NATURAL SCIENCES
GRADE 8
TERM 1
LIFE AND LIVING
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INDEX
TOPIC
PAGES
1
PHOTOSYNTHESIS AND
RESPIRATION
4
7
2
INTERACTION AND
INTERDEPENDENCE WITH IN THE
ENVIRONMENT
8
• INTRODUCTION TO
•
•
•
•
•
3
ECOLOGY
ECOSYSTEMS
FEEDING
RELATIONSHIPS
BALANCING IN
ECOSYSTEM
ADAPTATION
CONSERVATION OF
ECOSYSTEM
MICRO-ORGANISMS
• TYPES OF MICROORGANISMS
• HARMFUL MICROORGANISMS
• USEFUL MICROORGANISMS
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8
11
14
27
31
38
39
40
42
48
SESSION
1 – EARTH ASAND
A SYSTEM
1 – PHOTOSYNTHESIS
RESPIRATION
Energy is needed to sustain life and without it nothing would be able to live on Earth.
Our most important source of energy is the Sun. The two important processes we
are going to investigate are photosynthesis and respiration.
TERMS AND DEFINITIONS
Terminology is the key for understanding Natural Sciences. You need to understand
the scientific terms to understand the questions and to have the necessary
vocabulary to answer questions.
TERM
Chemical
Potential Energy
Chlorophyll
Chloroplast
Glucose
Photosynthesis
Radiant energy
Respiration
Starch
Interdependence
DEFINITIONS
Energy sored in an object or system
Green pigment in plants that give the green colour to plant
and absorb radiant energy
The Organelle
Simple sugar that is used by plants as food
The process by which plants use sunlight energy to
convert carbon dioxide and water into glucose (food)
Energy provided by the sun in the form of heat or light
Process by which energy is released from glucose
Excess glucose is stored in the form of starch
A relationship where both parties depend on each other
for something
1. Interaction and interdependence and the need for energy to sustain life
When you look at an ecosystem you will realise that there are so many things
happening. All living organisms interact with one another and are dependent on one
another for survival. We call this interdependence. It is this interaction and
interdependence in an ecosystem that drives the need of energy to sustain life.
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ACTIVITY 1
Use the above diagram and write down the 7 life processes and explain how each
one uses energy.
Use the table provided.
Life Processes
Use of Energy
1.1 PHOTOSYNTHESIS
The sun is the most important source of energy in an ecosystem for all living
organisms and it provide this energy in the form of light and heat that is known as
radiant energy.
The green pigment , chlorophyll in plants absorb the radiant energy (light) from
the sun and change it into chemical potential energy during the process of
photosynthesis
Photosynthesis is the chemical process by which green plants use the energy in
sunlight to convert carbon dioxide gas (from the atmosphere/air) and water (from
the soil) into glucose (food).
Oxygen gas is released into the air as a by-product
Photosynthesis represented in an equation
Chlorophyll
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Carbon dioxide + water
glucose + oxygen
Sunlight
Plants changes glucose into starch, cellulose and other chemical compounds to
enable processes such as growth and reproduction.
ACTIVITY 2
https://youtu.be/D1Ymc311XS8
Video clip on the process of photosynthesis
Questions to be answered after watching the video clip
1. How would you define photosynthesis?
2. What happens to the oxygen that is released during photosynthesis?
3. What would be the effect of removing chlorophyll and sunlight from the
equation representing the process of photosynthesis?
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PRACTICAL ACTIVITY 1 (EDUCATOR must demonstrate)
(Scientific process skills)
WORKSHEET: PRACTICAL INVESTIGATION TO TEST FOR THE PRESENCE OF
STARCH.
AIM:
What do you wish to establish by conducting this investigation?
HYPOTHESIS:
What do you think or predict will happen when you conduct this investigation?
VARIABLES:
Independent:
Dependent:
Control:
APPARATUS: Beakers, Bunsen burner or spirit light, test tube, white tile or any
white surface, iodine solution, ethanol/methylated spirit, green leaf.
METHOD:
Place a one pot plant in a cupboard for 48 hours and the other on a windowsill
1. Boil the water in 2 beakers.
2. Use forceps to place a leaf of each pot plant in the boiling water for one hour.
3. Remove the leaves and place it in test tubes with ethanol/methylated spirit
4. Place the test tubes containing the leaves in a hot water bath. (do not let the water
flow into the test tube
5. Remove the leaves from the test tube and rinse it in water.
6. Place the leaves on a white tile.
7. Use the dropper to drop the iodine solution on the surface of each leaf.
8. Observe changes.
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OBSERVATIONS:
What did you observe during the whole process?
CONCLUSION:
What conclusion can you draw from your results?
QUESTIONS
Based on the above experiment conducted, answer the following questions.
a). What organic substance does iodine solution indicate the presence of?
b). How do we know this is a positive test for this organic substance?
c). Why is the leaf boil in water first?
d). What have you observed about the leaf after it has been boiled?
e). Why is it necessary to boil the leaf in alcohol?
f). What is the appearance of the leaf after it has been boiled in alcohol?
g). Explain why the leaf needs to be rinsed with water.
h). Give an investigative question for this experiment?
i). What is your conclusion after doing this experiment?
1.2 RESPIRATION
The products of photosynthesis are the ingredients use to start the process of
respiration.
Respiration is a process that takes place in all living organisms.
Respiration is a chemical process by which energy is released from glucose (food)
Respiration represented in an equation
Glucose + oxygen
energy + carbon dioxide + water
ACTIVITY 3
1. Use the table provided to tabulate differences between photosynthesis and
respiration
Characteristics
Starting ingredients/
requirements (reactants)
End products / what the
process produces
Organisms where the
process takes place
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Photosynthesis
Respiration
When this process takes
place
2. Use information you have learned and write down equations for photosynthesis
and respiration.
PRACTICAL ACTIVITY 2 (EDUCATOR must demonstrate)
(Scientific process skills)
WORKSHEET: PRACTICAL INVESTIGATION: TO TEST FOR THE PRESENCE
OF Carbon Dioxide
AIM:
What do you wish to establish by conducting this investigation?
HYPOTHESIS:
What do you think or predict will happen when you conduct this investigation?
VARIABLES:
Independent:
Dependent:
Control:
APPARATUS: Clear limewater, clean water test tubes, straws
METHOD:
1. Pour some limewater into one the test tube and only clean water into the other test
tube
2. Place the straw inside both test tubes
3. Blow into the test tubes
4. Observe changes
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OBSERVATIONS:
What did you observe when air was blown (exhaled) into the clear lime water?
