MODULE mod7A mod7B mod7C mod7D mod7E mod7F mod7G mod7H mod7I mod7J mod7K mod7L mod8A mod8B mod8C mod8D mod8E mod8F mod8G mod8H mod8I mod8J mod8K mod8L mod9A mod9B mod9C mod9D mod9E mod9F mod9G mod9H mod9I mod9J mod9K mod9L 7ba1
7Ba/1 Sexual reproduction
Name _____________________________ Class ____________
1 The pictures below show some adult animals and their young. Adult animals which have reproduced are called parents and their young are called offspring.
a On the line below each animal, say whether it is a parent or offspring.
b Draw lines between the pictures to show which parents have which offspring.
____________
2 Choose words from the brackets to complete these sentences.
For animals to produce offspring __________________ (fertilisation/pollination) must
happen. In this process two __________________ (body/sex) cells join together. The male
cell is called the __________________ (egg/sperm) cell and the female cell is called the
________________ (egg/sperm) cell. The joining of these cells makes a _________________
(fertilised/pollinated) egg cell.
3 Female frogs produce up to 20 000 egg cells at a time. If all of these were fertilised, they would produce many thousands of tadpoles. Most female cats, however, only produce four egg cells at a time.
a How many kittens does a female cat normally give birth to at a time? ______________
b How many babies does a human woman normally give birth to at a time? ___________
c How many egg cells do you think a human woman produces at a time? _____________
d Look at the pictures in question 1. Apart from frogs, name one other animal that you think produces thousands of egg cells at a time.
______________________________________________________________________
e Why do you think some animals produce so many egg cells at a time? Tick the correct answer.
So more egg cells are likely to survive.
To provide food for other hungry animals.
So less egg cells get eaten.
So the egg cells can be easily spotted.
[ knowledge, literacy ]
7Ba/2 Animal reproduction - data sheet
The table below gives information about how different animals reproduce and look after their young. First, look at this explanation of what the labels in the boxes mean:
- Type of animal - Whether the animal is an amphibian, bird, fish, mammal or reptile.
- Time for development - The length of time in days for an animal to develop from a fertilised egg cell until it is born or hatches.
- Number of young - The number of offspring that are usually born or hatch after the animals have mated.
- Aftercare - How long the parents look after their offspring.
- Fertilisation - Whether fertilisation is internal or external.
- Development - Whether the offspring develop inside their mothers, like humans (internal), or outside, like fish (external).
- Survival rate - The approximate percentage of offspring who will survive long enough to have offspring of their own.
Black rat snake
Bullfrog
Cod
Gorilla
Grey squirrel
Grey wolf
Type of animal
Reptile
Amphibian
Fish
Mammal
Time for development
3 months
20 days
25 days
8.5 months
38 days
Number of young
20
5000
3000
1
5
Aftercare
None
2.5 years
13 weeks
1 year
Fertilisation
Internal
External
Development
Survival rate
50%
1%
2%
60%
20%
40%
Hare
Harvest mouse
King penguin
Human
Lion
Polar bear
Bird
1.5 months
19 days
2 months
9 months
8 months
2
6
3
1 month
16 days
16 years
30%
15%
99%
Rat
Salmon
Sea turtle
Stickleback
Tiger
22 days
7 days
3.5 months
7
200
150
2 weeks
1 week
2 years
5%
7Ba/3 Animal reproduction 1
You will need a copy of Worksheet 7Ba/2.
Your teacher will tell you which of the following questions to answer.
1 a What does the 'time for development' mean?
b Which animal on the sheet has the shortest 'time for development'?
c How many months does it take for a baby gorilla to develop?
d How long is a baby gorilla cared for after it is born?
2 Human offspring are produced by internal fertilisation. The fertilised egg cells develop inside the mother - internal development.
a Name two other animals which use internal fertilisation and internal development.
b Name two animals which use internal fertilisation but external development.
c Name two animals which use external fertilisation and external development.
3 Edward has been asked to describe the pattern between the number of offspring that a mammal has and the amount of aftercare. He has started his answer. Copy the start of his answer and complete it.
Some mammals have lots of offspring but do not spend much time looking after them. Other mammals have fewer offspring but
4 a Suggest one reason why internal development is an advantage for the offspring.
b Suggest one reason why aftercare is an advantage for the offspring.
5 Describe the pattern between the sort of development and the number of offspring. Look at all the animals.
6 a Describe the pattern between the amount of aftercare and the survival rate.
b Try to give a reason for this pattern.
7 Which features of reproduction are the same for all mammals?
8 Josh looked at Worksheet 7Ba/2 and wrote 'Most amphibians use external fertilisation'. Do you think that there is enough data in this table to be able to say this? Explain your answer.
9 The figures for survival rate in humans are for the UK.
a Suggest reasons why the survival rate is so high.
b The survival rate for humans in poorer countries is lower. Suggest why.
