Variation and Inheritance: Punnett Squares

We packed a lot into the short class period today.  To reinforce concepts introduced in the video yesterday but not covered in the reading assignment, we spent today learning and applying the vocabulary of inheritance.  We dusted off the cobwebs from student memories from middle school, reviewing the vocabulary words of genotype, phenotype, alleles, dominant, recessive, homozygous, and heterozygous.  We then applied the vocabulary to an example Punnett Square about eye color inheritance patterns.  Notes from the white board are pictured below:

We then applied these concepts to a Punnett Square worksheet.  We worked through the first two problems together (pictured below), and then students used the remainder of the class period to work through the remaining problems.


Students in 4th period were very interested in learning more about the genetics of eye color.  The NIH Genetics Home Reference website explains the genetics of eye color, complete with references to relevant scientific journal articles.  The Tech Museum of Innovation website has a lengthy article written in more student-friendly language (with graphics!) on the topic.  The article includes a calculator to predict the eye color of your offspring, and even provides evidence about how two blue-eyed parents can have a brown-eyed child (Surprise!  High school genetics is over-simplified!).  The question of traits “skipping a generation” also came up during 4th and 5th periods.  We used problem 1 from the worksheet to explain how a grandparent and a grandchild can both share a trait that “skips” the generation in between.