Agricultural Literacy Curriculum Matrix
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Inherited Traits in the Living Corn Necklace (Grades 6-8)
6 - 8
Students will observe the growth of Indian corn and popcorn seeds, observe similarities and differences between the two varieties, and discuss heredity.
- Pictures of crop plants
- Pictures or ears of dried popcorn and Indian corn
- Cotton balls, 1 per student*
- Small plastic jewelry bags, 1 per student*
- Popcorn seeds, 1 per student*
- Indian corn seeds, 1 per student*
- Necklace-length piece of yarn, 1 per student*
- Water, 1 cup per group
- Permanent markers, 1 per group
- Hand lenses, 1 per student or pair
- Metric rulers, 1 per student or pair
- Pictures of mature popcorn and Indian corn plants
- We’re Expecting... activity sheet, 1 per student
*These items are included in the Living Necklace Kit, which is available for purchase.
Essential Files (maps, charts, pictures, or documents)
tassel: the male part of a corn plant that emerges from the top of the plant and bears many small flowers that release pollen grains
self-pollination: transfer of pollen from the male part of a flower to the female part of that same flower or another flower on the same plant; in corn this rarely happens in the field, but it may be done by plant breeders to develop desired traits
open-pollination: pollination that occurs naturally without human interference; open-pollinated varieties are developed simply by saving seed from the most desirable plants, resulting in high genetic diversity among offspring
hybrid: produced by cross-pollinating two different inbred parent plants; plants are high-yielding and vigorous but results of saving seed are unreliable
ear: female part of a corn plant that contains the cob, the silks, and the eggs that will become kernels
kernel: the seed of a corn plant and the part that we eat
cross-pollination: transfer of pollen from one plant to another
Background Agricultural Connections
Interest Approach – Engagement
- Remind students about the similarities and differences among humans that come from inherited traits. Ask students to list various inherited traits.
- Ask students if plants have traits that are inherited through their genetics just like humans. Tell your class that you are going to investigate the genetic variation present in plants.
Activity 1: Trait Variation
- Remind students about the similarities and differences among humans that come from inherited traits. Tell them that the class is now going to investigate the amount of variation present in crop plants.
- Divide students into groups and provide each group with a picture of a field of crop plants, such as corn, beans, etc. Ask each group to make a chart of the similarities and differences they can see between plants in the pictures. Discuss how the amount of variation they observe compares to the amount of variation that can be observed in humans. As a class, brainstorm reasons why farmers might not want variation among plants they grow to produce crops.
- Show each group of students an ear of dried popcorn and an ear of Indian corn. If you do not have ears of corn available, you can use pictures or have students compare all of the popcorn seeds and all of the Indian corn seeds that will be used in Activity 2.
- Ask each group to make a chart of similarities and differences between the kernels on an ear (each kernel is an individual offspring of the plant that produced the ear). As a class, discuss their observations. Discuss the possible sources of variation (sexual reproduction, open pollination). Also compare the traits of the two corn varieties.
- Explain to the students that in general, it is easier for farmers to manage uniform crops. For example, most corn is harvested using a machine called a combine. All of the corn is harvested at the same time, so it is best if it all matures at the same time. However, sometimes variation is desirable. Indian corn is used mostly for ornamental purposes, so variation in the color of the kernels is desirable.
Activity 2: Living Corn Necklace
- Tell the students that they will continue their investigation of corn by observing how corn seeds germinate and begin to grow. They will observe two varieties, Indian corn and popcorn, that have been selected over time for different traits.
- Provide each student with one popcorn seed and one Indian corn seed. Ask each student to begin his or her corn journal by drawing a picture of each seed and writing several sentences to describe it.
- Provide groups with the materials needed for each student to make a “Living Necklace” (plastic jewelry bag, cotton balls, and yarn), permanent marker(s) and a cup of water. Use the Living Necklace Tutorial, or simply direct students to make their necklaces as follows:
- Use the permanent marker to label one side of the bag P and the other side I.
- Dip a cotton ball in water so that it is thoroughly wet but not dripping. Excess water will cause the seeds not to sprout.
- Place the cotton ball in the small plastic bag.
- Put one popcorn seed on the side of the cotton ball facing the label P.
- Put one Indian corn seed on the other side of the cotton ball, facing the label I. The labels will help students remember which seed is which.
- Seal the bag. String the yarn through the hole in the jewelry bag. Tie a knot in the end of the string to form a necklace.
- Bags can be hung from tacks on a bulletin board and taken down for student observations.
- Teaching Tip: The corn seeds will sprout in three to six days. Starting on a Friday and making the first observations on Monday will speed up this activity.
