Heredity: Inheritance and Variation of Traits

Transcription

1 Heredity: Inheritance and Variation of Traits Solving a Genetic Mystery LIFE SCIENCE DISCIPLINARY CORE IDEAS Copyright Rebecca Rehder Wingerden Activity- Modeling Mendel s Peas STAMP Date Introduction: 1. What does P represent? 2. What does it mean to be true breeding? 3. What does F1 represent? 4. What does F2 represent? 5. Why are there no white flowers in F1? 6. Where did the white flowers come from in F2? Data:

2 Date Activity- Modeling Mendel s Peas (continue) Post Activity- Analysis 1. Looking at the pea color characteristic (gene) which allele is dominant? Which allele is recessive? 2. Looking at the pea shape characteristic (gene) which allele is dominant? Which allele is recessive? 3. The parents of your cross are true breeding. What are the parental genotypes (P) in your cross? 4. Examine the F1 results then determine the genotype of the F1 generation? 5. What is the phenotype ratio of the F2 generation? 6. Looking at Figure 9.5A on page 160 of your text book. What hypothesis did the F2 generation results support? Date Activity- Modeling Mendel s Peas (continue) Post Activity- Summary: Write a paragraph summarizing what you did in this activity. Your summary should include the following vocabulary: dominant, recessive, P generation, F1 generation, F2 generation, genotype, phenotype, alleles, and segregation (Highlights 9).

3 Gregor Mendel ( ) is known as the father of modern genetics. Mendel s pea plant experiments established many rules of heredity, now referred to as the Laws of Mendelian Inheritance. In this activity you will discover what Mendel uncovered in his famous pea experiments. Gregor Mendel ( ) Mendel worked with seven characteristics of pea plants: seed shape and color, stem size, flower color, and pod shape, color and position.

4 Alleles, alternative versions of a gene. A somatic cell has two copies of each chromosome (forming a homologous pair) and thus two alleles of each gene, which may be identical (homozygous) or different (heterozygous). This figure depicts a homologous pair of chromosomes in an F1 hybrid pea plant. The chromosome with an allele for purple flowers was inherited from one parent, and that with an allele for white flowers from the other parent. What does P represent? What does it mean to be true breeding? What does F1 represent? What does F2 represent? Why are there no white flowers in the F1? Where did the white flowers in F2 come from?

5 In this activity we will be working with 2 characteristics: seed color and seed shape. green/round yellow/wrinkled green/wrinkled yellow/round Table 1: Seed Phenotypes Seed Phenotypes yellow/round green/round yellow/wrinkled green/wrinkled P F1 F2

6 Post Activity- Analysis: Answer in complete sentence. 1. Looking at the pea color characteristic (gene), which allele is dominant? Which allele is recessive? 2. Looking at the pea shape characteristic (gene), which allele is dominant? Which allele is recessive? 3. The parents of your cross are true breeding. What are the parental genotypes (P) in your cross? 4. Examine the F1 results then determine the genotype of the F1 generation? 5. What is the phenotype ratio of the F2 generation? 6. Looking at Figure 9.5A on page 160 of your text book. What hypothesis did the F2 generation results support? Post Activity- Summary: Write a paragraph summarizing what you did in this activity. Your summary should include the following vocabulary: dominant, recessive, P generation, F1 generation, F2 generation, genotype, phenotype, alleles, and segregation (Highlights 9).