The life cycle of a flowering plant
By the end of this chapter you will be able to
- Put the stages of a flowering plant's life cycle in order, from a seed back to a seed
- Say what pollination is, and how insects and the wind carry pollen from flower to flower
- Explain how seeds form inside a fruit after pollination, and name a bean plant's fruit
- Name four ways that seeds are dispersed, and say why spreading seeds helps a plant
- Say what a seed needs in order to germinate, and read a table from a fair test on germination
- Describe a seedling, and use a table to show how it grows
You should already know
- Parts of a flowering plant: roots, stem, leaves and flower (Year 3 Science, Chapter 2)
- What plants need to grow, and why crowded plants share light and water (Year 3 Science, Chapter 3)
Where this leads
- Food and nutrition, and why animals must eat food that they cannot make themselves (Year 3 Science, Chapter 5)
- Living things and their habitats, and how plants and animals depend on each other (Year 4 Science)
National Curriculum for England, Key Stage 2 science, Year 3. Content: P4 explore the part that flowers play in the life cycle of flowering plants, including pollination, seed formation and seed dispersal.
Exercise P Do you remember?
Method. Think about the part of the plant that is in the soil.
- Think about the soil. The part of the plant in the soil takes in water and nutrients.in the soil
- Name the part. That part is the roots.roots
- Write the answer. roots
Check. The roots take in water and nutrients. ✓
Method. Think about what a plant gets from its surroundings.
- Think about the list. A plant needs air, light, water, nutrients from the soil and room to grow.five needs
- Write the answer. Accept any one of: air, light, water, nutrients from the soil, room to grow.
Check. The five needs are air, light, water, nutrients and room to grow. ✓
Method. Think about the gas that plants give out.
- Think about the gas. Plants give out a gas that people breathe in.breathe in
- Name the gas. That gas is oxygen.oxygen
- Write the answer. oxygen
Check. Plants give out oxygen. ✓
Method. Think about the coloured part of a flower.
- Think about the colour. The bright, coloured parts of a flower are the petals.bright, coloured
- Think about the insects. Petals help to attract insects, such as bees.attract insects
- Name the part. The part is the petals.petals
- Write the answer. petals
Check. Petals are often bright and can attract insects. ✓
Method. Think about what a seed does first when it starts to grow.
- Think about the start of growth. A seed sends out its roots first, into the soil.roots first
- Think about the leaves. The leaves come later, once the shoot has grown up.leaves later
- Write the answer. roots
Check. The roots grow down into the soil first. ✓
The life cycle of a flowering plant
Plants, like all living things, have a life cycle. A life cycle is the set of stages that a living thing goes through, from the start of its life until it makes new living things like itself.
A flowering plant starts as a seed. The seed begins to grow, which is called germination. The young plant grows into a seedling, then a young plant, and then a flowering plant. The flowering plant makes flowers. The flowers are pollinated, and seeds form inside a fruit. Then the seeds are dispersed, which means they are spread away from the parent plant. A dispersed seed can start the cycle again.
So the life cycle goes round in a circle. The seeds that leave the plant become new plants.
Key ideas
- A life cycle is the set of stages that a living thing goes through.
- A flowering plant starts as a seed, which germinates and grows into a seedling, then a young plant and a flowering plant.
- Pollination, seed formation and seed dispersal happen after the plant has flowers.
- Seed dispersal spreads seeds away from the parent plant, and a dispersed seed can start the cycle again.
Method. Think about the order of the stages.
- Find germination. Germination is the stage in which the seed starts to grow.germination
- Find the next stage. The next stage after germination is the seedling.seedling comes next
- Write the answer. seedling
Check. The seedling grows from the germinated seed. ✓
Method. Start with the stage that comes first in the cycle.
- Start with the seed. A seed is the first stage of the cycle.seed first
- Next, germination. The seed germinates before it becomes a seedling.germination second
- Last, the seedling. The seedling comes after germination.seedling third
- Write the answer. seed, germination, seedling
Check. The order is seed, germination, seedling. ✓
Method. Think about what seeds do once they have been dispersed.
- Find seed dispersal. Seed dispersal spreads the seeds away from the parent plant.seed dispersal
- Follow the arrow. After seed dispersal, the cycle goes back to the seed.back to seed
- Write the answer. seed
Check. The cycle starts again with a seed. ✓
Watch out
Watch out: the life cycle does not end at the flower. The flower makes seeds, the seeds spread out, and each one can start the cycle again.
Try it at home or school (with a grown-up). With a grown-up, plant a bean seed in a pot of soil, or put one on damp cotton wool in a clear cup. Keep it in a warm place. Draw the seed on the first day, and then draw it again each week. Do not eat the seeds. Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “What stage is the plant at now? What stage do you think comes next?” Let your child point to each stage on the circle, and say it in order.
Exercise 4A The life cycle of a flowering plant
Method. Look at the start of the cycle.
- Find the first stage. The life cycle starts with a seed.seed first
- Write the answer. seed
Check. Every flowering plant starts as a seed. ✓
Method. Think about how a seedling grows.
