In this lesson, you will obtain an understanding of the pattern of genetic variation among humans.
Your first activity is to explore the interactive, Nowhere to Hide. After you have played the interactive activity and completed the “Learn More” section, answer the observation questions below. Also think through how you might respond to the questions that will be presented by your teacher for class discussion. You can record your answers to these questions on the Genetic Variation within the One Human Race student sheet.
- When the forest is green, which color prey (bugs) are most often picked off by their predators (birds)?
- When the forest is discolored by orange factory smoke, which color prey are most often picked off by predators?
- When the predators have eaten all the prey of one color, does the other color disappear forever?
- In a green forest, which bugs are best adapted to their environment, that is, which bugs have the best chances of surviving to the age of reproduction?
- When the forest is completely discolored by factory smoke, why do the green bugs never completely disappear?
- Let’s say that some of the green bugs living in a green forest migrate to a new forest near a factory. In several generations, what will probably be the primary color of the population of bugs that stays behind? In several generations, what will probably be the primary color of the population of bugs that moves to the new forest?
- How does this activity coincide with what you understand about natural selection and how natural selection plays a role in evolution?
Now, visit Race and Human Variation, which is a section of Race: Are We So Different? This section explains how genes vary within humans, with the greatest variety occurring within the population of Africa, where humans have lived longest. Also visit the National Geographic resource, The Human Journey: Migration Routes, to supplement your understanding of how the human gene pool has expanded as humans migrate across the globe.
As you go through these resources, you should think about your answers to these questions, which you can answer on your student sheet:
- Why does the continent of Africa contain the most diversity among humans?
- Do people indigenous to Africa have some genetic variations that are not found elsewhere in the world? Explain your answer.
- Do Asians and Europeans possess any variations not found among indigenous Africans? Explain your answer.
- If the “Out of Africa” map were to include North and South America, what color dots (representing genetic variation) might you expect to see on those continents?
You will be assigned to investigate a human trait. Your choices include:
- Chromosomal abnormalities
- Blood types
- Skin tone
- Handedness (left, right, or ambidextrous)
- Hair color (e.g., red, white blonde, black)
- Heterochromia iridum (differently colored eyes)
- Male-pattern baldness
- Tongue dexterity (ability to roll or point the tongue)
- Susceptibility to a particular disease (e.g., malaria, measles, Tay Sachs, Huntington’s, osteoporosis)
Find some facts about the trait, describe how or if it confers advantages or disadvantages to survival, and report on its incidence among populations across the world. Find and print one or more photographs, diagrams, or illustrations that help to explain the trait. Use the Genetic Variation for a Human Trait Project Sheet to compile the information and images. You can use these resources to help with your research:
- Help Me Understand Genetics
- Heredity and Traits
- Health Connections
- Understanding Gene Testing
- Specific Genetic Disorders
This esheet is a part of the Genetic Variation within the One Human Race lesson.