Download Multicellular Organisms Part 2 Reproduction

Multicellular
Organisms
Part 2
Reproduction
1
Reproduction Success Criteria
LI To explain what is meant by the term “reproduction” and name the sex
cells involved
LI To explain what happens during fertilisation
LI To be identify parts of the male and female reproduction organs and
state their function
LI To describe the journey of the zygote from site of fertilisation to
uterus and explain how the embryo is provided with food and protected in
the womb.
LI To understand that young mammals need care from parents in order to
survive
LI To describe fertilisation in fish and explain why this differs from
mammals
LI To observe the growth and development of Brine Shrimps and mating
pairs of adult Brine Shrimp
LI To explain the differences between mammals and fish in their care of
young
LI To understand the difference between sexual and asexual
reproduction in animals
LI To understand how growth and development of young after birth can
be affected by diet
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Reproduction
LI To explain what is meant by the term “reproduction” and name the sex
cells involved
Starter Activity: Play the true or false quiz with your teacher on power point 1
and test how much you know about reproduction!!
Reproduction is the production of new members of a species.
Discuss with your neighbour – why do you think reproduction is essential for the
survival of a species?
1. After class discussion, write a note explaining why reproduction is
essential for the survival of a species.
Sexual reproduction involves sex cells. Another name for sex cells is gametes.
The male gamete is called the sperm and the female gamete is called the egg.
2. Find the “Sex cells” diagram in your diagram pack and complete the
diagram using the information shown below:
Sperm
Egg
Nucleus
Head
Tail
Nucleus
Cytoplasm
(contains
food)
Cell membrane
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Your teacher will show you a presentation explaining the differences between
the sperm and the egg.
3. Copy the table below into your jotter and complete it using the word bank
at the bottom of the page.
Male
Female
Name of Sex Cell (gamete)
Size of Gamete
Food store
Ability to swim
Number of gametes
produced
Site of production (gonad)
Word Bank
ovaries
many
able to swim
larger
food store present
food store absent
sperm
few
smaller
testes
egg
unable to swim
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Fertilisation
LI To explain what happens during fertilisation
The egg produces a chemical that attracts the sperm. This causes the sperm to
swim towards the egg. The sperm’s aim is to try and fertilise the egg.
1. Read the following passage and answer the questions below.
Fertilisation is when the nucleus of the egg and sperm fuse. The egg and sperm
contain half the number of chromosomes of a normal body cell. When the
nucleus of the egg and sperm combine the fertilised egg will contain the correct
number of chromosomes, but a mixture of genetic information from both
parents (this increases variation in the species). Only one sperm can fertilise
one egg. When the sperm penetrates the egg, the egg creates a protective
barrier so no more sperm can enter. The fertilised egg is called a zygote. When
the zygote begins to divide by mitosis, it becomes known as an embryo. When it
begins to develop a distinct form it is known as a foetus.
Zygote
(fertilised egg)
The embryo continues to divide by mitosis
1. Complete the sentence using information from the passage:
When ……………………………….. occurs, the ………………………. of the sperm fuses with
the …………………………. of the ………………… The fertilised egg is known as a
……………………..
Fertilisation combines the ………………………. information which
is contained in the sperm and the egg.
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2. Complete the sentence by choosing the correct pairing in each bracket:
half the
The egg and the sperm contain
twice as much
genetic
information of a normal cell. When they combine the zygote
a full
contains
a double
complement of chromosomes.
3. How many sperm can fertilise an egg?
4. What is the name of the process that causes the zygote to divide,
becoming an embryo?
5. At what point does the embryo become known as a foetus?
Internal vs External Fertilisation
Some organisms carry out internal fertilisation, whilst others carry out external
fertilisation. Internal fertilisation occurs when the egg and sperm fuse inside
the body and is more common in land animals. External fertilisation is when
fertilisation occurs outside of the body and is more common in aquatic
organisms.
Sperm require a liquid in which to be able to swim. In land animals this is
provided by depositing sperm inside the female body, in liquid called semen. In
aquatic organisms sperm are deposited outside of the body.
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Discuss with your neighbour: Why do you think that it is necessary for land
animals to carry out internal fertilisation?
After class discussion, complete the question below:
1. Why is internal fertilisation essential for land animals?
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Human Reproductive System
LI To be able to identify parts of the male and female reproductive
systems and state their function
Mammals, including humans, use internal fertilisation. The male has a special
organ called the penis for placing sperm inside the female. During copulation
(mating) the penis is inserted into the vagina of the female and sperm are
released.
Listen as your teacher identifies parts of the male and female reproductive
systems and their functions.
1. Find you diagram of the “Human reproductive organs”. Label the
following structures on your diagram:

