Learning Exercise

Monohybrid Cross - Drosophila Online Lab

This lesson accompanies the use of the virtual courseware Drosophila online lab activity. This lesson was created as a part of a webinar for the Drosophila and Natural Selection virtual courseware applications.
Course: Life Science

The interactive web-based simulation activity engages students in an inquiry-based study of the principles of genetic... see more


1. Start defining scienctific vocabulary for students based on discussion. Dominant traits….are there more people with dark hair or light colored hair in the classroom? Traits that are seen more often are called dominant. Traits that are seen in smaller amounts within a population are considered recessive. 2. Introduce Drosophila to the class. Explain that there are many different types of alleles in Drosophila. Show students a list of different alleles present in Drosophila and what these traits look like when they are expressed. 3. Ask students to remember back to sixth grade when they learned about probability. Ask students what they remember about calculating probabilities and ratios. Explain that we use probabilities and ratios when learning about genetics to make predictions about the types of traits we will see in offspring. 4. Show a Punnett square. Demonstrate that in order to calculate probability of traits, scientists use punnett squares. Demonstrate how to use a Punnett square to do a monohybrid cross. As a class, work through a few more punnett square examples. 5. Demonstrate how to perform a monohybrid cross using the Drosophila online lab. Show students all the necessary steps for performing this genetic cross. Have them copy this information into their science/lab journals. 6. Teacher will assign students to a computer. If there are fewer computers than students, teacher will allow students to work with a partner to complete this lab.


Technical Notes

Students will require access to a computer so they can use the virtual courseware activity. Teacher must demonstrate how to perform crosses before allowing the students to perform their own cross.


Students must be able to calculate ratios (6th Grade Math Content Standard). Students will need to know examples of different traits found in humans (eye color, hair color, skin color, etc.)


Genetics, Monohybrid Cross

Learning Objectives

Students will be able to define the following terms: genotype, phenotype, monohybrid, dominant, and recessive. Students will predict the phenotypic and genotypic ratios for a monohybrid cross in the F1 and F2 generations.