CONCLUSION:
What conclusion can you draw from your results
QUESTIONS
Based on the above experiment conducted, answer the following questions.
a). Name the process that occur in the cells of living organisms that could provide
the carbon dioxide in exhaled air.
b). Explain the importance of the process in Question 1.
c). Name another by-product that is produce during this process.
2 – INTERACTION AND INTERDEPENDENCE WITHIN
THE ENVIRONMENT
2.1 INTRODUCTION TO ECOLOGY
•
Ecology is the study of interactions of organisms with one another and with
the physical and chemical environment
•
Scientists usually classify the study of ecological interactions into four levels;
populations, communities, ecosystem and the biosphere
•
A population is a group of organisms of the same species (similar organisms
that are able to breed with each other) that lives in a define area
•
A community is a group of different populations living in a define area
•
An ecosystem is all the living (biotic) and non-living (abiotic) things in an
environment and the different ways in which they interact with each other
•
The biosphere is the largest ecological unit and is the part of the Earth where
all living things (plants and animals) live.
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ACTIVITY 1
Study the diagram below and answer questions that follow:
1. Explain the meaning of biosphere and ecosystem?
2. Define each of the following: ecology, population, community and habitat.
3. Arrange the following words about levels in ecological interactions in order from
the largest to the smallest: Population, biosphere, community and ecosystem
4. Give 3 examples of an interaction between living things.
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ACTIVITY 2
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2.2 ECOSYSTEMS
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An ecosystem is all the living (biotic) and non-living (abiotic) things in an
environment and the different ways in which they interact with each other.
Ecosystems are defined by the network of inter actions among organisms and
between organisms and their environment.
Biotic and abiotic parts of ecosystems
An ecosystem consists of two parts:
a) Living part (factor) or biotic which include all living plants and animals.
b) Non-living part or abiotic, which are wind, gases, temperature light, soil,
stones, rocks, air, slope.
A non-living (abiotic) part of an ecosystem:
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(Source: quia.com/jg/1172905list)
•
•
An ecosystem is made up of two parts: the habitat where organisms live and
a community, the organisms living there.
All ecosystems (lithosphere, hydrosphere and atmosphere) combined make
up the biosphere.
•
An ecosystem consists of an ecological community that includes all living
organisms (biotic) such as plants and animals, together with the non-living
(abiotic) environment such as temperature, wind, water, interacting as a
system
•
The size of an ecosystem is not specifically defined and it usually
encompasses a specific, limited area (although it can encompass the entire
planet)
•
Survival of individual organisms and populations depends on the its ability to
cope with changes (adapt) in its habitat (the place where an organism lives) or
in the ecosystem
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Example of a marine ecosystem:
Example of a desert ecosystem:
(Source: quia.com/jg/1172905list)
(Source: fineartamerica.com)
FEEDING RELATIONSHIPS
Living organisms depend on each other for food. Organisms are classified by the
way they feed as producers, consumers and decomposers.
Producers
Green plants use sunlight energy, carbon dioxide, chlorophyll and water to make
glucose. This process is called photosynthesis. Living organisms that produce their
own food are called producers.
Consumers
Animals are consumers. Consumers are divided into three groups:
Herbivores, Carnivores and Omnivores
- Herbivores (plant eaters)
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- Carnivores (meat eaters) and
The group of carnivores includes:
•
•
•
Those (predators) that hunt other animals (prey), e.g. leopards, lions
Those that eat dead animals are scavengers, e.g. hyenas, vultures
Insectivores feed mainly on insects and other smaller invertebrates such as
worms.
Omnivores are animals that feed on both plants and animals, e.g. humans, pigs,
baboons
Examples of scavengers:
Vulture
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Hyena
Crab
Examples of insectivores:
Mole
Aardwolf
Hedgehog
Frog
Ant-eater
Chameleon
Swallow
Spider
- Omnivores (plant and meat eaters).
Omnivores obtain their food from plants and other animals. Herbivores get their food
from eating plants, e.g. sheep and cows. Carnivores get their food indirectly from
plants, by eating animals that have eaten plants, e.g. lions.
Decomposers
Decomposers break down the remains of dead plants and animals, e.g. bacteria,
fungi, earthworms. They recycle nutrients in the environment, useful minerals from
the bodies of plants and animals go back into the soil to be used again by plants to
make new nutrients.
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Flies lay their eggs in dung and rotting flesh. It provides food for their worm-like
larvae – maggots. Maggots eat only dead flesh.
Examples of decomposers:
(Source: sciencepiction.com)
Bacteria
Maggots
(Source: thisnext.com)
CASE STUDY (Source: OXFORD p 28, 29)
How herbivores help the Kruger Park ecosystem
Apart from providing food for carnivores, herbivores provide a useful service to the
ecosystem. In the Kruger National Park, for example:
•
•
•
Grazing animals encourage new grass growth. Buffalo are especially good at
this, because they can digest long, tough grass in old grazing areas
Although elephants have a reputation of being wasteful, destructive eaters,
their dung provides manure for the soil. Some seeds germinate better after
passing through their digestive systems
As warthogs dig around with their tusks looking for bulbs and rhizomes, they
loosen and aerate the soil.
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Hyenas are resourceful carnivores in the Kruger Park Ecosystem
When they are in packs, hyenas go for big game – wildebeest, zebra and kudu.
When they hunt alone, they go for smaller animals such as baboons, guinea fowls,
ostriches, snakes and tortoises.
Hyenas are known for their cunning. They watch the skies for circling vultures to
help them locate kills. They’ve been seen trying to scoop out fish at drying water
holes during times of drought.
Spotted hyenas have the reputation of being scavengers, but they hunt more than
they steal. They are the second major group of predators in the Kruger Park after
lion, probably responsible for more animal kills than leopard and cheetah combined.
They can eat up to a third of their own weight (15kg) in a single meal.
Activity 3: Individual work
Read the above case studies.
List and classify every animal mentioned in the table below.
Herbivore
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Carnivore:
Predator
Carnivore:
Scavenger
Carnivore:
Insectivore
Omnivore
Energy flow: Food chains and Food webs
Role of plants in the ecosystem
Plants and algae play an important role in an ecosystem, because they are
producers. They capture sunlight energy and use that energy to produce their own
food. Plants are called producers because they make their own food during a
process known as photosynthesis. Living things use only a small amount of the
Sun’s energy. This energy is passed along in an ecosystem from a producer to a
consumer. When a living organism dies, energy is released back into the
environment in the form of heat, because of its decaying body. The transfer of the
Sun’s energy through a green plant (producer) to a primary consumer (herbivore)
to a secondary consumer (carnivore) and finally decomposers is called a food
chain.
