Have Seeds, Will Travel

Have Seeds, Will Travel (Adapted Project Learning Tree Lesson): A plant is a biological system. Its systems, processes, and components enable it to grow and reproduce. By observing, collecting, and classifying seeds, students are introduced to one aspect of a plant’s reproductive system. 

Materials:

• A variety of seeds 
• Cups or containers (optional)

Background: For a seed to germinate and grow into a mature plant, environmental conditions must be just right. 

• If a seed drops from the parent plant, it might compete with the parents for essential resources and have difficulty growing. Therefore, most seed-bearing plants have developed a way to disperse seeds (and or fruits) away from the parent, giving the new plant a better chance to find what it needs to grow.
• Some plants rely on wind for seed dispersal, many plants depend on animals for seed dispersal, some even eject their seeds away from their parent plant.

What to do:

1. Go out and collect numerous seeds. They can be bird seeds, seeds from the kitchen, or gathered from the outdoors. 
2. Closely examine your seeds and come up with a system for classifying them. 
3. Write down different ways the seeds are dispersed. Here are some example categories of seed dispersal:
   • Floats in the air – dandelion, cottonwood, milkweed
   • Flies through the air – maple, ash, tulip, poplar
   • Floats on water – mangrove, cranberry
   • Bounces or rolls – acorn, tumbleweed (whole plant rolls)
   • Eaten by animals – cherry, peach
   • Stored by animals –  acorn, beech, hickory
   • Sticks to animals – burdock, Queen Anne’s lace
   • Thrown – locust, lupine, witch hazel
4. Group your seeds according to dispersal categories. 
5. Answer some of the following questions:
   • How do seed’s shape and size affect dispersal?
   • What other parts of the plant help it to reproduce?
   • Why is it important for seeds to be dispersed in different ways?
   • How far can seeds be dispersed? (seeds can glide on the wind for several miles, float on water for hundreds of miles, or travel with a bird for thousands of miles.)
   • Can some seeds go further than others? How is distance important? (reduces competition for a plant’s needs in a particular area. Widespread plants increase species’ chances of survival.)
   • What value might seed dispersal have for plants, wildlife, and humans?

Enrichment:

• Plant some of the seeds you collected so you can observe plant germination.
• Design your own seeds with specialized dispersal mechanisms (you can use toothpicks, cotton balls, string, rubber bands, and add these to collected seeds to make a new seed design.) 
• Drop seeds in front of a fan and note differences in movement, direction, speed, and rotation. You can graph the distance each seed traveled. 
• Not all plants reproduce from seeds. Research to find out about other plants (ferns, mosses) and other species (fungi, algae) that don’t bear seeds and generally use spores or buds. Compare the reproductive system of such species to those of seed bearing plants.