Penis

Vagina




Sperm duct
Testes
Scrotum
Urethra




Oviduct
Uterus
Cervix
Ovary
2. Insert an X on your diagram in the oviduct. Label it – “site of
fertilisation”.
3. Now complete the tables below the diagram using the phrases that follow:

Transports sperm from testes to urethra

Transports the egg from the ovary to the uterus by the action of cilia

Controls the temperature of the testis

Inserts into the vagina to deliver sperm

Connects uterus with external environment and site of insertion of the
penis

Site of attachment for embryo

Muscles that relax and dilate during child birth

Site of production of eggs (female gametes)

Site of production of sperm (male gametes)
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4. Complete your “Fertilisation” diagram in your diagram pack and stick in
your jotter.
5. Teacher Led Activity – optional
What to do
You will be given one of the following parts to play:




Ovary
Cilia
Sperm
Egg
Listen as your teacher tells you what to do.
Human Growth and Development – Puberty
Use the laptops to research the stages of puberty in males and females and
insert the information into your “Human Development – Puberty” diagram.
You can ask your teacher for where to look online if you need help.
A Step Ahead
Use any resources available to you to research the signs of:

Testicular Cancer

Cervical Cancer

Ovarian Cancer

Breast Cancer

Prostate Cancer
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Development of the Human Embryo
LI To describe the journey of the zygote from site of fertilisation to
uterus and explain how the embryo is provided with food and protected in
the womb.
Your teacher will show you several videos of a developing embryo:
babycenter.com
1. Teacher led Activity – Can you identify the human embryo from other
organisms on the PowerPoint?
What to do
Read the following passage very carefully and use the information to
complete the questions that follow:
The egg is fertilised in the oviduct and starts to develop as it passes to the
uterus. The fertilised egg (zygote) divides to produce a ball of cells. The
beating of tiny hairs and the muscular contraction of the oviduct move the
developing embryo towards the uterus.
In the uterus the embryo becomes attached to the lining of the uterus where it
continues to develop.
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The embryo is surrounded by the amniotic sac and is protected and cushioned
by amniotic fluid.
The embryo is attached to the placenta by the umbilical cord. In the placenta
food and oxygen pass from the mother to the baby and waste materials pass
from the baby to the mother.
At 8 weeks the embryo has a beating heart. By 12 weeks the embryo is now
called a foetus and all of its organs have developed including the brain. At weeks
13-16 the foetus can feel pain and kick its legs. By weeks 20-24 the foetus’
fingerprints are forming and it can practice breathing by inhaling amniotic fluid.
If the baby is born at weeks 25-28 it has a 60% chance of survival. The foetus’
brain is rapidly developing and it has control of some movements including
opening and closing its eyes. By weeks 29-40 the baby is now rapidly increasing
in size. Its head moves downwards, and by week 40 the baby’s eyes can
distinguish changes in light.
1. Complete the diagram “Protection of the Developing Embryo” using the
information in the passage to help you.
2. Complete the sentence below:
In mammals, a fertilised egg passes down the __________ and becomes
attached to the ______________ of the _______________. There it
develops inside a fluid filled bag called the ___________
________, which
cushions and protects the developing embryo.
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3. What is the name of the structure that allows the exchange of substances
between the mother and baby?
4. Draw and Complete the table and diagram below by inserting 2 substances:
 that pass from mother to baby
 that pass from baby to mother
Mother’s Blood
Placenta & Umbilical Cord
Embryo’s Blood
………………………………………………………..
………………………………………………………..
………………………………………………………
……………………………………………………..
5. Complete the diagram “The Developing Embryo” in your pack by cutting out
the diagrams and arranging them in the correct order. Then cut out and stick
the correct description of each stage of development under the diagram of the
developing embryo.
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Care of Young Mammals
LI To understand that young mammals need care from parents in order to
survive
When the baby has developed sufficiently to survive outside the mother’s body
it is born. The muscle walls of the uterus contract and push the baby out via the
vagina.
After birth the young mammals are dependent on the parents for care and
protection. This is particularly true for human babies who are dependent on
their parents longer than most mammals. The length and amount of protection
provided by parents greatly affects the offspring’s survival.
Young mammals are provided with on-going protection from
their parents after birth, such as:

the provision of food such as milk from the mother’s
mammary glands

the provision of shelter – building a “nest” to prevent
young mammals being taken by predators

