Part of Unit: Genetics and Heredity
Lesson Plan Overview / Details
Why are your eyes that color? Where did your facial expressions come from? What traits could you pass on to your children? The conversation begins here as we create a larger-than-life chromosome model to focus on genes and genetic traits. With a fun play on words, jeans and other clothing items are used to represent genes on giant chromosomes. Students tap into previous knowledge about DNA, explore the large chromosome models in their classroom, and investigate the important role genes play.
- Family Traits
- 5 Minutes
- K-W-L Chart
- 5 Minutes
- Modeling Chromosomes
- 10 Minutes
- Student Application
- 20 Minutes
- Key Terms Review
- 10 Minutes
- 5 Minutes
- 5 Minutes
California Career and Technical Education Standards
- ANR.C.C7.1 Differentiate between genotype and phenotype, and describe how dominant and rece...
- ANR.D.D5.4 Understand how to predict phenotypic and genotypic results of a dominant and rec...
- ANR.FS.11.0 Demonstration and Application
- ANR.FS.2.0 Communications
- ANR.FS.9.3 Understand how to organize and structure work individually and in teams for effe...
- ANR.G.G2.5 Understand plant inheritance principles, including the structure and role of DNA.
California Academic Content Standards (Reinforced)
Objectives and Goals
- Students will be able to recall the structure and function of DNA.
- Students will be able to describe the role of genes in heredity.
- Students will be able to compare and contrast homozygous and heterozygous traits.
- Students will be able to differentiate between dominant and recessive traits.
- Students will be able to distinguish between genotype and phenotype.
Activities in this Lesson
- Family Traits - Hooks / Set
Materials Needed: Sample photographs of individuals in a family (3-5 minimum)
The purpose of this activity is to connect and engage students by inviting them to evaluate family photographs to identify genetic traits. Prior to class, assemble sample photographs of individuals in a family. This can be a powerful example if they are photos of your family, however if you prefer, you can use generic photographs for this activity. Display photographs using a projector, or pass photographs around for students to observe. Ask students what similarities they notice amongst family members. What do we call these similarities? (traits) What do we call traits which are passed on from one generation to the next? (hereditary) The outward expression of these traits, what we see, is called phenotype. But what is phenotype controlled by? (genotype)
Today we will begin the process of exploring genetics, which is essential to understanding how we can produce quality plants and animals that possess desirable traits. In addition, genetics is the key to why you possess certain traits and what traits your future children might have!
The agriculture industry has seen great improvements in livestock and plant production because of our increased knowledge of genes, and how they control the outward expression of traits such as muscling and structure in cattle, as well as fruit quality and disease resistance in tree crops!
- K-W-L Chart - Other
Materials Needed: Wipe board or share sheet, markers
Assess student knowledge and prepare students for the acquisition of new knowledge through the use of a K-W-L chart. Create a chart on a wipe board or share sheet with three columns. Label the first column K (know), the middle W (want to know), and the final column L (learned). Begin by asking students what they know about DNA and genetics. As students recall information, capture this in the K column. Provide students the opportunity to share what they want to know, and capture this in the W column. Revisit the L column at the conclusion of the lesson.
Teacher Note: Student responses for what they "know" will vary by class and even class period. Take a moment to personally review what you have covered with your students regarding DNA and genetics, so that you have an expectation of what students may share. Recognize, however, that the K-W-L exercise is an opportunity for STUDENTS to recall what they have learned, not an exercise in re-teaching them what they should know.
- Modeling Chromosomes - Demo / Modeling
Materials Needed: Coat hangers (2), safety pins (20), jeans (2), T-shirts (2), shorts (2), gloves (2), socks (2)
Prior to class create a giant model of two homologous chromosomes using common clothing items. Each item of clothing represents a gene on the chromosome. String clothing together using safety pins and attach to a coat hanger at the top. Attach the coat hanger to the ceiling so that the chromosomes hang next to one another. One chromosome may begin with a pair of jeans, attached to a t-shirt, shorts, glove, and sock. The second chromosome, which is the homologous pair of the first, should have clothing assembled in the same order. However, some of the items may have variation. For example, begin building each chromosome with a pair of blue jeans. If the blue jeans are identical, the individual (whose chromosomes we are analyzing) is homozygous for that trait. Moving down the chromosome, if the t-shirts are two different colors, the individual is heterozygous for that trait. Continue in this fashion, including homozygous and heterozygous gene pairs. Refer to the supplemental handout "Building Your Chromosomes" for more information.
Walk students through this abstract example of a pair of chromosomes, making important curricular connections along the way. Begin by asking students to recall where DNA is located in a eukaryotic organism. (nucleus) How is DNA organized? (coiled into chromosomes) What are genes? (sections of DNA on a chromosome) What do genes code for? (traits) Refer back to the traits identified in the opening hook.
Describe each section of the chromosomes as you walk through the chromosome model. Help students identify homozygous and heterozygous traits. Share specific examples of traits each gene pair might code for to bring the illustration to life. Connect to previous knowledge by having students recall what homologous chromosomes are (chromosomes which are of similar size and shape that code for the same traits) and where these chromosomes came from (one from mom and one from dad).
Introduce the concept of dominant and recessive genes as you encounter a heterozygous pair. Briefly explain that genes interact in different ways. Sometimes one gene is expressed and the other is not. This gene is considered dominant, while the other is recessive. For example, if you have a blue sock and a white sock, explain that these might be genes coding for feather color in birds. If we assume the blue sock (gene) is dominant, what color will the bird be? (blue) Resist the urge to go too far into gene interaction at this point, to ensure that students get the basic concept of dominant and recessive traits. Further gene interaction can be explored at a later time.
This activity was adapted from: Vogt, J, & Yale, M. From genes to jeans. Retrieved from http://www.cfaitc.org/LessonPlans/pdf/407.pdf
- Building Your Chromosomes [ Download ]
- Student Application - Projects
Materials Needed: "The Perfect Pair of Genes" student handout
After walking through the chromosome models, students apply knowledge by completing "The Perfect Pair of Genes" student response sheet. Monitor student progress and clarify questions as students complete this document.
- Student Response Sheet [ Download ]
- Key Terms Review - Assessment
Materials Needed: Student notebooks
In order to reinforce key concepts and help English Language Learners acquire new terminology, have students review and define the following terms in their notes: DNA, heredity, chromosome, gene, trait, homozygous, heterozygous, dominant, and recessive.
After students have defined terms, divide the class in half. Instruct one group of students to stand in a line, shoulder to shoulder. The second group of students is to line up facing the first line, so that each person is facing a partner. Students are to orally quiz one another on the key terms. After each line gets a chance to share a definition, rotate one line so that students are paired with a new partner, and continue the review process.
- Revisit K-W-L - Closure
Revisit the K-W-L chart created at the beginning of this lesson. Have students revise any statements which may be incorrect in the K column. Ask students to share information they learned during this session (L), and add any items which they still want to know (W).
- Assessment Types:
Students briefly reflect on the lesson and create a journal entry in their notes summarizing information learned. Encourage students to review notes from class, highlight key information, and place a question mark by any concepts which remain unclear. Students are to summarize the lesson in two to three sentences. You may elect to collect journal responses and grade, or have students keep their notes to review.