Biochemical Education 27 (1999) 131 } 134
Biological methods: a novel course in undergraduate biology Michael Kotiw*, Robert P. Learmonth, Mark W. Sutherland Department of Biological and Physical Sciences, University of Southern Queensland, Toowoomba, Queensland, QLD 4350, Australia
Abstract We describe a novel course in "rst year undergraduate practical biology, which introduces students to the principles and practice of a variety of biological techniques. In addition, students develop conceptual skills in experimental design, problem solving, gathering and analysis of data and report writing. The course provides a theoretical foundation and repeated practice of a range of laboratory tasks. Students proceed to higher levels of study with experience in the application and use of basic spectrophotometry and light microscopy, the estimation of unknowns from standard curves, volumetric work including the performance of serial dilutions, and gram stains and the maintenance of bacterial cultures. The unit content can be modi"ed to suit speci"c curriculums without loss of e$ciency or impact. 1999 IUBMB. Published by Elsevier Science Ltd. All rights reserved.
1. Introduction The foundation of science is experimental investigation, in that theoretical models describing the natural world result generally from practical observation of phenomena. Thus it is important that our students, who will be the next generation of scientists, understand the experimental basis of the &&facts'' in their textbooks, and gain experience in the practical side of scienti"c investigation. Traditionally "rst year undergraduate laboratory practicals have been highly structured and used to illustrate and con"rm lecture material [1]. However, this alone does not meet all of the needs of students, consequently there has been a continuing trend to provide students with an increased opportunity to participate in more advanced scienti"c processes [2]. The objectives of practical work have been comprehensively summarised by Wood [3]. In addition to illustrating lecture material, objectives were categorised as developing &&laboratory skills'' and &&high level skills'' [3]. The laboratory skills involve learning how to follow protocols and work safely and e$ciently, including manipulative skills, equipment operation, data recording, data processing and reporting skills. The high level skills include planning experiments, preparing protocols, critical analysis of data and of the
* Corresponding author. Tel.: 0061-7-4631-2361; fax: 0061-7-46311530; e-mail:
[email protected].
literature, hypothesis forming, communication of data (verbally and written) and team work [3]. We would also add problem solving to the list of high level skills. Wellington [4] has suggested that the current &&information explosion'' has also resulted in a transition from content-led to a predominantly process-led approach in laboratory teaching, primarily because presented facts were being dated so quickly. The consequence of this transition is that in some instances instruction in transferable skills (Wood's [3] laboratory skills and high level skills) has become more relevant to students than factual knowledge. However, a risk associated with undertaking an entirely process led approach has been a loss of student interest in pursuing studies in science at higher levels [5]. Kirshner and Meester [6] defended the need for process-led learning in practical sessions, contending that it often provided the only means for practicing the skills necessary for the conduct of many scienti"c professions. In some laboratory-based disciplines practice is the only means for actually achieving desired skills involving manual dexterity [7]. In terms of course structure, Johnstone and Letton [8] expressed concern with laboratory practicals based on a discipline-associated approach, suggesting that students may not exercise laboratory skills regularly enough to su$ciently master them. Students then move to more advanced theoretical concepts which require the execution of novel, more advanced laboratory skills, before they are con"dent practitioners of the &&simpler'' skills upon which the
0307-4412/99/$20.00#0.00 1999 IUBMB. Published by Elsevier Science Ltd. All rights reserved. PII: S 0 3 0 7 - 4 4 1 2 ( 9 9 ) 0 0 0 0 2 - 3
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advanced skills are built. A consequence of students progressing without an adequate skill base is that it imposes signi"cant ine$ciencies on the management of laboratory time in more advanced units and confounds the successful demonstration of theoretical principles in associated laboratory sessions. Meester and Maskill [2] observed that although many laboratory courses in "rst year units provided training in manipulative skills, students often failed to develop higher academic skills such as hypothesising, design and problem solving. As a consequence they proposed dividing teaching periods into &&skill learning'' and &&skill experience'' sessions, the latter period potentially being extended to include problem solving tasks. In this paper we report a novel adaptation of the Meester proposal whereby a unit is o!ered which is entirely dedicated to developing practical, cognitive and report writing skills in "rst year biology students. The course also provides students with a theoretical and practical introduction to more advanced techniques which has facilitated an e$cient transition for students to higher levels of learning.
