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Genetics and Probability – Sex Ratios of Births

In this minds-on analysis and discussion activity, students analyze the inheritance of sex chromosomes. Students use a Punnett square to predict the sex ratio of births and compare their prediction to data for individual families and for the entire US.

As students analyze the reasons why many real families deviate from Punnett square predictions, they learn about the probabilistic nature of inheritance and the limitations of Punnett square predictions.

The Student Handout is available in the first two attached files and as a Google doc designed for use in online instruction and distance learning. The Teacher Notes, available in the last two attached files, provide instructional suggestions and background information and explain how this activity is aligned with the Next Generation Science Standards.

sex ratios SH.docx427.92 KB
sex ratios SH.pdf287.08 KB
sex ratio TN.docx38.42 KB
sex ratio TN.pdf288.55 KB


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