Reproduction in plants and animals
By the end of this chapter you will be able to
- Explain that reproduction is how living things make new living things of the same kind
- Describe how pollen, pollination and fertilisation lead to seeds, and how seeds are spread
- Describe how some plants can reproduce without seeds, by runners, plantlets or tubers
- Describe how the young of animals begin, by fertilisation of an egg
- Explain why many plants and animals produce many seeds or young
You should already know
- The parts of a flowering plant, and the life cycle of a flowering plant, including pollination and seed dispersal (Year 3 Science, Chapters 2 and 4)
- Life cycles of a mammal, an amphibian, an insect and a bird (Year 5 Science, Chapter 2)
Where this leads
- Growing up to old age in humans (Year 5 Science, Chapter 4)
- Properties and uses of materials (Year 5 Science, Chapter 5)
National Curriculum for England, Key Stage 2 science, Year 5. Content: LH2 describe the life process of reproduction in some plants and animals.
Exercise P Do you remember?
Method. Think about the male part of a flower.
- Think about the parts. The stamen is the male part of a flower, and it has an anther that makes pollen.male part
- Name it. The part that makes pollen is the stamen.stamen
- Write the answer. stamen
Check. The pollen is then moved to another flower. ✓
Method. Think about the female part of a flower.
- Think about the parts. The carpel is the female part, and its ovary holds the ovules.female part
- Name it. The part that holds the ovules is the carpel.carpel
- Write the answer. carpel
Check. Ovules become seeds after fertilisation. ✓
Method. Think about the fluffy seed.
- Think about the seed. A dandelion seed has a parachute of fine hairs.parachute
- Name the way. The parachute is carried by the wind.wind
- Write the answer. wind
Check. Seed dispersal means spreading seeds away from the parent plant. ✓
Method. Think about the start of a new plant.
- Think about the seed. A seed grows into a young plant.young plant
- Name it. The young plant that grows from a seed is called a seedling.seedling
- Write the answer. seedling
Check. A seedling then grows into an adult plant. ✓
Method. Think about the group of frogs.
- Think about the features. Amphibians have moist skin and usually lay their eggs in water.moist skin
- Name the group. The group is the amphibians.amphibian
- Write the answer. amphibian
Check. A frog is an amphibian. ✓
What reproduction means
Reproduction is the life process by which living things make new living things of their own kind. It is one of the seven life processes, and it keeps a type of plant or animal going from one generation to the next.
Some plants reproduce with seeds, which are made in flowers. Other plants can make new plants without seeds, by sending out runners, plantlets or tubers.
| Plant | The part that grows into a new plant |
|---|---|
| strawberry | a runner, which takes root and grows a new plant |
| spider plant | a small plantlet on the end of a long stem |
| potato | a tuber, which is planted to grow a new plant |
Key ideas
- Reproduction is how living things make new living things of their own kind.
- Some plants reproduce with seeds, which are made in flowers.
- Some plants can make new plants without seeds, from runners, plantlets or tubers.
- The new plant is a copy of its parent.
Method. Read the table in section 3.1.
- Find the runner. The table says that a strawberry sends out a runner, which takes root.runner
- Name the plant. The plant that sends out runners is the strawberry.strawberry
- Write the answer. strawberry
Check. The runner takes root and grows a new plant. ✓
Method. Read the row for the spider plant.
- Read the row. The spider plant makes a small plantlet on the end of a long stem.plantlet
- Decide. It makes new plants without seeds, so the answer is no.no
- Write the answer. no
Check. Plantlets grow into new plants without seeds. ✓
Method. Read the row for the potato.
- Read the row. The potato row says a tuber is planted to grow a new plant.tuber
- Name the part. The part that is planted is the tuber.tuber
- Write the answer. tuber
Check. A tuber is a swollen underground stem store. ✓
Watch out
Watch out: a runner, a plantlet and a tuber can make a new plant without any seeds. Do not say that all plants need seeds to reproduce.
Try it (with your teacher or a grown-up). Look at a strawberry plant in a garden or a pot, with a grown-up. If it has runners, follow one to the end and see if a small new plant is growing there. Draw the parent plant and the new plant, and label each one. Wash your hands afterwards.
Exam tip
Grown-up tip. Ask: “Where does the new plant come from? Is it the same kind of plant as the parent?” Let your child say the word reproduction.
Exercise 3A What reproduction means
Method. Read the definition in section 3.1.