Food chains
A food chain is a diagram showing the feeding relationships between living
organisms. There is always a continuous flow of energy in a food chain and the
organisms are found in sequence.
Example of a simple food chain:
(Food chain facts for kids)
In a food chain, we make use of arrows to indicate the direction of flow of energy.
The arrow means “is eaten by”.
We always start a food chain with a producer (plant) since they are the only
organisms that can produce their own food. The various consumers are then placed
next per their positions in a food chain. Food chains may consist of three to five links.
Different types of consumers are found in a food chain.
Primary consumer: The first consumer feeding on the producer. They are
herbivores (plant eaters). Examples: springbuck, rabbits, locust, sheep, snails etc.
Secondary consumer: The second consumer is usually a carnivore or omnivore
that feed of other animals. Examples: lion, snakes, owls, pigs etc.
Tertiary consumer: The third consumer in a food chain which is also usually a
carnivore or an omnivore.
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The last link in a food chain will be decomposers which release energy back into the
soil when they break down plants and animals.
In a simple food chain like the one above, decomposers are not always shown.
Scavengers, also play an important role in a food chain, because they get their
energy by feeding on dead plants and animals. Scavengers, like vultures, help to
break down dead material, which decomposers (e.g. bacteria), can break down
further.
Activity 4:
Identify organisms in a food chain
The diagram below represents the structure of a food chain:
SUN
A
B
C
Decomposers
Use the following list to answer the questions:
Producers, herbivore, predator, bacteria, photosynthesis, sunlight
1.1 Which type of organism will you find at A?
1.2 Which process takes place in the organism mentioned at A?
1.3 What type of energy would these organisms use for the process mentioned in
1.2?
1.4 Where does organism B get its energy from?
1.5 What type of organism would you find at B?
1.6 What type of organism would you expect to find at C?
1.7 Give two examples of organisms that are referred to as decomposers.
1.8 What would happen to this food chain if organism B is removed?
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2. Study the following food chain and answer the questions that follow:
leaf
locust
lizard
snake
2. Identify:
a) the producer
b) the primary consumer
c) the secondary consumer
d) the tertiary consumer
Food webs
Most animals do not eat only one kind of food. There are many food chains in an
ecosystem. For example, an owl does not only eat mice, but also feed on small
reptiles, like lizards and snakes. Different food chains are linked with each other to
form a food web. Food webs show us how different kinds of food are eaten by
different kinds of animals.
The food web below consists of different food chains.
grass
agapanthus
Acacia tree
shrub
(Source: Science today Grade 8 pg.65)
In a food web the producers are at the bottom, the herbivores are in the second row
and carnivores or omnivores in the third and fourth rows.
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ACTIVITY 5
Food webs and food chains
Study the food web below and answer the questions that follow.
(Source: Platinum pg. 30)
1. How many food chains can you identify from this food web?
2. Write down three food chains from the food web above.
3. From the food web write the name(s) of:
a) a producer
b) two herbivores
c) a carnivore
d) two omnivores
e) two predators
f) a decomposer
4. Describe the important role of decomposers in an ecosystem.
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Trophic levels
Usually there are several levels that energy flows through from producer to
consumer. Each level of a food chain is called a trophic level. At each trophic level
there is a transfer of energy and a loss of energy.
The diagram below shows a food chain with different trophic levels.
(Source: Top Class)
The grass absorbs sunlight energy to make nutrients that the grasshopper gets when
it eats the grass. When the frog eats the grasshopper, it gets some of the energy.
The hadeda ibis will also get some of that energy when it eats the frog.
Only about 10% of energy that is available at one trophic level is passed on to the
next trophic level. This is because 90% of the energy is used by an organism’s body
to grow and stay alive. Energy is used by living things for life processes such as
respiration, reproduction and movement. Energy is also lost in the form of heat.
The figure below shows some ways how energy is lost.
Energy lost as heat
energy
Energy lost in waste
material
Eating food
Moving around
(running, climbing etc.)
(Source: Science today gr8)
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We use energy pyramids to show how much food is available at each feeding level.
In other words, energy pyramids represent how much energy there is available in
each trophic level.
Because energy is lost at each level we use the shape of a pyramid where each
level becomes smaller and smaller.
Look at the energy pyramid below:
(Source: Spot on pg. 20)
The producers (pants) are always placed at the bottom of the pyramid, because
they make their own food and have the most energy. Producers are found in the first
trophic level. Herbivores are found in the next (second) trophic level where energy
is lost. The number of organisms will decrease as one moves up the food chain,
because of energy being lost at each level. The third trophic level contains a
carnivore or omnivore, with the least energy available. There is usually a maximum
of three or four trophic levels on an energy pyramid.
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ACTIVITY 6:
Drawing and analysing energy pyramids
Study the energy pyramid below and answer the questions that follow.
(Source: schoolworkhelper.net/energy-movement-in-ecosystems-trophic-energy-pyramid)
1. Explain what a trophic level is.
2. Name the trophic level that is always at the base of an energy pyramid.
3. Explain why secondary consumers rely on producers?
4. Name the trophic level where the secondary consumer is found.
5. Explain why there is less energy available at the top of an energy pyramid.
6. What was the percentage of energy lost at each trophic level?
7. What is the name of the tertiary consumer in the diagram?
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ACTIVITY: 7
1. a) Draw and label an energy pyramid for the following food chain and show
the amount of energy at each trophic level. Indicate each trophic level on the
pyramid as well.
Phytoplankton
blue tang fish
penguin
leopard seal
The phytoplankton have stored 86 986kJ of energy trapped from the sun. The
blue tang fish store 14 078kJ of energy, the penguins store 1 600kJ of energy
and the leopard seal stores 158kJ of energy.
c) Explain what would happen if all the phytoplankton is removed from the food
chain.
2. Give three ways how it is possible to lose energy at each trophic level.
Balance in an ecosystem
In an ecosystem, all biotic organisms and abiotic factors depend on each other to
survive. A balanced ecosystem provides enough resources such as water, food and
shelter for many organisms to survive. This is known as the carrying capacity of an
ecosystem. The number of organisms in such an ecosystem will decrease when
these resources become scarce. This is because the slightest change can upset the
balance in an ecosystem. All living organisms depend on this very delicate balance
in nature for their survival.
For example, if there are too many elephants in the Kruger National park, the
elephants will start to compete for food and space. The elephants will over-eat the
vegetation available; they might cause soil erosion in specific areas where they are
grazing. The overpopulation of elephants will also influence other herbivores in that
ecosystem. All these factors will disrupt the balance of an ecosystem.