the parent’s body heat – protecting young from low
temperatures.
1. Your teacher might show you a video of
what happens during birth – babycenter.com
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Reproduction in Fish – External Fertilisation
LI To describe fertilisation in fish and explain why this differs from
mammals
1. What is meant by the term external fertilisation?
2. Why is it possible for fish to use external fertilisation rather than internal
fertilisation?
Your teacher will show you a video:
“Medaka: Fish Reproduction” – Encyclopaedia Britannica
3. Watch the video carefully and answer the questions on the “Development of
the rice paddy fish” diagram in your diagram pack.
What to do
Now read the passage below and then answer the questions that follow:
Fish carry out external fertilisation. This means that they deposit their eggs
and sperm into the external environment where fertilisation takes place.
Very few species of fish protect their fertilised eggs; therefore many are
eaten by predators. Those that do survive rely mainly on the egg’s protective
membrane that is tough and flexible.
Fish embryos obtain food from the yolk contained inside the egg which remains
attached to the young hatchlings as a yolk sac. Even after the fish embryo has
hatched, many still do not survive and are eaten by predators.
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Fish lay a large number of eggs because there is a very low chance of sperm
actually reaching the eggs and because the unprotected fertilised eggs are
often eaten by predators. Producing many eggs ensures a sufficient number of
fish survive to adulthood to maintain the species. The following diagram shows
the life cycle of Salmon:
4. Complete the diagram in your diagram pack “Reproduction in Fish” using
information from the passage above.
5. Describe the level of care and protection fish provide their eggs. You should
mention:
 The structure of the egg
 The number of eggs produced
 How the fish embryo obtains food
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6. Give 2 reasons mentioned in the passage to explain why fish produce such a
large number of eggs.
7. Complete the “life cycle of fish” diagram by adding either a name or
description to each stage using the word bank provided to assist you.
What to do
You might watch the following clip from Finding Nemo.
Discuss with your neighbour: and answer the following questions?
1. Thinking about care of young in fish compared to mammals, give one true
representation and one fictional representation from the clip (hint: which part
was more like the care of mammals).
2. Thinking about chances of survival of fish embryos to adulthood, think of a
reason why Marlin would want most of the eggs to be called “Marlin Junior”?
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Brine Shrimp Practical
LI To observe the growth and development of brine shrimps and mating
pairs of adult brine shrimp
Copy the title, aim and results table for Experiment 1 below into your jotter.
Experiment 1: Life Cycle of brine shrimp
Aim: To observe the life cycle of Brine Shrimp
Method:
1. Add the dried brine shrimp eggs to the tank.
2. Each day you arrive in class for the next 3 weeks, check the brine shrimp
tank and record what you see in the table below.
Results:
Copy the following table into your jotter:
Day
Description of what you see
Number of Male Number of Female
Brine Shrimp
Brine Shrimp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
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1. Complete a “Life Cycle of brine shrimp” in your diagram pack and stick it in
your jotter diagram. Use the list below to help you label your diagram:
 Adults
 eggs
 hatching
 Naupliar (hatchling)
2. Complete the “Differences and Similarities of Male and Female brine
shrimp” diagram and stick it in your jotter. Use the information sheet at the
back of the pupil booklet to help you.
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Brine Shrimp Information Sheet
Adult brine shrimp are 8-14mm long. The males have a transparent body and a
blue-green colour and large claspers. The females are brown/red in colour and
have a brood pouch (or uterus) which hold many eggs.
Before the eggs are fertilised, the male clasps hold of the female with its
claspers and the pair swim around for some time. Brine shrimp differ from fish
fertilisation. The male brine shrimp inserts its penis into the uterus and
releases sperm, then the female releases the fertilised eggs.
Male
Female
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Experiment 2: Mating Pairs of Brine Shrimp
As you know, male and female brine shrimp have several physical differences
that allow us to identify them. Mating pairs will be seen to be clasped together
and swim faster than single female brine shrimps.
Brine shrimp will choose a suitable mate based on size. Large male brine shrimps
have more female mates than smaller male brine shrimps and large female brine
shrimps are less likely to mate with smaller males. Therefore, larger males
should be seen with larger females and vice versa. The following investigation
will be set up to test whether or not this is true.
Copy the title, aim, method and results table for Experiment 2 below into your
jotter.
Aim: To observe if size of male and female brine shrimp plays a part in mate
selection.
Method:
1. Observe the mating pairs and record the information in your table.
Results:
Complete the table by ticking the appropriate box for each mating pair
identified (add or remove the numbers of mating pairs depending on the sample
in front of you).
Number of
Mating Pairs
Large Male
with Large
Female
Large Male
with Small
Female
Small Male
with large
female
Small male
with small
female
1
2
3
4
5
6 (etc.)
Conclusion:
From your results – does size play a part in brine shrimp mate selection?
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Survival Values in Different Species
LI To explain the differences between mammals and fish in their care of
young
What to do
Animal
Rabbit
Trout
Human
Frog
1. Study the table below:
Number
of eggs
produced
8
3000
1
1000
Number
of eggs
fertilised
8
2000
1
750
Number
of eggs
diseased
0
200
0
50
Number
of eggs
eaten
0
800
0
200
Number
of Young
Eaten
4
850
0
400
2. Copy and complete the table below by using the data in the table above to
help you complete your calculations:
Animal
Total
Young
Surviving
Total
number
of eggs
produced
Percentage of Young Surviving to
adulthood (%)
total young surviving
total no. of eggs produced
x 100
Rabbit
Trout
Human
Frog
3. Use the results in your table to explain the relationship between the
following:



