Genetic Survivor

A lot of human trait variations are neutral. In other words, they’re not adaptive. But what if something were to suddenly change? Students inventory 5 of their traits that are neutral in our current environment. Then they imagine how their traits might affect their ability to survive and reproduce in an apocalyptic future with threats like tongue parasites or killer grandmas. Will they pass down their genes or be the last of their line?

Choose a version of the activity: online interactive or paper

• With the online interactive version, students can use the Student Sheet to record their results.
• With the paper version, you can have students determine their environment any number of ways: e.g., independently, as a small group, or as a class.

Make sure students understand that offspring don’t inherit all their parents' trait variations—even if those variations are helpful. The survivors have a chance to pass on their helpful alleles, and the resulting traits—but it’s no guarantee!

Talk about, or have students compare, variations within each category. For example, do all the students with dimples have the exact same type of dimples? What about hairline shape—how much variation is there in the categories of pointed hairlines and straight hairlines? What could be causing these differences?

Discuss what would happen in these scenarios if there were no trait variation.

• Whether a trait is harmful, helpful or neutral often depends on the environment.
• Some traits make an individual more successful at reproducing than others.
• Individuals with traits that favor survival and reproduction are more likely to have offspring.

A common misunderstanding is that “organisms change their traits to better fit a changing environment.” This activity highlights the idea that selection acts only on pre-existing trait variations.

It’s intuitive—but incorrect—to believe that “beneficial traits will always be beneficial.” In reality, context (like environmental conditions) always matters.

Copies, Dice (paper version), Student devices with internet access and headphones (interactive version)

Genetic Survivor (interactive)
Student sheet (pdf) — Make one per student.
Scenarios (pdf) — Make one per pair or small group.