The balance in ecosystems can be disrupted by natural factors and human
factors.
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Natural factors include extreme changes in patterns of weather and climate that can
affect an ecosystem. This includes:
•
•
•
Droughts that kill most plants and affect animals. Farmers cannot produce as
much food.
Floods that wash away soil and less food can be produced for animals
because this affects plant life.
Extreme and sudden changes in temperatures can kill plants and animals
because they are not use to these extreme cold or hot temperatures.
All these factors can destroy natural habitats and can lead to the loss of biodiversity.
Human factors include harmful activities of humans and how they disrupt the
balance of an ecosystem. This includes:
•
The removal of plants or animals from their natural habitat for example by
illegally hunting or poaching rhinos. Plants, like the Hoodia, are used for
medicinal purposes and too much of it is being removed.
•
Habitat loss endangers many species because humans destroy natural
habitats by cutting down trees, mining, farming, deforestation (cutting down
trees), building and developing cities. As a result plants and animals lose their
homes as well as food sources. These animals have to move away or start
dying because there is no food. These organisms’ existence is under threat.
•
Pollution of air, water and soil can kill organisms because of harmful
chemicals being released. Earth is also gradually getting warmer because of
an excess of greenhouse gases. This affects ecosystems for example the
Polar Regions are starting to melt. During the winter, polar bears hunt seals
on the ice sheets, but ice now melts more quickly in spring. This makes it hard
for the bears to hunt and they even get stranded on pieces of ice which
means that they starve or drown.
•
Alien invaders. Sometimes plants and animals species from one country are
brought into another country. These “invader” plants use more water and
nutrients and start taking over the habitat of the natural occurring plants and
they die.
All these natural and human factors can contribute to an imbalance in an ecosystem,
seriously impacting on its components and altering its nature.
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ACTIVITY 8
Read the following case studies and answer the questions that follow.
THE CANADIAN SEAL HUNT
Harp seal pups are famous for their big black eyes and fluffy white fur. These are their trademarks in their
first two weeks of life. But these beautiful and gentle creatures have the unfortunate status of annually
suffering the largest slaughter of any marine mammal species on the planet.
Most of the seal species do not have any natural predators since they are large in size and live in habitats
not suitable for other animals. However, seals can be killed by larger animals like sharks, whales or polar
bears. Harp seals feed on fish such as herring and capelin, as well as other invertebrates. The herring and
capelin are small forage fishes. They graze on dense swarms of plankton at the edge of the ice shelf.
Every spring, great numbers of pregnant harp seals gather together on the stark ice floes off the Canadian
Atlantic coastline of Newfoundland and Labrador and in the Gulf of St. Lawrence to the east of Quebec to
give birth to their babies.
Commonly referred to as “white coats”, these famous babies are astounding in their innocence, individuality,
and beauty. Their images have been captured in a thousand ways and distributed around the world, making
them the most recognizable and well known of nature's innocent and precious creatures. It is ironic and sad
that all this recognition does nothing to help their plight as these seal pups are the victims of a brutal annual
massacre in a politically-driven, propaganda-supported slaughter.
Every year, when the time is "right" (as soon as the ice conditions permit and the seal pups start shedding
their fuzzy white coats), a few hundred to a few thousand Canadian fishermen (almost all of European
descent), find their way to the floes and proceed to club, bludgeon, shoot, and skin tens to hundreds of
thousands of harp seals. About 95% of the seals killed in the commercial seal 'hunt' are 3 weeks to 3 months
old.
(Source: www.harpseals.org/about_the_hunt/index.php)
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KUDU POPULATION IN SMALL NATURE RESERVE
There is a small nature reserve just outside a village in Limpopo Province called Ikhaya Lendlovu. This
nature reserve is especially known for the beautiful kudu living there. The kudu is considered by many to be
the most handsome of all the tragelaphine antelope. Kudu are browsers and eat leaves and shoots from a
variety of plants for example the acacia tree. In the dry seasons, they even eat wild watermelons for the
liquid they provide.
There are sixty kudus living in the reserve and no large carnivores. Forty of the sixty kudu are female. In the
first-year half of the kudus had calves. The following year no calves were born and the nature conservation
officer found three dead kudus in the reserve. A week later he discovered that thirty kudus jumped the
fence and escaped from the reserve.
That same year lightning struck a large tree in the middle of the reserve. A wildfire broke out and spread
very quickly through the reserve towards the village. The fire killed all the Kudu, and smaller animals like
snakes, as well as four people in the village. All the animals that survived was both injured and died later
on, or they had to move away, because their homes were destroyed and food was suddenly scarce. It took
many years for the wildlife and ecosystems in the reserve to recover and to become the beautiful reserve it
ones were.
8.1 Identify the animals from the above case studies that have been disrupted by:
(Explain your answers)
a) Natural factors
b) Human factors
8.2 Why do humans kill the seal pups?
8.3 What effect could the killing of seal pups have on the seal population?
8.4
Write a food chain from the case study of the harp seals.
8.5
What would happen if all the herring and capelin was removed from the seal’s
habitat?
8.6
Suggest ways to stop the hunting and killing of seals.
8.7
What was the size of the kudu population in the first year?
8.8
What was the size of the population in the second year?
8.9
What happened to the kudu population? Suggest reasons for this.
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8.10
Why do you think there are no large carnivores in this reserve?
8.11
Give examples of three large carnivores.
8.12 Tabulate any three human factors and natural factors that have an impact on
the environment.
HUMAN FACTORS
NATURAL FACTORS
ADAPTATION
Why does a prickley pear have spines? Why does a leaf insect look like a leaf? Why
does a zebra have stripes?
All these organisms are well suited to their habitat because they adjusted to their
surroundings.
Adaptation is the change in the structural, functional and behavioural
characteristics of an organism, that contributes to the survival of an organism.
These changes are not sudden but occur over a long period of time. Adaptation
contributes to an organisms survival. This is because adaptation helps the
organisms to obtain water, light, oxygen and food; to escape from enemies;
reproduce and to survive when conditions change within the environment.
When organisms are unable to change and adapt to these changes within the
environment, they die out and become extinct.
ADAPTATIONS
Organism
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Structural
adaptation
Functional
adaptation
Behavioural
adaptation
Zebra
Locust
Hoodia
gordonii
luirig.altervista.org
(The plant or animals
has to be a certain
colour, shape or size
or has different
structures)
Has stripes to melt in with
it’s environment
(camouflage). It becomes
almost impossible to
detect when standing in
the shade of branches
(The plant or animal
has to function a
certain way)
(The plant or animal
has to behave or act
a certain way)
Strong muscular hind legs
to and sharp hooves kick
a predator.