- Read the definition. Reproduction is the life process by which living things make new living things of their own kind.own kind
- Name it. So the word is reproduction.reproduction
- Write the answer. reproduction
Check. Reproduction keeps a type of living thing going. ✓
Method. Read the table in section 3.1.
- Read the table. The strawberry sends out runners.runners
- Name the plant. So the answer is strawberry.strawberry
- Write the answer. strawberry
Check. A runner takes root at its end. ✓
Method. Read the table in section 3.1.
- Read the table. A potato grows a new plant from a tuber.tuber
- Name the part. So the answer is tuber.tuber
- Write the answer. tuber
Check. The tuber is planted in the soil. ✓
Method. Think about what the new plant is like.
- Think about the new plant. A new plant from a runner has the same features as its parent.same features
- Fill the gap. So the new plant is a copy of its parent.copy
- Write the answer. copy
Check. The new plant is genetically the same as the parent. ✓
Method. Read the row for the spider plant.
- Read the row. The spider plant makes a small plantlet on the end of a long stem.plantlet
- Decide. So a spider plant does not need seeds.no
- Write the answer. no
Check. Plantlets grow into new plants. ✓
Method. Think about the three ways in the table.
- Think about the table. Runners, plantlets and tubers all make new plants without seeds.without seeds
- Decide. So the statement is false.false
- Write the answer. false
Check. Some plants reproduce without seeds. ✓
Method. Count the rows in the table.
- Count the rows. The table has three plants: strawberry, spider plant and potato.three rows
- Write the number. So there are three ways in the table.3
- Write the answer. 3
Check. Each row is one way of making new plants without seeds. ✓
Method. Think about how runners work.
- Think about the runner. A runner takes root and grows a new plant, without seeds.without seeds
- Decide. So Priya is right, and the answer is yes.yes
- Write the answer. yes
Check. Runners are a way of reproducing without seeds. ✓
Method. Read the labels in the picture.
- Read the labels. The picture labels the parent plant and the new plant.parent and new
- Choose the new plant. The new plant is at the end of the runner.end of the runner
- Write the answer. the plant at the end of the runner
Check. The runner joins the two plants. ✓
Method. Think about where the new plant comes from.
- Think about the source. The new plant grows from a part of the parent plant.grows from the parent
- Write the reason. So it has the same features as the parent.same features
- Write the answer. Accept any sentence that says the new plant is made from part of the parent, so it has the same features.
Check. Reproduction without seeds makes a copy of the parent. ✓
Flowers, pollination and seeds
The male part of a flower is the stamen. It makes pollen. The female part is the carpel, which holds the ovules.
Pollination is when pollen moves from a stamen to the stigma of another flower. Insects and the wind can carry pollen. After pollination, a pollen grain joins with an ovule. This is fertilisation, and the ovule grows into a seed.
Seeds are then spread away from the parent plant, which is called seed dispersal. The table gives examples.
| Feature | Insect-pollinated flower | Wind-pollinated flower |
|---|---|---|
| Petals | large and bright | small or none |
| Scent | often has a scent | no scent |
| Nectar | makes sweet nectar | no nectar |
| Pollen | sticky, heavy pollen | light, dry pollen that blows |
| Example | bluebell, buttercup | grass, hazel catkins |
| Plant | How the seed is spread |
|---|---|
| dandelion | wind carries its fluffy seeds |
| coconut | water carries it along |
| burdock (burr) | hooks stick to the fur of animals |
| pea pod | the pod splits and throws the seeds away |
Key ideas
- The stamen makes pollen. The carpel holds the ovules.
- Pollination is when pollen moves to the stigma of another flower.
- Fertilisation happens when a pollen grain joins with an ovule, which then grows into a seed.
- Seeds are spread by wind, water, animals, or by the pod splitting open.
Method. Find the part that makes pollen.
- Look at the flower. The stamen has an anther that makes pollen.anther
- Name the part. The part that makes pollen is the stamen.stamen
- Write the answer. stamen
Check. The stamen is the male part of the flower. ✓
Method. Read the dispersal table.
- Read the row for the dandelion. The dandelion row says wind carries its fluffy seeds.wind carries
- Name the kind of dispersal. So the seed is dispersed by wind.wind
- Write the answer. wind
Check. The seed has a parachute of fine hairs. ✓
Method. Find the row about the example.