the number of eggs produced
the level of parental care
the percentage survival of young
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4. Copy and complete the following sentences by choosing the correct word in
each set of brackets:
lowest
Mammals have the
percentage survival.
highest
Mammals
Fish
have the lowest percentage survival of young.
fish
This is because
mammals
take better care of their young.
5. The table below summarises reproduction in fish compared to mammals. Copy
and complete the table below by adding the correct word from the word bank
below. The each word may be used once or more than once.
Animal
Type of
Number Chances of Protection Parental
Chances of
fertilisation of eggs
fertilisation of eggs
protection successful
produced
of young
development
of embryo
Fish
Mammal
Word Bank:
external
good
poor
many
few
internal
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Asexual Reproduction in Animals
LI To understand the difference between sexual and asexual
reproduction in animals
Discuss with a partner the differences between asexual and sexual
reproduction.
Can you think of any animals that reproduce asexually?
Your teacher will show you a video clip on one type of asexual
reproduction (budding).
What to do
 Now make a plasticine model of the stages of Hydra budding.
 ‘Budding in Hydra’ then use class resources to draw and label a
diagram of Hydra budding.
Binary Fission
Binary Fission is another type of asexual reproduction in which single
- celled organisms, e.g. Amoeba reproduces by splitting in two.
What to do
Complete your ‘Binary Fission’ diagram by labelling the pictures
appropriately.
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Advantages & Disadvantages of Asexual Reproduction
With a partner, complete the card sort activity by deciding whether
the statements on the card are an advantage or disadvantage of
asexual reproduction.
Teacher Check!
What to do
Copy and complete the following table, by writing the
statements under the correct heading.
Advantages of Asexual
Reproduction
Disadvantages of Asexual
Reproduction
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Growth and Development of Young
LI To understand how growth and development of young after birth can be
affected by diet
What to do
Create a pamphlet for parents and children, to be displayed in a health
centre that will highlight the importance of a healthy diet on children’s
growth and development.
Choose one of the following topic areas to research and create your pamphlet
on:






Failure to thrive
Obesity & Type to Diabetes
Anorexia Nervosa (you could link this to related disorders that occur in
young people with anorexia such as osteoporosis)
Rickets
Celiac Disease
Lactose intolerance
Your pamphlet should include:

A large title

The following information:
o A definition of the condition you are investigating
o The signs and symptoms of the condition you are investigating
o The causes of the condition you are investigating
o How to treat or avoid developing the condition you are investigating

A balanced mix of text and pictures

Sources showing where you found your information
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Growth & Development Disorders
Balloon Debate
There is a clear link between a person’s diet and growth or development
disorders.
 You are going to choose one of the components of a diet (below)
to research.
 You will come up with arguments as to why your dietary
component is the most important.
 You will then present your arguments to the class.
 The whole class votes on the dietary component that they think
are most important.
Choose one of the following components of a diet to research:
 Folic Acid
 Vitamin D
 Iron
 Calcium
 Iodine
 Vitamin B
 Vitamin A
 Vitamin K
 Protein
What to do
Here
1.
2.
3.
are some questions to help you get started:
Which foods contain your chosen component?
What is the function of your chosen diet component?
What happens if a person’s diet does not contain enough of it? Is
there a name of the disorder?
4. Are there any treatments for the person with the growth and/or
development disorder?
Government Scientists have advised that all people should have a balanced
diet. Why is this not possible throughout the world?
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