[ considering ]
7Ba/4 Frog reproduction
Most frogs normally reproduce in May and June. You can sometimes hear them 'croaking' at this time. Only the males croak and they do this to attract females. Each male frog finds an area (called a territory) on the bank of a pond. The male frogs will fight any other frogs that come into their areas.
Each different sort (species) of frog has its own croak and so females are only attracted to males of the same species. In bullfrogs, the females are most attracted to the bullfrog males with the deepest croaks.
When a female frog of the right species has come into a male frog's territory, the male doesn't mess around! He leaps onto her back and holds on very tightly. The two frogs go into the water and the female releases her egg cells. As she does this the male releases sperm cells onto them. The egg cells are then fertilised by the sperm cells.
The fertilised egg cells then grow into embryos. The egg cells have a jelly coating on them. This provides a source of food for the developing embryo. After two or three weeks the tiny tadpoles break out of the jelly coat. The tadpoles have gills to take oxygen out of the water. They feed on tiny plants.
Over a period of months, the tadpoles grow. They then lose their tails and gills and change into frogs. Adult frogs eat insects and breathe using lungs.
Fertilised frog egg cells are often called frog spawn.
A tadpole.
1 Write down four key points about frog reproduction. You should write four short sentences only. You may not write more than 25 words.
2 a What happens during fertilisation?
b Do frogs use external or internal fertilisation?
3 How do frogs make sure that they attract female frogs of the same species?
4 What is a lump of fertilised frog egg cells often called?
5 Write down one way in which frog reproduction is similar to human reproduction.
6 Write down one way in which frog reproduction is different to human reproduction.
7 Female frogs often release hundreds or thousands of eggs into the water. Suggest two reasons why less than half of these ever turn into tadpoles.
Optional extras
8 The turning of a tadpole into an adult frog has a special name. Find out what it is.
9 Make key points about reproduction in two other animals - one mammal and one bird. Use books, CD-ROMs or the internet to find your information.
[ knowledge, literacy, research ]
7Ba/5 Animal reproduction 2
1 a Describe the pattern between the amount of aftercare and the survival rate.
2 The figures for survival rate in humans are for the UK.
c The figures for the survival rates in the other animals are for one selected region. Why do you think the survival rates will vary from region to region?
3 What do you think are the advantages and disadvantages of internal and external fertilisation. You could think about:
- the amount of energy an animal uses to produce lots of egg cells.
- the amount of egg cells and sperm cells that are wasted.
- how much time and effort it takes to find a mate (some animals will just release sperm and eggs into the water in roughly the same place).
4 a A female bullfrog will produce about 20 000 egg cells. Suggest two reasons why only about 5000 offspring are produced.
b Of these offspring, how many are likely to survive or be able to reproduce?
5 Sticklebacks are unlike most fish in that they do care for their offspring. Find out how they do this.
6 Humans need a lot of care for a long time. Write down two things a human child will need to be helped with at each of the following ages:
a 6 months
b 18 months
c 5 years.
7Bb/1 The female reproductive system
1 Label the parts of the female reproductive system on the diagrams. Use the words in the box below. Each word can be used more than once.
2 Complete these sentences using the words in the box. Each word can be used more than once.
bladder cervix oviducts ovaries urethra uterus vagina
a The egg cells are released from the __________________ .
b Egg cells travel down the _________________ on their way to the ________________.
c When a women is pregnant the ___________________ helps to hold the baby in place.
d A baby develops in the ___________________.
[ literacy, knowledge ]
7Bb/2 The male reproductive system
1 Label the parts of the male reproductive system on the diagrams.
Use the words in the box below. Each word can be used more than once.
2 Complete these sentences using words in the box. Each word can be used more than once.
bladder foreskin glands penis scrotum sperm duct testes urethra
a Sperm cells are made in the ___________________ .
b The tubes that sperm cells travel down on their way out of the body are the
___________________ and ___________________.
c The head of the penis is protected by the ___________________ .
d ___________________ add special liquids to the sperm cells to make semen.
7Bb/3 Reproductive system wordsearch
1 Find the following words in the grid below. Draw a coloured line through the words that you find. If the word is something found in the female reproductive system, draw a red line through it. If it is something found in the male reproductive system, draw a blue line through it.* If it is found in both, draw two lines (one red and one blue) through the word.
bladder cervix egg cell oviduct sex cell ovary
penis scrotum sperm cell sperm duct testis
urethra uterus vagina
P
A
M
O
U
S
E
N
F
G
R
T
D
B
V
Y
J
K
H
Q
L
Z
W
C
I
X
2 a Take the first nine letters of the first row of the grid and rearrange them to make a word.
b Explain what this word means. _____________________________________________
7Bb/4 Sex cells
1 The male and female sex cells have different shapes to help them do their jobs. They are said to be adapted to their jobs.
