Lesson Plan : Genetics and Heredity
Teacher Name: | Ann E. Goewert |
Grade: | Grade 7-8 |
Subject: | Science |
Topic: | Mendelian Genetics and Heredity |
Content: | Define heredity, genes, alleles, dominant, recessive, homozygotes, heterozygote, genotype, phenotype, punnett square, and probablity |
Goals: | Students will be able to: 1. explain and define heredity 2. explain and define chromosomes 3. explain and define dominant and recessive alleles 4. understand that genes come in pairs, and that one set of genes is contributed by the mother, while the other, corresponding set of genes is contributed by the father 5. determine the probabilities for outcomes of simple events |
Objectives: | Students will be able to: 1. distinguish between genotypes and phenotypes. 2. determine the genotypes and phenotypes of offspring that could result from a given pair of parental genotypes. 3. describe why children are neither genetically nor phenotypically identical to their parents |
Materials: | Example: Red, White, and Pink Carnation Exercise: -50 Pink (XX) and 50 Blue (XY) cocktail toothpicks (representing chromosomes),# 38 brown paper lunch bags -80 red jelly beans (tongue rolling allele) beans and 70 pink jelly beans (non-tongue rolling allele) -100 purple jelly beans (long eye lash allele) and 50 white jelly beans (short eye lash allele) -90 black jelly beans (brown eye color allele) and 60 blue jelly beans (blue eye color allele) -80 orange jelly beans (detached ear lobes) and 70 yellow jelly beans (attached ear lobes) -15 sheets of construction paper -transparent tape |
Introduction: | Carnation Example and Jelly Bean Experiment |
Development: | Carnation Example: Red carnation, white carnation, and pink carnation 1. Cross Parents: Red (Dominant Phenotype, RR genotype) and White Carnation (Recessive Phenotype, rr genotype) F1-First Filial Generation: Pink (Rr) 2. Cross F1 Pink Hybrids (Rr) X (Rr) F2-Second Filial Generation: 25% Red (RR), 50% Pink (Rr), 25% White (rr) |
Practice: | 1. Sort the students in pairs 2. Designate one student as the female role and one as the male role 3. Designated female students choose jelly beans from brown bags that represent a pair of alleles for each of the four traits. Designated male students do the same. 3. Student pairs record their genotypes and phenotypes. 4. One at a time for each of the traits, female halves of the pairs place their jelly beans in a lunch bag and without looking, choose one to "give" to their baby. Male partners do the same. These are made into toothpick chromosomes for their baby. 5. The "parents" then obtain additional jelly beans and construct their own chromosomes, based on the genotypes recorded in step 3. 6. Students make observations of similarities and differences in genotypes and phenotypes parents and offspring. 7. Students determine theoretical probabilities for phenotypes of offspring, given parental genotypes. |
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