Episode SixEvolution of Skin Color

Lesson Goal Explore the connections between ancestry, geography, and natural selection in determining skin color.

Materials

Step One - Learn about the Evolution of Skin Color

  • Watch The Biology of Skin Color
  • Think & Write about this:

    Skin color plays several “roles.” What are they and why are they important enough to have “stuck around?”

    What role does folate play in human development?

    Why aren’t we all dark skinned?

  • Complete the Sunlight section of your The Evolution of Skin Color worksheet
  • Big Question:

    What does all of this mean, in terms of melanin, vitamin D, calcium, folate, birth defects, and where you live?

    Can you put it into your own words?

Step Two - Genotype and Phenotype Review

  • Quick Check:

    What is the difference between genotype and phenotype?

    Did you use genotype or phenotype to draw a conclusion and make an assertion about alikeness, or differentness?

    What do people generally use to determine skin color?

    What actually determines skin color?

Step Three - Let’s take another look at 23andMe

  • Sign in to 23andMe → Reports → Traits → Skin → Pigmentation → Freckles
  • Review what Elizabeth saw versus what you saw on the Genotype and Phenotype worksheet
  • Think & Write Skin Color: Graphs of the likelihood based on genetics that Elizabeth will have light skin.

    Surprised by anything?

    Does your genotype match your phenotype?

  • Think & Write about Freckles: Graphs of the likelihood based on genetics that Elizabeth will have freckles.

    Surprised by anything?

    Does your genotype match your phenotype?

  • What do you see when you look at all of the data together?

    How do you describe your skin color?

    How does one of your friends/classmates describe your skin color?

    What did 23andMe predict about your skin color?

Step Four - Examine Skin Color and Geographic Placement

  • Reflect on Geography and the Evolution of Skin Color:

    What do you know about skin color and where people live on the Earth?

    How has skin color evolved over time?

    What does “evolve” mean?

    Do you think geography (where you live) plays a role in the evolution of skin color?

    The image below represents the distribution of skin color across the globe. What do you notice?

    Distribution map of skin color across the globe.

    The image below represents the distribution of UV-B radiation across the globe. What do you notice?


    Distribution map ov UV-B radiation across the globe.

    What’s the connection between these two images?

Downloads

Customize the Full Curriculum

Are you interested in customizing your own Finding Your Roots - The Seedlings learning experience?

You can explore the full curriculum that was developed for our two-week intensive camp. Download it. Customize it. Make it your own!