Download Reproduction in Animals Learning Outcomes Reproduction

National 5 Biology – Multicellular Organisms – Reproduction
Reproduction in Animals
All living things need to reproduce and produce offspring similar to
themselves. If living things did not reproduce then their numbers would
decrease and they would become extinct.
Reproduction, asexual, gamete, zygote, haploid, diploid, sperm, ovum,
fertilisation
Learning Outcomes
You will be able to:

Describe the chromosome complement of gametes.

Describe the structure of the male and female gametes and where they
are produced.

Give details of the male and female reproductive structures and
functions.
Reproduction
Plants and animals produce offspring in the process called reproduction.
There are two types of reproduction, sexual and asexual. Asexual
reproduction involves only one organism producing offspring e.g. when a
bacterium divides to make an exact copy of itself. These offspring are
identical to the parent and to each other, so this type of reproduction
does not affect variety within a species. Sexual reproduction involves the
fusion of two gametes during fertilisation and is the key to variety and
therefore, to biodiversity.
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National 5 Biology – Multicellular Organisms – Reproduction
Gametes
Organisms need to produce gametes (sex cells) for reproduction to take
place. Gametes are haploid which means that they only have one set of
chromosomes. During fertilisation, the nucleus of the male gamete and
the nucleus of the female gamete fuse together to form a Zygote. Since
the zygote has two sets of chromosomes it is said to be diploid.
In animals the male gametes are called sperm and produced in the testes.
A sperm has a head section and a tail section that allows it to swim. A
Sperm cell also has many mitochondria. The female gamete is the ovum
(egg) produced in the ovaries. This is much larger than the sperm cell as
it has a large store of food in its cytoplasm.
A male mammal will produce a very large number of sperm whereas a
female mammal will produce a much smaller number of eggs.
Learning Activity 1
1. Collect the worksheet ‘Haploid or Diploid’ and label the main parts.
2. Describe the number of sets of chromosomes found in normal body cells
3. Describe the number of sets of chromosomes found in gametes.
4. Describe what happens at fertilisation to the number of sets of
chromosomes.
5. Describe the number of sets of chromosomes found in a zygote and
where these sets of chromosomes originated.
6. Name and make labelled diagrams of the gametes produced in a:

male animal

female animal
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National 5 Biology – Multicellular Organisms – Reproduction
7. Copy and complete the table to compare eggs and sperm in your jotter.
Gamete
Egg
Sperm
Site of production
Comparative size
Numbers produced
Number of sets of
chromosomes (haploid or
diploid)
Can swim?
Contains food store?
Reproductive Structures in Humans
Following production in the testes, the sperm travel from the testes along the
sperm ducts, past the bladder, along the urethra, which is the tube leading
from the bladder out of the penis. The ovary produces the female gametes,
eggs (ova). Eggs are released from the ovaries and travel along the oviducts to
the uterus. The vagina is the tube in which the penis is placed during sexual
intercourse.
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National 5 Biology – Multicellular Organisms – Reproduction
Fertilisation in Animals
For fertilisation to take place the nuclei of the male and female gametes need
to fuse together. The release of an egg (ovum) takes place once a month in
humans and is called ovulation. The ovum is released from the ovary into the
oviduct and is moved along the oviduct by tiny hair-like cilia which beat and
move the ovum towards the uterus. Following sexual intercourse, ejaculated
sperm swim up through the uterus and into the oviducts. Fertilisation takes
place in the oviducts. Although many sperm may meet an egg, only one sperm
fertilises the egg. The nucleus of the sperm fuses with the nucleus of the egg
forming a diploid cell called a zygote which contains genetic material from both
parents.
Learning Activity 2
1. Insert and complete the ‘Human Sex Organs’ diagram from your pack into
your notes.
2. Describe the process of fertilisation in humans, with reference to:

the pathway taken by the sperm

the exact location of fertilisation

the number of sperm fertilising an egg

the name of the cell formed as a result

the genetic information contained within this cell

the fate of this cell.
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National 5 Biology – Multicellular Organisms – Reproduction
Challenge task
Pick one of the following stages of human embryo/foetal development:
 weeks 1 to 10
 weeks 11 to 20
 weeks 21 to 30
 weeks 31 to 40
Make an A4 information sheet including the following:
 A TITLE showing the stage you are investigating.
 Pictures/diagrams
 Information about what is happening at this stage of development.
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National 5 Biology – Multicellular Organisms – Reproduction
Reproduction in Flowering Plants
Pollen, anther, stamen, ovules, ovary, stigma, pollination, pollen tube
Learning Outcomes
You will be able to:

Name the sex cells found in plants and where they are produced.