- Find the example row. The example row says bluebell, buttercup for insects, and grass, hazel catkins for wind.grass, hazel catkins
- Read the wind column. In the wind-pollinated column the example is grass and hazel catkins.grass, hazel catkins
- Write the answer. grass, hazel catkins
Check. Wind-pollinated flowers often have small or no petals. ✓
Watch out
Watch out: the pollen is not the seed. Pollination moves pollen to a flower, and fertilisation is what makes a seed grow from an ovule.
Try it (with your teacher or a grown-up). With a grown-up, look at flowers in the school garden. Do not pick any flowers, and never eat them. Watch a bee or a fly visit a flower, and draw the flower. Label the petals, and say whether the flower looks like an insect-pollinated flower or a wind-pollinated flower.
Exam tip
Grown-up tip. Ask: “Which part makes the pollen? Which part holds the ovules? Where does the seed come from?” Let your child name each part on the picture.
Exercise 3B Flowers, pollination and seeds
Method. Read section 3.2.
- Read the part. The stamen makes pollen.stamen makes pollen
- Name it. So the answer is stamen.stamen
- Write the answer. stamen
Check. The stamen is the male part of the flower. ✓
Method. Read section 3.2.
- Read the part. The carpel is the female part, and it holds the ovules.holds the ovules
- Name it. So the answer is carpel.carpel
- Write the answer. carpel
Check. The ovules grow into seeds after fertilisation. ✓
Method. Read the definition in section 3.2.
- Read the definition. Pollination is when pollen moves to the stigma of another flower.moves to another flower
- Name it. So the word is pollination.pollination
- Write the answer. pollination
Check. Insects and wind can both carry pollen. ✓
Method. Read the definition in section 3.2.
- Read the definition. After pollination, a pollen grain joins with an ovule. This is called fertilisation.joins with an ovule
- Name it. So the word is fertilisation.fertilisation
- Write the answer. fertilisation
Check. Fertilisation makes the ovule grow into a seed. ✓
Method. Read the definition in section 3.2.
- Read the definition. After fertilisation the ovule grows into a seed.grows into a seed
- Name it. So the word is seed.seed
- Write the answer. seed
Check. The seed can then be dispersed. ✓
Method. Read the definition in section 3.2.
- Read the definition. Seeds are spread away from the parent plant, which is called seed dispersal.seed dispersal
- Fill the gap. So the missing word is dispersal.dispersal
- Write the answer. dispersal
Check. Dispersal means scattering. ✓
Method. Read the row for the coconut.
- Read the row. The coconut row says water carries it along.water carries it
- Choose the word. So the coconut seed is spread by water.water
- Write the answer. water
Check. A coconut can float across the sea. ✓
Method. Read the table.
- Read the table. The burdock row says hooks stick to the fur of animals.hooks
- Name the plant. So the seed is from the burdock, which is also called a burr.burdock (burr)
- Write the answer. burdock (burr)
Check. Animals carry the seed away on their fur. ✓
Method. Read the insect column.
- Read the insect column. The insect-pollinated flower has large and bright petals, and often a scent.large and bright
- Choose the word. So the flowers are insect-pollinated.insect
- Write the answer. insect
Check. Insects are attracted by bright petals and scent. ✓
Method. Read the pollen row.
- Read the pollen row. Wind-pollinated flowers have light, dry pollen that blows.light, dry pollen
- Choose the word. So the flower is wind-pollinated.wind
- Write the answer. wind
Check. Grass has light pollen that the wind carries. ✓
Method. Read the labels in the picture.
- Read the labels. The label for the female part says carpel, which holds ovules.carpel
- Name it. So the answer is carpel.carpel
- Write the answer. carpel
Check. The ovules are inside the ovary. ✓
Method. Think about the steps from pollen to seed.
- Think about the pollen. Pollen must reach an ovule before fertilisation can happen.reach an ovule
- Write the reason. Only after fertilisation does the ovule grow into a seed.grow into a seed
- Write the answer. Accept any sentence that says pollen must reach an ovule, by fertilisation, before the ovule can grow into a seed.
Check. Pollination is the first step in making seeds. ✓
Reproduction in animals
Many animals reproduce by sexual reproduction. A male and a female are needed. The male makes sperm and the female makes eggs. When a sperm joins with an egg, this is fertilisation. The fertilised egg then develops into a new young animal.
In a frog, the eggs are fertilised outside the female, in water, as the male releases sperm over the spawn. In a blackbird, the egg is fertilised inside the female, and the egg is laid with a hard shell. In a cat, the young develop inside the mother.
| Animal | Where the young start |
|---|---|
| frog | eggs laid in water, as spawn |
| blackbird | eggs laid in a nest |
| cat | young develop inside the mother |
| butterfly | eggs laid on a leaf |
Key ideas
- Sexual reproduction needs a male and a female.
