Background

Objectives

Students will classify a variety of seeds
Students will dissect a lima or kidney bean to familiarize themselves with the anatomy of a seed.
Students will record their observations through drawings and bar graphs.

Materials

Variety of seeds: pinto, mung, soy, peas, "birdseed", radish, alfalfa, etc.
Large raw kidney or lima beans, enough for 5 seeds per student (3/4 of these should be soaked for 4 hours prior to lesson).
Magnifying lens
Paper
Crayons or markers
Newspaper
Planting soil
Copies of "My Seed!"
Clipboards

Season

Any season

Group Size

Individual learning and group work

California State
Content Standards

L.S. 2.b, 2.e
I.& E. 4.a, 4.b, 4.c, 4.d, 4.e

All wrapped up in one package, a seed provides protection, has stored food with which growth may begin, and has the plant’s next generation inside. Seeds come in many shapes, colors, textures, and tastes. Many animals use seeds as nutrition in their diets. Humans also take advantage of seeds as food such as corn, coconut, grains, and peas to gain proteins, fats and carbohydrates.

The anatomy of a seed is an amazing package to open. The seed’s protective outer layer is called the seed coat. Inside all seeds is an embryo, or new plant. Seeds also contain an embryonic root or shoot. As the embryo begins to grow it uses the stored food called endosperm. Often this endosperm is contained in the cotyledons, or seed leaves. In the case of the bean, the two halves are the seed’s cotyledons.

Seed begin to grow when the embryo is triggered by a stimulus such as water, temperature, movement (scarification), or oxygen. Once a seed begins to grow it is called germination.

There are two main types of seeds monocots and dicots. Monocots have one seed leaf (e.g., corn). Dicots have two seed leaves (e.g., beans). Other differences between monocots and dicots can be observed once the plant has matured. These differences include: flower part arrangement, internal structures, and vein patterns on leaves.

(Note: Seed Sensations was adapted from “Huntington Botanical Garden Programs: Seeds & Sprouts, Seeing Seeds”)

Vocabulary

Seed coat: the protective outer layer of the seed
Root: the part of the plant, usually underground, that uptakes water and nutrients
Seed leaves: also known as the cotyledons, these will “feed” the plant until it develops its new leaves
Seed: the part of a (flowering) plant that may grow into a new plant
Stem: the part of the plant that supports the leaves and transports water and food from the roots to the leaves.

Attention Grabber

Bring in sunflower seeds for students to eat! Make sure you get the whole seed with shell so students can begin to understand the shell is the seed coat. (Note: the shells can go into your compost pile!)

Garden Activity

Part 1-Seed Classification

In groups, students will talk about the similarities and differences of the seeds in their pile. Ask the class to share these characteristics (write these descriptive words on the board).
Have students sort the seeds into groups based on their characteristics. Start with color as a class (red, brown, green), and then have students come up with their own groups.

Part 2 Seed Dissection

Start by asking, “What will this seed grow into? What might you find inside the seed?” Pass out dry, raw (not soaked) kidney or lima bean to each student. Students should draw their prediction of what the seed will look like inside.
Allow students to use magnifying lens to examine the outside of the seed. (Any cracks or bumps? Any small spots that look like a hole? – All should have this spot; it is where the new plant will emerge.)
Pass out wet, raw (soaked) kidney or lima bean to each student. Allow students to use magnifying lens to examine any differences. Remove the “skin” or seed coat. Gently pry the seed in half and draw what is inside. Help students to find the root, shoot with new leaves, and the cotyledons, or seed leaves. Explanations of these parts can be done as a class or individually.
Use a pattern to create a model of a seed!
Time to sprout the seeds! Using the kidney or lima beans, soak a paper towel with water and place in a Petri dish (or other dish). Each student should try to sprout his or her own seeds. Have the students write down the day that the root comes out of the seed, the root grows longer to become a stem, and the leaves begin to form on the stem. Make a bar graph using this data with Seed Cycle on the x-axis and Time on the y-axis.
When the seeds have sprouted leaves and all information has been recorded, the students can plant them in the garden and watch them grow!

What's Next?

Students can use extra seeds, peanut butter and an empty toilet paper roll to make bird feeders.
Allow students to plant the other seeds in biodegradable cups. The students can bring this home, keep them in the greenhouse, or classroom!
Use the extra seeds to make mosaic art.

Download Materials

Student Worksheets

My Seed