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The Meaning of Genetic Variation (Grades 9-12)

Author/Source: National Institutes of Health (via Understanding Evolution)

Overview: Students investigate variation in the beta globin gene by identifying base changes that do and do not alter function, and by using several internet-based resources to consider the significance in different environments of the base change associated with sickle cell disease.

Concepts: This lesson covers the following concepts:

  • Evolution results from selection acting upon genetic variation within a population.
  • Mutations are random, but selection is not; selection is dependent on many factors.
  • Traits that are advantageous often persist in a population.
  • Inherited characteristics affect the likelihood of an organism's survival and reproduction.
  • Depending on environmental conditions, inherited characteristics may be advantageous, neutral, or detrimental.
  • Natural selection acts on phenotype as an expression of genotype.

Grade Level: 9-12

Time: two 50 minute periods

Teacher Background: Explore these links for additional information on the topics covered in this lesson:

Teaching Tips: This activity is the second in a series entitled Human Genetic Variation. We also recommend the introductory activity in this module: Alike but Not the Same. Before beginning this activity, students should understand basic Mendelian patterns of inheritance, especially autosomal-recessive inheritance; the basic structure of DNA; the transcription of DNA to messenger RNA; and the translation of messenger RNA to protein. This activity largely focuses on variation but could easily be extended or modified to emphasize variation's role in evolution to a greater degree.
 
Resource Type: 
Lesson plan

The Meaning of Genetic Variation: Grades 9-12

Students investigate variation in the beta globin gene by identifying base changes that do and do not alter function, and by using several internet-based resources to consider the significance in different environments of the base change associated with sickle cell disease.