A simple computer application for the identification of conifer genera.
The National Science Education Standards prescribe that an
understanding of the importance of classifying organisms be one
component of a student's educational experience in the life
sciences. The use of a classification scheme to identify organisms is
one way of addressing this goal. We describe Conifer ID, a computer
application that assists students in the identification of conifers
without requiring prior specific knowledge. Conifer ID promotes careful
observational skills and presents students with visual aids during the
identification to overcome some of the weaknesses of more traditional
Key Words: Simple computer program; conifer genera identification.
Computer simulation (Methods)
Conifers (Identification and classification)
Strain, Steven R.
Chmielewski, Jerry G.
|Publication:||Name: The American Biology Teacher Publisher: National Association of Biology Teachers Audience: Academic; Professional Format: Magazine/Journal Subject: Biological sciences; Education Copyright: COPYRIGHT 2010 National Association of Biology Teachers ISSN: 0002-7685|
|Issue:||Date: May, 2010 Source Volume: 72 Source Issue: 5|
|Geographic:||Geographic Scope: United States Geographic Code: 1USA United States|
As part of a life sciences curriculum, the National Science Education Standards (National Research Council, 1996) suggest the inclusion of activities to promote student comprehension of the importance of organization in biological systems as a way of understanding the world around us. This goal, as defined by the Standards, includes understanding how taxonomy allows us to meaningfully organize living organisms into groups. This goal can be profitably addressed from two opposite directions. The first is to ask students to group organisms on the basis of careful observations of the organisms' characteristics, in effect creating a classification scheme. This type of activity emphasizes an inductive form of reasoning. The second approach is to engage students in the use of a preexisting classification scheme to deductively identify biological specimens, again employing careful observation of the specimen to be identified.
Traditionally, four methods have been used to identify unknown biological specimens: expert consultation, recognition, comparison with specimens of known identity, and use of keys or similar devices. Although obtaining expert advice to of known identity, and use of keys or similar devices. Although obtaining expert advice to identify an unknown specimen would be ideal for a number of reasons, it is unlikely that an expert would be available for consultation in the classroom setting. Recognition as a means of identification presupposes past experience that many students do not have, so this method is generally unsuitable for the classroom. The likelihood of success using the comparison method depends on the suitability of the materials used for comparative purposes. Often, these are local field guides or picture books of the more common species found in a geographic region and are, therefore, limited in their usefulness. Such identification materials generally provide either photographs of specimens, in which relevant identification details may be difficult to see, or idealized artwork that tends to emphasize the details important for identification but that, as a consequence, may not match well with the specimen being identified. Additionally, none of these three methods promotes students' understanding of the organization underlying the classification of organisms. For these and other reasons, the most common identification method used in educational settings has been some form of a taxonomic key . Keys are readily available for a variety of different types of organisms, are reliable, and emphasize the organization behind the classification by grouping organisms that have similar characteristics.
The most common form of taxonomic key, the dichotomous key, originated with Jean de Lamarck in 1778 (Woodland, 1991). The dichotomous key employs a series of pairs of contrasting statements (couplets) related to morphological features of the organism being identified. Each couplet is considered in order, and the contrasting statements lead the key user either to another couplet or to an identification of the specimen. It is useful to consider a dichotomous key as a decision tree, with the first couplet representing the top of the tree and the contrasting statements leading the user either to the left or to the right to the next level down in the tree. Key formats in which more than two contrasting statements are considered simultaneously at each level of the decision tree are polychotomous. Although keys in this format generally lead to the identification of a specimen in fewer steps than a dichotomous key, they are much less commonly used.
