Examining the topical coverage of genetics and biological evolution in Canadian secondary science curricula: A comparative content analysis

Abstract

Introduction This study was a comparative content analysis of the Canadian secondary science curriculum documents with the overarching purpose of identifying the scope and sequence of topical coverage in genetics and biological evolution. Methods The units of analysis in this study, which were comprised of all the statements pertaining to genetics and biological evolution in the 45 secondary science curriculum documents in Canada, were identified through manual reading of the documents. Furthermore, using deductive category development techniques, we categorized the statements using a categorization scheme developed by Zorek and Raehl (2013). This scheme allowed us to categorize identified statements according to their applicability and accountability to our research objectives. Inter-rater reliability was assessed using intraclass correlation coefficients. Discrepancies between raters were negotiated until consensus was reached. Next, we employed inductive reasoning techniques to identify codes and generate common themes and categories relevant to the teaching and learning of both genetics and biological evolution. Results Of the 45 secondary science curriculum documents we analyzed, 28 contained statements that were relevant to genetics and biological evolution. Good to excellent degrees of reliability were found between rater-pairs. Final categorization, following negotiations, resulted in a total of 509 applicable statements across all curriculum documents, of which 198 (38.90%) were accountable and 311 (61.10%) were non-accountable. More than two-thirds of the accountable statements were relevant to genetics (68.18%). Most topics in both genetics and biological evolution are taught in Grade 12, accounting for 58.21% and 49.18% of all genetics-related and biological evolution-related accountable statements, respectively. A total of 16 major themes emerged from the inductive analysis of the 135 genetics-related accountable statements. These themes were organized into four broad categories: (1) Genetic Material (five themes); (2) Mutations (three themes); (3) Inheritance (six themes); (4) Reproductive Technology (two themes). In addition, a total of 12 major themes emerged from the inductive analysis of the 63-biological evolution-related accountable statements. These themes were organized into three broad categories: (1) Theory of Evolution (five themes); (2) Evolutionary Mechanisms (four themes); (3) Evolutionary Principles (three themes). Conclusion Analyses of the curriculum documents indicated that, depending on jurisdiction, biological evolution is largely taught in either Grade 11 or Grade 12, while genetics is largely taught in Grade 12. Significance Our findings denote that biological evolution is taught before and, in some jurisdictions, possibly in tandem with genetics. Accordingly, further investigation is warranted to examine exactly how these topics are taught, perhaps through qualitative research methods involving interviews with teachers nationwide. At present, nevertheless, policy and decision-makers in many Canadian jurisdictions are advised to revise their curricula in the direction of the literature's recommendations.