Here is a list of how cells can be adapted. In the space next to each sentence write the words sperm cell, egg cell, both or neither.
a It has a tail to help it to swim. __________________
b It has a food store. __________________
c It has special hairs on it to help it push things along. __________________
d It contains half the information needed to make a new life. __________________
e It has special chemicals on the tip of its head to help it get into things. __________________
f It has only a little cytoplasm so that it can have a thin, streamlined shape. __________________
2 a On the diagrams below label where the adaptations in question 1 are found. Just use the letters for the labels.
A sperm cell at a magnification of ×1000. An egg cell at a magnification of ×500.
b Look at the drawings of the sex cells above. On the lines below, write down how long or wide each one is in real life.
A sperm cell is _____________ mm long. Its head is _____________ mm wide.
An egg cell is _____________ mm wide.
[ knowledge, numeracy ]
7Bb/5 Reproductive organs
1 On the diagrams below, label the parts described in the sentences with the letters. The first one has been done for you.
A where female sex cells are made D where male sex cells are made
B where a baby could develop E a tube containing cells with cilia
C adds special fluids to sperm cells F protects the head of the penis.
2 Answer the following questions by circling the right answer.
a How often is an egg cell released from an ovary?
once a year once a day once a month once a decade never
b What does the cervix do?
holds a baby in place produces sperm cells produces egg cells
moves the egg cells
c What is the name given to the mixture of sperm cells and fluids?
sperm oviduct liquid scrotum urine semen
3 List the names of the tubes that sperm cells pass through on their way out of the body.
___________________________________________________________________________
4 Explain why sperm cells are made in a part of the body that hangs outside.
7Bb/6 Cervical cancer
Cervical cancer (cancer of the cervix) mainly affects women over the age of 20. Women are encouraged to go to the doctor to register for a 'smear test'. The 'smear test' is used to check whether a woman has any early signs of cancer. It needs to be repeated every 3 to 5 years during a woman's life. During the test a small sample of cells is taken from the cervix using a spatula. The cells are examined under a microscope to look for any that are a different shape from what they should be.
If some cancer cells are found, various treatments can be used. If the disease is found early enough, the treatment may be simple and the cancer cells can be removed by freezing them or treating them with a laser. If the cancer is more advanced, surgery may be needed along with chemotherapy (using chemicals to kill the cancer cells).
Although all women are advised to have regular 'smear tests', some women do not get them done. This may be because they feel they don't have time or because they do not like having the test done. The test is not painful but can be a little uncomfortable. 'Smear tests' were introduced in 1967 and at the moment about 80% of women in the UK have regular tests.
The graph shows the death rates from cervical cancer between 1950 and 1989 for women aged between 45 and 54.
1 What part of the body does cervical cancer affect?
2 a What is the test for cervical cancer commonly called?
b Explain what happens in this test.
c What are the advantages of having this test?
d What percentage of women do not get this test done?
e Give one reason why some women do not get the test done.
3 a Look at the graph. In 1965, how many women per million, between the ages of 45 and 54, died from cervical cancer?
b What has happened to the number of women dying from cervical cancer in this age group over the years?
c Give one reason why this has happened.
4 What is chemotherapy?
5 How would you try to encourage more women to go for regular tests for cervical cancer? Design a leaflet or poster.
[ knowledge, literacy, considering ]
7Bc/1 Fertilisation
Read the following passage and then answer the questions below.
About once every 28-32 days, an egg cell is released from an ovary. The egg cell travels down the oviduct. If it meets a sperm cell swimming in the opposite direction it will be fertilised. The fertilised egg cell continues down the oviduct. As it does this it divides into a ball of cells called an embryo. In the uterus, the embryo places itself in the uterus lining. This is called implantation. The uterus lining gives the embryo food and oxygen to grow.
1 The diagram below shows half of the female reproductive system. Cut out the pictures at the bottom of the page and stick them in the right places on the diagram.
2 Write a sentence for each one saying what is happening.
3 On the diagram, label the words in bold in the passage.
7Bc/2 Chromosome sorting
Cut out the chromosomes at the bottom of the page and stick them in pairs in the boxes. Each pair should look the same.
[ observing ]
7Bc/3 Human reproduction
1 Draw lines to match the words below with the correct meaning.
The first one has been done for you.
2 Which of these sentences are about human reproduction? Tick the correct boxes.
The sperm cell and the egg cell join (fuse) outside the female.
The sperm cell and the egg cell fuse inside the oviduct.
The sperm cell and the egg cell fuse inside the sperm duct.
The fertilised egg cell divides into two.
A ball of cells that will grow into a baby is called an embryo.
The embryo grows inside the uterus.
The embryo grows inside the ovary.
The embryo grows outside the female.