- The male makes sperm, and the female makes eggs.
- Fertilisation is when a sperm joins with an egg.
- The fertilised egg develops into a new young animal.
Method. Read the table in section 3.3.
- Read the table. The table says the cat’s young develop inside the mother.inside the mother
- Name the animal. So the animal is the cat.cat
- Write the answer. cat
Check. A mammal’s young develop inside the mother. ✓
Method. Read the key idea in section 3.3.
- Read the key idea. The male makes sperm, and the female makes eggs.male makes sperm
- Name it. So the male makes sperm.sperm
- Write the answer. sperm
Check. Sperm and egg join in fertilisation. ✓
Method. Read the description of the frog.
- Read the description. In a frog, the eggs are fertilised outside the female, in water.outside the female
- Decide. So the answer is no.no
- Write the answer. no
Check. The male releases sperm over the spawn in water. ✓
Watch out
Watch out: sperm and eggs are not the young animal. Fertilisation makes one fertilised egg, which then develops into a young animal.
Try it (with your teacher or a grown-up). Look at pictures of animal parents and their young, in a book or on a poster. For each animal, write whether the young develop inside the parent, or start as an egg outside it. Draw one arrow from each parent to its young, and label it. This is a model, so do not touch any real animals.
Exam tip
Grown-up tip. Ask: “Where is the egg fertilised? Where do the young develop?” Keep to the animals in the chapter, and let your child answer in their own words.
Exercise 3C Reproduction in animals
Method. Read the table in section 3.3.
- Read the table. The frog lays its eggs in water, as spawn.in water
- Name the animal. So the animal is the frog.frog
- Write the answer. frog
Check. Frog spawn is fertilised in the water. ✓
Method. Read the table in section 3.3.
- Read the table. The cat’s young develop inside the mother.inside the mother
- Name the animal. So the animal is the cat.cat
- Write the answer. cat
Check. Most mammals develop their young inside the mother. ✓
Method. Read the key idea in section 3.3.
- Read the key idea. The male makes sperm, and the female makes eggs.male makes sperm
- Name it. So the word is sperm.sperm
- Write the answer. sperm
Check. Sperm and eggs are the reproductive cells. ✓
Method. Read the key idea in section 3.3.
- Read the key idea. When a sperm joins with an egg, this is fertilisation.joins with an egg
- Name it. So the word is fertilisation.fertilisation
- Write the answer. fertilisation
Check. The fertilised egg then develops into a young animal. ✓
Method. Read the key idea in section 3.3.
- Read the key idea. Sexual reproduction needs a male and a female.a male and a female
- Fill the gap. So the missing word is female.female
- Write the answer. female
Check. The female makes eggs. ✓
Method. Read the description in section 3.3.
- Read the description. In a blackbird, the egg is fertilised inside the female, and then laid with a hard shell.inside the female
- Decide. So the answer is yes.yes
- Write the answer. yes
Check. The hard shell is added after fertilisation. ✓
Method. Read the description in section 3.3.
- Read the description. In a frog the eggs are fertilised outside the female, in water.outside the female
- Decide. So the answer is no.no
- Write the answer. no
Check. The male releases sperm over the spawn. ✓
Method. Read the table, and find the rows that say the young start inside.
- Read the rows. The cat’s young develop inside the mother. The blackbird’s egg is fertilised inside the mother.two rows
- Name the animals. So the two animals are the cat and the blackbird.cat and blackbird
- Write the answer. cat and blackbird
Check. The table gives the frog and butterfly as the other two. ✓
Method. Read the table.
- Read the rows. The frog lays spawn in water, and the butterfly lays its eggs on a leaf.outside
- Name the animals. So the two animals are the frog and the butterfly.frog and butterfly
- Write the answer. frog and butterfly
Check. Both lay their eggs outside the body of the parent. ✓
Method. Think about what the joined cell is called.
- Think about the join. When a sperm joins with an egg, the cell formed is called a fertilised egg.fertilised egg
- Name the cell. So the answer is fertilised egg.fertilised egg
- Write the answer. fertilised egg
Check. The fertilised egg develops into a young animal. ✓
Method. Think about the start of a new animal.
