Discovering Biology in a Digital World

The learning objective: To understand the inheritance of blood type.

In this activity students:
1. Identify which blood type a person would have based on their alleles,
2. Observe the alleles that an offspring would have and identify the blood types of the offspring,
3. Use the observations and rules gleaned from step 2 to predict the blood types of other offspring, when given the genotypes of their parents.

Materials:

Paper clips ( multiply the number students x two thirds)
Paper clips attached to strips of paper (use two different colors of paper, for each color multiply the number students x two thirds)

Prepare the strips of paper and paper clips:
Find two different colors of paper and use a paper cutter to the pages into strips. Attach paper clips to the ends of the paper strips. The paper clips with paper strips are blood cells with A (one color) or B (the other color) carbohydrates. Type O is represented by plain paper clips, since there isn't an O carbohydrate.

The strips of paper are used to help make it clear that the blood cells with either A or B carbohydrates, or both A and B carbohydrates, have something that the type O blood cells are missing.

Procedure:
1. Hand the strips of paper and paper clips out randomly to the students so that everyone gets two objects (alleles).

2. Next, ask the students write down which carbohydrates are on their red blood cells and their blood type.

3. Then tell the students that they get to pick whether they're male or female (if they want to change sex, that's okay, at least during the lab activity).

4. Now, the students need to go reproduce. Tell the students that they need to have children with other students in the class. They can either have both children with one partner or two partners and one child. This is intentionally funny It will help everyone if you can make the students laugh.

For each reproduction event, they will need to write down the blood group of their partner, predict the blood group of the imaginary child, and last, they need to work with their partner and make that child - well - okay, that child's blood group.

6. Then the students record the blood type of that imaginary child and whether or not the new blood type matched their prediction. If the prediction was wrong, they need to figure out why it was wrong.

Then they repeat this process and record their results once again. They can either have a second "child" with the same partner or a new "child" with a new partner.

7. At some point, during or after the class they complete the table in a worksheet (like this) and answer additional questions.

View a larger image. If you right-click the imagine and open it in a new window, you can print it.

There are three last points about blood typing labs in general:

1. Many schools will not let students work with blood - especially non-nursing or biology majors- even if it is their own, because blood is a safety hazard. Blood carries pathogens like HIV, hepatitis B, C, D, and others nasty things, in the future, you might want to get fake blood from Carolina or Wards.

2. Blood typing seems straightforward, but we often covered this topic after we had talked about Mendelian genetics - and had students do problems with Punnett squares. Our biology courses laid the groundwork for a topic like blood typing by making sure that students knew that they got one chromosome from Mom and one from their Dad.

3. I've heard it said (by several people) that about 30% of all children have fathers that are different from the fathers of record. Sometimes students know the blood types of their parents and find out that theirs doesn't make sense in light what they're learning. You don't want to go there. Let students discover their paternity somewhere else.

technorati tags: biology, teaching, blood typing, Science education