3 The nucleus of the egg cell contains half the instructions about how a new animal will look. The nucleus of the sperm cell contains the other half of the instructions. On the diagrams below label the nucleus in the sperm cell and the nucleus in the egg cell.
[ knowledge ]
7Bc/4 Making an embryo
1 The place where fertilisation normally occurs is marked on the diagram. Sperm cells start swimming when they get to the oviduct. A sperm cell is marked. Sperm cells swim about 1 mm in every minute.
a Work out how long it would take for the sperm cell to get to the egg cell.
Show your working.
b In the places marked on the diagram draw in the fertilised egg cell and the embryo.
c The fertilised egg cell turns into an embryo by cell division. The fertilised egg cell divides into two new cells. These two new cells divide into two more cells each. Draw two more diagrams to show what happens.
¾¾¾¾→ ¾¾¾¾→
fertilised egg cell
d Look at the last drawing you did. If each of these cells divides into two, how many cells
will the embryo now have? ________________________________________________
e What is implantation? ___________________________________________________
f On the diagram, label the place where implantation occurs.
2 These sentences are about twins. Write 'true' or 'false' by each sentence.
a Identical twins happen when a fertilised egg cell divides in two, but the two cells split apart. _______________
b Identical twins will always be different sexes. _______________
c Non-identical twins happen when two egg cells are fertilised. _______________
d Non-identical twins can be the same sex or different sexes. _______________
e Identical twins happen when two egg cells are fertilised. _______________
f Non-identical twins happen when egg cells turn into embryos on their own. _______________
7Bc/5 Contraception and sexually transmitted diseases
Many people want to have sex but do not want to have a baby. Unwanted pregnancies can be avoided by using contraception.
Some types of contraception stop sperm cells reaching the eggs.
Contraceptive pills (often known as 'the pill') work differently. They contain sex hormones which stop ovulation.
A month's supply of contraceptive pills
A condom is put over the man's penis.
A diaphragm is fitted over the woman's cervix.
These methods are very good at stopping pregnancies but none of them will prevent pregnancies 100% of the time.
Having sex carries the risk of getting a sexually transmitted disease. Some of these are caused by bacteria which get passed between men and women during sex. Syphilis is an example of a disease like this. It is an unpleasant disease but can be treated using antibiotics. Some sexually transmitted diseases cannot be cured. AIDS is a disease like this. It is caused by a virus called HIV. Using a condom helps to stop people catching these diseases since the rubber prevents the man's and woman's reproductive organs touching each other.
1 Name one form of contraception used by men and one used by women.
2 Do you think it is a good idea that humans can't reproduce until puberty? Why? Think about what life would be like for eight-year-olds if they were able to have babies.
3 Imagine you are 15. How would having a baby, which you have to look after all the time, affect your life at this age?
4 a Name two sexually transmitted diseases.
b For each, say what causes it.
5 Which form of contraception helps to prevent people catching these diseases?
[ literacy ]
7Bd/1 Being pregnant
Cut out the pictures below and stick them in the correct areas on the picture of the pregnant woman. Label the 'developing baby', 'bag filled with fluid' and the 'cord'.
7Bd/2 The menstrual cycle 1
1 The drawings at the bottom of the page show what the uterus lining looks like at various times during the menstrual cycle. Cut out the line which shows the number of days and then cut out the other drawings. Stick the drawings in order along the line showing the days.
2 a An egg cell is released about 14 days after the start of the menstrual cycle. What is this process called?
b If a woman starts her period on 3 January, on what date is the egg cell likely to be released?
3 The menstrual cycle varies in length from person to person but it normally takes about a month. If a woman has her period every 28 days, and she starts her period on 14 June, on what day would she expect to start her next period?
4 On the picture you made in question 1, label the following:
The lining gets thicker An egg is released
Fertilisation most likely to occur The lining breaks down
The lining stays thick
7Bd/3 The menstrual cycle 2
1 The diagram shows how the thickness of the lining of the uterus changes. Write these labels in the spaces above the diagram.
The lining breaks down The lining stays thick
2 Now complete these sentences using the words in the box.
blood fertilised menstruation ovaries ovulation period vagina
a Egg cells are released from the ___________________ . The time when they are
released is called ___________________. If the egg cell meets a sperm cell it
will be ___________________. If it does not, it will die.
b The time when the uterus lining breaks apart is called ___________________ . Another
name for this is 'having a ___________________.' During this time the uterus lining
and a little ___________________ passes out of the ___________________.
7Bd/4 Pregnancy
1 Fill in the missing words in the sentences below.
Use the words in the box.
bag of fluid carbon dioxide cord oviducts fertilisation
placenta oxygen sperm cell uterus
When a __________________ joins with an egg cell, this is called __________________ . It
happens in the __________________ . This is the start of a new life. The developing baby
grows inside the __________________ surrounded by a __________________ ______
__________________.
The developing baby is attached to the mother by the __________________.