- Find the seedling. A seedling is a young plant that has grown from a seed.seedling
- Find the next stage. As it grows, the seedling becomes a young plant.young plant
- Write the answer. young plant
Check. The seedling becomes a young plant. ✓
Method. Think about the shape of the cycle on the board.
- Read the sentence. The cycle goes round and round, so it is a circle.circle
- Write the answer. circle
Check. The cycle starts again with a seed. ✓
Method. Think about the stage that spreads seeds.
- Read the sentence. Seed dispersal spreads seeds away from the parent plant.dispersal
- Write the answer. dispersal
Check. Seed dispersal is spreading seeds. ✓
Method. Find pollination on the ring, and follow the arrow.
- Find pollination. Pollination is one of the boxes on the ring.pollination
- Follow the arrow. The next box after pollination is seed formation.seed formation
- Write the answer. seed formation
Check. After pollination, seeds start to form. ✓
young plant, germination, seedling
Method. Start with the stage that comes first, and go in the order of the cycle.
- Start with germination. Germination is the first of these stages.germination first
- Next, the seedling. The seedling comes after germination.seedling second
- Last, the young plant. The young plant comes after the seedling.young plant third
- Write the answer. germination, seedling, young plant
Check. Germination, then seedling, then young plant. ✓
Method. Think about what happens to the seeds that a flower makes.
- Think about the flower. The flower makes seeds, but the cycle does not stop there.not the end
- Think about the seeds. Seeds are dispersed, and a seed starts the cycle again.seed starts again
- Write the answer. No. Accept any answer that says a seed starts the cycle again.
Check. The cycle goes round, so it does not end at the flower. ✓
Method. Count the boxes around the circle, one at a time.
- Count the boxes. Each box is one stage, and there are eight of them.8 boxes
- Write the answer. 8
Check. The eight stages are seed, germination, seedling, young plant, flowering plant, pollination, seed formation and seed dispersal. ✓
Method. Think about what happens when a seed starts to grow.
- Think about the seed. When a seed starts to grow, it is called germination.germination
- Name the stage. So Mo is watching germination.germination
- Write the answer. germination
Check. Germination is the start of growth from a seed. ✓
Method. Think about where the cycle goes after the seeds are dispersed.
- Think about the seeds. The seeds leave the plant and can grow into new plants.new plants
- Give the reason. So the cycle goes round, and starts again with a seed.starts again
- Write the answer. Accept any sentence that says the seeds spread from the plant and grow into new plants, so the cycle starts again.
Check. A circle has no end, just as the cycle starts again. ✓
Method. Think about what crowded plants have to share.
- Think about the seeds. Seeds that fall close together grow close to the parent plant.close together
- Give the reason. They have to share the light, water and nutrients, so each one gets less.share
- Write the answer. Accept any answer that says seeds near the parent must share light, water and nutrients with it and with each other.
Check. Dispersal gives each new plant room to grow. ✓
Flowers and pollination
A flower has a few main parts that work together in the life cycle:
- the petals, which are often bright and coloured, and sometimes scented. They help to attract insects;
- the male part, which makes pollen. Pollen is often a yellow powder;
- the female part, in the centre of the flower. Seeds form in its base after pollination.
Pollination is the moving of pollen from the male part of a flower to the female part of a flower. The pollen can move to a flower on the same plant, or to a flower on another plant of the same kind.
Many flowers are pollinated by insects, such as bees, butterflies and hoverflies. An insect visits a flower to feed on nectar, which is a sweet liquid made by the flower. As it feeds, pollen sticks to its body and is carried to the next flower.
Some plants, such as grasses, are pollinated by the wind. Their flowers are often small and plain, and they make lots of light pollen, which the wind can blow to other flowers.
Key ideas
- Pollination is the moving of pollen from the male part of a flower to the female part.
- Insects, such as bees, carry pollen from flower to flower when they feed on nectar.
- Wind-pollinated flowers are often small and plain, and make lots of light pollen.
- Petals are often bright and sometimes scented, which helps to attract insects.
Method. Think about the part of the flower that is coloured.
- Read the description. The part that is bright, coloured and sometimes scented is the one that attracts insects.bright and scented
- Name the part. That part is the petals.petals
- Write the answer. petals
Check. Petals help to attract insects. ✓
Watch out. The male part and the female part make pollen and seeds. They do not attract insects with colour.
Method. Think about the word for moving pollen.
- Read the description. The moving of pollen from the male part to the female part is one process.moving pollen
- Name the process. The process is called pollination.pollination
- Write the answer. pollination
Check. Pollination is the moving of pollen. ✓
Method. Think about what carries the pollen.
- Read the description. A bee is an insect, and it carries the pollen.bee carries
- Name the type. So this is insect pollination.insect
- Write the answer. insect
Check. Insects carry pollen when they feed on nectar. ✓
Watch out
Watch out: pollination is not the same as a seed. Pollination only moves the pollen to the female part. Seeds form later, after pollination has happened.
Try it at home or school (with a grown-up). With a grown-up, sit still in a sunny flower bed or garden, at a safe distance from the flowers and any nests. Watch for five minutes. Tally each kind of insect that lands on a flower: bee, butterfly or fly. Do not touch any insect. Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “Which insects came to the flowers? What were they doing?” Let your child tally each kind of insect in a simple table.
