Heredity
Heredity
Objectives
In this lesson, students discover how heredity follows certain patterns based on the laws of probability. Students will learn how Mendel’s experiments with garden peas began the study of genetics. They will also learn to solve genetics problems using Punnett squares and determine phenotypic and genotypic ratios. Students will:
- differentiate between alleles, genes and chromosomes.
- state Mendel’s Laws of Inheritance and apply them when solving genetics problems.
- predict the offspring of a genetic cross using a Punnett square.
- differentiate between incomplete dominance and codominant alleles.
- explain how multiple alleles and polygenic traits increase variation in the population.
- recognize sex-linked genes.
- recognize linked and nonlinked genes.
Essential Questions
Vocabulary
- Alleles: Forms of genes responsible for controlling the same trait; different versions of the same gene.
- Autosome: A chromosome that is not a sex (X or Y) chromosome.
- Codominant: Alleles that are fully expressed in the heterozygous condition.
- Dominant Allele: An allele that is always expressed when it is present in an individual.
- Gene: The fundamental, physical, and functional unit of heredity.
- Hybrid: Offspring produced from a cross between two purebred organisms.
- Incomplete Dominance: Traits in which the heterozygote shows a different phenotype from the homozygous dominant phenotype.
- Phenotype: The physical characteristics of an organism.
- Polygenic: Traits in which several genes contribute to the overall phenotype.
- Recessive: An allele that is only expressed when the dominant allele for a trait is not present.
- Sex-linked Traits: Phenotype of an allele located on a sex chromosome.
- Trait: A specific characteristic that varies from one individual to another.
- Genotype: The genetic makeup of an organism.
- Heredity: The passing of genetic factors from parent to offspring.
- Heterozygous: Having dissimilar alleles that code for the same gene or trait.
- Homozygous: Having two identical alleles that code for the same trait.
Duration
At least one week
Prerequisite Skills
Prerequisite Skills haven't been entered into the lesson plan.
Materials
- number cubes, one pair for each pair of students
- Phenylthiocarbamide (PTC)
- Heredity PowerPoint (S-B-8-1_Heredity PowerPoint.ppt)
- Non-Mendelian Heredity PowerPoint (S-B-8-1_Non-Mendelian Heredity PowerPoint.ppt)
- copies of Genetics Problems 1 (S-B-8-1_Genetics Problems 1 and KEY.doc)
- copies of Genetics Problems 2 (S-B-8-1_Genetics Problems 2 and KEY.doc)
- copies of Genetics Problems 3 (S-B-8-1_Genetics Problems 3 and KEY.doc)
- People Search (S-B-8-1_People Search.doc)
- PTC paper (paper impregnated with phenylthiocarbamide) and control paper lacking PTC. Taste test strips and control strips are inexpensive and can be ordered from Flinn Scientific at www.flinnsci.com.
- color pencils
- paper
Related Unit and Lesson Plans
Related Materials & Resources
The possible inclusion of commercial websites below is not an implied endorsement of their products, which are not free, and are not required for this lesson plan.
- Myths of Human Genetics: Tongue-Rolling: The Myth
http://udel.edu/~mcdonald/mythtongueroll.html
- A film on Gregor Mendel and his achievements, not experiments (30 minutes)
https://www.youtube.com/watch?v=6OPJnO9W_rQ&feature=related
- Portraits of the Habsburg royal line, and the “Habsburg Jaw.”
http://www.paradoxplace.com/Perspectives/Genl%20Images/Single%20Frames/Maximilian%20I.htm
- Animation of independent assortment
http://www.sumanasinc.com/webcontent/animations/content/independentassortment.html
- Video summary of meiosis
https://www.youtube.com/watch?v=D1_-mQS_FZ0&feature=related
- Virtual fruit fly lab
http://www.mhhe.com/biosci/genbio/virtual_labs/BL_15/BL_15.html.
- Cooperative Learning and Science High School Activities by Michael Michels, Angela Manzi, and Janina Mele. Kagan Publishing, 2003.
Formative Assessment
Suggested Instructional Supports
Instructional Procedures
Related Instructional Videos
Note: Video playback may not work on all devices.
Instructional videos haven't been assigned to the lesson plan.
DRAFT 05/26/2011