Seed Scatter
Focus Question
How are seeds distributed?
Activity Synopsis
Students will discover seed dispersal methods of common coastal plants while playing a board game.
Time Frame
1 hour
Student Key Terms
· seed
· wind
· water
· disperse
· vector
· ovule
· stamen
· pistil
· ovary
Objectives
The learner will be able to:
· Name methods of seed dispersal used by common coastal plants.
· Classify a few common coastal plants according to their habitat.
First Grade Standards Addressed
Science Standards
IA1a, IA4a, IB1a, IIA2a, IIA2c, IIC1a
Background
Relevant pages in:
Keener-Chavis, Paula and Leslie R. Sautter. 2002. Of Sand and Sea: Teachings from the Southeastern Shoreline. S.C. Sea Grant Consortium, Charleston, SC, Chapter 4 Coastal Ecosystems.
Key Points
Key Points will give you the main information you should know to teach the activity.
· Common methods of seed dispersal include wind, water, and distribution by an animal vector.
· The cabbage palmetto is the state tree of South Carolina. Birds, mammals, and water distribute its seeds.
· The live oak is a common tree in the Lowcountry of South Carolina. Birds such as turkey, bobwhite, and grackles, and mammals such as squirrels distribute the acorns.
· Winged loblolly pine seeds are distributed by the wind. Songbirds and fox squirrels also help the pine distribute its seeds.
· Water, as well as birds distribute Spartina seeds.
· Many coastal residents and visitors are familiar with the prickly seeds of the dune sandspur. The seeds are spread by hitching a ride in the fur (or bare skin!) of a mammal.
Detailed Information
Detailed Information gives more in-depth background to increase your own knowledge, in case you want to expand upon the activity or you are asked detailed questions by students.
Two groups of plants, the gymnosperms and the angiosperms, produce seeds. The gymnosperms include pine trees. Angiosperms are flowering plants.
For simplicity, we will look at the pine tree as representative of the gymnosperm group. Each tree produces both male cones and female cones. The female cones are the ones that are most noticeable and that some people collect to decorate their homes. Male cones are much smaller and are often overlooked. One top of each scale of the female pinecone, two ovules are produced. As they develop, they produce a sticky substance, nutrient tissue and an egg cell. The pollen grains develop on the male cones. The pollen is then blown by the wind to the female cones. Most of us are very familiar with this process, as every year cars, houses, and plants are covered with a yellow dusting of pine pollen! The pollen then gets caught in the sticky fluid produced by the ovule and a pollen tube extends from the pollen grain into the ovule. Then, a sperm swims down the pollen tube to the ovule and fertilizes the egg cell. A zygote is formed and the zygote develops into an embryo.
The flowering plants, or angiosperms, also make seeds. Flowers are the reproductive organs of the angiosperms. Plants with large, showy flowers often use insects as a vector for pollen dispersal. Plants with small, nondescript flowers, such as grass, usually depend on the wind to distribute their pollen grains. The reproductive organs are located inside the flower. The male organ, the stamen, is where the pollen grains form. In turn, sperm develop inside the pollen grain. The female reproductive organ, the pistil, is made of a stigma where the pollen grains land, a stalk-like style, and an ovary. The ovary is the swollen base of the pistil where the ovules are formed. As the ovule develops, eggs are produced. As alluded to earlier, pollen is moved by wind, or by insects, birds or mammals. The pollen grains land in the stigma, the pollen tube grows down through the style and into the ovary until finally it reaches the ovules. Again, the sperm travels down the pollen tube and fertilizes the egg. Pollination is the transfer of pollen grains from the stamen to the ovule. The embryo contains cotyledons, a stem and a root. The embryo is protected by the seed coat and has a supply of food called endosperm. Following germination, the embryo uses the endosperm until it has the ability to produce its own food. The seeds grow within the ovary and as the ovary grows larger it becomes a fruit. Any food containing a seed is a fruit! It is a common misconception that fruits such as tomatoes, squash, zucchini, and beans are actually vegetables.
Seeds are moved from the parent plant when: (1) the fruit is eaten and the seeds are dropped elsewhere, (2) the seeds are eaten with the fruit and then dispersed in the animal’s feces (a perfect pile of fertilizer for a growing plant), (3) by wind, (4) by water, or (5) by hitching a ride on fur or clothing!