- Think about the egg. An egg alone does not develop into a young animal.alone
- Write the reason. Fertilisation makes the fertilised egg, which develops into the young.develops into the young
- Write the answer. Accept any sentence that says fertilisation is needed to make the fertilised egg, which then develops into a young animal.
Check. Fertilisation is the start of a new animal. ✓
Many young and many seeds
Many plants make a lot of seeds, and many animals make a lot of eggs or young. Not all of them will survive. Some will be eaten, some will land where they cannot grow, and some will not find enough food or water.
By making many seeds or young, a plant or animal increases the chance that some of them will survive to reproduce. Plants and animals both reproduce in this way.
The table in the class investigation shows the counts of seeds on five dandelion seed heads. Each head is one trial.
| Seed head | Seeds counted |
|---|---|
| Head 1 | 94 |
| Head 2 | 102 |
| Head 3 | 88 |
| Head 4 | 110 |
| Head 5 | 96 |
Key ideas
- Many plants make many seeds, and many animals make many eggs or young.
- Not all seeds or young survive, so making many gives a better chance that some will.
- Seeds can be carried far from the parent plant by the wind, water or animals.
- The mean of several trials is found by adding them and dividing by how many there are.
Method. Find the row for head 4.
- Find the row. Head 4 is the fourth row in the table.head 4
- Read the count. The count on head 4 is 110 seeds.110
- Write the answer. 110
Check. The count for head 4 is the largest in the table. ✓
Method. Add the five counts, then divide by five.
- Add the counts. The five counts add together to make 490.94 + 102 + 88 + 110 + 96 = 490
- Divide by five. Divide 490 by 5 to find the mean.490 divided by 5 is 98
- Write the answer. 98
Check. Check: 98 + 98 + 98 + 98 + 98 = 490. ✓
Watch out. Divide by five, because there are five seed heads.
Method. Find the smallest count.
- Look at the counts. The counts are 94, 102, 88, 110 and 96.88 is smallest
- Name the count. The smallest count is 88, on head 3.88
- Write the answer. 88
Check. The mean is 98, and 88 is below it. ✓
Watch out
Watch out: a plant that makes many seeds does not guarantee that all of them will grow. Many seeds give a better chance, but not a certain one.
Try it (with your teacher or a grown-up). With a grown-up, find a dandelion seed head in a garden or a park, but only pick one if it is on the ground. Count the seeds on it. Then gently blow on it, away from your face, and watch which way the seeds go. Repeat with a second seed head, and find the mean of your two counts.
Exam tip
Grown-up tip. Ask: “Why do you think the plant makes so many seeds? Where did each seed go?” Let your child find the mean of two counts.
Exercise 3D Many young and many seeds
Method. Find the second row of the table.
- Find the row. Head 2 is the second row.head 2
- Read the count. The count for head 2 is 102.102
- Write the answer. 102
Check. Head 2 has more seeds than head 1. ✓
Method. Compare the counts.
- Compare the counts. The counts are 94, 102, 88, 110 and 96.110 is largest
- Name the head. The largest count is 110, on head 4.Head 4
- Write the answer. Head 4
Check. Head 4 has 110 seeds. ✓
Method. Add the five counts.
- Add the counts. Add 94, 102, 88, 110 and 96.94 + 102 + 88 + 110 + 96
- Find the total. The total is 490.490
- Write the answer. 490
Check. Check: 490 divided by 5 is 98. ✓
Method. Divide the total by five.
- Find the total. The total is 490 seeds.490
- Divide by five. Divide 490 by 5 to find the mean.490 divided by 5 is 98
- Write the answer. 98
Check. Check: 98 times 5 is 490. ✓
Method. Compare each count with the mean.
- Compare the counts. Head 2 has 102, and head 4 has 110. Both are above 98.102 and 110
- Name the heads. Heads 2 and 4 are above the mean.Head 2 and Head 4
- Write the answer. Head 2 and Head 4
Check. The other counts are 94, 88 and 96, all below 98. ✓
Method. Subtract the smallest count from the largest.
- Find the largest and smallest. The largest is 110, and the smallest is 88.110 and 88
- Subtract. The difference is 110 minus 88, which is 22.110 - 88 = 22
- Write the answer. 22
Check. Check: 88 + 22 = 110. ✓
Method. Read the key idea in section 3.4.
- Read the key idea. Many seeds give a better chance that some will survive.better chance
- Fill the gap. So the missing word is chance.chance
- Write the answer. chance
Check. Not all seeds or young survive. ✓
Method. Think about what happens to seeds.
