Cycles - Seed Dispersal

Focus: An important part of the life cycle of many plants is the dispersal of ripe seeds to new locations, and this is accomplished in a variety of ways.

Puppets (Mary Maple Seed (on a dowel so she spins), Mama Maple Tree, Milkweed Seed, Carol Cranberry, Charlie Chipmunk, Maple Seedling)

Materials Checklist
See Inside a Seed (unshelled peanuts or soaked lima beans or other big beans, hand lenses, seed anatomy chart)
Puppet show (puppets, sign saying, "Next Spring ...", script)
Mix and Match (seeds taped to 3" x 5" cards, matching seed-bearing structures, optional hand lenses)
Milkweed Race (milkweed seeds)
Seed Scavenger Hunt (Seed Hunt cards, collecting bags, old wool sock tops or sweater sleeves, hand lenses)
Fruit and Nut Snack (a variety of fruits and nuts)
Seed Sketches (5/6 ELF) (Seed Sketch sheet, pencils, erasers, hand lenses, variety of seed cases, optional clipboards)

Supplementary Reference Materials (Seed Dispersal song, Seed Hunt cards, Common Seed Travelers, Lima Bean parts, Lima Bean Information, 5/6 ELF Activity: Seed Sketches, Sketch sheet and examples)

Additional Reading/Resources
How Seeds Travel, by Cynthia Overbeck, Shabo Hani, and Cynthia Bix, Lerner Press, Minneapolis, MN, 1982.
Faith in a Seed: The Dispersion of Seeds and Other Late Natural History Writings, by Henry David Thoreau, Shearwater Books, Washington, DC, 1993.
Check out Wayne's Word website for nice articles on botanical trivia and natural history notes.

For Younger Children
Many of the activities in VINS's new Small Wonders book can be used in ELF, too. To find appropriate activities for children aged 3-6, click here.

Teaching suggestions

See Inside a Seed
Instead of or in addition to peanuts in this activity, you can use large (Fordhook) frozen lima beans, freshly thawed.

If the light isn't very good, it's hard to see the various lima bean parts, especially the plumule, which has nice little leaf veins. They can easily be stained with a water-based ink like in a Pilot pen or a Crayola marker.

Mix and Match
Bring a coconut and aquarium to show how it floats, also cranberries to float.
Put burdocks and cattails in plastic bags to avoid mess.
Bring in magazine pictures or field guides that show the different plants in bloom.
For younger students, use fewer types of different seeds and pods so kids don't get overwhelmed.
Spread the cards with seeds out across a big table. Hand each student a seed head card and have the kids work in pairs to match their seed heads with the correct seed. Label the back of all cards so kids can doublecheck their matches.

Milkweed Race
Test wind direction before beginning this activity so you can mark start and finish lines accordingly.

If it is wet outside, bring pods in a day or two ahead of time so they can dry out.

Seed Scavenger Hunt
Give each team a paper bag and have them collect different kinds of seeds and seed heads. Then regroup and spread out a sheet. Have each group share their finds and talk about strategies for dispersal. Then read tasks from Seed Scavenger Hunt list and have children point out each kind.

You can end this activity by having kids shake, blow on, or toss a seed head to help with dispersal.

Assign each team one type of dispersion method for collecting seeds (hitchhiker, wind, spring loaded, animal).

Fruit and Nut Snack
In cross section you can see where the three rows of large seeds grow in wild bananas.

Volunteers with knives and cutting boards can do this in stations, two or three fruits each.

5/6 ELF Activity – Drawing Seeds
The drawing activity and template uses the term “seed case,” but this can confuse students if the seeds aren't actually encased. The term “seed head” may be preferable.

Extensions
-Ahead of time, send a note asking kids to collect seeds at home to bring in on ELF workshop day. Then sort these according to how they're dispersed.
-From Outdoor Biology Instructional Strategies: Challenge students to work in small groups to modify a seed in one of the following ways: to fly at least three feet, to float on water, that can be thrown by some mechanism at least two feet, to hitchhike on an animal, to attract a bird or other animal. Provide bean seeds, construction paper, tape, rubber bands, balloons, plastic bags, pieces of cork, cotton or feathers, small metal springs, colored pencils, and other craft materials.
-Put confetti in a balloon and blow it up. Then, pop the balloon with a pin to demonstrate (sort of) how seeds might be dispersed from an explosive seed pod like jewel weed.

REMEMBER: Set up bird feeders with this unit, so they'll be in place for January's Fly Away or Stay? unit. You can put some seeds on the feeders.

Seeds' Needs - one group started seeds in plastic bags with damp paper towels - beans, bean soup mix, sunflower seeds.

You might want to mention the efficient seed dispersal of invasive plants. For example: Purple loosestrife can produce 3 million seeds per plant. These seeds have high germination rates, but can go dormant for 3 years if necessary. Seeds travel by wind, water, and in mud transported by people, birds, and animals. Pieces of loosestrife roots and stem can also regenerate into new plants. Flooding, which can kill other plants, does not seem to affect loosestrife, except to transport its seeds more widely. For more, see the Vermont Agency of Natural Resources website and the slide show therein.

Learning Goals

Concepts/Ideas:

• A seed contains an embryo that will develop into leaves, stem, and roots.
• Plants have different strategies for the dispersal of seeds by wind, water, or animals. Seeds can travel great distances from their parent plants.
• There are many varieties of seeds and seed-bearing structures.
• Humans contribute to seed dispersal in a number of ways.

Vocabulary: Cycle, Seed, Dispersal, Embryo, Ovary, Seed coat, Cotyledon, Plumule, Hypocotyls, Radicle, Leaf, Stem, Root

Skills:

• Examining a seed with a hand lens and naming the parts of a seed using a diagram.
• Comparing and contrasting some of the different strategies plants have for the dispersal of seeds.
• Testing how far a seed can travel.
• Searching for and observing a variety of seeds and seed-bearing structures outdoors and discussing how they are dispersed.
• Dissecting fruits humans eat to see where seeds are. Discussing the role of humans in seed dispersal.

Grade Expectations:
Grades PK-K (S30, S38) A seed comes from a living plant; it has parts that will grow into a new plant when it is exposed to water and sunlight. Seeds are food for people and other animals.

Grades 1-2 (S30, S31) Plants develop from seeds produced by 'parent' plants. Plants have mechanisms that disperse the seeds. Wind, water, and/or animals may help disperse seeds.

Grades 3-4 (S30, S38, S39) A seed contains an embryo that will develop into leaves, stem, and roots when it gets adequate water, warmth and light to grow. There are many different kinds of seeds; they may be grouped according to similarities in structure.

Grades 5-6 (S31, S38) Seeds are produced by flowering plants. The structural characteristics of a seed directly relate to the way it is dispersed.

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