The purpose of the interactive Family Portrait activity is to teach your young scientists about inheritance. By comparing their facial features with the facial features of their parents, the students should be able to recognize similar characteristics between the generations and that they resemble their biological parents.
You can extend this concept of inheritance with your young scientists by asking them about their pets:
Did their puppy look like its mommy? Why does a labrador retriever ("lab") look like a lab and not a dachshund ("wiener dog")?
By drawing these connections in your students' lives, they should start to see that inheritance plays an important part in determining the physical characteristics of the living world around them.
The Science Behind Family Portraits Interactive
Four physical features were chosen for comparison in this activity: Ear lobe attachment, nose shape, hair type, and the ability to roll one's tongue. In addition, the printable worksheet allows your students to expand these observations to include eye color and hair color.
Like many characteristics, ear lobes, hair, and tongue rolling are genetically determined. The following provides you information on the inheritance patterns for family genes representing these features.
Ear Lobe Attachment
Unattached, or free, ear lobes are dominant (U). Attached ear lobes are recessive (u).
Hair type is determined by co-dominance. Curly hair (C) is dominant, and straight hair (s) is recessive. However, if one parent has curly hair (C) and the other has straight hair (s), all of their children will have genes for both curly and straight hair (Cs), causing them to have wavy hair, a compromise between curly and straight hair.
The ability to roll one's tongue (in an upward U-shape) is dominant (R). The inability to roll one's tongue is recessive (r). One variation of rolling the tongue is the dovetail shape ( } ), displayed in the facial features on the activity.
Nose shape is determined by many different factors (multiple genes). The nose shapes in these exercise are some of the more common shapes. Have your students examine different parts of the nose, and compare the features of the individual parts with their parents.
Please note: All of these traits can be affected by environmental factors such as hair treatments, physical limitations, and others, so ask your students to interview their parents to find out if they naturally have certain characteristics. This may facilitate further conversations between the students and their families to learn more about family traits and history.