- Think about the seeds. Some seeds are eaten, and some land where they cannot grow.eaten
- Decide. So not every seed grows into a plant, and the answer is no.no
- Write the answer. no
Check. This is why plants make many seeds. ✓
Method. Think about the chances of survival.
- Think about the many. Many seeds or young are made because many will not survive.many will not survive
- Write the reason. So more of them have a chance to survive and reproduce.survive and reproduce
- Write the answer. Accept any sentence that says many seeds or young give a better chance that some will survive to reproduce.
Check. Survival of some young keeps the species going. ✓
Method. Think about the seed and the wind.
- Think about the parachute. The seed has a parachute of fine hairs.fine hairs
- Write the reason. The wind carries the seed away, so it has room to grow.room to grow
- Write the answer. Accept any sentence that says the parachute of fine hairs lets the wind carry the seed away from the parent, so it is less crowded.
Check. Seeds that land far away have less competition from the parent. ✓
Comparing reproduction in plants and animals
Plants and animals both reproduce. Both produce new living things of their own kind. Some plants make seeds, and some animals make eggs. Some plants can also make new plants without seeds, by runners, plantlets and tubers.
Comparing them helps us see what is the same and what is different:
- a flowering plant makes seeds after pollination and fertilisation; an animal makes young after fertilisation of an egg;
- both plants and animals produce many seeds or young, so that some will survive;
- a runner or a plantlet is a copy of its parent, so it has the same features.
Key ideas
- Plants and animals both reproduce to make new living things of their own kind.
- A flowering plant makes seeds. An animal makes eggs or young.
- Fertilisation is needed to make a seed or a fertilised egg.
- Many plants and animals produce many seeds or young, so that some will survive.
Method. Think about what fertilisation makes.
- Think about fertilisation. Fertilisation makes the ovule grow into a seed.grow into a seed
- Name it. So the answer is seed.seed
- Write the answer. seed
Check. A runner is made without seeds, so it is not made by fertilisation. ✓
Method. Think about how the new plant is made.
- Think about the runner. The new plant grows from part of the parent, without seeds.grows from the parent
- Decide. So the new plant is a copy of its parent.yes
- Write the answer. yes
Check. Runners give plants with the same features. ✓
Method. Read the animal table in section 3.3.
- Read the table. The cat’s young develop inside the mother.inside the mother
- Name the animal. So the answer is cat.cat
- Write the answer. cat
Check. A frog lays its eggs in water. ✓
Watch out
Watch out: a runner is not a seed. A new plant from a runner is made without seeds, and it is a copy of its parent.
Try it (with your teacher or a grown-up). Make a two-column table with your teacher. In one column write what a plant does to reproduce, and in the other what an animal does. Find one thing that is the same, and one thing that is different. Read your table aloud to a friend.
Exam tip
Grown-up tip. Ask: “What is the same about plants and animals when they reproduce? What is different?” Let your child explain using the table.
Exercise 3E Comparing reproduction in plants and animals
Method. Read the first paragraph of section 3.5.
- Read the paragraph. Plants and animals both reproduce.both reproduce
- Name the process. So the word is reproduce.reproduce
- Write the answer. reproduce
Check. Reproduction makes new living things of their own kind. ✓
Method. Read the bullet points in section 3.5.
- Read the bullet. A flowering plant makes seeds after pollination and fertilisation.makes seeds
- Name it. So the answer is seed.seed
- Write the answer. seed
Check. The ovule grows into a seed after fertilisation. ✓
Method. Read the bullet points in section 3.5.
- Read the bullet. An animal makes young after fertilisation of an egg.fertilisation of an egg
- Name it. So the word is egg, which is fertilised first.egg
- Write the answer. egg
Check. The fertilised egg develops into the young. ✓
Method. Think about how a runner grows.
- Think about the runner. A runner grows from part of the parent plant, without seeds.without seeds
- Decide. So a runner is not made by fertilisation.no
- Write the answer. no
Check. Runners reproduce without seeds. ✓
Method. Think about what the new plant comes from.
- Think about the source. The new plant grows from part of the parent.part of the parent
- Decide. So it has the same features, and the answer is yes.yes
- Write the answer. yes
Check. A plant from a runner is a copy of its parent. ✓
Method. Read the word in the key ideas for section 3.4.
- Read the key idea. The mean is found by adding the trials and dividing by how many there are.adding and dividing
- Name it. So the average of the five counts is the mean.mean
- Write the answer. mean
Check. The mean of the five counts is 98. ✓
Method. Read the animal table in section 3.3.
