The aim of this research was to study applicability of a teaching method of using supplementary printed student worksheets together with two educational Web sites--"Estonian Vertebrates" and "Estonian Plants." The teaching method was fully approved by the expert group of 27 pilot teachers. A case study focused on development of secondary school students' abilities to analyze and synthesize the information presented to them. Results demonstrated the applicability of educational Web pages together with appropriate teaching methods to develop students' higher order thinking skills. The impact of computerized biology lessons on students' motivation and their attitudes toward the problems of environmental protection and Estonian nature was also examined. Students' responses to a questionnaire suggested that this approach was justified. (Author/AEF)