One of the primary limitations of the dichotomous key format is that users must begin at the first couplet and progress sequentially through subsequent couplets until an identification is made, a restriction that unfortunately implies a hierarchy among the characteristics used to identify a specimen, whether intended or not. This limitation is a direct consequence of the dichotomous key design, in which the identification relevance of the characteristics considered by a particular couplet relies entirely on the prior accumulation of information about the specimen in the preceding couplets. This also leads to a potential difficulty in using such single-entry keys with students in the classroom (i.e., the inability to accurately consider the morphological characteristics addressed by a couplet prevents the user from completing the identification). This inability could be caused by lack of familiarity with the terminology used in the couplet, by a specimen in poor condition, by seasonal effects making the characteristic unavailable for observation, or by a mistake made earlier in the key. Regardless of the cause, such roadblocks can lead to considerable frustration among students attempting to use dichotomous keys and may lead to disengagement from the activity. One method of dealing with this limitation is provided through the use of polyclonal, or multi-entry, keys. This key format has traditionally used a set of stacked cards, each representing one of the possible identities of the unknown specimen. The cards have holes or punched edges or are color-coded in such a way that groups of cards that share characteristics with the unknown specimen can easily be separated from those that lack the characteristics. Relevant characteristics can be considered in any order, and the process of eliminating groups of cards is continued until only a single card with the unknown specimen's identity remains. Unfortunately, the increased complexity of traditional, printed multi-entry keys makes them more difficult for students to use, and they are far less commonly available than single-entry keys.
With the increased availability of computers in educational settings, many previous difficulties associated with the complexity or inflexibility of various taxonomic key formats have become less of a consideration. Here, we describe Conifer ID, a computer application and associated conifer database we developed to assist students who have little or no prior identification experience in identifying common conifers. Conifer ID uses both a polychotomous, multi-entry key and a comparative approach to identifying specimens, while insulating students from the details involved in using these methods. Visual aids in the application provide explanations of terminology that may be unfamiliar to students, which helps reduce frustration with the identification process. By addressing the classification of conifers as an example of the usefulness of organization in biological systems, and by encouraging the use of computers in an educational setting, Conifer ID will help instructors develop a curriculum that meets the requirements of the National Science Education Standards.
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* Installing & Using Conifer ID
Conifer ID is designed to be used in the classroom or the field, using either desktop or portable computers. To provide flexibility, installation requirements have intentionally been kept to a minimum, and the software can be run directly from a CD-ROM disk or copied to the computer's hard drive. Regardless of the installation method used, Conifer ID is started by opening the CID.exe file. Conifer ID has been tested using Windows 98, 2000, XP, Vista, and 7 and works best with a screen resolution of at least 800 x 600 pixels. Macintosh computers capable of running Windows should also support Conifer ID. Conifer ID is provided free on CD-ROM from the authors, and users are encouraged to make any number of additional copies of the CD-ROM for use on multiple computers.
The Conifer ID user interface is simple by design and consists of a single screen divided into three areas: the character panel on the left, and the image and information panels on the right (Figure 1). Conifer ID assists in identifying a conifer specimen by asking the user to provide specific information about the specimen for the five characteristics shown in the information panel: leaf position, shape, association and arrangement, and type/position of the fruit. In keeping with Conifer ID's design as a multi-entry identification method, the characteristics can be considered in any order, by using the forward and back buttons at the bottom of the characteristics panel to cycle among them or by selecting a characteristic in the information panel. As each characteristic is visited, the user is presented with a question at the top of the character panel, followed by a set of radio buttons from which the user can choose an answer based on careful observation of the specimen. To the left of each choice is a help button that will provide the user with visual assistance about that choice in the image panel.
As information about the specimen is provided by the user for the characteristics, conifers in the Conifer ID database are gradually eliminated as possible candidates for the specimen's identity. The progress of the elimination process is shown at the bottom of the character panel, where the number of conifers remaining under consideration is displayed and continually updated as additional specimen information is provided. At any time during the identification process, the user can browse through photographic images of the conifers remaining under consideration by using the forward and back buttons in the image panel.
The conifers are an ideal group of plants for students to use in a learning exercise investigating taxonomic organization. Not only are conifers common native or cultivated components of the vegetation in most areas, they maintain nearly all the morphological characteristics needed for identification throughout the year, in contrast with the seasonal availability of suitable specimens of deciduous trees or herbaceous vegetation. This provides instructors with considerable flexibility in scheduling such an exercise as part of their curriculum.
