Year 3 Science: Seed dispersal
Part of the Year 3 Science the life cycle of a flowering plant chapter. Chapter overview · whole chapter on one page
Seed dispersal
Seed dispersal means spreading seeds away from the parent plant. Seeds are dispersed so that:
- new plants do not crowd the parent plant, and each one has its own room, light, water and nutrients;
- the plant can grow in new places.
Plants use different ways to disperse their seeds. The table shows some of them.
| Method | Example | How the seed moves |
|---|---|---|
| wind | dandelion | a fluffy parachute is carried on the breeze |
| wind | sycamore | a wing lets the seed spin and drift down |
| water | coconut | the seed floats on water and is carried away |
| animals | burr | hooks on the burr stick to fur and are carried |
| animals | apple | the seeds are eaten inside the fruit and dropped or passed out elsewhere |
| split pods | gorse | the dry pod splits open with a pop and throws the seeds out |
Key ideas
- Seed dispersal means spreading seeds away from the parent plant.
- Plants use the wind, water, animals and splitting pods to disperse their seeds.
- Dispersal helps new plants to have room, light, water and nutrients.
- A dispersed seed can grow into a new plant and start the life cycle again.
Method. Look at the method in the table for a parachute.
- Find the seed. The dandelion has a fluffy parachute, which catches the breeze.parachute
- Find the method. A seed moved by the breeze is dispersed by the wind.wind
- Write the answer. wind
Check. The table shows that the dandelion uses the wind. ✓
Method. Think about which seed floats.
- Read the coconut. A coconut floats on water and is carried away.coconut floats
- Read the burr. A burr hooks on to fur, so it is carried by an animal.burr on fur
- Choose the seed. So the coconut is the seed carried by water.coconut
- Write the answer. coconut
Check. The coconut floats, so it is dispersed by water. ✓
Method. Look for the seed with a wing in the table.
- Find the wing. The sycamore has a wing that lets it spin and drift down.wing
- Name the example. So the example is the sycamore.sycamore
- Write the answer. sycamore
Check. The sycamore seed is dispersed by the wind. ✓
Watch out
Watch out: a plant does not decide where its seeds go. Its seeds are carried by the wind, by water, by animals, or by pods that split open.
Try it at home or school (with a grown-up). With a grown-up, find a dandelion clock or a sycamore seed that has already fallen, in a park or school field. Do not pick any plant. Drop each seed from the same height, about one metre, and watch how it falls. Which one falls more slowly? Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “How does this seed move? What does it need to be carried?” Let your child explain what the wing or the parachute does.
Exercise 4D Seed dispersal
Method. Think about the stage that spreads seeds.
- Read the definition. Spreading seeds away from the parent plant is called seed dispersal.seed dispersal
- Write the answer. seed dispersal
Check. Seed dispersal moves seeds away from the parent plant. ✓
Method. Think about what carries a parachute seed.
- Read the table. A seed with a fluffy parachute is carried by the breeze.breeze
- Name the method. The method is the wind.wind
- Write the answer. wind
Check. The dandelion is dispersed by the wind. ✓
Method. Think about what a coconut floats on.
- Read the sentence. A coconut floats on water.water
- Write the answer. water
Check. The coconut is dispersed by water. ✓
Method. Think about what a burr hooks on to.
- Read the sentence. Hooks on the burr stick to an animal's fur.fur
- Write the answer. fur
Check. Animals carry burrs on their fur. ✓
Method. Find the seed with a wing.
- Find the wing. The sycamore seed has a wing.wing
- Name the example. So the example is the sycamore.sycamore
- Write the answer. sycamore
Check. The sycamore is spread by the wind. ✓
Method. Think about how a gorse pod throws its seeds.
- Read the description. A dry gorse pod splits open with a pop, and throws the seeds out.splits open
- Name the method. So the method is split pods.split pods
- Write the answer. split pods
Check. Some pods split open and throw seeds out. ✓
Method. Find the panel with an animal in it.
- Find the animal. The animal in the picture has a burr stuck to its fur.burr on fur
- Read the label. The label says the burr is on the fur.burr
- Write the answer. burr
Check. The burr hooks on to fur and is carried away. ✓
Method. Look at the table for fruit that is eaten.
- Read the table. The apple is eaten by animals, and its seeds are carried away from the parent.apple eaten
- Name the method. So the method is animals.animals
- Write the answer. animals
Check. Animals eat the fruit and spread the seeds. ✓
| Method | Example | How the seed moves |
|---|---|---|
| wind | dandelion | a fluffy parachute is carried on the breeze |
| wind | sycamore | a wing lets the seed spin and drift down |
| water | coconut | the seed floats on water and is carried away |
| animals | burr | hooks on the burr stick to fur and are carried |
| animals | apple | the seeds are eaten inside the fruit and dropped or passed out elsewhere |
| split pods | gorse | the dry pod splits open with a pop and throws the seeds out |
Method. Look for the rows that say wind.
- Find the wind rows. Two rows of the table say wind: the dandelion and the sycamore.dandelion, sycamore
- Count them. So two examples are dispersed by the wind.2
- Write the answer. 2
Check. The dandelion and the sycamore are the two wind examples. ✓
Method. Take the seeds that blew away from the total.
- Read the two numbers. The head has 40 seeds and 15 blow away.40 and 15
- Subtract. The seeds left are the total, minus the seeds that blew away.40 − 15 = 25
- Write the answer. 25 seeds
Check. 15 + 25 = 40, so the answer is right. ✓
Method. In a fair test only one thing changes, so everything else stays the same.
- Find the thing that changes. The wing is the thing that changes between the two seeds.wing changes
- Name a thing that stays the same. The height it is dropped from and the place must stay the same.height and place
- Write the answer. Accept any answer that names one thing kept the same, such as the height it is dropped from, or the place.
Check. Only the wing changes in a fair test. ✓
Method. Look at the methods in the table.
- Check the table. The table shows wind, water and split pods, as well as animals.other methods
- Decide. So Sam is not right, and wind, water or split pods is another method.not right
- Write the answer. No. Accept wind, water or split pods.
Check. Seeds are dispersed in several ways. ✓
Method. Think about what crowded plants have to share.
- Think about crowding. Seeds that fall next to the parent must share its light, water and nutrients.share
- Give the reason. Spread-out seeds have room, light and water of their own.own room
- Write the answer. Accept any sentence that says spread-out seeds do not crowd the parent, so each new plant has room, light and water.
Check. Dispersal helps each new plant to grow well. ✓