Problem Solving in Biology a Methodology: A Methodology Is Described That Teaches Science Process by Combining Informal Logic and a Heuristic for Rating Factual Reliability. This System Facilitates Student Hypothesis Formation, Testing, and Evaluation of Results, and in Conjunction with the Logic Path of the Theory of Natural Selection Is Used to Interpret New Data

Article excerpt


While teaching methods have changed over the years, the products of a biological education have remained the same--knowledge, translation, and interpretation--items at the low end of Bloom's Taxonomy scale. In undergraduate instruction, the higher-level, problem-solving skills of application, analysis, synthesis, and evaluation have been largely ignored.

We first recognized this as a shortcoming almost two decades ago after being exposed to the works of John Dewey and Ralph Lewis (see Table 1). Dewey described the "scientific method" as a student activity, which was subsequently organized into a five-part analysis format that includes hypothesis formation and testing, and requires Bloom's highest cognitive levels. Lewis expressed the organizing principles of biology in simple terms with the goal of using them to problem solve, as is done in chemistry and physics. The common ground of these two concepts eventually occurred to us: The five-part analysis and Lewis's general principles both present findings in the form of an argument, a series of premises and conclusions subject to the rules of science and of informal logic. We realized that if the Dewey/Lewis concepts could be integrated functionally, it would facilitate problem solving at the upper end of the Bloom scale.

The science of biology has two main products: factual information and scientific argument. Undergraduates generally lack the time, laboratory training, and field experience to collect new factual information, but they can evaluate presentations of fact by others if they are given criteria. Similarly, with training and practice, students have the capacity to analyze scientific arguments on biological topics, and to construct and evaluate fact-based, scientific arguments of their own.

Our scheme begins with simple, relativistic criteria for determining factual reliability, and gradually expands it to more closely reflect scientific practice. We connect fact to argument using a premise/conclusion format adapted from informal logic, and demonstrate the relative reliability of conclusions based on argument type and construction. Students evaluate the reliability of conclusions based on the dual criteria of fact and argument type/construction. This leads to five-part analysis problems, which require students to construct their own arguments based on data gathered by scientific professionals. After problem solving with this scheme, students are asked to examine and evaluate arguments for the underlying principles of biology, and apply them to new sets of facts.

Reliability of fact

Not all "facts" are of equal reliability. To introduce the idea of relative reliability, we rely on examples from a variety of media sources that offer a variety of current topics, simply presented, and spanning the spectrum of reliability. Through experience we have learned that when doing something different, start small. We begin with a simplified version of our final rubric. It is based on the primary criteria of science: observation, repeatability, source, and because science is a community activity, consensus.

After student practice with media examples, we add other concepts to the rubric shown in Table 2, including adequate sample size, and control and experimental groups. Our final table presents additional and more sophisticated criteria for judging relative reliability of factual information to be used in conjunction with Table 3. Throughout a 16-week semester, this material is used in lecture and laboratory, and is supported by homework, in-class collaborative assignments, and individual assignments.

Reliability of arguments in science

Next we introduce aspects of informal logic including inductive, deductive, and conditional deductive arguments. Our focus is on the relative reliability of conclusions based on argument type. In-class and homework assignments give students practice in identifying the argument types presented in popular science articles (see example below), arguments that may be outlined and analyzed using the premise/conclusion format. …