**Lesson 3- Punnett Squares**

*Duration: 2 Days*

**Day 1**

**Day 1**

**Hook**: Introduce the concept of probability to students.

Image Citation: http://www.wscbrc.com/2 012/03/22/the-history-behind-flipping-a-coin/

Have students take a turn in tossing a penny and record the amount of times it lands on heads and tails after about 20 tries.

**Body:**Using a laptop and a projector, open the following link to a virtual lab on Punnett squares. Together with the class, go through the steps of developing a Punnett square with students and have them write along with you.Image Citation: http://en.wikipedia.org/wiki/File:Punnett_Square.svg

**Assessment:**Using a sample question, show students how to implement the use of a Punnett square in determining probably offspring of a cross.

Provide them with an additional sample question to be completed on their own and submitted or taken up (time permitting) by the end of class.

__Sample Question__: Two heterozygous yellow seed plants (Yy) are crossed. Determine the genotype and

phenotype ratios of the F2 generation.

**Homework:**Provide students with additional problem samples which can be found in any textbook on Mendelian Genetics or you may wish to use an online resource. The link below provides examples of such for monohybrid crosses. Have students use Punnett Squares to answer the questions from this link where necessary.

**Additional Teaching Resources for Punnett Squares:** The link to the following website includes a Punnett square calculator. Click on which ever cross you'd like to calculate and the Punnett square image will open.

Day 2

Hook: Take a question from the online quiz assigned from the previous day and have students answer independently. This is a diagnostic assessment for learning.

**Body:** Review how to use Punnett squares to solve problems. Assign a work period of problems from the textbook where you can help students work through problems. The following link can be used to review how to construct a Punnett square as well as how to interpret the results.

__Hook:__

Day 2

Day 2