2. Course design The unit was o!ered in 2 modules, the "rst being 9 weeks duration and the second 5 weeks, and was based broadly on the Meester and Maskill [2] proposal. The "rst module consisted of 14 formal lectures supporting
a series of independent controlled exercises and short activities designed to introduce and develop laboratory skills (Table 1). The practicals included training in use and comparative accuracy of volumetric devices (including micro-pipetting devices), microscopy and identi"cation of microorganisms, centrifugation, spectrophotometric assay of substances (glucose and protein) and measurement of enzyme activity, and gel "ltration (separation of dextran blue and haemoglobin). This corresponds to the proposed &&skill learning'' sessions [2] although once introduced, skills were practiced throughout subsequent classes, providing su$cient repetition to enable mastery of techniques. Thus the "rst module combined &&skill learning'' with subsequent &&skill experience'' once a technique was introduced. In other words, &&old'' skills were practiced concurrently with introduction of &&new'' skills. Students were able to gain experience in the theory and practice of speci"c technologies, analytical methods and report writing. The second module was o!ered in the form of an extended practical experiment, investigating the nature of microbial competition in a controlled environment (Table 1), using the analytical techniques learnt in the "rst module. This equates to the proposed &&skill experience'' sessions [2]. Students were divided into groups which alternated experimental tasks (microbiological or biochemical assays) on a weekly basis. As the outcome of the experiment was unknown at the commencement of the course, students were exposed to a continual process of experimental
Table 1 Biological methods: principles and practice. Lecture and practical schedule Week Module 1 Week 1
Week 2 Week 3
Week 4 Week 5 Week 6 Week 7 Week 8 Week 9
Lecture
Practical
1. Course outline, The science of clinical biology 2. Principles of microscopy
1. Laboratory safety plus (a) An introduction to biological methods (b) Viable counts 2. Microscopy and staining
3. 4. 5. 6.
pH, bu!ers and biological solutions Principles of centrifugation Principles of spectrophotometry Principles of enzymes
7. Methods for separation of macromolecules 8. Physical, inorganic and organic changes in biological systems 9. Concepts of biological change 10. The nature of microbial competition 11. Notes on presenting the investigative report 12. Principles of "eld observations 13. Introduction to the nature of ecosystems 14. Course review Theory examination 1.5 h
3. Biological methods (a) pH and bu!ers (b) Biological solutions 4. Centrifugation 5. Spectrophotometry 6. Enzyme reactions 7. Field excursion 8. Column separation techniques 9. Research project set up
Module 2 Week Week Week Week Week
10 11 12 13 14
10. 11. 12. 13. 14.
Project analysis 1 Project analysis 2 Project analysis 3 Collation of class data on module 2 Practical examination
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design and problem solving, as well as being provided with an opportunity to continue practice of skills acquired in the "rst module. Students were required to record physical, chemical and microbiological data using laboratory apparatus such as spectrophotometers, bench centrifuges, microfuges, oxygen meters and pH meters, as well as perform microbiological methods such as biological staining, microscopy and bacterial culture. Essentially, on a progressive weekly basis, students identi"ed and enumerated microorganisms from mixed cultures, and measured pH, oxygen concentration and glucose utilisation rate of the cultures. The aim was to determine the relative survival of aerobic bacteria, facultative anaerobic bacteria and yeasts, and to relate the measured parameters to density of microorganisms. Finally, students were required to collate individual and class data and to present an analytical report in the conventional IMRD (introduction, materials and methods, results and discussion) format. Training and feedback in investigative methods was provided during the "rst module in the form of short assessable tasks and in the second module, as a handout providing guidelines for the presentation of scienti"c reports. Under minimal supervision students were entirely responsible for the conduct, recording and analysis of the experiment.
3. Student resources Because of the diverse nature of the course, no single text could be found that was entirely suitable and consequently the authors developed an in-house laboratory manual [9]. Pechenick's &&A Short Guide to Writing About Biology'' was recommended as a guide for writing technique [10]. In addition, published scienti"c papers were added to the recommended reading lists to assist research endeavours, and students were encouraged to use hard copy and electronic resources of the university library.
4. Assessment The course was assessed in two parts. Assessment of methods contributed to 50% of the total assessment and consisted of two short computations and techniques reports (10%), an open-book practical examination (25%) and an experimental report (15%). The conceptual basis of the course was assessed by a closed-book theoretical examination (50%) of 1.5 h duration.