- Read the table. The frog and the butterfly both lay their eggs outside the parent.outside the parent
- Name the animals. So the two animals are the frog and the butterfly.frog and butterfly
- Write the answer. frog and butterfly
Check. Blackbirds and cats do not lay eggs outside the parent in this way. ✓
Method. Think about what plants and animals share.
- Think about the process. Plants and animals both reproduce to make new living things of their own kind.their own kind
- Write one thing. Both also make many seeds or young, so that some survive.some survive
- Write the answer. Accept any one of: both make new living things of their own kind; both make many seeds or young so that some survive.
Check. Reproduction is the same life process in both. ✓
Method. Think about the seeds and the young.
- Think about the seeds. A flowering plant makes seeds in flowers.seeds in flowers
- Think about the animals. An animal makes eggs or young that develop into young animals.eggs or young
- Write the answer. Accept any one of: plants make seeds in flowers, but animals make eggs or young; some plants reproduce without seeds, using runners.
Check. The methods are different, but the life process is the same. ✓
Method. Compare how each starts a new plant.
- Think about the runner. A runner grows a copy of the parent without seeds.without seeds
- Think about the seed. A seed comes from fertilisation and can be spread away from the parent.spread away
- Write the answer. Accept any sentence that says a runner grows a copy of the parent without seeds, while a seed comes from fertilisation and can be spread away.
Check. Both ways make new plants, but they start differently. ✓
Chapter summary
| Skill | Method |
|---|---|
| Reproduction | Living things make new living things of their own kind. |
| Flowers and seeds | Pollen moves to a stigma; fertilisation joins a pollen grain with an ovule, which grows into a seed. |
| Seed dispersal | Seeds are spread by wind, water, animals or by pods splitting open. |
| Without seeds | Runners, plantlets and tubers can make new plants that are copies of the parent. |
| Animals | A sperm joins with an egg in fertilisation. The fertilised egg develops into a young animal. |
| Many young | Many seeds or young give a better chance that some will survive. |
Can you…?
- I can explain what reproduction means, and give examples of plants that reproduce without seeds
- I can describe pollination, fertilisation and seed dispersal in a flowering plant
- I can describe how a sperm and an egg join, and how the young of some animals develop
- I can explain why many plants and animals make many seeds or young
- I can compare how plants and animals reproduce, using a table
Key terms
- reproduction
- the life process by which living things make new living things of their own kind
- pollination
- when pollen moves from a stamen to the stigma of a flower
- fertilisation
- when a pollen grain or a sperm joins with an ovule or an egg
- seed dispersal
- the spreading of seeds away from the parent plant
- runner
- a stem that grows along the ground and roots to make a new plant
- plantlet
- a small new plant that grows on the end of a stem
- tuber
- a swollen underground part of a plant, which can grow a new plant
- sperm
- the male cell that joins with an egg
- ovule
- the part inside the ovary that becomes a seed after fertilisation
- sexual reproduction
- reproduction that needs a male and a female, and joins a sperm with an egg
Exercise 3Z Check-up
Method. Read the labels in the picture.
- Read the labels. The female part is labelled carpel, and it holds the ovules.carpel
- Name it. So the answer is carpel.carpel
- Write the answer. carpel
Check. The ovules become seeds after fertilisation. ✓
Method. Read the labels in the picture.
- Read the picture. The arrow shows pollen moving from one flower to another.arrow
- Name it. The word is pollination.pollination
- Write the answer. pollination
Check. Pollination comes before fertilisation. ✓
Method. Think about how runners work.
- Think about the runner. A runner takes root and grows a new plant without seeds.without seeds
- Decide. So the answer is no.no
- Write the answer. no
Check. Runners are a way to reproduce without seeds. ✓
Method. Read section 3.2.
- Read the definition. Seed dispersal is the spreading of seeds away from the parent plant.spreading
- Name it. The word is dispersal.dispersal
- Write the answer. dispersal
Check. Seeds can be dispersed by wind, water, animals or pods. ✓
Method. Read the dandelion row.
- Read the row. The dandelion row says wind carries its fluffy seeds.wind
- Name it. So the dandelion seed is spread by wind.wind
- Write the answer. wind
Check. The fine hairs act like a parachute. ✓
Method. Read the animal table in section 3.3.
