Lesson Plan: Methods of Seed Dispersal

This is a lesson plan to help students learn about different methods of seed dispersal. Students will begin by observing how dandelion seeds travel in the wind. They will then learn the 3 main methods of seed dispersal, and then participate in an experiment to determine the method of dispersal of various seeds.This lesson plan is geared towards the fourth grade, however, it may be used in a 3rd or 5th grade classroom or adapted to suit younger or older students.

Grade: 4

Pre-Requisite knowledge: Students will already have basic knowledge of plant parts and how a plant forms from a seed.

Objective: Students will understand the different methods seed dispersal occurs through.

Standards: NYC Science Standard S2 Life Science Concepts

Rationale: This lesson is part of the New York City K-8 Science Scope and Sequence as well as the New York State Standards.

Procedure:

Initiating Activity

Begin by showing the class a dandelion that is ready to spread its seeds. Ask if anyone has ever picked a dandelion and blown its seeds. Then pass around dandelions to the class and let them try blowing the seeds. Hold a dandelion against a fan and turn it on. Observe how far the seeds travel. Explain to the class that traveling by wind is just one way seeds can travel so that they can grow up far away from the parent plant.

Lesson Development:

As a class, brainstorm ways plants' seeds can travel. Start the slideshow of seed pictures (explained in the materials section) on the Smart board, and make a list on the chalkboard.

1. Start with the category of wind. Talk about how wind is a way that seeds travel. Ask children to examine a dandelion seed for a minute, and turn to the slide of a picture of a dandelion seed. Then ask them what properties they think helps it travel by wind.

2. Next talk about animals dispersing seeds. Animals help disperse seeds in two ways. Ask students if they can think of the two ways. Turn to the next slide and ask students to look at the picture of an apple with its seeds inside. Tell them that animals eat the fruit, seeds and all, and the seeds go through their digestive system unharmed. They then come out and can form new plants. Next ask them to look at the picture of the burdock seed. Have them take note of the hooks on the ends, and tell them how Animals also can help disperse seeds in other ways, such as when a squirrel buries and acorn and forgets about it and then it germinates and forms a new tree. Tell them that they can even help disperse seeds if one gets caught on their clothing and then falls off somewhere.

3. Next talk about how some seeds travel by water. Turn to the next picture in the slideshow, a coconut. Ask if they knew that a coconut is actually the seed of the plant. Ask children to guess what property it might have that makes it able to travel by water (it floats).

Coached practice:

Pass out pieces of construction paper to each student and have them choose a plant that was talked about in class. Have them draw its seeds being dispersed, for example, a dandelion's seeds flying in the wind, or a squirrel burying an acorn.

Conclusion:

Hand out seeds to each table. Seeds should include sycamore seeds, acorns, milkweed seeds, apple seeds, burdock seeds, and any other easily accessible seeds. Ask kids to hypothesize what method each seed might use to disperse. Then pass out a container of water and a washcloth to each table. Have them test their theory by seeing if each seed floats in the container of water, sticks to the cloth, or floats in the air when they blow it. If the seed is contained in a fruit, they can hypothesize that it spreads by animals eating the fruit. Let them know that a seed can have more than one way of spreading.

Timetable:

This lesson will take one to two class periods.

Homework Assignment

Students must choose a type of flower or plant and research how its seeds spread. Write a short paragraph describing the process.

Assessment

Pass out the second handout. Ask students to list special properties different seeds may have that allow them to disperse.

Extension

Have students write a paragraph about why they think plants need their seeds to travel away from the parent plant.

Materials and Equipment

Dandelions

Sycamore seeds, acorns, half an apple, milkweed seeds, and other various seeds

Slideshow for Smartboard: pictures of a dandelion seed, apple with seeds, burdock seed, acorn, coconut

A container of water and washcloth for each table