Exercise 4B Flowers and pollination
Method. Think about which part of the flower makes pollen.
- Read the chapter. The male part of the flower makes pollen.male part
- Write the answer. male part
Check. Pollen is made by the male part. ✓
Method. Think about the centre of the flower.
- Read the description. The female part is in the centre, and seeds form in its base.centre
- Name the part. So the part is the female part.female part
- Write the answer. female part
Check. Seeds form in the female part after pollination. ✓
Method. Think about the word for moving pollen.
- Read the sentence. Moving pollen from one part to another is pollination.pollination
- Write the answer. pollination
Check. Pollination moves pollen. ✓
Method. Think about the sweet liquid in a flower.
- Read the sentence. The sweet liquid made by a flower is nectar.nectar
- Write the answer. nectar
Check. Insects feed on nectar. ✓
Method. Read the story again.
- Find the insect. In the story, a bee lands on one of the flowers.bee
- Write the answer. bee
Check. The bee visits the flower to feed on nectar. ✓
Method. Follow the orange arrow in the picture.
- Read the arrow. The arrow starts at flower 1, where the pollen is made.flower 1
- Name the flower. So the pollen comes from flower 1.1
- Write the answer. 1
Check. The bee carries pollen from flower 1 to flower 2. ✓
| Insect | Visits in 10 minutes |
|---|---|
| bee | 14 |
| hoverfly | 6 |
| butterfly | 3 |
Method. Take the hoverfly visits away from the bee visits.
- Read the two numbers. The bee made 14 visits and the hoverfly made 6 visits.14 and 6
- Find the difference. The difference is how many more visits the bee made.14 − 6 = 8
- Write the answer. 8
Check. 6 + 8 = 14, so the answer is right. ✓
| Insect | Visits in 10 minutes |
|---|---|
| bee | 14 |
| hoverfly | 6 |
| butterfly | 3 |
Method. Add the visits made by each insect.
- Read the three numbers. The visits were 14, 6 and 3.14, 6, 3
- Add them together. The total is the number of visits by all three insects.14 + 6 + 3 = 23
- Write the answer. 23 visits
Check. 23 is the total of the three numbers. ✓
| Insect | Visits in 10 minutes |
|---|---|
| bee | 14 |
| hoverfly | 6 |
| butterfly | 3 |
Method. Find the biggest number in the table.
- Read the numbers. The numbers are 14, 6 and 3.14 is biggest
- Name the insect. The bee has the biggest number of visits.bee
- Write the answer. bee
Check. The bee made 14 visits. ✓
Method. Think about what carries the pollen when no insects visit.
- Think about the flowers. Small, plain flowers do not attract insects much.not attract insects
- Predict. The wind can carry the pollen, so wind pollination is most likely.wind
- Write the answer. wind
Check. Wind-pollinated flowers are often small and plain. ✓
Method. Think about what the bee carries.
- Think about the pollen. The bee carries pollen from one flower to another.carries pollen
- Give the reason. After pollination, seeds can start to form.seeds form
- Write the answer. Accept any sentence that says the bee carries pollen from one flower to another, so seeds can form.
Check. Pollination must happen before seeds form. ✓
Method. Think about what wind-pollinated flowers look like.
- Think about the wind. The wind moves the pollen by itself, so it does not need petals to find the flower.wind does not need petals
- Think about the flowers. Wind-pollinated flowers are often small and plain.small and plain
- Write the answer. No. Accept any reason that says the wind does not need petals, and wind-pollinated flowers are often small and plain.
Check. Petals attract insects, and wind does not. ✓
Seed formation and fruit
After pollination, the petals of the flower usually dry up and fall off. The female part of the flower then starts to change. Seeds form inside the female part, and its lower part swells and grows into a fruit.
A fruit is the part of a flowering plant that contains seeds. The fruit protects the seeds while they develop. The fruit of a bean plant is a pod. Other fruits include apples and tomatoes. A tomato is a fruit, even though many people use it as a vegetable.
Seed formation is the stage in which the seeds form inside the fruit. A pod can hold several seeds, and they keep growing until they are ready to be dispersed.
Key ideas
- After pollination, seeds form inside the female part of the flower.
- A fruit is the part of a flowering plant that contains seeds.
- The fruit of a bean plant is a pod, and the pod holds the seeds.
- The fruit protects the seeds while they develop.
Method. Think about which part holds the seeds.
- Read A. The pod is the fruit of the bean plant, and it holds the seeds.A: pod holds seeds
- Read B. The root takes in water and nutrients, and does not hold seeds.B: root
- Choose. So the pod is the fruit.A
- Write the answer. A
Check. The fruit holds the seeds, and the pod is the bean plant fruit. ✓
Watch out. The root is in the soil. It does not make or hold seeds.
Method. Multiply the number of pods by the seeds in each pod.
