National Agricultural Literacy Curriculum Matrix
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Peas in a Pod
3 - 5
Students will explore the concept of inherited traits by using magnetic pompoms to diagram Punnett squares and will learn about the significance of Gregor Mendel's discoveries related to heredity.
- 12 large green pompoms
- 12 large yellow pompoms
- 24 round magnets; use a hot glue gun to attach to pompoms
- 1" yellow pompoms,* 12 per group
- Pea Plant Traits Chart
- Punnet Square activity sheet, 1 per student
- Punnet Square Chart, 1 per group
- 1" green pompoms,* 12 per group
- Lunch-size paper bags,* 1 per group
*These items are included in the Pompom Punnet Square Kit, which is available for purchase from agclassroomstore.com.
Essential Files (maps, charts, pictures, or documents)
hybrid: the offspring produced by two different types of animals or plants
chromosomes: threadlike structures in the nucleus of the cell that control the cell’s activities
dominant gene: a gene that can hide the effect of a recessive gene
gene: section of a chromosome that controls a trait
heredity: the passing of traits from a parent to its offspring
inherited: a trait passed on from the parent organism to offspring
offspring: the child or young of two parents
organism: any living thing made of cells
purebred: the offspring produced by parents of the same breed
recessive gene: a gene whose expression can be hidden
species: a group of organisms sharing common traits that can produce offspring together
trait: a distinguishing characteristic or quality
Background Agricultural Connections
Interest Approach – Engagement
- Ask your students what a trait is. Allow students to offer their answers and guide them to the correct answer. Traits are distinguishing characteristics. Explain that many traits are determined by genetics.
- Ask students to list different plants or animals that a farmer might raise. List them on the board. Students could list livestock such as cattle, sheep, or pigs as well as plants such as wheat, corn, fruits, and vegetables.
- Using the list on the board, ask students if there are any specific traits a farmer would want to have in their plants or animals. Allow students time to think about the question and then give them an example. For example if they named a strawberry farmer in step 2, explain that strawberry farmers want their strawberries to be juicy, sweet, and medium sized. Each of these characteristics are traits that are influenced or determined by the plant's genetics. After giving the example, see if students can think of any more traits for the remaining farm crops or livestock.
- Explain that farmers use their knowledge of inherited traits to try to produce the best product.
Activity 1: The Friar Who Grew Peas
- Discuss the information found in the Background Agricultural Connections section of the lesson. You may want to use the PowerPoint “Peas in a Pod” or excerpts from the book Gregor Mendel: The Friar Who Grew Peas by Cheryl Barbadoe.
- Make a Punnett square model on the board to illustrate the results of Mendel’s experiments with pea plants. Yellow pompoms represent the dominant gene for yellow seeds and green pompoms represent the recessive gene for green seeds. Use two yellow pompom magnets for Parent 1 and two green pompom magnets for Parent 2. In this case, we are crossing two parents with purebred traits. When a purebred pea plant with yellow seeds is crossed with a purebred pea plant with green seeds, there is a 100% probability that the offspring will have yellow seeds. If this F1 generation (the first filial generation resulting from a cross between the first set of parents) is crossed, the results will be different.
- Discuss the meaning of the Punnett square with the students. Write the following on the board to explain how dominant and recessive genes are expressed: When two dominant genes are present, the dominant gene will be expressed. When a dominant and a recessive gene are present, the dominant gene will be expressed. When two recessive genes are present, the recessive gene will be expressed.
- Make another Punnett square model on the board to illustrate the F2 generation (the second filial generation resulting from a cross between two individuals from the F1 generation). Use one yellow and one green pompom magnet for Parent 1 and one yellow and one green pompom magnet for Parent 2. In the F2 generation, we are crossing two parents with hybrid traits. When a hybrid pea plant with yellow seeds is crossed with another hybrid pea plant with yellow seeds, there is a 75% probability that the offspring will have yellow seeds and a 25% probability that the offspring will have green seeds. It is important to note that in the case of a hybrid, the dominant trait is what will be expressed.
Activity 2: Pompom Punnett Squares
- Fill lunch-size paper bags with 12 yellow and 12 green pompoms. Divide students into groups of four. Provide each student with a Punnett Square activity sheet and each group with a Punnett Square Chart and a bag of yellow and green pompoms.
- In each group, students will take turns being Parent 1 and Parent 2. Each parent will close their eyes and choose two pompoms from the bag. They will then begin creating a Punnett square on their chart by placing their pompoms in the space provided for Parent 1 and for Parent 2. The group will use the remaining pompoms to fill out the rest of the Punnett square.