Zebra mother will keep
her new born calve
aside until it has
memorised her stripes.
Zebras stay in herds for
a better chance of
survival.
Zebra males fight for
dominance of the herd.
Tough external skeleton
(exoskeleton) that
protects it’s internal
organs and prevent their
bodies from drying out.
Wings to enable it to
spread to new areas and
find mates.
Green colour to blend in
with grass (camouflage)
Mouth parts are bitingchewing.
No leaves, only spines
that cuts down the
surface area and less
water is lost by
evaporation.
Thick waxy layer covers
the stem to reduce water
loss.
Stem is grooved to allow
plant to swell or shrink
depending on amount of
water stored.
Thick fleshy stem to store
water.
Legs and in claws to
improve grip when
climbing.
Social insect that lives in
colonies for better
survival.
Bitter taste to protect itself
from being eaten by
herbivores.
Produce beautiful
flowers to attract birds
and insects to help with
reproduction.
ADAPTATIONS OF PLANTS
Most animals can move around, but plants have to adapt to the conditions in their
environment to survive.
Some plants are adapted to live in hot, dry conditions for example the prickley pear
or aloe. They have thick fleshy stems or leaves to store water and thorns to protect
them.
Others are adapted to live in water or close to water for example the water lily. The
water lily has broad flat leaves that float on the water and catch sunlight easily. It has
32 | P a g e
a long, flexible petiole covered wit antiseptic mucous layer. The leave and petiole
have large air chambers filled with gases to help the plant float.
ACTIVITY 9:
How plants are adapted to their environment
1.Describe how the Baobab tree is adapted to its environment.
2.How does it protect the tree’s fruit from the monkeys?
3.The flowers smell like rotting meat to attract bats, flies and moths at night. Why do
you think the baobab tree needs to attract these animals to its flowers?
ADAPTATIONS OF ANIMALS
Adaptations for extreme environments
Deserts are very hot in the day and can be cery cold at night. Animals like the camel
and gemsbok, that live in the desert adapted to live in these hot conditions where
there is very little water.
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The Gemsbok
The gemsbok has intriguing characteristics to endure and withstand the very hot
conditions of the Kalahari desert.
(Source: www.kalahari-trophyhunting.com/gemsbok)
This antelope use different strategies to adapt to the Kalahari’s harsh environment.
Whenever possible, gemsbok will retreat to the shades of trees to avoid overheating.
When no shade is available or when it needs to graze, the animal will keep the
smallest part of his body turned to the sun and the biggest part to the breeze. This is
to dump excess body heat. Its white belly also helps to redirect heat from the red, hot
sands during daytime.
The gemsbok grazes at night when the moisture content of grasses and plants is
higher. This way a lot of energy and fluids are saved and the animal can stay more
inactive during the hottest parts of the day.
The gemsbok has a special blood system in the nasal passages that cools blood
before it goes to the brain. This keeps the brain cooler than the rest of the body. All
the excess body temperature gained during daytime is lost at night, when
temperatures in the Kalahari are always cooler.
The Arctic fox
This Arctic fox is found in the far north, mainly in the Arctic Circle and is well adapted
to the cold harsh conditions of the Arctic. The fox will burrow dug into the side of a
hill, cliff or riverbank or lives in a den that has more than one entrance. The fox is
able to remain active at temperatures of around -50 ̊C.
34 | P a g e
http://animals.nationalgeographic.com/animals/mammals/arctic-fox/
The fox has brown fur in summer to camouflage itself because the snow melts and
brown ground is exposed. The coat changes to a thick white coat in winter when it
snows. It also develops an insulating layer of fat under the coat to protect against the
cold. The fox even has fur on the bottom of its paws. It’s got keen hearing to detect
underground lemmings and short legs in comparison to body size. This ensures that
the fox runs fast and jump high. It also has a thick bushy tail so that it can curl up in
the snow and cover its nose and face with its tail to keep warm.
Females give birth to as many as 25 cubs per year but most of the cubs do not
survive for more than 6 months. Therefore, the high birth rate helps to maintain
population growth. Arctic foxes do not hibernate during the winter and will follow
polar bears to feed on the left-overs.
Adaptations of a predator.
The lion and great white shark are both predators that adapted to catch and hold
their prey.
Lions are strong, fast and have excellent eyesight. They have
strong jaws with sharp canines to bite into the flesh of their
prey and sharp claws to hold the prey. Lions are well
camouflaged and blend in with their environment stalking their
prey, getting as close as possible.
Lions also hunt in packs and work as a team to better their
chances of catching prey.
thetbjoshuafanclub.wordpress.com
The great white shark has about 3000 razor sharp teeth
35
| P a g ein several rows. The first two rows of teeth are used
arranged
for grabbing and cutting prey to rip flesh out, while the teeth in
the last rows rotate into place when front teeth are broken,
worn down, or fall out.
oceanlink.island.net
Camouflage and Mimicry
Most animals have different colouring or patterns that help them to blend in with their
environment. This is to protect themselves from predators or so that predators are
not seen by their prey when stalking them.
The manner in which an animal’s shape or colour blends in with its surroundings, to
make itself difficult to see is known as camouflage.
Many insects take on the shape of parts of plants on which they live. The leaf insect
below looks like a leaf and stick insects pretends to be one of the stick on a branch
by being motionless. The owl in the picture below has colours that blend in with the
tree it lives in.
Leaf insect
Stick insect
http://simple.wikipedia.org/wiki/Stick_insect
Owl
buffetcomplet.blogspot.com
Mimicry is when some animals imitate the colours, shape and behaviour of other
animals.
These harmless animals usually imitate or resemble dangerous, aggressive or
poisonous animals or animals that are unpleasant to eat, to scare of predators.
36 | P a g e
The hoverfly is harmless but imitates the colours of a wasp that is aggressive and
can sting. The non-venomous Scarlet King Snake conveniently looks very much like
the Eastern Coral Snake, which is very poisonous.
These colours or shapes scare of carnivores or predators that would normally catch
and eat the harmless animal or insect.
