- Students will understand how seeds are dispersed.
Wind, water, and animals are all helpful in dispersing seeds. This is important so that plants will have enough space, sunlight, water, and nutrients to grow. Light seeds are blown by the wind to new places. Other seeds are moved by running water, and sticky seeds or seeds with hooks get stuck to the hair or skin of animals and get moved to new places before they fall off. Still others that are located inside the fruit are eaten by animals, pass through the animals’ digestive tracts, and are deposited in other locations.
- Notebooks and pencils
- Worksheet 1: Whirlybird
- Paper clip
1.Using the background information above, discuss seed dispersal with the students.
2. To show how seeds are dispersed by the wind, make a paper “whirlybird,” using the pattern provided in Worksheet 1: Whirlybird, scissors, and a paper clip. Cut on the dashed lines only; fold on the solid lines, following the directions. Have the students drop the whirlybird to demonstrate how a seed is carried by the wind.
3. Collect some seeds and see if the students can tell how they would be dispersed.
1. Planting Seeds
Plant some seeds and watch them grow. The students can keep a record of their growth. By putting some in sunlight and some in a dark place, you can show that plants need light to grow. Collect seeds from fruits and vegetables. Label the seeds and add them to your collection. Plant some of them, too.
2. Planting Trees
Plant some indigenous seedlings and saplings around the school. As the trees grow, watch for changes in the bark and branches. At what height do the branches begin? What animals do you see using the trees and what are they being used for? How do people use trees? (For firewood and making charcoal, for example). What happens if trees are overused by people?
3. Seed Dispersal Game
- 4 blindfolds
- bag with painted stones or crumpled up pieces of paper (so they don’t blow away) in two different colours
Students will laugh a lot and giggle throughout this. Smile and laugh along with them! It’s FUN!
Explain the important role of animals as seed dispersers in African forests and grasslands. In short, animals eat seeds, the animals’ digestive process removes tough seed coats, and the animals defecate (or poop) in an area far from the parent plant, leaving the seed in a pile of rich fertiizer where it can germinate and grow. Some birds pick through the dung of other animals and eat seeds that they find.
1. Mark off an area in which to play the game. Within that area, mark off two smaller areas to represent fertile areas.
2. Choose four children to be seed dispersing animals. Choose two as antelopes (gazelles) that poop in a pile, marking their territories, and two as zebras that drop their poop as they walk along.
3. Give each of these students a bag of stones or crumpled up paper. Give the two gazelles one colour, the two zebras the other. Tell them this represents their poop.
4. Blindfold those four students.
5. Have the rest of the students be observers. They should stand around the game area to make sure the blindfolded students stay within the game area.
6. After you move them around a little within the area, the four blindfolded students walk around the area, pooping three times. The gazelles drop a handful of stones all at once, the zebras drop them one at a time.
7. When they’ve finished, choose a student to be a hornbill. The hornbill picks up five stones or pieces of paper and randomly drops them again.
8. Count the number of stones that fell in the fertile areas. If possible, you can replace each one with something that looks like a plant or a marker to show how many can germinate. Count the number of stones/papers that fell in the infertile areas and compare. Discuss.
Discuss the importance of animals and birds as seed dispersers. For example, if all the seeds of a tree or plant fall under the tree, they won’t have a good chance of survival: they’ll be shaded by the tree, won’t get enough sunlight or space to grow. Animals and birds help carry the seeds far from the parent plant, where they may have a better chance to grow.