Name:_________________________________

Dominant and Recessive Traits

Problem:
What are the phenotypes of some dominant and recessive human traits?

Procedure:

  1. For your group, record how many of you have each of the traits listed in the table.  Tongue rolling is the ability to roll the tongue into a U-shape.  Free ear lobes are those that hang below the point of attachment to the head.  Attached ear lobes are attached directly to the side of the head. A widow's peak is a distinct point in the hairline in the center of the forehead.  Record your results in the data table.
  2. Share your information with the class.  Determine the percentage of the class who demonstrate each trait as follows:  Divide the number of students who have the trait by the total number of students in your class and multiply by 100.  Record the percentages in the data table.

 
Dominant Traits Recessive Traits Number of Students
with Dominant Trait
Number of Students 
with Recessive Traits
Percentage with
Dominant Trait
Percentage with
Recessive Trait
Tongue Roller Non-roller . . . .
Free ear lobes Attached ear lobes . . . .
Non-red hair Red hair . . . .
Dark hair Light hair . . . .
Widow's peak Straight hairline . . . .
. . . . . .
. TOTALS . . . .