UniServe Science News Volume 16 July 2000


The Biology of Frogs

Ross A. Alford
School of Tropical Biology, James Cook University

I was looking forward to reviewing this CD-ROM. I teach aspects of frog biology in several subjects, and am always eager to have a look at anything that may be useful as an instructional aid or as a supplement to my lectures and practicals.

Figure 1.

Now that I've spent several hours working with it, my feelings are a bit mixed. I think it could be a useful supplement for high school or undergraduate tertiary teaching, but I'm not as enthusiastic as I had hoped that I might be.

First, a general description: the CD-ROM uses a combination of animations, text and audio clips to present information on frog biology. It covers the evolution of frogs (briefly), presents a moderate amount of detail on their anatomy and ecology, and spends some time on their conservation status. The information that is presented is mostly accurate and in an intelligible format. The level of the information seems to me to be variable. Some sections read as though they are aimed at school students, while others appear more oriented to first year or even more advanced tertiary students. The word 'read' in the previous sentence is important; although the reading is enlivened to a variable extent by animations and some interactive illustrations, students will not really learn a lot from this CD-ROM unless they read the detailed text that accompanies most sections. I think that one of the purposes of instructional multimedia should be to cause students to learn as much as possible without doing the equivalent of reading from a textbook; in this sense this CD-ROM was only moderately successful.

Some specifics about the program and its operation: it requires at least a Pentium 133, 32 Mb of memory, and an 800 x 600 x 256 colour display to run, and will certainly take advantage of faster processors and more available memory, but will not do anything with a larger screen. It can be installed on a hard drive, requiring 190 Mb of free space, or (a major plus) will run directly from the CD-ROM. All information is presented through a constant, if somewhat cluttered, interface. Text appears in a scrollable region at the left of the display; graphics, animations and some additional text appear in a large region at the centre. A series of navigation buttons are at the bottom, and are labeled with their functions when active. Navigation instructions appear at the top right, and a tree diagram that can be used for navigation appears at the top. A 'G' button, also at the top, will activate the glossary when it is boldfaced. There is a large area at the lower right that, according to the introduction, is supposed to store and display detailed information related to the topic at hand, but rarely contains anything.

The opening sequence of the program sets the scene. There is a nice animation of a day at a pond as background, with scrolling text explaining that frogs are presently of particular concern as they are thought to be in decline. The text can be a bit hard to read, but is repeated in the scroll box at the left of the screen. When the animation finishes you are left looking at a blank screen and need to work out what to do next to continue. The option to bypass this sequence is presented when you open the program.

The next step is to click on 'Main menu' in the navigation area. The main menu appears bottom centre, with an animated croaking frog above it, and some (quite important) instructions about the screen layout and navigation in the text box. Unfortunately, while looking at the main menu, the constant 'croaking' of the animated frog can become quite annoying, causing the user to skip carefully reading the navigation information, which will make some aspects of the layout more confusing than they need to be.

If the navigation information is read carefully, navigation is reasonably straightforward, and the program allows the user to work his or her way through a series of modules on the evolution, ecology, anatomy, and conservation of frogs, plus a self-evaluation model that quizzes on the knowledge gained in the other sections.

Figure 2.

The evolution section is brief but provides most of the necessary background for a simple understanding of the origins of anurans. The ecology section was somewhat disappointing. It is in this section that many of the most fascinating aspects of frog biology were covered, and some of the coverage seemed rather thin. For instance, students are usually keenly interested in the wide variety of modes and methods of reproduction used by frogs. In this CD-ROM, the discussion of reproductive modes is very short, presenting only a fraction of the diversity that occurs. It has few illustrations, and lacks details for some of the examples that are given, e.g. the final example used just says 'One of the more fascinating egg deposition sites is where the females swallow the fertilized eggs ...' without naming the frogs (the gastric brooding frogs Rheobatrachus spp.) or providing any additional details (for example the fact that they live in fast-flowing mountain streams, which is likely to be one reason this mode evolved). The audiovisual material used was also disappointing. There are some animations, which are well done and illustrate basic points nicely, but no video footage of real frogs and very little audio of real frog calls (five North American Rana and one hylid), and relatively few photographs. Plenty of good audio and video of all aspects of frog reproduction and many aspects of ecology exists, and would have been a real addition to this section.

The anatomy section uses the capabilities of a multimedia presentation to better advantage. It presents a series of interactive animations illustrating the external anatomy and dissections of the musculature, skeleton, brain, and body cavity, with a reasonable level of information on the functions of the parts being illustrated. There were some places in which I would have liked more anuran-specific information, for example, the Anatomy; Head; Ear section misses out altogether the fact that frogs have an unusual system, the operculum-papilla amphibiorum complex, that receives and processes low frequency sounds picked up from the substrate, and the section on the eye mentions that there are four different types of photoreceptors, but fails to say what they do, thus leaving unanswered a common question, e.g. 'do frogs have colour vision?'

The section on conservation of frogs is well balanced, presenting the generally accepted picture that amphibian populations in many places are in decline, probably for a variety of reasons, combining local and global problems. As with other parts of the CD-ROM, the presentation could have been made more stimulating by the inclusion of more audiovisual material and a more dense linkage, for example adding some form of hypertextual links to relevant aspects of the ecology and anatomy sections when discussing threats that frogs are vulnerable to and why.

The self-evaluation section at the end is reasonably well-presented. It presents an extensive set of questions in a variety of formats, including multiple choice and fill-in-the-blanks, and provides immediate feedback and correct answers. Sometimes the feedback is provided as soon as the answer is complete, while at other times the user must click a button to receive it, but this section is certainly useful.

There is an extensive glossary that is available from any point in the CD-ROM, except the self-evaluation section. This system is helpful, but does suffer from a number of flaws and apparent bugs. Flaws included some extremely brief and possibly uninformative definitions. For example, in the section on ecology, the text says 'The tadpole undergoes a dramatic metamorphosis into a very different adult form'. The word metamorphosis is highlighted, indicating that there is a glossary entry. Clicking on it in the hopes of finding out more about the topic will be a disappointment, though, as the glossary entry says 'metamorphosis - the transformation of a larva into an adult'. This does not add a great deal of information. It is also generally incorrect for anurans, in which the usual end product of metamorphosis is a juvenile, which is often behaviourally, ecologically, and to a greater or lesser extent morphologically distinct from the adult. Some other glossary definitions are self-referential, e.g. 'sacrum - a single sacral vertebrae (sic) with a thicker transverse process than those found in other trunk vertebrae ...'.

Another problem that a heavy glossary user would find frustrating is that once the glossary is called up, it remains in view until one of the navigation buttons is pressed - there's no way to recover the main illustration for the current topic. An apparent bug is that clicking on more than one glossary item on the last screen of a section causes the labels on the 'next' and 'last' navigation buttons to appear, but pressing either of these returns you to the start of the section.

In summary, although various aspects of this CD-ROM can be criticised, it does a competent job of presenting a summary of the basics of frog biology and conservation. A student who conscientiously follows through the package will learn a lot about these subjects, and although the presentation could have included many more media clips and internal links, it is certainly more exciting than reading the same material in a text. As a supplement for interested students, it may be a worthwhile investment.

The Biology of Frogs, Version 1.0, is written by P. Reinthal and published by RANACO.

The Biology of Frogs is available from:
Lynn Huggins
Tucson, AZ

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UniServe Science News Volume 16 July 2000

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