Earlobes

The form of the earlobes varies in humans. At one extreme, the lowest point on the earlobe is attached to the flesh of the cheek. If not, the earlobe is to varying extents "free" to dangle downward.

Geneticists have often claimed that the earlobe form is a Mendelian trait. But more recent studies indicate that several genes are involved in the trait's variation.

As a class, you will investigate the pattern of variation in earlobe form. The method you will use is seriation, putting individuals in a morphological order.

Get together with your classmates and line up in order of earlobe form. It will be up to you to decide exactly how to compare each other. Your ordering of the class is called a seriation.

Once you are in order, decide where to divide the class into attached and free earlobe forms. You can place the dividing line anywhere that makes sense to you. If you decide that no one in the class has attached earlobes, for example, that is fine.

Your dividing line will separate the class into two categories. Delegate one student to draw a line drawing of the ear that you decided is the first of the free earlobes, closest to the dividing line. Record the number of students that you classified in both categories, attached and free.