Miss Wilcox

Biology I

Natural Selection – June 27, 2007

Approximate time: 50 minutes

Objectives: TSW

1. Examine inheritance patterns using pedigrees. 5f

Materials:

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

Warm-up:

Color blindness is a recessive trait carried on the X chromosome. If a woman who has normal color vision but who carries the recessive allele for color blindness marries a man with normal color vision, will their children have normal color vision?

Set: (review, objectives, involve, relevance)

Say, “Have you ever seen your family tree? What is a family tree? A diagram that shows different generations and members of your family. Scientists who study genes—geneticists--use something similiar to a family tree to show genetic inheritance. Define pedigree in your notebook (2 min). Pedigrees can help geneticists determine if a trait is inherited, how a trait is passed from one generation to the next, and help determine whether an allele for a trait is dominant or recessive. Yesterday, Miss Lewis introduced sex-linked genes to you. What are sex-linked genes? Today, we will examine inheritance patterns, including those with sex-linked genes, using pedigrees.”

Procedures:

1.Allow students to copy notes on sample pedigree from transparency and explain.

2.Do example: In the sample pedigree, determine the genotypes of the parents in the P1 generation.

3.Have students do worksheet.

4.Time permitting, collect and go over.

Closure: (restate, review, involve, preview)

Say, “Today, we examined inheritance patterns using pedigrees. What is a pedigree? What can it help us determine? Tomorrow, we are going to have a brief review of the unit on Mendelian genetics and a worksheet which you will turn in for a quiz grade. Questions?”

Assessment:

    Informal: TTW observe independent work and listen to responses and questions asked during class.

    Formal: TTW grade worksheet for accurate application of pedigrees in explaining inheritance patterns. The grade will be recorded in the gradebook.