The paper analyzes comparative effectiveness of the use of educational software and traditional teaching methods in biology instruction for high school students. A random sample consisted of 173 students of grade 12 of a high school in Zrenjanin, Serbia, who were randomly distributed into the control and experimental groups. The students in the experimental group learned biology content (Mechanisms of Heredity) using educational software, whereas the students in the control group learned the same content using the traditional teaching methods. The research was carried out using the pretest - posttest equivalent groups design. All instruments (the pretest, the posttest and the retest) contained the questions belonging to three different cognitive domains: knowing, understanding and reasoning. The analysis of the posttest and the retest results showed that students from the experimental group achieved significantly higher quantity and quality of knowledge in all three cognitive domains than the students from the control group. It can be concluded that educational software has a positive impact on improving students’ achievement in biology teaching.Key words: achievement; genetics; teaching efficiency; traditional teaching.---SažetakU radu se prikazuje komparativna analiza učinkovitosti upotrebe edukativnog računalnog programa i tradicionalnih nastavnih metoda u nastavi biologije u srednjoj školi. Stratificirani slučajni uzorak sastojao se od 173 učenika 12. razreda srednje škole u Zrenjaninu u Srbiji, a koji su bili nasumično svrstani u kontrolnu i eksperimentalnu skupinu. Učenici u eksperimentalnoj skupini učili su nastavne sadržaje biologije („Mehanizmi nasljeđivanja“) uz pomoć edukativnog računalnog programa, a učenici u kontrolnoj skupini učili su iste sadržaje primjenom tradicionalnih nastavnih metoda. Istraživanje je provedeno s pomoću istraživačkog dizajna s predtestom i posttestom u ekvivalentnim skupinama. Svi instrumenti (predtest, posttest i retest) sadržavali su pitanja iz tri različite kognitivne domene: znanja, razumijevanja i razmišljanja. Analiza rezultata posttesta i retesta pokazala je da su učenici iz eksperimentalne skupine postigli znatno veću kvalitetu i kvantitetu znanja u sve tri kognitivne domene nego što je to bio slučaj kod učenika iz kontrolne skupine. Može se zaključiti da edukativni računalni programi imaju pozitivan učinak na poboljšanje učeničkih postignuća u nastavi biologije.Ključne riječi: postignuće; genetika; učinkovitost poučavanja; tradicionalna nastava.

In pedagogical research the results of which are presented in this paper, the teaching topic was Fundamentals of molecular biology of the biology curriculum for the fourth year of grammar school of the natural sciences and mathematics department. The experiment was carried out during 13 lessons of interactive computer-assisted teaching in the experimental group and by traditional teaching in the control group. The survey was conducted on a sample of 142 students in two grammar schools in the Republic of Serbia. The aim of this study was to determine whether the application of computer-assisted interactive teaching has achieved better results in helping learners acquire complex content in biology and reach higher levels of quality and quantity of knowledge in comparison with traditional teaching. The analysis of the study results confirmed higher efficiency of interactive computerassisted biology teaching compared to the traditional approach to learning the same content. Differences which are statistically significant were found in student achievement between the experimental and control group in the final test and in the retest as a whole, and at individual levels of knowledge. They were: knowledge of the facts, understanding of concepts and analysis and reasoning. The research results recommend greater application of interactive computer-assisted biology teaching in grammar schools and in other high schools, especially when learning difficult educational content.