Hoverfly mimics a dangerous, unpleasant wasp
(Source:talktalk.co.uk/reference/encyclopaedia/Hutchinson)
mimicry)
(Source: seekerblog.com/2011/01/04/a-batesian-
Poorly adapted organisms
There is a continuous fight, in any ecosystem, for resources needed to survive. The
resources might be food, water, space, shelter, sunlight. Sometimes an environment
37 | P a g e
changes drastically and organisms adapt to the new situation. Only the organisms
best adapted to their environment will survive. This is because these plants or
animals can still reproduce, grow etc. The organisms which are less well adapted die
and do not reproduce. We say they become extinct because their whole species die
and disappear from the ecosystem. Today humans are the main cause of species
becoming endangered and eventually extinct
ACTIVITY 10:
Adaptations in animals
1. Read about how animals adapted to live in extreme environments (artic fox and
gemsbok) and being good predators (Great white shark and lion).
11.1 List three adaptations in the arctic fox and gemsbok that help them to survive
in their extreme environments.
11.2 Describe how the shark and lion are adapted to be good predators.
11.3 Explain what camouflage is by using an example.
11.4 Explain what mimicry is by using an example.
ACTIVITY 11
Read the information about the arctic fox and gemsbok and complete the table
below.
ADAPTATION
Structural adaptation
ARCTIC FOX
GEMSBOK
Functional adaptation
Behavioural adaptation
CONSERVATION OF THE ECOSYSTEM
Our country is one of the most naturally diverse in the world. This means that
we have many different species and habitats and ecosystems here, more than
38 | P a g e
most other places in the world.
Our country's natural beauty and diversity attract thousands of tourists each
year, but it is under severe threat from poaching, pollution and other human
influence. Ecosystems are able to naturally recycle materials like water, carbon
dioxide and other gases and the remains of organisms, if they are left alone. But
ecosystems cannot do this effectively if we interfere.
These human interferences include:
• Habitat destruction like deforestation and burning
• Pollution causing global warming
• Alien invasive plants taking over ecosystems
• Hunting, poaching and other killing of wildlife
These pressures have caused great loss in biodiversity. Some ecosystems are
under strain and others have already collapsed. There are many reasons why it
is important for humans to care about the environment. As we have learnt,
everything in an ecosystem is connected. Therefore harming one component of
the ecosystem will have a ripple effect that can damage all the other systems.
Environmentalists and others work towards managing ecosystems, such as control
of alien vegetation and preservation of wetlands.
Individuals can contribute to conservation in various ways, such as appropriate
waste disposal (including recycling, reusing)
ACTIVITY 12
Finding solutions to environmental problems
INSTRUCTIONS:
1. The following table below is a list of environmental issues.
2. Educator give learners directions on these environmental problems:
air pollution, water pollution, landfills and climate change.
INSTRUCTIONS:
1. Write down the effect (consequence) of this issue on the ecosystem (or on
humans). Write down a possible solution or a simple action that you can
take to help.
Environmental Issue
Inappropriate waste
disposal: Air pollution
Inappropriate waste
disposal: Water pollution
Inappropriate waste
disposal: Landfills and
littering
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Consequence
Action
Carbon emissions and
climate change
3 – MICRO-ORGANISMS
•
Micro-organisms are living things
•
They are too small to see with the naked eye [they can only be seen under a
microscope]
•
There is a variety of micro-organisms, including Viruses, Bacteria, Protista
and Fungi
•
Micro-organisms including the bread mould observed carry all processes involved in
life. Therefore, they are living organisms.
•
Antonie van Leeuwenhoek designed and built his own microscopes. In 1674
he became the first person to see and describe microscopic organisms like
bacteria, yeast and many other microorganisms.
Antonie van Leeuwenhoek is considered to
be the first microbiologist
Some of the microorganisms which van
Leeuwenhoek observed and first described.
He called them 'animalcules
3.1 TYPES OF MICRO-ORGANISMS
Micro-organisms live all around us, in the soil, water, air, on our skin, hair and inside
our bodies
Viruses, bacteria, protists and fungi are examples of micro-organisms.
40 | P a g e
a. VIRUSES
Virus is the Latin word for poison
Viruses are microscopic, acellular particles
Viruses came in all shape and sizes and cause
many diseases
Viruses are inactive outside a living cell and only
became active once in contact with the cell
They are classified according to the host they infect and are not place in any of the
five kingdoms of living organisms
Examples of Diseases caused by Viruses:
Common colds, flu, chicken pox, measles, polio, mumps, polio, AIDS, glandular
fever, COVID 19
b. BACTERIA
Bacteria are bigger than viruses but still
microscopic
Bacteria are living things that are neither
plant nor animal
They belong to a Kingdom called Monera
They are found everywhere on the Earth
There are many different types of bacteria
and are grouped and classified according to the shape of the bacterial cell
Examples of Diseases caused by Bacteria:
Tuberculosis, cholera, food poisoning, syphilis and tooth decay
c. PROTISTS
Protists belong to the Kingdom Protista
Protists are unicellular
Protists lives in water or where there is moist
Plant-like protists produce their own food
Examples of Diseases caused by Protist:
Sleeping sickness, amoebic dysentery and malaria
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d. FUNGI
There are a huge variety of fungal species
Fungi are decomposers
Fungi are unicellular such as yeast or multicellular
such as mushrooms
Breadmould also an example of fdungi
Examples of Diseases caused by Fungi:
Ringworms, athlete’s foot and thrush
https://www.youtube.com/watch?v=OShyfL078Ko
MICROGRAPH
A micrograph is a photo taken with a microscope
HOW TO USE A SCALE TO ESTIMATE THE SIZE OF A MICRO-ORGANISM IN A
MICROGRAPH
42 | P a g e
ACTIVITY 13
1. How would you define a micro-organism?
2. Give three groups of micro-organisms and one example for each.
3. Calculate the size of any given micro-organism.
3.2 HARMFUL MICRO-ORGANISMS
Some micro-organisms cause diseases and can lead to dead.
An organism that causes diseases are called a pathogen
These pathogens infect other organisms and cause various signs and symptoms in
the organism
Diseases such as TB (caused by bacteria), AIDS (caused by HI virus), malaria
(caused by a protist)
• disease causing organisms are found almost everywhere,
such as at ATMs, handrails of staircases and toilets
• waterborne diseases (such as cholera and diarrhoea) account
for many child deaths
Diseases
AIDS
Causes
By the HI Virus
that enters the
body and
reproduce
Having
unprotected
sex
Mother unborn
foetus
transmission
Drug users
Blood
transfusion of
infected blood
Effects
Weakens the
immune
system –
cannot fight
germs
Symptoms
Night fever
Swollen lymph
glands in the
neck
Tired
Treatment
Cannot be
cured
Antiretroviral
drugs
(ARVs)
Tuberculosis
By the
bacterium
Micobacterium
tuberculosis
Inhaling of
infectious
droplets
Weakens the
immune
system –
cannot fight
germs we
Fever and chills
Tired
Headaches
Weight loss
Cough
Increased
sputum
Coughing up
blood
Two
antimicrobial
medicines
taken for six
months
43 | P a g e
Malaria
By the female
Anopheles
mosquito
The infected
female
mosquito
carries and
passes on the
malaria
parasite to
people she
feeds on
The red blood
cells, liver and
brain are
infected
Takes two
weeks to show
symptoms
Flu-like
symptoms
Headaches
High fever
Chills
Shivering and
sweating
Muscular and
back pains
Muscle fatigue
Dry cough
Spleen infected
and swollen
Nausea
vomiting
Anti-malarial
medicine
such as
quinine
Blood
transfussion
Transmission of infectious diseases
We can come into contact with various dangerous micro-organisms each and
every day, whether it is when you open the door handle of a toilet or use a
trolley at the shopping centre. Pathogens can spread between humans and
other organisms in many different ways, for example:
.