- Read the two numbers. There are 4 pods, and each pod has 5 seeds.4 pods, 5 seeds
- Multiply. The total is the number of pods times the seeds in each pod.4 x 5 = 20
- Write the answer. 20 seeds
Check. 5 added 4 times is 20. ✓
Method. Think about the order of the stages.
- Read the order. Pollination comes before seed formation in the life cycle.pollination first
- Choose the word. So pollination must happen before seeds form.pollination
- Write the answer. pollination
Check. Pollination comes first, then seeds form. ✓
Watch out
Watch out: the petals are not the seeds. The petals fall off, and the seeds form inside the female part, which grows into the fruit.
Try it at home or school (with a grown-up). With a grown-up, look at a dry bean pod from a garden plant, or a pea pod from the kitchen. Open it carefully and count the seeds inside. Write the number in a table. Do not eat the seeds unless a grown-up says they are safe to eat. Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “How many seeds are in this pod? Why do you think the pod holds them?” Let your child count the seeds aloud, one at a time.
Exercise 4C Seed formation and fruit
Method. Think about the part that holds the seeds.
- Read the definition. A fruit is the part of a flowering plant that contains seeds.fruit
- Write the answer. fruit
Check. Apples, tomatoes and pods are fruits. ✓
Method. Think about the fruit of a bean plant.
- Read the chapter. The fruit of a bean plant is a pod, which holds the seeds.pod
- Write the answer. pod
Check. A bean pod holds the seeds. ✓
Method. Think about the part that is coloured and falls off.
- Read the sentence. After pollination, the petals usually fall off.petals
- Write the answer. petals
Check. The petals dry up and fall off. ✓
Method. Think about where the seeds form.
- Read the sentence. Seeds form inside the fruit.fruit
- Write the answer. fruit
Check. The fruit holds the seeds. ✓
Method. Think about which part holds the seeds.
- Read the two parts. The male part makes pollen. The female part is where the seeds form.female part
- Choose the part. So the female part grows into the fruit.female part
- Write the answer. female part
Check. Seeds form in the female part. ✓
Method. Count the seeds inside the pod, one at a time.
- Count the seeds. There are five seeds inside the pod.5 seeds
- Write the answer. 5
Check. Each seed is inside the pod. ✓
Method. Think about what a fruit is.
- Read the definition. A fruit is the part of a flowering plant that contains seeds.contains seeds
- Check the tomato. A tomato grows from a flower and contains seeds, so it is a fruit.tomato has seeds
- Write the answer. yes
Check. A tomato is a fruit of the plant. ✓
Method. Add the seeds in the three pods.
- Read the numbers. The pods have 5, 4 and 6 seeds.5, 4, 6
- Add them together. The total is the seeds in all three pods.5 + 4 + 6 = 15
- Write the answer. 15 seeds
Check. 5 + 4 + 6 = 15, so the answer is right. ✓
Method. Take the seeds that were planted away from the total.
- Read the two numbers. Mo has 20 seeds and plants 6 of them.20 and 6
- Subtract. The seeds left are the total, minus the seeds planted.20 − 6 = 14
- Write the answer. 14 seeds
Check. 6 + 14 = 20, so the answer is right. ✓
Method. Check whether the three numbers are the same.
- Read the record. The pods hold 5, 4 and 6 seeds.5, 4, 6
- Compare the numbers. The numbers are not all the same, so the pods do not hold the same number.not the same
- Write the answer. no
Check. Pods can hold different numbers of seeds. ✓
Method. Think about what the petals do after pollination.
- Think about the petals. The petals dry up and fall off.petals fall off
- Name where seeds form. The seeds form inside the female part, which becomes the fruit.female part
- Write the answer. No. Accept any answer that says the seeds form inside the female part of the flower, which becomes the fruit.
Check. The petals do not become seeds. ✓
Method. Think about the order of the stages.
- Think about the pollen. The pollen has to reach the female part of the flower.pollen reaches
- Give the reason. Only after pollination do the seeds start to form, inside the fruit.then seeds
- Write the answer. Accept any answer that says the pollen must reach the female part first, and only then do the seeds start to form.
Check. Pollination comes before seed formation. ✓
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. ✓
Germination: what a seed needs
A bean seed is a tiny living package. It has a seed coat on the outside, which protects it. Inside, there is stored food, and a tiny young plant with a root, a shoot and leaves.
Germination is when the seed begins to grow. To germinate, a seed needs:
- water, which soaks into the seed and makes it swell;
- a suitable temperature, which means a warm place, not a very cold one;
- air, which the seed needs in order to grow.
A seed does not need soil to germinate. At first it uses the stored food inside it. The soil is needed later, when the young plant needs nutrients.
Priya and Noah set up a fair test with three dishes. Each dish has 10 bean seeds. Dish A is damp and warm. Dish B is dry and warm. Dish C is damp and cold. The table shows the results after 7 days.
| Dish | Water | Temperature | Seeds that germinated (out of 10) |
|---|---|---|---|
| A | damp | warm | 9 |
| B | dry | warm | 0 |
| C | damp | cold | 3 |
Key ideas
- A seed needs water, a suitable temperature and air to germinate.
- A seed has a seed coat, stored food and a tiny young plant inside.
