Biointeractive: The Biology of Skin Color

Instructor Activity

Display a world map.

Ask:

• Why do people around the world have different skin colors?
• Do you think skin color has any connection to climate or geography?

Record student responses without evaluating them.

Student Activity

Students complete a quick-write:

"What factors do you think influence skin color?"

Transition

Explain:

"Today, we will examine scientific evidence that helps explain human skin color variation."

Instructor Mini-Lesson

Introduce key vocabulary:

• Melanin
• Melanocyte
• Ultraviolet (UV) radiation
• Vitamin D
• Folate
• Adaptation
• Natural Selection

Explain that melanin is produced by specialized skin cells called melanocytes and helps protect the body from UV radiation.

Prediction Question

Ask students:

"Would darker skin be more common in areas with high UV radiation or low UV radiation? Why?"

Students discuss with a partner.

Activity #1: Guided Video Viewing

Play the video.

Stop periodically for discussion.

Segment 1: What Determines Skin Color?

Students complete guided notes:

• What is melanin?
• What cells produce melanin?
• How does melanin affect skin color?

Discuss findings.

Segment 2: Skin Color and UV Radiation

Students observe the relationship between global UV intensity and skin color.

Questions:

• What pattern do scientists observe?
• How does UV radiation influence adaptation?

Segment 3: Evolutionary Explanation

Discuss:

• Why would darker skin be advantageous in high-UV environments?
• Why would lighter skin be advantageous in low-UV environments?

The film explains that darker skin helps protect folate from UV damage while lighter skin allows greater vitamin D production in regions with lower UV exposure.

Co-Use Activity #2: Evidence Detective

Students work in pairs.

One student serves as the "Evidence Finder" and the other as the "Science Reporter."

Partners complete the chart:

Evidence                        What Scientists Observed          What It Suggests
UV Radiation Map
 
 Skin Color Distribution
 
 Vitamin D Production
 
 Folate Protection
 
 
After completing the chart, partners switch roles and review responses.

Group Discussion

Ask:

• What evidence supports the adaptation hypothesis?
• Which evidence was most convincing?

Exit Ticket

1. What pigment largely determines skin color?
2. What environmental factor influenced the evolution of skin color?
3. How does darker skin help protect the body?
4. Why can lighter skin be beneficial in regions with less sunlight?
5. Define adaptation in your own words.

Success Criteria

Students can:

✓ Explain the role of melanin
✓ Describe how UV radiation affects skin pigmentation
✓ Explain skin color as an adaptation
✓ Support claims with evidence from the video

Modern Connections

Students discuss one of the following:

• Why might vitamin D deficiency be more common in some populations today?
• How has human migration changed the relationship between skin color and environment?
• Why is it important to understand the scientific basis of human variation?

Reflection Writing

Prompt:

"One new thing I learned about human skin color is..."

Students write a brief paragraph using at least three vocabulary terms from the lesson.