By combining the use of a polychotomous, multi-entry key with a comparative approach to the identification of conifers, Conifer ID generally leads to specimen identifications more rapidly and with greater flexibility than a comparable dichotomous key. The latter method would typically require a total of 22 couplets to identify the conifers in the Conifer ID database, whereas Conifer ID accomplishes the same identification using only five characteristics. This increased efficiency permits greater time in the classroom for discussion and inquiry. At the same time, treating characteristics as single entities with multiple alternative forms rather than as a series of couplets emphasizes to students the way in which morphological characteristics are used to group organisms. As a multi-entry key, Conifer ID permits students to address characteristics in whatever order they choose or to skip those characteristics that may not be clear from the specimen at hand. In the latter case, browsing through the images provided by the application permits students to use the comparison method to identify the specimen, avoiding a common source of frustration with single-entry keys.
* Students' Perceptions of Using Conifer ID
To evaluate students' experience with the Conifer ID application as compared with a traditional, printed dichotomous key, students enrolled in several sections of our Introductory Biology Laboratory were asked to complete a voluntary anonymous survey after identifying specimens using both methods. Each student used a dichotomous key to identify five deciduous tree specimens and Conifer ID to identify a similar number of specimens from conifers. The survey collected information about the students' experience with the two methods regarding relative ease of use, which methods they enjoyed using more, whether they found the availability of photographic images useful, and which method they would use if given the choice. Students were also asked to provide demographic information and to rate their comfort level with using computers. Frequencies of student responses were analyzed using Mathematica, version 6 (Wolfram Research, Champaign, IL), for heterogeneity, goodness-of-fit, and independence by G-tests, employing Williams's correction where appropriate (Sokal & Rohlf, 1981). The administration of this survey was approved by the Slippery Rock University Institutional Review Board (IRB Protocol #2010-004-08-A).
A total of 171 students in nine sections of our Introductory Biology Laboratory course completed the survey. A test of the level of heterogeneity among the results for the criteria ease of use, level of enjoyment, and overall user's choice of methods from the several sections of the course was not significant (P > 0.05 for each criterion), and further analysis considered the data from the sections pooled into a single sample (Table 1).
The results showed a clear preference for using Conifer ID over the dichotomous key. Departures of the observed response frequencies from those expected under a null hypothesis of a 30:70 ratio (dichotomous key:Conifer ID) were significant for each of the three criteria (Table 1), with the observed proportion of students preferring Conifer ID consistently greater than expected. The 30:70 expected ratio was chosen for tests of significance as it represents an internal assessment standard used in our department for the acceptance of curricular and policy changes.
Students were asked to self-report their level of comfort in using computers on a scale of 1-5 (not at all comfortable to very comfortable). Using a score of 3 as an average level of comfort, students were categorized into those possessing a below-average comfort level (scores of 1 or 2) and those having an average or above-average comfort level (scores of 3 or above). Two-way tests of independence between comfort level and identification method preference for each of the criteria in Table 1 revealed no significant association between the two (P > 0.05 for each criterion), which indicates that a lower-than-average comfort level with using computers does not preclude a preference for Conifer ID over more traditional identification methods.
* Student Engagement
A common challenge in courses for students from diverse majors is maintaining a level of engagement conducive to inquiry and learning. Nearly 95% of the students who completed the survey reported their academic major as being outside the science disciplines. This is consistent with the general trend of enrollment in our Introductory Biology Laboratory course by students fulfilling an institution-wide science laboratory requirement. As a consequence, the survey reflects student perceptions in a population drawn from diverse majors throughout the institution. Taking student preference for Conifer ID over the use of a dichotomous key as an indication of the level of engagement, Conifer ID appears to be the more effective method. The students' preference for Conifer ID may be partly attributable to its being a computer-based method. This is consistent with recent studies that demonstrate a connection between computer use in the classroom and levels of student engagement and motivation (House, 2002, 2009; Udovic et al., 2002; Presland & Wishart, 2004).
