Essential Question: How have the roles of minority groups (women & blacks) changed in the United States? Objective I can define minority groups. I can explain how the roles of minority groups have changed. Background This lesson is the second of three that are intended to help students understand the different types of human migration and how it impacted the roles of different minority groups. Preparation Prepare for this lesson by accessing the Materials tab in this lesson. Teachers will have a Powerpoint presentation, worksheet packet for students, and additional resources to share. Material Duration: 60 Minutes.