National Agricultural Literacy Curriculum Matrix
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6 - 8
Students will learn about two types of plant propagation – seed planting (sexual) and stem cuttings (asexual) and recognize the genetic differences in these processes, as well as the advantages and disadvantages of each method.
- Seed to Seed 101 handout
- Internet access
- Seeds (soybean seeds and corn kernels work well but any seed that sprouts will do!)
- Jeweler size plastic bags (these can be purchased from craft stores, online or might even be free from a jewelry store)
- Cotton balls
- Hole punch
- Yarn or string
- Clean scissors
- Soil or potting mix
- Planting pots
- OPTIONAL: The Living Necklace Kit, see companion resources
Essential Files (maps, charts, pictures, or documents)
tassel: the mail part of a corn plant which is found at the top
silks: the female parts of the corn plant which are found in the shoot that will develop into the ear of corn
Background Agricultural Connections
Interest Approach – Engagement
- Tell students to look around the room. Ask students:
- "What differences do you see in your classmates?" (hair color, eye color, skin color, height, foot size, etc.)
- "Why don’t we all look the same?" (genetics from our parents)
- "Why don’t you look identical to your siblings – you have the same parents?" (Each parent only passes on half of their genetic information. So siblings receive different combinations of their parents’ genes)
- Display a variety of seeds and/or seed packages and ask students to contemplate what these seeds have in common with humans and genetics. Have students share their thoughts.
Session 1: Sexual Reproduction - Seed Genetics
- Inform students that seeds are the offspring of plants. Just like a human baby, a seed contains genetic information from a male parent and a female parent.
- Instruct the students to read Seed to Seed 101. Inform students to think about the steps in the process of seed formation as they read. After students are finished reading have them record in their notebook or a journal, using words and pictures, how a plant produces a seed.
- Have students (working in teams or individual) select a seed and research (using the internet or print resources) the flower structure of the specific plant the seed belongs to. Instruct students to diagram and describe how the specific plant produces a seed. As the teacher, you can model what you want students to diagram and describe using the Background information on corn. Have students share and compare their results.
- Instruct students that they will be planting their seed and observing how the embryo inside the seed develops into a plant that contains the genes from its parents.
- Model the steps below:
- Punch a hole in the top of a small jewelry sized plastic bag.
- Dip a cotton ball in water. Give the cotton ball three “flat” squeezes to remove excess water.
- Place the cotton ball inside the plastic bag.
- Place two seeds in the plastic bag, one on each side of the dampened cotton ball.
- Tie a string or piece of yarn through the hole punched in the top of the plastic bag. Wear the string and bag like a necklace.
- DO NOT close or seal the plastic bag – the seed needs air to sprout!
- The seeds should soon swell up from the moisture and germination should take place in about three days.
- Assist students making their necklaces and encourage them to wear them.
- Each day have students record in their journals the changes they observe in their seeds. Review the reproduction process and have students use their knowledge of genetics to hypothesize how closely the new developing plants would resemble their parents.
- Once one of the seeds has germinated, remove the other seed. There is only enough room and moisture to support the growth of one seed.
- The seed can be transplanted into soil by cutting off the bottom of the bag, pulling out the germinated seed (cotton ball and all), and transplanting to a container with soil.
Session 2: Asexual Reproduction – Stem Cuttings
- Ask students to list as many differences and similarities between plants and humans. Have students work in teams or individually to record these items in a Venn Diagram or other graphic organizer.
- If it is not brought up (which it probably won’t be!) ask students if humans can regenerate body organs. Ask students:
- If you cut off your finger, does a new one grow back? (NO!!)
- If you cut your toe, does a new toe sprout where the old one was cut? (NO!!!)
- Explain that plants are able to generate a new plant from just a small piece of stem, leaf, or other plant tissue.
- Use the Background information to explain the process of asexual reproduction (AKA vegetative propagation). Have students work in teams or individually to list the similarities and differences between this asexual reproduction method and the sexual reproduction method (seeds!) that they learned about previously. Once again a Venn Diagram or other graphic organizer works well.
- Prompt students to compare the genetic differences in the offspring of a new plant produced from a seed (sexual reproduction) and a cutting (asexual reproduction).
- Is the new plant produced from a seed genetically identical to its parents? (No – it is a combination of genes from both parents)
- Is the new plant produced from asexual propagation genetically identical to its parents? (YES – no genetic variation exists because the new plant is coming entirely from one “parent” or “stock” plant.)
- Inform students that they will be creating new plants that are genetically identical to a parent plant. Model the steps below:
- Fill a small container (2 inch pot or small cup with holes in the bottom) with potting soil.
- Find a section of plant stem that is 4 inches long and has about 2-4 leaves.
- Find a node on this section of stem. A node is where the leaf attaches to the stem. This is where new roots will form so the cut will be made just below the node.
- Using a clean, sharp scissors, cut the stem about ½ inch below a node at an approximate 45 degree angle. The angle increases water intake for the cutting.
- If there is a leaf at the node you cut below, gently remove it.
- Place the cutting in the container with soil. The roots will form from the bottom node, so be sure that the node is below the surface of the soil and the remaining stem and leaves are above the surface of the soil.
- Water the soil immediately. Apply water until you can see it flow out the holes in the bottom of the container. Place the container with the cutting in bright, indirect sunlight.
- Monitor the cuttings daily – make sure they are moist (not soaking wet) and receive plenty of light. Each day have students record in their journals the changes they observe and monitor root growth. Compare this development to their seeds. Review the reproduction process and have students use their knowledge of genetics to hypothesize how closely the new developing cutting resembles its parent. (It will be exactly the same!)
Concept Elaboration and Evaluation
After conducting these activities, have students:
- Define asexual propagation and also sexual propagation.
- Challenge the students to list and describe the benefits and challenges to using each techniques in food production.
- Have students hypothesize as to why farmers and agriculturalists use seeds (sexual reproduction) for growing crops like corn, soybeans, wheats and oats, but use cuttings (asexual propagation) for growing fruits like grapes, apples, strawberries and blueberries. Students can record their thoughts in their lab notebook or you can facilitate a class discussion.
Suggested Companion Resources
- Seed, Soil, Sun: Earth's Recipe for Food (Book)
- The Story of Seeds (Book)
- Living Necklace Kits (Kit)
- Crop Modification Techniques (Poster, Map, Infographic)
- Parts of a Flower Poster (Poster, Map, Infographic)
- Genetic Science Learning Center (Website)
Agricultural Literacy Outcomes
Science, Technology, Engineering & Math
- Describe how biological processes influence and are leveraged in agricultural production and processing (e.g., photosynthesis, fermentation, cell division, heredity/genetics, nitrogen fixation) (T4.6-8.b)
Education Content Standards
Plant Science Systems Career Pathway
PS.02.02Apply knowledge of plant anatomy and the functions of plant structures to activities associated with plant systems.
PS.03.01Demonstrate plant propagation techniques in plant system activities.
MS-LS1 From Molecules to Organisms: Structures and Processes
MS-LS1-4Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction of animals and plants, respectively.
MS-LS3 Heredity: Inheritance and Variations of Traits
MS-LS3-2Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation.
Common Core Connections
Speaking and Listening: Anchor Standards
CCSS.ELA-LITERACY.CCRA.SL.2Integrate and evaluate information presented in diverse media and formats, including visually, quantitatively, and orally.