5. Discussion The nature of biological sciences requires undergraduates to acquire a wide array of manipulative skills,
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which often incorporates the use of highly sophisticated technologies. Students are required to develop cognitive and analytical skills in a setting, which particularly at "rst year level includes the delivery of a mass of factual information [11]. Wet laboratory sessions are the means for delivering technique instruction and practice and have been traditionally designed to support speci"c theoretical discourses. Laboratory content in speci"c disciplines is usually teacher-dependent and generally highly focused [2]. This can lead to di$culties in linking laboratory exercises leading to limited skill practice [8]. Collectively the introductory courses may generate de"ciencies in the students' necessary skill base, particularly in terms of experimental design, analysis and report writing. Students are also often eager to experience, even at rudimentary levels, the advanced techniques of higher levels. It is recognised that e!ective learning is in#uenced by the teaching strategies employed. For example Ritchley and La Shier [12] found that in some science courses, students were so directed towards the &&relevant'' data when confronted with a mass of laboratory information, that they failed to develop cognitive and analytical skills. In particular this strategy fails to teach the student to do it for themselves and in so doing developing skills in abstracting appropriate information from a background of irrelevant material [13]. In our course we have taken a strategy which has been recognised to enhance cognitive and manipulative skills [2]. We have recognised, as have others [7], that no single discipline-based unit has the capacity to adequately present both its own theory and practice, and to also encapsulate the more holistic needs of science practicals. To this end we have devoted an entire unit to the development of laboratory skills and scienti"c practice. This unit has been run annually since 1995. The educational e!ectiveness of the unit has not been rigorously evaluated, although unit evaluations by students have been conducted and sta! have informally assessed the unit. Student responses have been very supportive, as have responses by sta! interacting with past students at higher levels. For example, students undertaking studies in microbiology and biochemistry were observed to proceed more rapidly in practical sessions, presumably due to the established foundation in laboratory methods. Students came to microbiology classes with skills in microscopy and staining; and in biochemistry students brought experience in volumetric techniques and spectrophotometry. These classes were able to begin at a more advanced level, allowing students to concentrate on higher level skills from the outset. The unit has also facilitated the standardisation of basic scienti"c and reporting methods across disciplines, reducing potential for confusion amongst students who otherwise may have had to negotiate their way through con#icting instructions. The unit is amenable to alteration and is largely independent of the disciplines taught. In our case the course is centred on biochemistry and microbiology,
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however we are currently trialing the inclusion of simple ecological sampling methods. There are no constraints for including other science disciplines. The strength of the unit is its holistic approach to the scienti"c process and a design that facilitates learning and practice of skills. We believe that further improvements to the course can be made, particularly in terms of greater student participation in the format for assessment. For example, a signi"cant improvement in student participation in the learning process has been observed when student groups are required to present a "nal seminar or poster on experimental outcomes, rather than a written report [14].
References [1] P.J. Fensham, Science education at "rst year level, Int. J. Sci. Edu. 14 (5) (1992) 503}514. [2] M. A. M. Meester, R. Maskill, First-year chemistry practicals at universities in England and Wales: aims and the science levels of experiments, Int. J. Sci. Edu. 17 (5) (1995) 574}558. [3] E. J. Wood, Laboratory work in biochemical education: purpose and practice, Biochem. Edu. 24 (3) (1996) 132}137.
[4] J. Wellington, Skills and Processes in Science Education, Routledge Publishers, London, 1989, pp. 5}20. [5] D. Hodson. Rede"ning and reorientating practical work in school science, School Sci. Rev. 73 (1992) 65}78. [6] P. A. Kirschner, M. A. M. Meester, The laboratory in higher science education: problems, premises and objectives, Higher Edu. 17 (1988) 81}98. [7] R. T. White. The link between laboratory and learning. Int. J. Sci. Edu. 18 (7) (1996) 761}774. [8] A. J. Johnston, K. Letton, Is practical work practicable? J. College Sci. Teaching 18 (1989) 190}192. [9] M. Kotiw, R. P. Learmonth, Unit 62121 Biological Methods: Course Manual, USQ Press, Toowoomba, Queensland, Australia, 1996. [10] J. A. Pechenick, A Short Guide to Writing about Biology, 2nd ed., Harper Collins Publishers, New York, 1993. [11] L. S. Shulman, P. Tamir, Research on teaching in natural sciences, in R. M. W. Travers (Ed.), Second Handbook on Research on Teaching, Rand-McNally Publishers, Chicago, 1973. [12] P. A. Ritchley, W. S. La Shier, The relationship between cognitive style, intelligence and instructional mode to achievement of college science students. J. Res. Sci. Teaching 18 (1981) 41}45. [13] W. Macnab, M. H. Hansell, A. H. Johnstone, Cognitive style and analytical ability and their relationship to competence in the biological sciences, J Biol. Edu. 25 (2) (1991) 135}139. [14] L. A. J. Stefani, V. N. T. Tariq, Running group practical projects for "rst-year undergraduate students. J. Biol. Edu. 30 (1) (1996) 36}39.