Procedures
Materials
· Copy of the game board
· “Seeds”
· Copy of dispersal method cards
· Game pieces (the teacher can use any available material)
· A game spinner with four slots (labeled 1,2,3, and “Scatter your Seeds”)
Procedure
- Begin by asking the students to brainstorm ways that seeds might be distributed. Have they ever blown the “white fuzz” from a dandelion? They were actually helping to distribute wind-blown seeds! Could seeds be distributed by water? If so, would it be important for the seed to be able to float? Why? Who likes to eat apples, oranges, plums, etc.? Do you eat the seeds? Do you think animals eat the seeds? Explain to the students that animals will eat the same part of the fruit that we do, and then drop the seed – and then they’ve helped the plant distribute seeds! Some animals actually do eat the seed, and then the seed is distributed in the fecal matter. What a lucky beginning for the plant – a perfect landing in a nice pile of fertilizer!
- Tell the students that we will play a game to learn about seed dispersal of some common coastal plants.
- Show the students the sketches of the plants. Who has seen a palmetto? A live oak? A pine tree? A sandspur (students will most likely only be familiar with the seed of this plant)? Spartina or marsh grass? The cabbage palmetto is very important in our state – it is our state tree!
- Explain the methods of seed dispersal used by these plants.
- 5 students may play the game at a time. Give each player a dispersal method card. (Note: If you’d prefer the whole class play, project a copy of the game board on the overhead projector. Assign each student a dispersal method and have him or her get into small groups – all waters together, all raccoons together, etc. Each time, allow a different student in the group to spin. You may distribute one cup per group to hold the seeds.)
- Explain the dispersal cards. The student will represent a squirrel, a raccoon, a bird, wind, or water. On the bottom of the card are the plants that use that seed dispersal method. For example, the raccoon eat palmetto seeds and walk through dunes, where they “pick up” sandspur seeds. Have each student look at his/her card and describe the types of seeds he/she disperses.
- Explain the game. Each time the student lands on a plant that is on his/her dispersal card, the student will get a seed. If the student does not land on plant that is listed on his/her card, the student does not get a seed. Whichever student has the most seeds wins the game.
- The spinner is labeled 1, 2, 3 and “Scatter Your Seeds”. The student should move the number of spaces on which he/she lands. If the student lands on “Scatter Your Seeds”, then he/she loses all of the seeds he/she has collected.
- At the end of the game, have the students create bar graphs of the number of seeds collected by each dispersal method. Discuss the results.
How to make a spinner: On cardstock, draw a large square split into four smaller squares and an arrow. Label the four boxes 1, 2, 3 and “Scatter Your Seeds”. Laminate the cardstock. Cut out the spinner and the arrow. Use a hole punch to make a hole in the center of the arrow. Use a knife to punch a smaller hole in the center of the large square. Push a brad through the hole in the arrow. Put a medium-sized washer between the arrow and the square. Work the brad through the smaller hole in the center of the square.
Assessment
The teacher should collect a variety of seeds from the schoolyard and home. Each student will be given a seed and asked to determine whether wind, water or the “hitchhiker” method disperses the seed. You will need a fan, a stuffed animal, and a container of water. Give the student a seed and show him your “props”. How would we determine if the seed is dispersed by the wind? Have the student perform the test. How would we determine if the seed is dispersed by water? Have the student perform the test. How would we determine if the seed is a “hitchhiker”? Have the student perform the test. How is your seed dispersed? If the seed didn’t pass any of the other tests, how is it likely dispersed? (Have the student think back to the ‘players’ in the board game. What do animals do with the seed when they’re finished eating the fruit?)
Mastery/Nonmastery: The student correctly explains how his/her seed is distributed and how he/she knows that the plant does not use the other methods.
Members of the COASTeam Aquatic Workshops development team include: Katrina Bryan, Jennifer Jolly Clair, Stacia Fletcher, Kevin Kurtz, Carmelina Livingston, and Stephen Schabel.
From COASTeam Aquatic Workshops: the Coast (Grade 1); a joint effort between the COASTeam Program at the College of Charleston and the South Carolina Aquarium – funded by the SC Sea Grant Consortium.
4
The Squirrel
Scatters seeds from
The Live Oak The Pine tree The Palmetto
The Pine Tree Spartina