- A seed does not need soil to germinate; it uses its stored food at first.
- In a fair test, only one thing changes at a time.
Method. Look for the one thing that is different between the two dishes.
- Read dish A. Dish A is damp and warm.damp, warm
- Read dish B. Dish B is dry and warm. Both dishes are warm, so only the water is different.dry, warm
- Name the one thing. The one thing that is different is the water.water
- Write the answer. water
Check. Only the water changes between A and B. ✓
Watch out. The temperature is the same in dishes A and B, so it is not the thing that changes.
Method. Take the seeds that germinated away from the seeds in the dish.
- Read the two numbers. Dish A had 10 seeds, and 9 of them germinated.10 and 9
- Subtract. The seeds that did not germinate are the total, minus the ones that germinated.10 − 9 = 1
- Write the answer. 1
Check. 9 + 1 = 10, so the answer is right. ✓
Method. Take the smaller number away from the bigger number.
- Read the two numbers. Dish A had 9 seeds germinate, and dish C had 3.9 and 3
- Find the difference. The difference is how many more seeds germinated in dish A.9 − 3 = 6
- Write the answer. 6
Check. 3 + 6 = 9, so the answer is right. ✓
Watch out
Watch out: a seed can be damp and still not germinate well if it is cold. Dish C was damp, but it was cold, and only 3 seeds germinated. Both water and warmth are needed.
Try it at home or school (with a grown-up). With a grown-up, put 10 bean seeds on damp cotton wool in a clear cup on a windowsill. Put 10 more on damp cotton wool in a cool cupboard. Keep both damp. Each day for a week, count how many seeds have started to grow, and write the numbers in a table. Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “What is different about the two cups? What is the same?” Let your child count the seeds that have started to grow each day, and write the numbers in a table.
Exercise 4E Germination: what a seed needs
Method. Think about what helps a seed to swell and grow.
- Think about water. A seed needs water to soak into it.water
- Think about warmth and air. A seed also needs a suitable temperature and air.warmth and air
- Write the answer. Accept any two of: water, warmth, air.
Check. Water, a suitable temperature and air are needed to germinate. ✓
Method. Read the table.
- Read the water column. Dish B is marked dry in the water column.dry
- Name the letter. So the dry dish is dish B.B
- Write the answer. B
Check. Dish B had dry cotton wool. ✓
Method. Read the table.
- Read the temperature column. Dish C is marked cold in the temperature column.cold
- Name the letter. So the cold dish is dish C.C
- Write the answer. C
Check. Dish C was cold. ✓
Method. Think about what soaks into a seed.
- Read the sentence. Water soaks into the seed and makes it swell.water
- Write the answer. water
Check. Water makes a seed swell. ✓
Method. Think about the food inside a seed.
- Read the sentence. The stored food inside the seed helps the young plant at first.stored food
- Write the answer. stored food
Check. The stored food helps the seed to start growing. ✓
Method. Read the label under each dish.
- Read the labels. Dish A is labelled damp, warm.damp, warm
- Name the letter. So the dish that is damp and warm is dish A.A
- Write the answer. A
Check. Dish A had damp cotton wool and was warm. ✓
Method. Read the results.
- Read the results. Dish B had 0 seeds that germinated out of 10.0 germinated
- Name the letter. So dish B gave no seeds that germinated.B
- Write the answer. B
Check. Dish B was dry, and none of its seeds germinated. ✓
Method. Read the height of the bar for dish C.
- Find dish C. The bar under C is labelled with its value.bar C
- Read the value. The label on the bar for dish C says 3.3
- Write the answer. 3
Check. The bar for dish C shows 3 seeds. ✓
Method. Find the tallest bar on the chart.
- Compare the bars. The bar for dish A is the tallest.tallest A
- Name the letter. So dish A had the most seeds germinate.A
- Write the answer. A
Check. Dish A had 9 seeds germinate. ✓
Method. Take the seeds that germinated away from the 10 seeds in the dish.
- Read the two numbers. Dish C had 10 seeds, and 3 germinated.10 and 3
- Subtract. The seeds that did not germinate are the total, minus the ones that germinated.10 − 3 = 7
- Write the answer. 7
Check. 3 + 7 = 10, so the answer is right. ✓
| Dish | Water | Temperature | Seeds that germinated (out of 10) |
|---|---|---|---|
| A | damp | warm | 9 |
| B | dry | warm | 0 |
| C | damp | cold | 3 |
Method. Add the numbers that germinated in the three dishes.
- Read the three numbers. The dishes had 9, 0 and 3 seeds germinate.9, 0, 3
- Add them together. The total is the seeds that germinated in all three dishes.9 + 0 + 3 = 12
- Write the answer. 12
Check. The total of the three dishes is 12. ✓
Method. Check what was different about dish B.
- Read the test. Dish A and dish B were both warm. Only the water was different.both warm
- Decide. Because the warmth was the same, the warmth did not cause the result. The answer is no.not fair
- Write the answer. no
Check. Only the water changed between A and B. ✓
Method. Think about what a damp, warm dish gives the seeds.
