Modify a seed

By Bert Wartski

This activity is set up so that students will try to modify their model seed, so that it conforms to an assigned seed dispersal strategy.

Learning outcomes

Using a dry kidney bean, students will try to modify the bean, so it will have a seed dispersing strategy.

Teacher planning

Time required for lesson

45 minutes

Materials/resources

  • forty index cards
  • pile of junk
  • kidney bean

Pre-activities

You will need to prepare the index cards before the activity. These can be kept indefinitely.

Activities

Teacher Prep

Purpose: using a dry kidney bean, students will try to modify the bean so it will have a seed dispersing strategy.

Introduction: over the years, plants have developed a number of seed dispersal strategies. They disperse their young because it would be unwise for the young to compete with the parent plant for resources. In fact, any seed that landed near the mom plant would not grow. Plants landing far away from mother would survive and reproduce since there would be no competition for light or nutrients. This activity is set up so that the students will try to modify their seed with junk, and so that seed conforms to an assigned seed dispersal strategy.

Seeds can disperse in a number of ways:

  1. Seeds can float in the air or glide: like the maple seed.
  2. Seeds can be carried: like burdocks.
  3. Seeds can be flung: like touch-me-nots.
  4. Seeds can be digested: like apples.
  5. Seed can float: like coconuts.

You will have forty cards made up. Each card will have one of five different dispersal strategies on it. Student groups will pick a card, and using a junk pile, modify the seed so it will satisfy the dispersal strategy. Students will be graded on completeness.

Note: For strategies that do not work, we have the other students in the class vote on the failed solution. This gives the class a fun atmosphere. You may need to emphasize to the students when they are constructing their solutions that some of the seed needs to be exposed and able to touch the ground. This will allow the seed to germinate and grow. If the seed is covered, then the seed will not be able to touch the ground and will not be able to germinate and grow.

Procedure:

  1. Assign student groups.
  2. Groups pick a card with a dispersal strategy.
  3. Groups modify their seeds.
  4. Test the seed dispersal strategies.

Here is what to put on the index cards:

  1. Modify your seed so that it will be carried by something for five meters. The animal that carries the seed must not know that the seed is being carried.
  2. Modify your seed so that it will be flung for one meter away from the parent plant (which, for the purpose of this activity, is you and your group).
  3. Modify your seed so that it will glide or float in the air for two meters when dropped from the top of the parent plant. Remember the seed must be dropped, not pushed.
  4. Modify your seed so that animals will find it desirable to eat.
  5. Modify your seed so that it will float for two minutes despite wind and waves. Make sure that the seed is allowed to germinate (the seed must touch the ground) when it hits land.

Assessment

The strategies are graded pass/fail.

Supplemental information

Comments

The junk is usually dry trash: newspaper, cereal boxes and plastic bottles (dried). You can also add tape, glue, paper, rubber bands or paperclips. This is a fun activity. I usually grade all the activities at the end of class with the class watching.

North Carolina Curriculum Alignment

Science (2005)

Grades 9–12 — Biology

  • Goal 4: The learner will develop an understanding of the unity and diversity of life.
    • Objective 4.03: Assess, describe and explain adaptations affecting survival and reproductive success.
      • Structural adaptations in plants and animals (form to function).
      • Disease-causing viruses and microorganisms.
      • Co-evolution.