The role of genetics in students' understandings of biological evolution.

摘要

An important element of an education is an understanding of biology. Science education researchers have shown that both high school and college biology students finish their biology instruction with a poor understanding of evolution, an important unifying concept of the discipline. The goal of this study is to examine the role of genetics in students understanding of evolution. Eight introductory college biology students' understandings of evolutionary biology and their use of genetics concepts as they addressed problems in evolution were examined. Data collected included students' classwork and individual student interviews. Data analysis began with an examination of each students understanding of evolution concepts. The framework for this analysis was based on Mayr's (1982) description of Darwin's five theories: evolution as such, common descent, natural selection, gradualism, and multiplication of species. The descriptions of students' understandings of evolution are followed by an account of how students used genetics concepts to support their explanations of evolutionary processes.; The data from this study illustrate how students used transmission genetics, molecular biology and population genetics to support their understandings of evolution. The students in this study constructed syntheses of genetics and evolution concepts that they employed to solve problems. These syntheses fell into three categories: productive, semi-productive and obstructive. Students who achieved a productive synthesis of genetics and evolution concepts also held appropriate understandings of common descent, natural selection, gradualism, and speciation. Students who constructed either a semi-productive or obstructive synthesis of genetics and evolution did not benefit in the same way.; Productive synthesis students benefited from their syntheses of genetics and evolution concepts in three ways. They were able to construct complete problem solutions for evolutionary problems, to dismiss common misconceptions associated with natural selection, and to construct an appropriate understanding of evolutionary processes, particularly natural selection and speciation.; The findings of this study suggest one way teachers can help their students to develop an understanding of evolution is to teach genetics first. Knowledge of genetics provided students in this study a tool to explain the origin of variations in populations, evidence for common descent, and strengthened their understandings of the mechanisms of evolution.