- Think about the conditions. The seeds in dish A have water and warmth.water and warmth
- Make the prediction. So more seeds may germinate, and the young roots and shoots may grow longer.more grow
- Write the answer. Accept any prediction that says more seeds will start to grow, or the young roots and shoots will get longer.
Check. A prediction can be checked by counting again after a week. ✓
Method. Think about what seeds need first.
- Think about water. A seed needs water to soak in and make it swell.water
- Give the reason. Dish B was dry, so the seeds could not soak in water and start to grow.dry
- Write the answer. Accept any sentence that says dish B was dry, so the seeds had no water to soak in and start to grow.
Check. Water is one of the three things that a seed needs. ✓
Seedlings and growth
A seedling is a young plant that has grown from a seed. Its root grows down into the soil, and its shoot grows up towards the light. Its first leaves open out.
At first, the seedling uses the stored food from inside the seed. Soon its leaves can make food, using light, water and carbon dioxide. Its roots take in water and nutrients from the soil.
As the plant grows, it becomes a young plant, and then a flowering plant. When it flowers, the plant can be pollinated and make seeds, and the life cycle goes on.
Amira measured one seedling with a ruler, every two days. The table shows its height.
| Day | Height of the seedling |
|---|---|
| day 2 | 1 cm |
| day 4 | 3 cm |
| day 6 | 6 cm |
Key ideas
- A seedling is a young plant that has grown from a seed.
- The root grows down into the soil, and the shoot grows up towards the light.
- At first the seedling uses stored food; then its leaves make food.
- The young plant grows into a flowering plant, and the life cycle goes on.
Method. Look at the picture of the seedling.
- Look at the picture. The part that goes down into the soil is in the soil.in the soil
- Name the part. This part is the root.root
- Write the answer. root
Check. Roots grow down and take in water and nutrients. ✓
| Day | Height of the seedling |
|---|---|
| day 2 | 1 cm |
| day 4 | 3 cm |
| day 6 | 6 cm |
Method. Take the height on day 2 away from the height on day 4.
- Read the two heights. The seedling was 1 cm on day 2 and 3 cm on day 4.1 and 3
- Find the growth. The growth is the later height minus the earlier height.3 − 1 = 2
- Write the answer. 2 cm
Check. 1 + 2 = 3, so the answer is right. ✓
| Day | Height of the seedling |
|---|---|
| day 2 | 1 cm |
| day 4 | 3 cm |
| day 6 | 6 cm |
Method. Compare the growth in each part of the table.
- Day 2 to day 4. The seedling grew 2 cm.2 cm
- Day 4 to day 6. The seedling grew 3 cm, which is more.3 cm
- Choose the days. The most growth was between day 4 and day 6.day 4 and day 6
- Write the answer. day 4 and day 6
Check. 3 is bigger than 2. ✓
Watch out
Watch out: a seedling does not keep using the stored food for ever. Its leaves must make food, and that needs light. A seedling kept in the dark soon grows weakly once its stored food has run out.
Try it at home or school (with a grown-up). With a grown-up, find a flower in a garden or park, and do not pick or touch it. Look at its petals and its centre, using a magnifying glass if you have one. Watch from a safe distance for an insect that visits it. Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “Where is the middle of the flower? Which parts are the petals?” Let your child find the petals, and say why an insect might visit.
Exercise 4F Seedlings and growth
Method. Think about where a seedling comes from.
- Think about the start. A seedling comes from a seed that has started to grow.from a seed
- Write the meaning. It is a young plant that has grown from a seed.young plant
- Write the answer. Accept any sentence that says a seedling is a young plant that has grown from a seed.
Check. A seedling is a young plant. ✓
Method. Think about the part in the soil.
- Read the chapter. The roots take in water and nutrients from the soil.roots
- Write the answer. roots
Check. The roots take in water and nutrients. ✓
Method. Think about the part that uses light.
- Read the chapter. The leaves use light to make food.leaves
- Write the answer. leaves
Check. Leaves make food in the light. ✓
Method. Think about the food inside the seed.
- Read the sentence. At first the seedling uses the stored food inside the seed.stored food
- Write the answer. stored food
Check. The stored food helps the seedling at first. ✓
Method. Think about what leaves use to make food.
- Read the sentence. Leaves use light, water and carbon dioxide to make food.light
- Write the answer. light
Check. Light is needed to make food in the leaves. ✓
Method. Look at the arrow beside the shoot.
- Read the arrow. The arrow beside the shoot points up.points up
- Name the direction. So the shoot grows up.up
- Write the answer. up
Check. The shoot grows up towards the light. ✓
| Day | Height of the seedling |
|---|---|
| day 2 | 1 cm |
| day 4 | 3 cm |
| day 6 | 6 cm |
Method. Find the row for day 4.
- Find the row. The row for day 4 shows the height.day 4
- Read the height. The height on day 4 is 3 cm.3 cm
- Write the answer. 3 cm
Check. The table says 3 cm for day 4. ✓
| Day | Height of the seedling |
|---|---|
| day 2 | 1 cm |
| day 4 | 3 cm |
| day 6 | 6 cm |
Method. Take the height on day 4 away from the height on day 6.
