Life on Earth
N4
Homework Booklet
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Life on Earth Homework 1: Food Webs
The diagram below shows part of an urban food web.
1. Name the producer (1)
2. From the food web, produce one food chain showing the flow of energy (1)
3. Explain why the thrush in this web is described as an ‘omnivore’ (1)
4. What name is given to the type of organism, like the earthworm, that feeds on dead
and decaying material? (1)
5. What do the arrows in this food web represent? (1)
6. Name the source of energy for all food webs (1)
7. Give two ways in which energy can be lost from a food chain (2)
8. Less household waste is available to wildlife because of the type of disposal bins in
which it is now collected. Predict the effect this will have on the number of mice and
give a reason for your answer (2)
9. Name 2 organisms in competition with each other (1)
10. Describe:
a) What is meant by an ecosystem (4)
b) Methods of sampling plants and animals in an ecosystem (6)
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Life on Earth Homework 2: Pyramids
1. The table below shows information about 3 food chains:
Producer
200 leaves
Primary
Consumer
100 caterpillars
5 cabbages
Secondary
Consumer
5 thrushes
100 caterpillars
Tertiary
Consumer
1 kestrel
5 thrushes
500 flies
20 water weeds
200 insect larvae
5 small fish
1 otter
a) Draw a Pyramid of Numbers for each food chain.
b) The average masses for the organisms in these food chains are:
Leaf (5g), caterpillar (4g), thrush (70g), kestrel (250g), waterweed (250g),
insect larvae (10g), small fish (300g), otter (1Kg), cabbage (300g), flea
(0.04g).
i) Draw a biomass pyramid for each food chain using this data.
ii) What differences can you see between each pyramid of number and each
pyramid of biomass?
2. A community in a woodland consists of oak trees, caterpillars, voles and owls.
Many thousands of caterpillars feed on the leaves of a single oak tree. A
single vole may eat a hundred caterpillars each day. An owl may eat three
voles in one day.
a) The diagram shows 4 pyramids of numbers:
A
Owl
B
Owl
C
Owl
D
Owl
Vole
Vole
Vole
Vole
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Oak
Oak
Oak
Oak
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PTO for questions
i)
ii)
iii)
iv)
Which pyramid of numbers is correct for the woodland community?
What is meant by the term biomass?
Draw a pyramid of biomass for the woodland community.
Explain how energy is lost to the surroundings between each level of your
pyramid of biomass.
c) In a town near to the woodland many additional houses and factories are
built. Suggest and explain one effect this might have on the woodland
community.
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Life on Earth Homework 3: The Nitrogen Cycle
The diagram above shows part of the nitrogen cycle.
1. Use letters from the diagram to complete the following table about some events of the
nitrogen cycle.
Event
Death and decay
Action by denitrifying bacteria
Lightning
Letter
2. Explain why event A can take place in some plants such as clover, peas and beans, but not
in others.
3. Name compound X.
4. The diagram below shows three possible fates of nitrates which have been added to the
soil as fertiliser.
Nitrates
absorbed by plants
converted to nitrogen
gas
runoff into
lochs
1. Why are nitrates essential for plant growth?
2. What type of bacteria convert nitrate to nitrogen gas?
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P.T.O
3. Explain how the runoff of nitrates into a loch ecosystem might result in a drop in the
oxygen concentration of the water.
4. Describe two ways by which the nitrate content of the soil can increase naturally.
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Homework 4
Biodiversity
1. Above is a picture illustrating a form of atmospheric pollution. Put the following statements in
the correct order to show the effects of this type of pollution on the environment:
A: Acid rain falls on land and water environments.
B: Fossil fuels burned by industry, power stations and motor vehicles.
C: Acid gases form acid rain clouds.
D: Trees suffer dieback and fish die.
E: Acid gases released into the atmosphere.
2. Imagine that McDonalds were trying to build a new restaurant near to the site of a country
park near your home. The park is not only popular in the summer for visitors, but it is also
home to a variety of plants and trees, and well as many different types of wildlife.
 Take the position of either a park ranger, against the new McDonalds, or the big
boss of McDonalds trying to build the restaurant.
 Bullet point a reasoned argument either for or against the building on or near the
site.
 You must include arguments surrounding the variety of plants and animals that may
be affected.
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Homework 5
FOOD CHAINS HOMEWORK
1. Complete the paragraph below by filling in the gaps:
Producers are able to make their own F______. Producers are fed upon by herbivores or
P_________ consumers. These in turn provide food for S__________ consumers. Dead and
decaying material provides food for D_________. Feeding relationships can be shown in
food C_______ and in food W_____.