1. In droplets from the air that we breathe: When an infected person
sneezes or coughs, the pathogen travels in the drops of spit or mucus to
another person.
2. In untreated and contaminated water: The pathogen is transmitted in
contaminated water, especially if it has been in contact with human
sewage. These diseases are called waterborne diseases, such as cholera
and typhoid, and cause diarrhoea.
3. In contaminated food: Sometimes people prepare food without washing
and disinfecting their hands properly and the food can become
contaminated.
4. Through cuts or wounds: Many pathogens enter our bodies via cuts or
wounds. For example, tetanus bacteria live in the soil and when someone
hurts themselves on a piece of rusty metal, this pathogen can infect the
person.
5. Through bites from animals: Some pathogens can spread via bites from
infected animals. For example, the rabies virus from infected animals and
malaria is transmitted to humans through mosquitoes.
PREVENTING THE SPREAD OF DISEASES
Effective methods of preventing the spread of diseases caused by micro-organisms
include washing hands and sterilising
Keep food covered to avoid flies landing on it
Do not let your pet lick your face or eat off your plate
Do not drink water from streams
Use only clean, treated or boiled water
When you have a cold, cover your mouth when you cough or sneeze
44 | P a g e
Cover cuts with plaster to prevent bacterial infections
Wash all raw food wit clean, treated or boiled water
Always cook meat well
When you are infected quarantine yourself
Modern scientists such as Louis Pasteur play an important
role in identifying and developing cures for some diseases
He was a scientist in medical microbiology
He was a French chemist and microbiologist. He discovered a way to
reduce death rate in many diseases and created the first vaccines
for rabies and anthrax.
ACTIVITY: 14
Preventing the spread of diseases
.
Malaria is a disease caused by a protist. The protist enters the human body via
the bloodstream when an infected female Anopheles mosquito bites a person.
The protist travels to the liver of the person and starts to reproduce. Malaria
causes high fever and severe headaches, and can lead to a coma and death.
The Anopheles mosquito which spreads the
protist that causes malaria in humans
the
mosquito
.
45 | P a g e
The protist (purple) that causes malaria is
moving through the gut of
in this image
1.How the spread of malaria can be prevented and what you should do if you are travelling
to an area where there is a high risk of malaria.
2. Airborne diseases such as tuberculosis (TB) caused by a bacteria, and influenza (flu)
caused by a virus, can spread very easily. How do these disease spread and how can we
reduce the transmission of these diseases?
.
ACTIVITY: Typhoid Mary
.
Typhoid is a disease caused by a bacterial infection. Some people can have these
bacteria inside their bodies without realising it, and without ever getting ill from it.
They are called 'carriers'. This was the case with Mary Mallon or Typhoid
Mary who was a carrier of the disease
Typhoid Mary
Mary Mallon emigrated from Ireland to America at the age of 15. When she
arrived she became a servant, and soon discovered a talent for cooking. Since
the cook in households earned a higher salary, she was happy to change from a
simple servant to this role. She worked in 8 households from 1900-1907 as the
cook, leaving a trail of 51 people seriously ill with typhoid, one of whom, a small
girl, died of the disease.
When she was eventually identified as the
cause of the many illnesses, authorities at first
tried to persuade her to volunteer samples
of her faeces, blood and urine to be tested.
She refused, although she did admit that she
seldom washed her hands when working with
food. She didn't think it was necessary.
Eventually, after putting up a tremendous fight,
she was taken with the help of 5 policemen,
to the nearby hospital where the samples were
removed. These proved that she was in fact
infected with typhoid although she was not sick
at all. The authorities sent her to a small island
near the city where she was kept away from
others for fear of infecting them too. Apart
from a short 'parole period', she remained on
this island, in full health, until her death.
Mary Mallon. also known as
'Typhoid Mary', was a carrier of
46 | P a g e
typhoid without knowing it.
3.3 USEFUL MICRO-ORGANISMS
Many decomposers are microorganisms. These microorganisms play a very
important role in ecosystems as they break down dead plant and animal matter.
They help to return the nutrients to the soil so that they are recycled. Some bacteria
remove nitrogen (N2) from the air and convert it to nitrogen compounds that animals
and plants can use. In plants such as legumes, the roots actually contain nodules
with the bacteria inside of them.
Nitrogen-fixing bacteria form root nodules
these roots, which contain Rhizobia
Can you see the white root nodules on
in some plants, such as legumes bacteria
These nitrogen-fixing bacteria, called Rhizobia, cannot live independently and
need a plant host. The bacteria get glucose from the plant and the plant benefits by
getting the nitrogen compounds which the bacteria fixed from the soil. What is this
kind of symbiotic relationship called?
We also have bacteria which live inside of us and help the functioning
of our bodies! Escherichia coli is found in the lower intestine of many
warm-blooded animals. They are part of the natural flora of the gut.
They can help the animal by producing vitamin K2 and help prevent other harmful
bacteria from growing in the gut
MICROORGANISMS USED BY PEOPLE
You might be surprised at how many of our day to day experiences are
somehow due to microorganisms.
Have you ever seen the side of a yoghurt container which says it contains 'live
cultures'? This refers to the bacteria inside the yoghurt. People use microorganisms
for processing foods, such as when brewing beer, making wine, baking bread and
pickling food. Microorganisms are also used in the fermentation process when
producing dairy products, such as yoghurt and cheese.
47 | P a g e
Yeast is one of the micro-organisms humans have used for food-processing. The
most common uses of yeast are in producing alcoholic beverages, such as beer
and wine, and in baking, as yeast is used to make dough rise.