- Read the table. The cat’s young develop inside the mother.inside the mother
- Name the animal. So the animal is the cat.cat
- Write the answer. cat
Check. Most mammals develop their young inside the mother. ✓
Method. Read the labels in the picture.
- Read the labels. The egg and the sperm join to make one cell.one cell
- Name it. The joined cell is a fertilised egg.fertilised egg
- Write the answer. fertilised egg
Check. The fertilised egg develops into a young animal. ✓
Method. Add the counts, then divide by five.
- Add the counts. The counts add to 490.490
- Divide by five. Divide 490 by 5 to get 98.98
- Write the answer. 98
Check. Check: 98 times 5 is 490. ✓
Method. Think about what happens to the young and the seeds.
- Think about the many. Not all seeds or young survive.not all survive
- Write the reason. So making many gives a better chance that some will survive.better chance
- Write the answer. Accept any sentence that says many seeds or young give a better chance that some will survive to reproduce.
Check. Survival of some keeps the living thing going. ✓
Method. Think about the steps.
- Think about the pollen. Pollen must reach the stigma of a flower.reach the stigma
- Write the reason. Fertilisation then makes the ovule grow into a seed.grow into a seed
- Write the answer. Accept any sentence that says pollen must reach an ovule by pollination and fertilisation before the ovule can grow into a seed.
Check. Pollination is the first step in making a seed. ✓
Total 16 marks. Allow about 16 minutes.
Exercise 3X Practice test questions
Method. Read the definition in section 3.1.
- Read the definition. Reproduction is the process by which living things make new living things of their own kind.their own kind
- Name it. The word is reproduction.reproduction
- Write the answer. reproduction
Check. Reproduction keeps a type of living thing going. ✓
Method. Think about the male part of the flower.
- Think about the parts. The stamen makes pollen.makes pollen
- Name it. The word is stamen.stamen
- Write the answer. stamen
Check. The carpel is the female part. ✓
Method. Read the dispersal table.
- Read the table. The burdock, or burr, has hooks that stick to the fur of animals.hooks
- Name the plant. So the word is burdock.burdock
- Write the answer. burdock
Check. The hooks stick to fur, so animals carry the seed away. ✓
Method. Read section 3.3.
- Read the key idea. When a sperm joins with an egg, this is fertilisation.joins with an egg
- Name it. The word is fertilisation.fertilisation
- Write the answer. fertilisation
Check. Fertilisation starts the development of a young animal. ✓
| Seed head | Seeds counted |
|---|---|
| Head 1 | 94 |
| Head 2 | 102 |
| Head 3 | 88 |
| Head 4 | 110 |
| Head 5 | 96 |
Method. Find the third row of the table.
- Find the row. Head 3 is the third row, with a count of 88.head 3
- Read the count. So head 3 had 88 seeds.88
- Write the answer. 88
Check. The mean of all five heads is 98. ✓
Method. Add the counts, then divide by five.
- Add the counts. The counts add to 490.94 + 102 + 88 + 110 + 96 = 490
- Divide by five. Divide 490 by 5 to get 98.490 divided by 5 is 98
- Write the answer. 98
Check. Check: 98 times 5 is 490. ✓
Method. Think about where the new plant grows from.
- Think about the runner. The new plant grows from part of the parent plant.part of the parent
- Give the reason. So it has the same features as the parent.same features
- Write the answer. yes. Accept any reason that says the new plant grows from part of the parent, so it has the same features.
Check. Reproduction without seeds makes a copy. ✓
Method. Compare the two.
- Think about the plant. A flowering plant makes seeds after pollination and fertilisation.seeds
- Think about the frog. A frog’s eggs are fertilised outside the female, in water, as spawn.in water
- Write the answer. Accept any one difference, such as: a flowering plant makes seeds after pollination, but a frog’s eggs are fertilised in water as spawn.
Check. Both reproduce, but in different ways. ✓
Method. Think about what happens to the young.
- Think about the many. Not all of the seeds or young will survive.not all survive
- Write the reason. So making many gives a better chance that some will survive.better chance
- Write the answer. Accept any sentence that says many seeds or young give a better chance that some will survive to reproduce.
Check. Survival of some young keeps the living thing going. ✓
Method. Compare where the young start.
- Think about the frog. The frog lays its eggs in water, outside its body.outside its body
- Think about the cat. The cat’s young develop inside the mother.inside the mother
- Write the answer. Accept any sentence that says the frog lays eggs outside its body in water, while the cat’s young develop inside the mother.
Check. Where the young start is one main difference. ✓