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‘Practicals’ Virtual Special Issue

JBE editorial board member Gary Skinner introduces a virtual special issue of classic papers from the journal on biology practicals.

Recent changes to A level Science included the introduction of the practical endorsement.  Amongst other effects, this removed student hands-on performance from their overall grade in the subject.  Some feel this is a retrograde step.  The TES in August 2017 reported that:

Changes to stop practical experiments counting towards tomorrow's A-level science grades could damage students’ motivation and put them off applying to study it at university, a leading charity (The Wellcome Trust) has warned.

(From https://www.tes.com/news/school-news/breaking-news/removing-practicals-a-level-science-grades-could-damage-pupils)

However others, including most commentators on the TES report, welcome the changes.  In the old courses, students may have been required to do as few as two practicals for assessment purposes and maybe did no more.  The new system requires a minimum of twelve.  In addition, it demands that 15% of marks on written papers are based on practical work carried out in the course.  The changes have certainly stimulated discussion about the role of practical work in science education at this level and have, in the opinion of this writer, raised its profile.  Furthermore, skills and techniques, dormant for some years in the school biology laboratory, have resurfaced.   Boards variously require dissection of animals and plants, respirometry, chromatography and potometry along with many others.  In view of all this, it was felt timely to put together this virtual issue containing, a selection of papers from JBEd addressing such skills and techniques.

Dissection occupied a prime position in A levels 40 years ago but, for various reasons, has declined since then.  With the new specifications in 2015 it made a comeback.   Although the standard “dissect a rat” of yore is not required, boards ask for fish heads, hearts, large insects, flowers and plant or animal transport systems.  Clark’s paper on the dissection of a stick insect (1976) should prove very useful for those feeling a little inexperienced in this area.  The paper by Yeung Chung Lee (2004) includes some useful extras to include in a heart dissection, as does Measurement of transpiration rate often proves problematic, so the paper by Hardwick (1972) should prove useful. The emphasis on microscopy, measurement and an understanding of standard form and conversion of units is required by the new specifications.   Apparatus requirements include an eyepiece graticule (grid) and a stage micrometer.  The latter can be shared quite easily but each microscope should ideally be fitted with a graticule.  These can be prohibitively expensive if large numbers are needed.  The short note by Daley, Donaldson and Hillier (1981) may help to facilitate this requirement.

The results from paper chromatography of leaf pigments are often disappointing.  Generally, more acceptable separation is achieved using thin-layer chromatography (TLC).   However, the cost of TLC plates can be prohibitive for all but very large centres.   The paper by Sparrow and Rumsby (1976) could well afford a solution.  Further advice on achieving the best results is given in Katayama, Kanaizuka, Sudarmi and Yokohama (2003).  Another important tip, not included in these papers, is to make very thin capillary spotters (see, for example, http://www.chemistryviews.org/details/education/2102991/Tips_and_Tricks_for_the_Lab_How_to_Make_a_Capillary_TLC_Spotter.html)

The effect of antibiotics on bacterial growth features as a practical on a number of the new specifications.   Most will no doubt use the agar diffusion test, but this has its limitations.   The paper by Longtin, Guilfoile and Asper (2004) would prove a useful piece of extension reading in this context. The measurement of both photosynthetic and respiration rates are also widely required, but experience suggests that standard methods used in the A level laboratory are not always successful in producing expected outcomes.  The paper by Takaoki and Kitao (1992) offers some alternative suggestions, which may be considered.

Fieldwork is expensive, time-consuming, potentially hazardous and disruptive. In view of all this it is important to make it as successful as possible.  The paper by Fenner (1997) provides some ideas for preparation before the trip, which might help the actual field visit go more smoothly and improve the learning gained from it.  King and Woodell (1975) provide a specific application of random sampling which is readily available to most.  Finally, Fido (1980) demonstrates how the transect (in this case across a rocky shore) can be a more satisfying experience.  A preparation in which dividing cells can be viewed is required by most of the specifications.  Gill (1981), Gill (1980) makes very useful suggestions to improve the reliability of this occasionally challenging practical.

Readers will need to carry out their own risk assessments in accordance with their local authority guidelines before doing any of these practicals.  
Article Title AuthorJournal TitleVolumeIssue
The dissection of a stick insectClark, J. T. Journal of Biological Education101 (1976)
A relatively cheap photographic film eye-piece gridDaley, M, Donaldson, S. and Hillier, D Journal of Biological Education154 (1981)
Evaluation of methods for estimating vegetation cover in a simulated grassland swardFenner, M Journal of Biological Education311 (1997)
Zonation studies on a rocky shoreFido, H Journal of Biological Education144 (1980)
A review of techniques for the experimental study of mitosisGill, J Journal of Biological Education152 (1981)
An Easily Constructed, “Indestructible” PotometerHardwick, K. Journal of Biological Education65 (1972)
An improved method for extraction and separation of photosynthetic pigmentsKatayama, N, Kanaizuka, Y and Yokohama, Y Journal of Biological Education374 (2003)
The use of the mounds of Lasius flavus in teaching some principles of ecological investigationKing, T.J and Woodell, S Journal of Biological Education93 - 4 (1975)
Genotypic detection of antibiotic resistance in Escherichia coli.: a classroom exerciseLongtin, S, Guifoile, P and Asper, A Journal of Biological Education391 (2004)
An inexpensive and rapid method for preparing thin-layer chromatography plates for use in the classroomSparrow, S and, Rumsby, M. B. Journal of Biological Education101 (1976)
Measurement of photosynthesis and respirationTakaoki, T and Kitao, K Journal of Biological Education261 (1992)
There is more to the dissection of a pig's heartYeung Chung Lee Journal of Biological Education384 (2004)

These articles are available exclusively via this page until December 2019

Journal of Biological Education

Journal of Biological Education is firmly established as the authoritative voice in the world of biological education. The journal aims to bridge the gap between research and practice, providing information, ideas and opinion, in addition to critical examinations of advances in biology research and teaching. Through the coverage of policy and curriculum developments, the latest results of research into the teaching, learning and assessment of biology are brought to the fore.

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