One of the primary advantages of Conifer ID is the assistance it provides to students as they complete the identification of a specimen. The instructors leading the classification exercise in our Introductory Biology Laboratory course reported that a considerable amount of explanation was required to prepare students to use a dichotomous key. By contrast, students seemed to find the use of Conifer ID more intuitive and required little explanation. As noted previously, a common source of frustration among students with little or no experience in the use of identification methods is unfamiliar terminology. Conifer ID addresses this potential issue by providing images that visually clarify the contrasting statements associated with a characteristic. Approximately 94% of the students surveyed indicated that they found these images helpful during the identification process. In addition, as students progress through the identification of a specimen, Conifer ID disables the choices for each characteristic that are no longer relevant to identification of the specimen, permitting students to focus only on the choices that remain important. Finally, as students browse through the images of known conifer specimens in the image panel, the correct choice for each characteristic is highlighted, allowing students to more easily determine the proper response to a characteristic using the comparison method.
* Suggestions for Using Conifer ID
Although we have described Conifer ID primarily in terms of its use in identifying conifer specimens, the application is flexible enough to be used in other ways to address the educational goals set by the National Science Education Standards, depending on the specific goals of the instructor.
For example, the visual aids that Conifer ID provides can be used to gradually expose students to the terminology important for plant identification. Rather than being given a list of definitions, the students are exposed to terms as they are needed and learn the terminology by actually applying the knowledge instead of by rote memorization. In the sense that "a picture is worth a thousand words," having access to the images supplied by Conifer ID may be helpful in getting students to understand and correctly apply the terminology. Conifer ID can also be used to emphasize the manner in which taxonomic classification schemes group organisms on the basis of similarities by allowing students to browse through the images of specimens in the Conifer ID database and to note that the members of the database remaining under consideration become increasingly more similar as more characters are specified by the student.
It is worth noting that the database of conifers used by Conifer ID is located in a text-based file separate from the main application. As a consequence, it is possible to edit the database to suit a particular need, such as more or less sophisticated terminology, to extend the database to include additional conifers, or even to construct a new database dealing with the classification of items other than conifers, whether biological or otherwise. More advanced students could be asked to develop a classification system based on careful observations and construct an appropriate database for use with the application. To assist with this type of learning activity, a separate computer application that will simplify the construction of new database files is currently in development.
We are grateful to the instructors and students involved in the evaluation of Conifer ID in the classroom.
House, J.D. (2002). The motivational effects of specific teaching activities and computer use for science learning: findings from the Third International Mathematics and Science Study (TIMSS). International Journal of Instructional Media, 29, 423-439.
House, J.D. (2009). The effects of instructional and computer activities on interest in science learning for students in the United States and Korea: results from the TIMSS 2003 assessment. International Journal of Instructional Media, 36, 119-131.
National Research council. (1996). National Science Education Standards. Washington, DC: National Academy press.
Presland, A. & Wishart, J. (2004). Secondary school pupils' motivation to use an integrated learning system. British Journal of Educational Technology, 35, 663-668.
Sokal, R.R. & Rohlf, F.J. (1981). Biometry, 2nd Ed. NY: W.H. Freeman.
Udovic, D., Morris, D., Dickman, A., Postlethwait, J. & Wetherwax, P. (2002). Workshop biology: demonstrating the effectiveness of active learning in an introductory biology course. BioScience, 52, 272-281.
Woodland, D.W. (1991). Contemporary Plant Systematics. Englewood Cliffs, NJ: Prentice Hall.
STEVEN R. STRAIN (firstname.lastname@example.org) is Associate Professor of Biology, and JERRY G. CHMIELEWSKI (email@example.com) is Professor of Biology at Slippery Rock University of Pennsylvania, Slippery Rock, PA 16057.
Table 1. Summary of student survey responses (N = 171) for using a dichotomous key versus Conifer ID for identification of plant specimens. The data show the numbers of students who preferred each method with regard to ease of use, enjoyment of use, and which method would be chosen preferentially for future identifications. P values test the goodness-of-fit of the data to a 30:70 expected ratio of preference for the dichotomous key and Conifer ID, respectively. Frequency (%) Dichotomous Conifer ID Criterion Key Software P Ease of use 37 (21.6) 134 (78.4) <0.02 Enjoyment 31 (18.1) 140 (81.9) <0.001 User's choice 33 (19.3) 138 (80.7) <0.01
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