At the end of the cord is the __________________ . This takes food and
__________________ from the mother's blood to give to the developing baby. Waste
materials, like __________________ __________________, are sent back to the mother here.
2 Draw lines from the diagram on the left to the correct name and then to the correct job.
Name
Bag of fluid
Placenta
Cord
Job
carries oxygen, food and waste between mother and baby
takes oxygen and food from the mother's blood
protects the baby
7Bd/5 The developing fetus
1 a Label the following parts on the drawing below.
amniotic fluid umbilical cord fetus placenta vagina uterus
b Add an arrow in pen to show the direction food and oxygen takes between the placenta and umbilical cord.
c Add an arrow in pencil to show the direction carbon dioxide and waste takes between the placenta and umbilical cord.
2 Fill in the table to show what each part does.
Part
Amniotic fluid
Umbilical cord
3 What do you think happens to the uterus as the fetus grows?
4 Name one thing that a pregnant woman should avoid doing and explain why.
7Bd/6 Pregnancy and birth
1 a On the diagram below, label the arrows to show what the fetus takes from the mother and what it gives back to the mother.
b The diagram is life size. Measure the width of the head. Use the graph to work out how
old it is. It is ____________________ old.
c For each of the substances that the baby takes from the mother, complete the table below to show what the substance is needed for and how it got into the mother.
Name of substance
What it's needed for
How the mother got it
2 Babies normally have a mass of about 4 kg when they are born. Sometimes babies are born early and they are much smaller than they should be.
a What is the name given to babies like this? ____________________________________
b Give one reason why a baby might be born like this. ____________________________
c Try to find out how babies like this are cared for in hospital and why they need special care.
[ knowledge, research, numeracy ]
For a diagram of a fetus without labels see Summary Sheet 7B.
7Bd/7 Growth and development of the fetus
The diagram shows how a baby develops during the course of pregnancy.
a fetus at 8 weeks at a scale of × 0.5
a fetus at 10 weeks at a scale of × 0.5
a fetus at 15 weeks at a scale of × 0.5
a fetus at 20 weeks at a scale of × 0.5
a fetus at 30 weeks at a scale of × 0.25
a fetus at 40 weeks at a scale of × 0.25
1 Why does the fetus appear to get smaller in the drawings at 30 weeks?
2 Measure the width of the head at each stage. Draw a table to show the weeks, the width of head on the drawings and the width of the head in real life.
3 Draw a line graph to show how the width of the head in real life changes over the weeks.
4 Use your graph to estimate the width of the head at 25 and 35 weeks.
5 Use your graph to find out how long it takes for the head to become 5 cm and 7 cm wide.
6 The head of the developing fetus grows much faster than other parts of the body. Why do you think this is?
7 What features are visible at 30 weeks which are not visible before this?
[ knowledge, numeracy, observing ]
7Be/1 Moral dilemmas
'A man has a very ill wife who is in a lot of pain. He can't afford the medicine that she needs to relieve the pain and so he breaks into a doctor's surgery and steals the medicine. Was he right to do this?'
1 Write down what you think about the man's actions.
Some people will say that the man was definitely right or wrong. Other people say that it depends on how ill the woman was or whether the man asked his friends to lend him some money first. They will not be able to give a definite answer.
Method
Conduct a survey. Ask people the question at the top of the page. Don't give them any help! Make a table like the one below for your results. You do not need to find people in every age group but you should ask a variety of people of different ages.
Recording your results
Considering your results/conclusions
2 Look at your results. Are older people less likely to give a 'yes' or a 'no' answer?
3 Try to explain why this is.
4 If you did this survey again, what would you do to improve it?
[ knowledge, considering, evaluating ]
7Be/2 Heights
You are going to measure the heights of the people in your class and plot a bar chart to show the heights.
Apparatus
- Metre ruler or tape measure
- Pencil
- Large blank sheet of paper
- Sticky tape or Blu-Tak
1 Find a wall that people can stand up against.
2 Stick the large piece of paper onto the wall, so that people's heads can rest against it.
3 Get each person in your group to stand up against the wall in turn.
4 Mark where the top of each person's head is, on the piece of paper.
5 Measure from the floor to each mark and write down the heights.
Results
1 Copy out the tally chart below. The left-hand column contains a series of height groups. Put a '1' in the middle column for each person you measured, putting the '1' in the correct height group. For example, if you have somebody with a height of 122 cm, you would put a '1' in the 120-124 height group.
Height group (cm)
People in the height group
Total number of people in the height group
100-104
105-109
110-114
115-119
120-124
125-129
130-134
135-139
140-144
145-149
150-154
155-159
160-165
Total number of people measured
2 Draw a bar chart to show this data. Put the total number of people in the height group on the vertical axis and the height groups on the horizontal axis.
