As students enter the room I have them respond to the following prompts in their science journal:
What is sickle-cell anemia?
How does it impact people who have this condition?
How does a person come to have this condition?
Students can work on their own or in small groups to answer this question. If you have access to computers, you might allow some time for research (I sometimes make this a race to encourage students to complete this task quickly).
Students seem to think of natural selection and adaptation as processes that affect plants and animals but don't see the role they play within the human population. This video from HHMI Biointeractive is excellent for showing a real world example of natural selection within humans and how scientists use the scientific method to answer questions, both important for students to understand.
I show the video and stop at key points to ensure students understand and are following along. Additionally, this provides students with the opportunity to ask questions and helps them stay on task. I have found this process of pausing, and talking, a strategy that helps students make stronger connections to the material and as the year progresses they are better able to pull important information out of videos shown during class.
The following video points out what I believe to be an important part of the HHMI video that should be pointed out to students to ensure their understanding.
The content referred to in this part of the video relates to what my students were introduced to during their 7th grade year (we follow the integrated NGSS model). If this is new information for your students, you may need to take some time to more fully explain this material.