Yeast grows under specific conditions. As it grows it uses sugar for energy and
converts it into carbon dioxide and alcohol. This process is called fermentation.
We can measure the amount of carbon dioxide that is produced to see how well
the process works.
What are the best conditions for this to take place? Is there an optimal amount
of sugar and what about the best temperature? These are all questions which
curious people have asked over time!
Besides the use of microorganisms in food and food-making processes, there
are also other processes for which we use micro-organisms? Specific
micro-organisms are used in water treatment, like when treating sewage on a
large scale.
In biotechnology research, microorganisms are being used to produce
alternative, renewable energy, for example, biogas and biofuels.
Microorganisms are used in the development of various medicines, for example,
antibiotics. Penicillin is a group of antibiotics which come from Penicillium
fungi. The discovery of penicillin and its uses to treat certain bacterial infections
happened by chance. This was due to the curiosity of a scientist, Alexander
Fleming, and this led to the discovery of many more antibiotics.
Sir Alexander Fleming, who discovered penicillin in 1928.
Microorganisms are also used in many fields of science and medical research.
Scientists use yeast to learn more about many other types of organisms. The
use of viruses is also currently being explored in many universities around the
world to actually help with cures for various conditions, even cancer! The
possibilities for discovery are endless!
48 | P a g e
PRACTICAL ACTIVITY (TEACHER DEMONSTRATION)
Yeast growth in different sugar concentrations
AIM:
INVESTIGATIVE QUESTION:
HYPOTHESIS:
MATERIALS AND APPARATUS: TAKE NOTE There are different kinds of yeasts.
The one we are using breaks down sugar in dough. Others breakdown wood and
cornstalks and produce ethanol (alcohol) while another breaks down the sugar in
fruits, nectar, molasses or sorghum.
• 6 balloons
• 14 grams (2 packets) of dry yeast
• white sugar
• mass scale
• funnel
• 6 x 50 cm string
• 2 - 50 ml graduated cylinders
• 600 ml beaker
• overflow pan
• permanent markers
• ice packs
METHOD:
1.Demonstration by teacher and work individually.
2. Use the permanent marker to label each balloon A, B, C, D, E and F. (educator)
3. Each balloon will need to be filled with 2 g of yeast and a different quantity of
sugar. Balloon A will need to get 2 g of sugar, B will get 3 g of sugar, C will get 4 g of
sugar and so on. (See the table below.) Use a plastic spoon or spatula to place the
yeast and sugar into the balloon.
4. Use a funnel and pour 50 ml lukewarm tap water into each balloon.
5. One person should hold the balloon and funnel while the other pours in the water.
6. As soon as the balloon has been filled, take a piece of string and tie off the balloon
as close as possible to the level of the water without trapping any air.
7. Knot the balloon's rubber neck to ensure that no air can get in or water can get
out.
8. Place each prepared balloon on ice to prevent the fermentation process from
starting.
9. Before you allow the fermentation process to start, you need to determine the
starting mass and volume of each balloon.
10. MASS: Determine the mass of the tied balloon to the nearest 2 decimal places.
Return it to the ice.
11. VOLUME: Use the water displacement method to determine the volume of the
balloon.
a) Place water in a large jug level with the top of the jug.
49 | P a g e
b) Completely submerge the balloon under the water in the jug: push the balloon and
allow the water to flow over the sides into the overflow pan. You should stop when
your fingers touch the water.
. c) The water in the overflow plan is therefore the volume of water that the balloon
displaced.
d) Carefully measure the water in the overflow pan. Record your measurements in
the table below.
e) Return the balloon to the ice as soon as possible.
12. PREPARE FOAM COOLER BOX: You are going to place the balloons inside a
foam cooler box with warm water in (the box should keep the water warm). Pour 40
0
C water into the cooler box (as it normally cools down quite quickly).
13. FERMENTATION INCUBATION: You are now ready to start the process of
incubating the yeast. a) Place each balloon into the warm water. b) Record which
balloons sink and which float. c) Leave the balloons in the warm water for 20 - 30
minutes during which time the yeast will ferment the sugar. d) Record the exact time
that you used for incubation: minutes.
14. AFTER INCUBATION: Use a paper towel to dry the balloons. a) Determine the
volume of each balloon. b) Determine the mass of each balloon. Tip: It is really
important that you work fast and accurately at this point. Your team should really
consider letting one pair determine the mass and the other the volume of each
balloon.
15. Calculate what changes (if any) occurred during incubation to the mass and
volume of each balloon.
16. Hang your balloon on a clothesline or hanger in the class to dry.
17. Clean up your work area and wash, dry and pack away all equipment that you
used.
18. THREE DAYS LATER: remove your balloons from the clothes line / hanger.
Record all observations that you can make - remember to use ALL your senses.
19. Use the same methods to determine the mass and volume of each balloon and
record this on the table.
20. AFTER measuring the mass and volume of each balloon, carefully cut it open.
Make careful notes to describe your observations of the contents of each balloon.
21. Use your table of measurements to draw a graph. RESULTS AND
RESULTS AND OBSERVATIONS:
Complete the table with the correct information obtained from your work.
Balloon Yeast Sugar Balloon
(g)
(g)
mass before
fermentation
(g)
Balloon
Sink
volume
/
before
Float
fermentation
(g)
Balloon
volume after
fermentation
(g)
Balloon
mass after
fermentation
(g)
1. Describe the changes that you observed happening in your balloons from the start
to the end of the incubation
2. Were the changes the same in each balloon?
50 | P a g e
3. Explain why you think these changes occurred differently in the contents of each
of your balloons.
4. How did you expect the balloons to react after 3 days?
5. Describe how each of the balloons actually looked after the 3 days.
6. Provide a possible explanation for your observations. Think for instance of what
could possibly have been lost from the balloons.
7. At the start you added yeast, sugar granules and water. Describe how the
contents of each of the balloons looked at the end of the investigation.
References
SOLUTIONS FOR ALL-NATURAL SCIENCES GRADE 9: Publisher - Macmillan
South Africa
Siyavula Open Textbooks
This work is licensed under a CC-BY-ND license.
Via Afrika Natural Sciences Grade 8 Learner's Book ISBN 9781415444726
Author(s): A.C. Visser; C.E. Whitlock; J.J.J. de Beer; D.B. Gibbon; R. Jones; F.T.
Kunene; M.E. Patrick; J.A. Sampson; T. Subramani
Platinum Natural Sciences Grade 8 Learner’s Book
Author: J. Avis, A.J. Clacherty, S. Cohen, S. Doubell, K.S. Dilraj, J. Erasmus, A.
Joannides, G. Lombard, E
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