Article

UniServe Science News Volume 9 March 1998

Production of Video Images to Enhance Teaching of First Year Undergraduate Botany

Introduction

The effectiveness of computer based learning in science education has been extensively analysed at several Australian universities. Summing up the Proceedings of the Dry Labs Workshop (1996), Johnston and Peat state that computer based technology should be regarded as an opportunity to "enhance the laboratory experience" rather than as a means of replacing "wet" laboratories. Pamula et al (1996) and Whittington (1997) describe its use in teaching biology.

In recent years, severe funding cuts to tertiary education, combined with large student numbers and reductions in establishment staffing levels have required an increased dependence on casual staff. In lectures to large first year classes of up to 300 students, there is little opportunity for synthesis of information. Laboratory based practical classes and the associated tutorials are critical in providing an opportunity for two way communication between student and teacher. To date we have been able to allocate two staff to every 24 students in each laboratory. Even with this apparently favourable staff to student ratio, one or two students may engage the attention of staff members, to the exclusion of other students. To circumvent this, we have used computer software to develop videotaped images of plant tissue sections, which can be projected simultaneously into several first year teaching laboratories.

In first year botany courses at James Cook University, we try to maximise the student's "hands on" experience. The merits of this in terms of information processing and retention are well established (Richardson, 1995). Our course on the Diversity of Plant Life, provides an introduction to the biology of plants for students with varying backgrounds. Most of them will have completed Senior Biology, but others previously have not studied biology. The subject encompasses anatomy, reproduction, classification and evolution of the whole range of organisms generally regarded as members of the plant kingdom. The approach is descriptive/analytical rather than generating data which requires subsequent processing. In this respect it differs from some other branches of science that have recently been addressed, such as biochemistry (Learmonth 1996) and chemistry (Capon 1996).

Aim

We aimed to enhance the efficiency of first year teaching, and to provide a means of quality control with respect to the delivery of teaching in a subject that relies on the use of casual, relatively inexperienced staff. To achieve this, we developed a series of videotapes that were projected into several laboratories simultaneously at those times when the students were examining the specimens concerned.

Methods

The material that we have so far captured on video includes stained sections of plant tissues in stems, roots and leaves and whole mounts showing reproductive structures such as the receptacle of the brown alga, Fucus and zygospore formation in the fungus Rhizopus. To use these images as effective teaching tools, we added appropriate labels, as shown in figures 1 and 2.

Figure 1.

Figure 2.

The videotapes were displayed through the audiovisual system already established in the first year laboratories. The graphics, which formed the basis of the videotapes, were developed using computer software, then transferred to videotape. This was a three-step process, involving:

1. Image capture
2. Image tuning
3. Image output to videotape

1. Image capture
   Images were taken from microscope slides of stained plant tissue sections via a CCD camera mounted on the drawtube of a high power microscope. The video signal was passed through a Video-Vue board, which permitted real time preview of the image on the computer monitor. Colour balance, contrast and focal adjustments were then performed. The image was captured and saved to the computer hard drive in a 24 bit true colour or 256-colour TIF file format.

2. Image tuning
   The image was then loaded into Photofinish and enhanced by cropping, removal of artefacts and colour balancing. The enhanced image was resaved and imported into Corel Draw where labels, identifying arrows and scale bars were superimposed over the bitmapped image. Using Corel Draw's preview facility, the image was then displayed on full screen without showing menu bars or control cursors.

3. Image output to videotape
   This was created using AverKey , a PC to TV signal converter. AverKey produced a composite image of the computer screen onto an attached TV monitor. After adjusting the location and colour balance of the image on the computer screen to suit the dimensions of the TV monitor, the image was recorded to videotape via an attached VCR. Each image was recorded for a set period of time depending on the rationale for using each specimen. Some were intended simply for the identification of cell and tissue types, others were to assist the students construct cell detail diagrams.

Effectiveness of the videotaped images

Practical classes are conducted concurrently in four laboratories. The video images of labelled tissue sections can be viewed by all students simultaneously. This permits students to identify the structures on the slides being viewed on their own microscopes, without placing excessive demands on tutors' time. The system has multiple benefits for both students and staff:

1. It provides quality control with respect to teaching effectiveness. Undergraduate laboratory classes typically employ a large cohort of casual tutors. The use of labelled video images ensures that the correct information is being disseminated and that students attending different class sessions have access to the same information.

2. Rather than being "tied" to one student, tutors are able to respond quickly to student questions as well as to comment constructively on diagrams. New terms and concepts can be introduced in a consistent and authoritative way. Thus, the practical classes permit student-staff interaction but provide video images, to which students relate well.

3. At tutor briefing sessions, the tutors can confirm that they understand the relevant plant material. The presence of the labelled images also strengthens tutor self-confidence, provides an opportunity for them to address several students at once and enhances their enthusiasm for the subject.

4. This system has overcome the concern that the use of computer software means a lack of "hands on" experience. The images are integrated with the use of whole plant specimens and tissue sections. Opportunities are provided for interaction and re-enforcement: students prepare slides of tissues they have cut and stained. Their preparations may be transmitted through to other laboratories and this has generated greater enthusiasm for plant anatomy.

5. Finally, the use of videotaped images allows students to work at their own speed. The duration of video presentation can be varied to allow time for other practical exercises.

Conclusions

Working within severe financial constraints (a budget of $1,800) we have developed a series of labelled videotaped images which have been effective in enhancing student confidence, motivation and analytical skills. There is a new sense of cohesiveness in these classes. A question about the videotape may reveal to the tutor a potential difficulty for many students. By referring to the image on the TV screen, the tutor can address the group, pre-empting difficulties before more students encounter them. Since our initial hardware purchases, video capture technology has improved in definition and costs have been reduced. However, we envisage that the system we have developed will continue to be an important component of our first year practical classes in botany, given the capital investment (estimated at $100,000) that would be required to fully equip our four first year laboratories with computers.

References

Capon, R. (1996) The reality of virtual laboratories: a chemist's perspective. UniServe Science Proc. Dry Labs Workshop University of Sydney 13-18.

Johnston, I. and Peat, M. (1996) What did we learn from the dry labs workshop? UniServe Science Proc. Dry Labs Workshop University of Sydney 1-3.

Learmonth, R. (1996) Dry labs in biochemistry departments. UniServe Science Proc. Dry Labs Workshop University of Sydney 28-31.

Pamula, F., Pamula, Y., Wigmore, G.J. and Wheldrake, J.F. (1996) The use and benefits of computer mediated learning in teaching biology. UniServe Science Proc. Dry Labs Workshop University of Sydney 19-24.

Richardson, L. (1995) The medium and the message. Australian Journal of Educational Technology 11(1), 1-11.

Whittington,P. (1997) Interactive multimedia computer tutorials in basic biology. UniServe Science News 7, 19-20.

Leone Bielig
Tropical Plant Sciences
School of Biological Sciences
James Cook University
Leone.Bielig@jcu.edu.au

and

Gordon Bailey
Tropical Plant Sciences
School of Biological Sciences
James Cook University
Gordon.Bailey@jcu.edu.au

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