- Read the two heights. The seedling was 3 cm on day 4 and 6 cm on day 6.3 and 6
- Find the growth. The growth is the later height minus the earlier height.6 − 3 = 3
- Write the answer. 3 cm
Check. 3 + 3 = 6, so the answer is right. ✓
| Day | Height of the seedling |
|---|---|
| day 2 | 1 cm |
| day 4 | 3 cm |
| day 6 | 6 cm |
Method. Work out the growth from day 2 to day 6.
- Read the two heights. The seedling was 1 cm on day 2 and 6 cm on day 6.1 and 6
- Find the growth. The growth is 6 − 1 = 5 cm, not 7 cm.5 cm
- Write the answer. no
Check. 1 + 5 = 6, so Ali is not right. ✓
Method. Add the same growth to the height on day 6.
- Read the height on day 6. The seedling was 6 cm on day 6.6 cm
- Add the growth. It grows another 3 cm, the same as from day 4 to day 6.3 cm
- Find the prediction. The predicted height is the height on day 6, plus the growth.6 + 3 = 9
- Write the answer. 9 cm
Check. A prediction can be checked by measuring again on day 8. ✓
Method. Think about what the stored food does.
- Think about the stored food. The stored food runs out, and the seedling needs more food.runs out
- Give the reason. Its leaves make food from light, so they must keep working to help it grow.leaves make food
- Write the answer. Accept any sentence that says the leaves make food from light, so the plant needs them to keep growing.
Check. Leaves make the food that a growing plant needs. ✓
Method. Follow the life cycle from the seed.
- Start with the seed. The seed germinates and grows into a seedling, then a young plant.germination
- Continue to flowers. The young plant becomes a flowering plant, and its flowers are pollinated.pollination
- End with new seeds. Seeds form in a fruit, and are dispersed to grow into new plants.dispersed
- Write the answer. Accept any answer that links at least three stages, such as germination, flowering and pollination, ending with seeds that are dispersed.
Check. The life cycle goes round from seed to seed. ✓
Chapter summary
| Skill | Method |
|---|---|
| Life cycle | Seed, germination, seedling, young plant, flowering plant, pollination, seed formation, seed dispersal, and back to a seed. |
| Pollination | Pollen moves from the male part of a flower to the female part, often carried by an insect or by the wind. |
| Seed formation | After pollination, seeds form inside the female part of the flower, which grows into a fruit. |
| Seed dispersal | Seeds are spread away from the parent plant by the wind, by water, by animals or by splitting pods. |
| Germination | A seed needs water, a suitable temperature and air to germinate. It uses its stored food at first. |
| Seedlings | A seedling uses its stored food first; then its leaves make food from light, and its roots take in water and nutrients. |
| Fair tests | Change only one thing, keep the rest the same, count or measure, and show the results in a table or bar chart. |
Can you…?
- I can put the stages of a flowering plant's life cycle in order, from a seed back to a seed
- I can say what pollination is, and how insects and the wind carry pollen from flower to flower
- I can explain how seeds form inside a fruit after pollination, and name a bean plant's fruit
- I can name four ways that seeds are dispersed, and say why spreading seeds helps a plant
- I can say what a seed needs to germinate, and read a table from a fair test on germination
- I can describe a seedling, and use a table to show how a seedling grows
Key terms
- life cycle
- the stages a living thing goes through, from its start until it makes new living things like itself
- germination
- when a seed begins to grow
- seedling
- a young plant that has grown from a seed
- pollen
- a powder made by the male part of a flower, often yellow
- pollination
- moving pollen from the male part of a flower to the female part
- nectar
- a sweet liquid made by flowers, which insects feed on
- male part
- the part of a flower that makes pollen
- female part
- the part of a flower where seeds form, which grows into the fruit
- seed formation
- the stage in which seeds form inside the female part of a flower, which grows into a fruit
- fruit
- the part of a flowering plant that contains seeds
- seed dispersal
- spreading seeds away from the parent plant
- seed coat
- the tough outer cover of a seed, which protects it
- stored food
- food inside a seed that helps the young plant to start growing
- suitable temperature
- a temperature that is warm enough for a seed to germinate
Exercise 4Z Check-up
Method. Think about the stage after a seed starts to grow.
- Think about germination. After germination, the young plant is called a seedling.seedling
- Write the answer. seedling
Check. A seedling grows from a seed that has germinated. ✓
Method. Think about the coloured part of the flower.
- Think about the colour. The bright, coloured part of a flower is the petals.petals
- Write the answer. petals
Check. Petals help to attract insects. ✓
Method. Think about the word for moving pollen.
- Read the definition. Moving pollen from the male part to the female part is pollination.pollination
- Write the answer. pollination
Check. Pollination moves pollen between flowers. ✓
Method. Think about the fruit that holds the seeds.
- Read the chapter. The fruit of a bean plant is a pod.pod
- Write the answer. pod
Check. A bean pod holds the seeds. ✓
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 helps a seed to start growing.
- Think about water. A seed needs water to soak in.water
- Think about warmth and air. A seed also needs a suitable temperature and air.warmth and air
- Write the answer. Accept any two of: water, warmth, air.