- For one week have students record in their journals the changes they observe in their seeds, including information about observable traits such as: number of days from “planting” until the root and the shoot can be seen; root and shoot lengths and color; and number of leaves and roots.
- Use hand lenses to observe the roots and shoots as they emerge and grow.
- Use rulers to measure the length of roots and leaves as they grow.
- Teaching Tip: It is difficult to take the seedlings out of the bags and get them back in without breaking the roots. Ask students to measure through the bag instead. The roots will curl, so you may want to suggest measuring them in sections and estimating as necessary.
- In small groups, have students make charts or graphs of the data they collected for measurable traits (leaf and root length). Ask them to look for differences between the popcorn and Indian corn.
- As a class, discuss how each group compared their data for popcorn and Indian corn. Which kinds of charts or graphs worked the best? Were there noticeable differences between the popcorn and Indian corn seedlings?
- Discuss how plant breeders control inheritance and work to develop seeds that will reliably express desired traits. Popcorn has been selected for different traits than Indian corn.
- Compare the traits of the corn seedlings to those of mature corn plants (using photographs).
- Use the We’re Expecting... activity sheet to review the difference between cross-pollination and self-pollination and to introduce the concept of dominant and recessive traits.
Concept Elaboration and Evaluation
After conducting these activities, review and summarize the following key concepts:
- Plants inherit specific traits from the parent plant just like humans or animals inherit traits from their parents.
- Farmers use science and genetics to improve their crops.
Assign students to compare similarities and differences in traits among plants of a species growing in the wild and among plants of another cultivated species.
Grow the Brassica butterfly, which lives on Fast Plants®, enabling students to observe the life cycle stages of an insect undergoing metamorphosis from egg to adult butterfly in just 26 days. Brassica butterfly eggs are available from Carolina Science and Math (Item #144100).
Use the lesson plan Peas in a Pod to further explore heredity by modeling the probability of dominant and recessive trait inheritance with the Punnett square.
Grow Fast Plants®, and use the activities in Spiraling Through Life with Fast Plants: An Inquiry-Rich Manual by Robin Greenler to follow germination, growth and development, flowering, and pollination.
Suggested Companion Resources
- Wisconsin Fast Plants® (Activity)
- Four Seasons of Corn: A Winnebago Tradition (Book)
- Living Necklace Kits (Kit)
- America's Heartland: Nebraska Corn Farm (Multimedia)
- How Mendel's Pea Plants Helped Us Understand Genetics (Multimedia)
- Popped Secret: The Mysterious Origin of Corn (Multimedia)
- Garden Genetics: Teaching With Edible Plants (Teacher Reference)
- Native American Gardening (Teacher Reference)
- DNA Learning Center (Website)
- Genetic Science Learning Center (Website)
State Standards for Utah
Grade 7: Science Standard 4Students will understand that offspring inherit traits that make them more or less suitable to survive in the environment.
Objective 1Compare how sexual and asexual reproduction passes genetic information from parent to offspring. Meeting one or more of the following indicators: a) Distinguish between inherited and acquired traits. b) Contrast the exchange of genetic information in sexual and asexual reproduction (e.g., number of parents, variation of genetic material). c) Cite examples of organisms that reproduce sexually (e.g., rats, mosquitoes, salmon, sunflowers) and those that reproduce asexually (e.g., hydra, planaria, bacteria, fungi, cuttings from house plants). d) Compare inherited structural traits of offspring and their parents.
Objective 2Relate the adaptability of organisms in an environment to their inherited traits and structures. Meeting one or more of the following indicators: a) Predict why certain traits (e.g., structure of teeth, body structure, coloration) are more likely to offer an advantage for survival of an organism. b) Cite examples of traits that provide an advantage for survival in one environment but not other environments. c) Cite examples of changes in genetic traits due to natural and manmade influences (e.g., mimicry in insects, plant hybridization to develop a specific trait, breeding of dairy cows to produce more milk). d) Relate the structure of organs to an organism’s ability to survive in a specific environment (e.g., hollow bird bones allow them to fly in air, hollow structure of hair insulates animals from hot or cold, dense root structure allows plants to grow in compact soil, fish fins aid fish in moving in water).
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)
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.
Biotechnology Systems Career Pathway
BS.03.04Apply biotechnology principles, techniques and processes to enhance plant and animal care and production (e.g., selective breeding, pharmaceuticals, biodiversity, etc.).
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.
MS-LS4 Biological Evolution: Unity and Diversity
MS-LS4-5Gather and synthesize information about technologies that have changed the way humans influence the inheritance of desired traits in organisms.