- Each student will record the results on their Punnett Square activity sheet using a Y to represent yellow seeds and a g to represent green seeds. Underneath each Punnett square, students can record the probability of the offspring having yellow or green seeds.
- This process can be repeated as many times as desired by choosing new pompoms from the bag. Pompoms can be replaced with other props to represent different pea plant traits, such as tall and short pipe cleaners for stem height. Use the “Pea Plant Traits” chart to determine whether the traits are dominant or recessive when creating Punnett squares for different traits.
Concept Elaboration and Evaluation
After conducting these activities, review and summarize the following key concepts:
- Punnett squares are a tool used to predict the traits of an offspring.
- Farmers use their knowledge of genetics and biology to select ideal traits in the crops or livestock that they produce.
- Dominant traits are strongest. They are the traits that will be seen in the offspring.
- Recessive traits are not expressed in an offspring, but they are passed or carried by the offspring.
Use this Pea Plant Breeding movie from the USA Dry Pea and Lentil Council to show students how breeders take pollen from one plant and use it to pollinate another plant's flower to create the desired genetic cross.
Suggested Companion Resources
- How to Extract DNA from Anything Living (Activity)
- First Peas to the Table (Book)
- Gregor Mendel: The Friar Who Grew Peas (Book)
- Bitter/Sweet Cucumber Taste Test (Kit)
- Dwarf "Space Plant" Seeds (Kit)
- Parent/Offspring Cards (Kit)
- Pompom Punnet Square Kit (Kit)
- SpaceLite (Plant Light) (Kit)
- How Mendel's Pea Plants Helped Us Understand Genetics (Multimedia)
- Jr. Sprout - Funky Foods (Booklets & Readers)
- Build Your Own GrowLite (Teacher Reference)
- DNA Learning Center (Website)
- Heredity (UEN Sci-Ber Text for 5th Grade) (Website)
Agricultural Literacy Outcomes
Culture, Society, Economy & Geography
- Explain how agricultural events and inventions affect how Americans live today (e.g., Eli Whitney - cotton gin; Cyrus McCormick - reaper; Virtanen - silo; Pasteur - pasteurization; John Deere - moldboard plow) (T5.3-5.c)
Science, Technology, Engineering & Math
- Identify examples of how the knowledge of inherited traits is applied to farmed plants and animals in order to meet specific objectives (i.e., increased yields, better nutrition, etc.) (T4.3-5.c)
Education Content Standards
K-4 History Standard 8A:The development of technological innovations, the major scientists and inventors associated with them and their social and economic effects.
Objective 6Identify and describe the significant achievements of important scientists and inventors.
NCSS 8: Science, Technology, and Society
Objective 4The ways in which scientific findings and various forms of technology influence our daily lives.
3-LS3: Heredity: Inheritance and Variation of Traits
3-LS3-1Analyze the interpret data to provide evidence that plants and animals have traits inherited from parents and that variation of these traits exists in a group of similar organisms.
Common Core Connections
Language: Anchor Standards
CCSS.ELA-LITERACY.CCRA.L.6Acquire and use accurately a range of general academic and domain-specific words and phrases sufficient for reading, writing, speaking, and listening at the college and career readiness level; demonstrate independence in gathering vocabulary knowledge when encountering an unknown term important to comprehension or expression.
Mathematics: Practice Standards
CCSS.MATH.PRACTICE.MP2Reason abstractly and quantitatively. Students make sense of quantities and their relationships in problem situations. They bring two complementary abilities to bear on problems involving quantitative relationships: the ability to decontextualize—to abstract a given situation and represent it symbolically and manipulate the representing symbols as if they have a life of their own, without necessarily attending to their referents—and the ability to contextualize, to pause as needed during the manipulation process in order to probe into the referents for the symbols involved. Quantitative reasoning entails habits of creating a coherent representation of the problem at hand; considering the units involved; attending to the meaning of quantities, not just how to compute them; and knowing and flexibly using different properties of operations and objects.
CCSS.MATH.PRACTICE.MP4Model with mathematics. Students can apply the mathematics they know to solve problems arising in everyday life, society, and the workplace. Students who can apply what they know are comfortable making assumptions and approximations to simplify a complicated situation, realizing that these may need revision later. They are able to identify important quantities in a practical situation and map their relationships using such tools as diagrams, two-way tables, graphs, flowcharts and formulas. They can analyze those relationships mathematically to draw conclusions.