Check. Water, a suitable temperature and air are needed. ✓
seed dispersal, pollination, seed formation
Method. Start with the stage that comes first.
- Start with pollination. Pollination comes first, after flowering.pollination first
- Next, seed formation. Seeds form inside the fruit after pollination.seed formation second
- Last, seed dispersal. The seeds are dispersed at the end of this part of the cycle.seed dispersal last
- Write the answer. pollination, seed formation, seed dispersal
Check. Pollination, then seed formation, then seed dispersal. ✓
| Dish | Water | Temperature | Seeds that germinated (out of 10) |
|---|---|---|---|
| A | damp | warm | 9 |
| B | dry | warm | 0 |
| C | damp | cold | 3 |
Method. Take the smaller number away from the bigger number.
- Read the two numbers. Dish A had 9 seeds germinate, and dish C had 3.9 and 3
- Find the difference. The difference is how many more seeds germinated in dish A.9 − 3 = 6
- Write the answer. 6
Check. 3 + 6 = 9, so the answer is right. ✓
Method. Think about what the seed uses at first.
- Think about the stored food. At first the seed uses the stored food inside it, not the soil.stored food
- Decide. So a seed does not need soil to germinate, and Sam is not right.no
- Write the answer. no
Check. The soil is needed later, for nutrients. ✓
Method. Think about what crowded plants have to share.
- Think about crowding. Seeds that fall next to the parent share its light, water and nutrients.share
- Give the reason. Dispersed 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. ✓
Total 19 marks. Allow about 19 minutes.
Exercise 4X Practice test questions
Method. Find pollination, and follow the next stage.
- Find pollination. Pollination is followed by seed formation.seed formation
- Write the answer. seed formation
Check. Seeds form after pollination. ✓
Method. Find the panel with water in it.
- Find the water panel. The panel with water in it shows a coconut floating.coconut floats
- Name the seed. So the seed carried by water is the coconut.coconut
- Write the answer. coconut
Check. A coconut floats, so it is dispersed by water. ✓
Method. Think about what carries the pollen.
- Read the description. A bee is an insect that carries the pollen.bee
- Name the type. So this is insect pollination.insect
- Write the answer. insect
Check. Insects carry pollen when they feed on nectar. ✓
Method. Look at the labels on the picture.
- Find the labels. The labels show the seed coat, the stored food and the tiny young plant.three labels
- Name two. Two of these parts are the seed coat and the stored food.seed coat and stored food
- Write the answer. seed coat and stored food
Check. The seed coat protects the seed, and the stored food helps it to start growing. ✓
Method. Think about what a seed needs first.
- Think about water. A seed needs water to soak in and start to grow.water
- Give the reason. Dish B was dry, so the seeds could not soak in water.dry
- Write the answer. Accept any sentence that says dish B was dry, so the seeds had no water to soak in and start to grow.
Check. Water is one of the three things a seed needs. ✓
| Dish | Water | Temperature | Seeds that germinated (out of 10) |
|---|---|---|---|
| A | damp | warm | 9 |
| B | dry | warm | 0 |
| C | damp | cold | 3 |
Method. Find the difference, then compare the two dishes.
- Find the difference. 9 − 3 = 6, so dish A had 6 more seeds germinate.6 more
- Compare the dishes. Both dishes were damp, but dish A was warm and dish C was cold.temperature
- Write the answer. 6; the temperature was different
Check. 3 + 6 = 9, so the answer is right. ✓
Method. Start with the seed, and follow the stages in order.
- Start with the seed. A seed is the first stage.seed
- Then the other stages. The seed germinates, then becomes a seedling, then a young plant.germination, seedling, young plant
- Write the answer. seed, germination, seedling, young plant
Check. Each stage follows the one before it. ✓
Method. Think about what the bee gets from the flower.
- Name the liquid. The sweet liquid made by a flower is nectar.nectar
- Give the reason. The bee visits to feed on nectar, and pollen sticks to its body.feed on nectar
- Write the answer. nectar. Accept any answer that says the bee feeds on nectar, and gets pollen on its body.
Check. Insects feed on nectar, and carry pollen to the next flower. ✓
Method. Follow the pollen from one flower to the next.
- Follow the pollen. The bee carries pollen from the male part of one flower.male part
- Name the place. The pollen reaches the female part of another flower.female part
- Say where the seeds form. After pollination, seeds form inside the female part, which grows into the fruit.inside the fruit
- Write the answer. Accept any answer that says the bee carries pollen from the male part of one flower to the female part of another, and seeds form in the female part.
Check. Pollination must happen before seeds form. ✓
Method. Think about what a fair test changes and keeps the same.
- Find the thing that changes. The amount of water changes between the dishes.water changes
- Find two things that stay the same. The type of seed, the temperature and the number of seeds stay the same.seed, temperature, number
- Put the parts together. One thing changes, and the other things are kept the same.one changes
- Write the answer. The water changes. Accept any two things kept the same, such as the type of seed, the temperature, the number of seeds or the dish.
Check. Only the water changes in a fair test. ✓