1. Human Traits - Background

Teacher Background
If you were asked to describe yourself to a stranger so they could recognize you at the airport, what would you say? What traits make you unique and different from others? The general ways one person can different from another – height, eye color, hair color, build, complexion, etc – are called characteristics. The precise description of an individual – 5’2”, brown eyes, brown hair, fairly thin, etc. – are called the person’s traits.

In this activity, students survey themselves and others that aren’t in the school for a wide array of traits. Some are “yes/no” traits – dimples/no dimples, freckles/no freckles, attached earlobes/unattached earlobes, etc. Others are “multiple choice” traits – blond/red/brown/black hair, blue/green/hazel/brown eyes, etc. Others vary even more widely – reaction time, hand span, reach, etc. In fact, most of these when plotted on a histogram will generate a bell curve.

These differences relate to the number of genes controlling that characteristic. Most simple “yes/no” traits are controlled by a single gene. Most “multiple choice” traits are controlled by a small number (2-4) genes. The widely varying traits are governed by a large number of genes.

In running this activity, it is essential to be sensitive to the different family situations your students may be in. In the past, it has been traditional to survey one’s immediate family for a series of traits and generate a family pedigree. However, with the number of divorced, adopted, single-parent, and same-sex families in our schools today, it becomes much more difficult to negotiate a unit on inheritance without hurting someone’s feelings. Therefore, my approach is to ask students to survey any two people from outside the school. If it is possible to survey your biological parents, great! If not, any two people from outside school is fine.

Student Prerequisites