3 What trend (or pattern) does your chart show?
4 Now look at this graph. It shows the heights of 3193 12 year olds from around the UK. How does your bar chart compare to this one - what are the main differences in shape?
Evaluation
5 a Why would it not be fair to add your teacher into this chart?
b What would happen to its shape if only girls' heights were measured?
c Are there any other factors (variables) that might change the way your chart looks?
6 The number of people that you measured is called the sample size. What sample size did you use?
7 a If you measured the height of every 12 year old in the country, would you expect it to look more like the graph of your class or the graph of the 3193 12 year olds?
b Explain why you think this. Use the words 'sample size' in your answer.
[ observing, considering, evaluating ]
7Be/3 Female changes
1 The drawing below shows how a girl changes into a woman. Either cut out the labels for each change and stick them into the correct boxes on the drawing or write the labels in the correct boxes.
2 Now label the 'uterus' and 'ovary'.
Breasts develop
Pubic hair grows
Hips get wider
Ovaries start to release eggs
Underarm hair grows
Periods begin
7Be/4 Male changes
1 The drawing below shows how a boy changes into a man. Either cut out the labels for each change and stick them into the correct boxes on the drawing or write the labels in the correct boxes.
2 Now label the 'penis' and 'testes'.
Shoulders get wider
Hair grows on face, chest and under arms
Voice deepens
Testes and penis get bigger
Testes start to make sperm cells
7Be/5 Giving birth
1 Number the sentences below to show which order they occur in.
Order
Stage of birth
The bag of fluid bursts
The baby is pushed out head first
The uterus starts to contract
The baby starts to breathe
The placenta is pushed out of the vagina
2 a The drawing below shows a new baby. On the drawing label the navel.
b What is the navel? _______________________________________________________
c The drawing is ten times smaller than real life. Measure the length of the baby and work
out how long it is in real life. _______________________________________________
d The baby has no teeth. Explain how it gets its food. _____________________________
e As soon as it is born, the baby starts to breathe. What organs does it use to do this?
f Draw in the positions of these organs on the drawing.
7Be/6 Human life-cycle
Here are some key features of the human life cycle. Use them to help you write a report. You will need to add extra information and you may have to remind yourself of some of the things. You could use diagrams in your report but keep your report short.
There are some blank boxes, so you can write down other things you want to write about. You may find it helpful to add arrows between the boxes to help you plan the order in which you will cover the features.
In the menstrual cycle, an egg cell is produced each month.
Men produce sperm cells in their testes.
Fertilisation occurs in the oviducts.
The embryo implants itself into the uterus lining.
The placenta takes substances from the mother's blood.
Pregnancy lasts 9 months.
The uterus contracts during birth.
The baby can be fed on milk produced in the breasts.
Big changes occur in boys and girls at puberty.
7Be/7 Problem page
How would you cope with being an agony aunt or uncle? Using your scientific knowledge, write answers to these problems. You need only write a sentence or two for each.
2 3
4 5
7Be/8 Being born
1 Write these words in order of size, smallest first: baby, fertilised egg cell, fetus, embryo.
2 a Label the drawing below with the following words:
uterus amnion cervix vagina placenta cord
b Which parts does the baby go through on its way out of the uterus?
c Which part breaks when the baby is ready to be born? ___________________________
d Which part needs to be cut after the baby has been born? ________________________
e Which part comes out as the afterbirth? _____________________________________
f How does a woman know that she is about to give birth? ________________________
g What is a navel? ________________________________________________________
3 a How is the baby protected inside the uterus? __________________________________
b How is it protected after birth? _____________________________________________
4 a How does the baby get food and oxygen in the uterus? __________________________
b How does it get these after birth? ___________________________________________
7Be/9 Drawing a growth graph
Mark's mother measured him regularly as he grew up. The data she collected is
shown below.
Age (years)
Height (cm)
0
50
121
12
156
0.5
67
6.5
124
12.5
Not measured
75
129
13
161
1.5
83
7.5
131
13.5
170
87
8
133
14
2.5
8.5
138
14.5
177
100
9
15
182
3.5
9.5
144
15.5
4
108
10
145
16
4.5
112
10.5
149
16.5
114
11
152
17
187
5.5
116
11.5
1 Use the data to plot a chart or graph. The first thing you need to decide on is whether you will use a bar chart or a line graph. Also, make sure you label the axes clearly. Make your horizontal axis go up to 20 years.
Use your chart or graph to answer the following questions.
2 Mark grew very quickly at two times in his life. Times when people grow very quickly are called 'growth spurts'.
a Between which ages did Mark have his first growth spurt?
b Between which ages did Mark have his second growth spurt?
c Do you think that all people have growth spurts at the same time? Explain your answer. You might consider other people in your class or in the year above.
