5.3    Computer-based simulations in biology

Due to technical and resource limitations, laboratory work in biology courses can become stereotyped, with students doing little more than following instructions and with little genuine experimentation. Furthermore, some biology experiments cannot be undertaken at all for various reasons:

• they take too long, such as experimenting with the growth of trees;
• they involve problems which are not amenable to experimental manipulation, such as altering the environment in a lake;
• they would be unethical, such as experimenting with human patients.

Students are denied the direct experience of active experimentation with these phenomena. All of these examples, however, are amenable to simulation on a microcomputer.

There are a number of examples of computer packages which simulate biological processes. One such package, developed at the Medical School at Manchester University, simulates aspects of human physiological processes in a sophisticated way. It is so fast and so accurate that it is used by anaesthetists in operating theatres to help them to make decisions about the air and oxygen mixture they administer to patients. A package of this kind can be used to provide biology students with substitute experiences of experimentation with, for example, human respiratory functioning.

In the Biology Department at a polytechnic, students are taught about the physiology of respiration in lectures and told how a simulation programme called MACPUFF works. This programme calculates vital measures of body functions, such as pulse and respiration rate, on the basis of calculations involving many complex biochemical reactions. When a simulated 'patient' is 'run', the program prints out detailed data about the patient every three seconds, for a minute. You are then able to change a variable (such as the percentage of oxygen in the air supply) and 'run' the patient for another minute to see what happens.

The students are posed a problem. They have to 'set up' a simulated patient on the program, with particular characteristics such as blood pressure, temperature, respiration rate, and so on. They are set the task of bringing the patient to a specified more healthy state (for example a lower pulse rate and higher blood oxygen) within a set time (for example six minutes). To achieve this the students have to manipulate some of the variables (such as the rate of respiration).

It is possible for students to devise an experiment ( for example to see what happens if the percentage of oxygen is increased), run this experiment with the computer simulation, and see what happens. On the basis of the results of this experiment they could devise another experiment and carry it out, and so on. As the experiments only take a few seconds it is possible to carry out a large number very easily. It is the ease of experimentation which makes simulations of this kind so valuable.

However, this strategy would not succeed. It involves active experimentation and experience, and even some reflection on the outcomes of the experiments. But the number of biochemical reactions and variables involved is so large that such a trial and error approach is unlikely ever to lead to a workable solution, let alone to an understanding of what is going on.

To be successful the students need to refer back to their lecture notes and design experiments on the basis of knowledge of principles about the physiology of respiration. The outcomes of experiments may only make sense if the students refer to a textbook and recognise the causes of the effects created in the experiment. In fact students have to go round the complete experiential learning cycle many times before they can generate a solution to the problem and manipulate the appropriate variables in an effective way. It can take students six hours and numerous trips to the library as well as dozens of experiments to succeed.

All the tutor has to do is ask the students to produce a printout of a successful intervention in the 'patient's' functioning. It is virtually impossible to produce a printout of a successful intervention by trial and error, so the tutor can be confident that the students understand the underlying physiological processes . Every student will have produced an individual solution (so copying can be easily identified) and all solutions are clearly either successful or not, making marking easy. Students can be encouraged to work together provided that each student submits an individual printout.

In terms of the experiential learning cycle this use of a simulation involves the following stages:

Further reading