In this activity, students learn and apply the principles of Mendelian inheritances by virtual experimentation with Drosophilia melanogaster (fruit fly). Students make hypotheses for monohybrid, dihybrid and sex-linked traits and test their hypotheses by selecting fruit flies with different visible mutations, mating them, and analyzing the phenotypic ratios of the offspring. As students work through the assignments, they can capture and save data and figures, and write their own notes into their virtual notebooks. Students also learn to organize results into a scientific report that can be graded on-line by their teacher. The activities include an online assessment quiz that consists of randomized interactive questions. The teacher must create a free teacher account at: http://ScienceCourseware.org/vcise/trwg.html. This link includes directions for adding classes, editing templates, rubrics, and reports, and reviewing students’ performance. The teacher’s account includes learning objectives reports that quickly gauge how well the key concepts were understood.