English abstract
This study aimed at identifying the understanding level of genetic concepts among 12 grade students, its relation to their logical thinking level and discovering their alternative concepts for these concepts. The study sample consisted of (362) male and female students in a group of Dakhilia Region's schools in the school year 2010
2011. To answer the study questions, two research instruments were constructed. They are Genetic Concepts Test which consisted of (25) multiple choice questions with explanation in both classical genetics and modern genetics with a reliability value of (0.82). The second instrument is Logical Thinking Test which consisted of (8) questions covered four skills that are: proportional reasoning, controlling variables, probalistic reasoning and correlational reasoning with a reliability value of (0.72) The study results revealed that the understanding level of genetic concepts among 12 grade students and their logical thinking level were low. In addition, there were statistically significant differences at (a= 0.001) in understanding level of genetic concepts between students' grades in gender variable in favour of female students, in the level of logical thinking variable in favour of abstract thinking students and in the interaction between them in favour of female abstract thinking students. In addition, the study recorded distribution of alternative concepts among students with high percentages. The study recommends focusing on alternative concepts by exploring them and changing through using new teaching strategies and applying technology.
