performing dissection, they feel they learn something. Further, these students now feel more part of the class, since they have not completely withdrawn from the exercise. Second, most students report that they use the animation as a review for the exam. Third, use of the animation during the dissection exercise was a pleasant unintended consequence. Clearly, in my view, this has been a successful addition to my course.

Finally, I learned that having this animation on the web has led to use by students and faculty outside the college. Analyses of the hits to the site show that a significant fraction is from educational sites around the country and the world. This is gratifying, as it shows the power of the web to span large distances.

There are some serious drawbacks in developing such exercises. The animation is still incomplete in spite of spending two years on the project. The demands on my time--to supervise the preparation of high-quality images, the manipulation of the digital images, and the writing of Lingo scripts for Macromedia Director animations--is tremendous. Without the help of a dedicated computer center multimedia specialist, I know that the product would be of much lower quality.

Return to the VPD dissection home page.