3 Mark's mother forgot to measure him sometimes. From your graph, what height do you think Mark was when he was:
a 3.5 b 9 c 14?
4 Mark stopped growing when he was 19. Extend the line on your graph so that you can estimate what height Mark is now. Write down your estimate of his height.
5 a What happened to the number of cells in Mark's body as he grew?
b By what process does this happen?
7B Summary Sheets
Reproduction
Reproduction produces new living things (offspring). In sexual reproduction the nucleus in a male sex cell joins (fuses) with the nucleus in a female sex cell. This is called fertilisation and produces a fertilised egg cell. When fertilisation happens outside an animal's body it is called external fertilisation. Animals that use this method produce a lot of eggs since some will be eaten by other animals. Humans use internal fertilisation.
The fertilised egg cell grows into an embryo and the embryo eventually becomes a new living thing. Sexual reproduction needs two parents. The offspring from sexual reproduction are different from the parents; they are new varieties.
The human reproductive systems
Humans have reproductive organs so that they can reproduce. The ovaries and testes produce sex cells.
Puberty and adolescence
The reproductive organs get bigger and start to make sex cells at puberty. This is a time when major physical changes occur in our bodies. These changes are caused by sex hormones.
Changes in boys Changes in girls
- voice deepens ('breaks') - underarm hair grows
- shoulders get wider - breasts develop
- hair grows under arms, on face and on chest - ovaries start to release egg cells
- pubic hair grows - hips get wider
- testes and penis get bigger - pubic hair grows
- testes start to make sperm cells - body smell increases
- body smell increases
Adolescence is the time when puberty is occurring and emotional changes happen.
It starts between the ages of 10-15 and ends at about 18. The changes start sooner
in girls. After puberty, men produce sperm cells for the rest of their lives. Women stop releasing egg cells at the age of 45-55. This is called the menopause.
The menstrual cycle
The menstrual cycle starts with menstruation (the loss of the uterus lining and some blood through the vagina). It takes 28-32 days for each cycle. About 14 days after menstruation starts, an egg cell is released from an ovary. This is called ovulation. If the egg cell is not fertilised, the uterus lining starts to break down and the cycle starts again.
Sex
The sperm cells enter the vagina during sexual intercourse. Semen (sperm cells mixed with special liquids from the glands) is forced out of the penis and into the top of the vagina. This is called ejaculation. The semen is moved into the top of the uterus and the sperm cells can swim down the oviducts.
Egg cells and sperm cells are adapted to their functions.
Pregnancy
If the egg cell meets a sperm cell in an oviduct fertilisation can occur. The fertilised egg cell divides to form a ball of cells (an embryo). The embryo travels to the uterus where it sinks into the soft lining (implantation). The woman is now pregnant. Once it has developed all its organs (after about 10 weeks) it is called a fetus. It takes about 40 weeks (9 months) for a fertilised egg cell to grow into a baby ready to be born. This time is called the gestation period.
The fertilised egg cells of many animals grow and develop outside their parents. This is called external development. Humans use internal development and produce less offspring than animals using external development since the growing embryos are protected inside the mother.
While inside the uterus, the fetus is supplied with oxygen and food by the placenta. The placenta also gets rid of waste (especially carbon dioxide) from the fetus. The cord (or umbilical cord) connects the fetus to the placenta.
If a mother smokes, drinks too much alcohol or takes drugs while pregnant she might damage the baby. The baby might be premature.
Birth
When the baby is ready to be born, the uterus starts contractions and the woman goes into labour. The muscles of the cervix relax. The baby is pushed out head first through the cervix and the vagina. After birth, the baby starts to breathe and the cord is cut. The scar left behind is the navel. After this the placenta is pushed out of the uterus. This is the afterbirth. The baby is fed on milk, often from the mother's breasts which contain mammary glands that produce milk. The milk contains antibodies which help destroy microbes that might cause a disease in the baby.
For diagrams of where fertilisation occurs and a sperm cell see End of Unit Test 7B.
7B Target Sheet
Topic
Targets
Before the unit
I have learned this
I have revised this
7Ba
Know what fertilisation is.
Know why some animals produce large numbers of egg cells.
Know where the offspring of mammals develop inside their mothers.
Know why internal development of the offspring is better than external development.
7Bb
Know the names of the human reproductive organs and where they are.
Know how sperm cells are adapted to their functions.
Know how egg cells are adapted to their functions.
Know about the menopause.
7Bc
Know where fertilisation happens.
Know how a fertilised egg cell develops into an embryo.
Know about implantation.
Know why offspring have features from both parents.
7Bd
Know about the menstrual cycle.
Know how the developing baby is protected.
Know how the developing baby is supplied with food and oxygen and how waste is taken away.
Know some of the things a pregnant woman should avoid doing and about premature babies.
