Procedure: 1. Show students an overhead/picture of a Cassit Bird Family. Keep the phenotype information covered. Explain to students that these are Cassit birds (made-up for purposes of simplicity). Ask students to identify some of the distinguishing phenotypes (features) of the birds. Write these on the board. Explain that what they listed are phenotypes and are the result of gene expression (H.S. You can discuss that not all features are determined by genes). Uncover the phenotype information. Explain that students will concentrate on the following phenotypes: beak shape, chest patches, and sex.

2. Ask students to identify similarities and differences between the parents and offspring and between offspring. Ask students how this happens. Students brainstorm responses, which should lead to a discussion of inheritance.

3. Show students the Cassit Bird Cells as an overhead. Explain that this is a representative cell taken from a Cassit bird. It shows the genetic material/chromosomes in each cell, which is the basis for the features expressed in the birds. Ask students the following questions. These may be a review of previous concepts covered in class:

4. Show students the gene locations for the features that they will be keeping track of (beak shape, chest patches, sex). Explain that the genes for two of these features are found on the same chromosome (#1). The combination of the genes determine the phenotype of that offspring. Discuss homozygous, heterozygous.

5. Have students work in pairs to determine the genotype and phenotype of the different birds in the family, then share their responses with the rest of the class.