Where Did I Get This Hair?
Exploring the basics of heredity using observation, surveys, and simulation.
By Erin Bailey
The scientific process begins with observation. Children are natural observers because so much of the world is new to them. This two-day exploration will sharpen their observation skills while they study the topic of genetic inheritance.
Day 1: Observation
To open the lesson, ask your class to observe the face of a person sitting next to them for thirty seconds. Encourage them to remember as many details about their partner as possible. When the time is up, call on volunteers to close their eyes and recite the details that they remember. You can make a list of these items on the board. When several participants have had a chance, draw attention to traits that were mentioned more than once, such as brown hair, eye color, and freckles.
Explain that the way we look and some of the things we like are due to a secret code called genotype. Examples might be hair color, liking spicy food, or being allergic to cats. Tell them that information about these traits is carried in genes. The genotype is a record of all the genes a person has. To solve the secret codes, scientists get hints from another code called phenotype. Phenotype isn’t secret though. Instead, you can see what it says just by looking at it. For example, I can tell that Tommy has a gene for brown hair because Tommy has brown hair. And I can tell that Susan has a gene for dimples because I can see her dimples.
Show students some pictures of common observable traits and have them record the data for themselves with the help of a partner on the inherited traits record sheet. Your young scientists will extend this lesson by taking the record sheet home and observing the same traits in their families. Instruct them to answer this question for Day 2: Where do our genes come from?
Day 2: Simulation
Ask for a few volunteers to share their answer to the question, “Where do genes come from?” Explain that Gregor Mendel was the first scientist to discover that genes are passed from parent to offspring using pea plants. He found that every living thing receives two genes for every trait—one gene from the father and one gene from the mother.
Next, have students share the results of their take-home study of inherited traits. Encourage individuals to focus on the traits that are shared among family members. If you have time, let children make a class graph of the results on a large piece of chart paper.
Your class will explore how traits are passed down through generations by conducting the following simulation from the Genetic Science Learning Center at the University of Utah. Each group of three to four students will need the following: a paper bag, six paper cups, six red counters, six green counters, six yellow counters, six blue counters, four clear counters, crayons in corresponding colors, and the gingerbread man worksheet.
- Step 1: First have students label the cups Grandfather A, Grandmother A, Grandfather B, Grandmother B, Mom, and Dad. All the counters should go into the bag.
- Step 2: One student draws six counters and places them in the Grandfather A cup. This step is repeated until each of the grandparent cups have six counters. The results are recorded in crayon on the worksheet. IMPORTANT: Remove the leftover counters from the bag and set them aside.
- Step 3: Without looking, one student takes three counters from Grandfather A and three from Grandmother A and places them into the Mom cup. Repeat this step with the B set of Grandparents and place them in the Dad cup. Color the results.
- Step 4: Without looking, one child takes three counters from the Mom cup and three from the Dad cup. This is Gingerbread Baby #1. Have them color the results. This time, the counters are put back in their respective Mom and Dad cups and traits for another Gingerbread Baby are drawn. Repeat this step until all of the Gingerbread Babies are colored.
Because this simulation doesn’t address dominant and recessive characteristics, it is perfect for younger scientists who are just beginning to explore the topic. Of course, older participants will benefit from it as well.
Ask individuals to look at their gingerbread family and observe all of the family members who share common traits as indicated by common colors. Traits are shared because a person’s genes come from their parents (and grandparents). Hang the gingerbread people around the room as a reminder of the lesson.
This resource introduces the basics of traits that are inherited and those that aren’t. Participants make a bar graph of eye color, read “Raven Lost His Eye” and separate a list of traits into two groups.
Children dissect and name a flower’s parts. They study pollination and then predict what the next generation of plants will look like.
Pupils flip a coin to determine which traits a fictional offspring will have. Each trait is indicated by heads or tails and the partners use their flips to draw the resulting offspring.