Miss Wilcox

Biology I

Genetics – June 22, 2007

Approximate time: 50 minutes

Objectives: TSW

1. Apply genetic principles to solve monohybrid cross inheritance problems. 5e

Materials:

Whiteboard, markers, overhead, transparencies, vis-a-vis pens

Warm-up: To be done in notes...

1.Define: monohybrid cross, Punnett square.

2.Copy math review chart.

Set: (review, objectives, involve, relevance)

Say, “Last class, we started to talk about the story of Gregor Mendel and his pea plants. What did we learn about? Our objective today is to build on what we learned yesterday about the genes, alleles, genotypes, phenotypes, and the Law of Dominance to solve monohybrid cross inheritance problems. What is a monohybrid cross? What is a Punnett square? By the end of today, we will be able to predict the genotypes and phenotypes of offspring resulting from a monohybrid cross. (For example, predicting eye color, hair color, etc).”

Procedures:

1.Discuss the Law of Segregation. (each allele for a trait separates during gamete production so that each gamete carries only one of the genes).

2.Discuss probability. (Probability predicts what is most likely to occur, but what actually occurs may be different. Each outcome is not influenced by the outcomes before it. Your actual results will be closer to the predicted results if you have a large number of outcomes.)

3.Introduce and illustrate a Punnett square. Have students copy notes on making, using, and interpreting them.

4.Do practice problem.

5.Have students work on worksheet, aiding and instructing as necessary.

6.Review sheet.

Closure: (restate, review, involve, preview)

Say, “Today we applied genetic principles (the Laws of Dominance and Segregation) and probability to predict the offspring of monohybrid crosses. What do we mean by monohybrid crosses? What is a Punnett square? How do we use it? Yesterday and today, we predicted offspring from crosses in which dominance was clear. On Monday, we will begin to discuss the topics of incomplete and codominance and multiple alleles.”

Assessment:

    Informal: TTW observe students during independent work on Punnett squares.

    Formal: TTW grade student worksheets on using Punnett squares to predict offspring. The grade will be recorded in the grade book.

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