Describe the reproductive structures found in plants and give
their functions.

Describe the process of fertilisation in plants.

Explain the chromosome complement of a gamete and a zygote in
plants.
Gamete Production in Plants
In flowering plants, the flowers are the part of the plant responsible for
reproduction. All flowers have the same basic structure. Usually both
male and female parts are present in the same flower. Male parts of the
flower are the stamens. The stamens are made up of an anther and a
filament. The anther produces the male gamete pollen. The female part
of the flower is made up of the stigma and the ovary. The stigma is
where pollen lands during pollination and the ovary is the site of ovule
production (female gamete).
Formatted: Indent: Left: 1.27 cm,
Line spacing: Multiple 1.15 li
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National 5 Biology – Multicellular Organisms – Reproduction
Learning Activity 1
1.
Collect the diagram ‘Sexual Reproduction in a Flower’.
2.
Label the following parts of the flower:
3.
SEPAL, PETAL, NECTARY, STIGMA, STAMEN, OVARY, ANTHER
4.
Copy and Complete the table below by matching the flower part with the
correct function.
Part
Function
Stigma
Produces the female sex cells
(ovules)
Stamens
Produce sugary nectar which
attracts insects
Anther
Collects the pollen grains and starts
them growing
Ovary
Produces the male sex cells (pollen)
Petals
Protects the unopened flower bud
Nectaries
May be brightly coloured to attract
insects
Sepals
Male parts of the flower consisting
of the anther and filament
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National 5 Biology – Multicellular Organisms – Reproduction
Collect the experiment cards ‘Dissecting a Flower’ and ‘Examining Pollen
and Ovules’.
Carefully follow the instructions on the work cards to complete the
experiment.
Copy and complete the table to compare ovules and pollen in your jotter.
Gamete
Site of production
Comparative size
Comparative Numbers
numbers produced
Number of sets of
chromosomes (haploid or
diploid)
Do they move from site of
production?
Contains food store?
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Ovules
Pollen
National 5 Biology – Multicellular Organisms – Reproduction
Pollination
Pollination is the transfer of pollen from an anther to a stigma. There are
two types of pollination. Self-pollination involves pollen moving from the
anther to the stigma of the same plant. Cross-pollination involves the
tranfer of pollen between different plants. Cross-pollination can be
brought about by different methods. Some plants use the wind to
transfer their pollen while other plants may rely on insects. Wind
pollinated flowers are very different in structure to insect pollinated
flowers.
Fertilisation
When a pollen grain lands on the stigma,
it responds to the presence of sugar on
the stigma, the pollen uses the sugar as
a source of energy to grow a pollen
tube. The pollen tube grows down
towards the ovary. The haploid pollen
nucleus makes it way down the pollen
tube into the pvary and fuses with the
haploid ovule nucleus, forming a diploid
zygote. Eventually this zygote will form
a seed, and the wall of the ovary will
develop into a fruit.
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National 5 Biology – Multicellular Organisms – Reproduction
Learning Activity 2
1. Before fertilisation can occur in a flowering plant pollination must take place.
Describe this process with reference to:

where the pollen grains have to be transferred from and to

the role of the pollen tube.
2. Describe the process of fertilisation in a flowering plant, with reference to
the:

name of the gametes involved

exact location of fertilisation

name of the cell formed as a result

genetic information contained within this cell

fate of this cell.
Challenge task
The shape, size and surface marking of a grain of pollen are unique to
each species of plant. Pollen grains have a tough outer coat, which enables
them to survive harsh conditions. Fossilised pollen has been found which
was made millions of years ago.
Carry out some research to try and answer the following questions:
1. What information does fossilised pollen provide us with?
2. The pollen found in honey can be analysed, what will this tell us about
the bees that made the honey?
3. How can pollen be used to solve crimes?
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