7Be
Know how long pregnancy lasts and how birth occurs.
Know how a new baby is fed and cared for.
Know what happens during puberty.
Know about growth and 'growth spurts'.
7B Word Sheets
Word sheets that include new words from the 'Focus on:' pages are available on the Exploring Science website.
7Ba - Starting out in life
Word
Pronunciation
Meaning
egg cell
The female sex cell.
external fertilisation
When fertilisation happens outside the bodies of the parents.
fertilisation
fert-ill-eyes-ay-shun
Fusing of a male sex cell with a female sex cell.
What is produced when a sperm cell fuses with an egg cell.
fuse
When two sex cells join together to form a fertilised egg cell they are said to fuse.
internal fertilisation
When fertilisation happens inside the bodies of the parents.
offspring
New organisms produced in reproduction.
parent
An organism that has had offspring.
sex cell
A cell used for sexual reproduction.
sexual reproduction
Producing new organisms by the joining of two sex cells.
sperm cell
The male sex cell.
uterus
you-ter-ous
A reproductive organ in female mammals where her fertilised egg cells grow and develop.
7Bb - Reproductive organs
vix
sir-vicks
Ring of muscle at the bottom of the uterus in females.
cilia
sil-lee-ah
Small hairs on the surface of some cells.
circumcision
sir-cum-siz-shun
Removal of the foreskin.
foreskin
A covering of skin protecting the head of the penis.
function
Something's job.
glands
The glands in the male reproductive system add a special liquid to the sperm cells to make semen. There are other sorts of glands in the body.
menopause
men-O-paws
When the ovaries in women stop releasing eggs.
ovary
O-very
Female reproductive organ. Produces egg cells.
oviduct
Carries egg cells from the ovaries to the uterus in women. Fertilisation happens here.
reproductive organs
Organs used in sexual reproduction.
reproductive system
All the reproductive organs.
scrotum
scrow-tum
Bag of skin containing the testes in males.
semen
see-men
A mixture of sperm cells and special fluids released by men during sexual intercourse.
sperm duct
Tube that carries sperm from the testes to the urethra.
testis
Male reproductive organ. Produces sperm cells. Plural = testes.
urethra
you-ree-thra
A tube carrying semen or urine running down the centre of the penis in males. A tube carrying urine in females.
Organ in females in which a baby develops.
vagina
vaj-eye-na
Tube in females. The penis is placed here during sexual intercourse.
7Bc - Sex
ejaculation
edge-ack-you-lay-shun
Semen is pumped out of a man's penis into the top of the vagina during sexual intercourse.
embryo
em-bree-O
Tiny new human life which grows by cell division from a fertilised egg cell.
erection
When the penis becomes stiff.
implantation
im-plant-ay-shun
When an embryo sinks into the soft lining of the uterus.
pregnant
When a woman has an embryo growing inside her uterus.
7Bd - Periods/Being pregnant/A healthy fetus
amnion
am-nee-on
Bag containing amniotic fluid.
amniotic fluid
am-nee-ot-tick
Liquid surrounding the growing embryo and protecting it.
ante-natal class
A pregnant woman and the father of the baby attend this to find out more about what happens during pregnancy and childbirth.
cord
Carries food, oxygen and waste between the placenta and the growing fetus.
fetus
fee-tus
After an embryo has grown all its organs it is called a fetus. This is usually at about 10 weeks.
mature
Another word for develop.
menstrual cycle
men-strew-al
Series of events lasting about a month, happening in the female reproductive system. The cycle causes ovulation and the lining of the uterus is replaced.
menstruation
men-strew-ay-shun
When the lining of the uterus and a little blood pass out of the vagina as part of the menstrual cycle.
ovulation
ov-you-lay-shun
Releasing of an egg cell from an ovary in women.
placenta
plas-en-ta
Attached to the uterus wall, this takes oxygen and food out of the mother's blood and puts waste materials into the mother's blood.
premature baby
A small baby born early.
sex hormones
hor-moans
Chemicals released in our bodies that control the menstrual cycle and puberty.
umbilical cord
um-bill-ick-al
See 'cord'.
7Be - Giving birth/Growing up
acne
ack-nee
Spots on the skin.
adolescence
add-ol-less-sense
Time when both physical and emotional changes occur in humans.
afterbirth
When the placenta is pushed out through the vagina.
antibodies
Substances produced by white blood cells that help to fight microbes which might cause diseases.
contractions
con-track-shuns
The uterus starts to push out the baby during labour.
gestation period
jess-tay-shun
The length of time from fertilisation to birth.
labour
Time when the baby is about to be born.
mammary glands
Glands contained in the breasts of women which produce milk after childbirth.
navel
nave-ell
Scar left by the cord. Often called the 'belly-button'.
puberty
pew-bert-ty
Time when physical changes happen in the body between the ages of about 11 and 15.