The paper deals with research of the knowledge acquisition of the teaching unit Gymnosperms after it has been taught by different teaching methods. The study included 182 second grade students from four high schools in the Split-Dalmatia County, deployed in eight classes. The classes were divided into two groups. One group was marked as a control group, being the group in which the classroom teaching was conducted in a classical manner, while the other group was labelled as experimental, with teaching conducted in a modern way. At the beginning of the lesson, students were given an initial test to determine their knowledge level. At the end of the lesson, they were given a final revision test to verify the acquisition of knowledge. After processing the results, it was found that the total solving rate of the initial test was 52.37%, with the initial test being better solved by the students of the experimental group. The final test solving rate was 46.69%, with better results being achieved in the control group. The results infer that the examined students are passive lesson participants, not accustomed to more modern teaching methods, since the lessons in examined classes are performed in a lecture mode. Active learning and teaching methods should be pursued in persistent efforts to introduce more modern teaching methods, leading to student's logical and critical thinking ability and problem solving development.