Date of Award

1995

Document Type

Thesis

Publisher

Edith Cowan University

Degree Name

Bachelor of Education Honours

School

School of Education

Faculty

Faculty of Education

First Supervisor

Dr Mark Hackling

Abstract

Teachers rate genetics as one of the most difficult biology topics for high school students to understand (Finley, Stewart & Yarroch, 1982). It has been observed that some students are able to solve genetics problems using routine algorithmic methods, without understanding the basic underlying concepts (Stewart, 1982). The aim of this study was to identify the procedural errors and conceptual misunderstandings that the students had when attempting to solve genetic pedigree problems. Genetic pedigrees are diagrammatic representations of the members and ancestral relationships in a family (Cummings, 1991). Two male and two female students were selected from each of four Year 10 classes. They were required to solve three genetic pedigree problems, identifying the most likely mode of inheritance for each problem. The interviews were tape-recorded and transcribed, and these were followed up with a debriefing session in which each subject’s knowledge of the conceptual basis of these problems was probed. The results showed that many students made similar errors in procedure and many lacked the conceptual knowledge to produce meaningful solutions. The most common procedural error was the failure to falsify all the possible hypotheses, which resulted in students failing to provide complete and conclusive solutions. Other procedural errors included the incorrect use of genotypes. the failure to identity and correctly interpret critical patterns, and the misinterpretation of non-critical patterns. The conceptual misunderstandings included the lack of knowledge regarding the meanings of dominant and recessive, and the mechanisms of X-linkage. The recommendations for improved teaching of this topic focus on making procedural steps more explicit, and making the link between the procedural steps and underlying conceptual knowledge clearer.

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