Year 5 Science: Many young and many seeds
Part of the Year 5 Science reproduction in plants and animals chapter. Chapter overview · whole chapter on one page
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. ✓