2. Look at the woodland food web:
OWL
CHIFFCHAFF
BLUE TIT
LADYBIRD
SPIDER
STOAT
MOTH LARVA
VOLE
APHID
PLANTS
a) Give one example from the food web, of each of these:
i) a producer
ii) a primary consumer
iii) a secondary consumer
b) How many carnivores are there in the food web?
c) Draw a food chain with 5 links in it.
d) If all the spiders were killed by disease what would happen to the numbers of:
i) moth larvae
ii) Plants?
e) Construct, using the food web, two different food chains, each with 4 links.
f) Why do most food chains begin with green plants?
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Homework 6
Life on Earth Homework 2
1. Describe what is meant by a producer and a consumer.
2. a) Using the table below, construct a food web.
Organism
Grasshopper
Lizard
Hawk
Mouse
Rabbit
Fox
Sparrow
Grass Snake
Food
Grass, wheat
Grasshoppers
Rabbits, lizards, sparrows, grass snakes
Grass, wheat
Grass
Rabbits
Grasshoppers
Lizards, mice
b) Give an example of a food chain in the web.
(c) Describe the effects of the removal of grasshoppers from this food web on the
following organisms and give a reason for your answers.
 Sparrows
 Wheat
 Mice
d) What do the arrows in a food web show?
e) State 2 ways in which energy can be lost from a food web.
4. What is meant by the terms pyramid of a) numbers and b) biomass?
5. What does the growth of a population depend on?
6. Describe the growth curve of a population under ideal conditions.
7. State 3 factors which can limit the growth of a population.
8. Describe and explain the growth curve of a population under ideal conditions.
9. Why does competition occur?
10. Give two examples of resources which may cause competition.
11. What are the effects of competition?
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Homework 7
PYRAMIDS WORKSHEET
3. The table below shows information about 3 food chains:
Producer
Primary
Consumer
100 caterpillars
200 insect larvae
100 caterpillars
Tertiary
Consumer
1 kestrel
1 otter
500 flies
200 leaves
20 water weeds
5 cabbages
Secondary
Consumer
5 thrushes
5 small fish
5 thrushes
d) Draw a Pyramid of Numbers for each food chain.
e) The average masses for the organisms in these food chains are:
Leaf (5g), caterpillar (4g), thrush (70g), kestrel (250g), waterweed (250g), insect larvae
(10g), small fish (300g), otter (1Kg), cabbage (300g), flea (0.04g).
iii) Draw a biomass pyramid for each food chain using this data.
iv) What differences can you see between each pyramid of number and each pyramid of
biomass?
4. A community in a woodland consists of oak trees, caterpillars, voles and owls. Many
thousands of caterpillars feed on the leaves of a single oak tree. A single vole may eat a
hundred caterpillars each day. An owl may eat three voles in one day.
a) The diagram shows 4 pyramids of numbers:
A
Owl
B
Owl
C
Owl
D
Owl
Vole
Vole
Vole
Vole
Caterpillar
Caterpillar
Caterpillar
Caterpillar
Oak
Oak
Oak
Oak
v) Which pyramid of numbers is correct for the woodland community?
vi) What is meant by the term biomass?
vii) Draw a pyramid of biomass for the woodland community.
viii) Explain how energy is lost to the surroundings between each level of your pyramid
of biomass.
f) In a town near to the woodland many additional houses and factories are built. Suggest
and explain one effect this might have on the woodland community.
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Homework 8
Fertiliser Composition - Homework
Strength of fertiliser to
be made up.
Volume of stock solution Volume of water to be
to be used (cm3)
used (l).
Full
Half
Quarter
100
50
25
10
10
10
The table above gives information needed to make up solutions of a type of liquid
fertiliser.
1a) A gardener decided that she needed approximately 20 litres of full strength fertilizer.
What volume of stock solution should she add to 20 litres of water?
1b) A second gardener added 50cm3 of stock solution to 20 litres of water. What strength
of fertilizer did he make up?
1c) A third gardener found that she had 25cm3 of stock solution left and she needed
fertilizer of half strength. What volume of water should she use?
Type of
Flowering Plant
Begonia
Dahlia
Fertiliser A
Up to April
-
Delphinium
Fuschia
Gladiolus
Rhododendron
Rose
Sweet Pea
Up to May
Up To April
Up to April
Time when fertiliser should be used
Fertiliser B
Fertiliser C
Fertiliser D
May Only
From June on
To end of June From July on
Up to April
June only
-
From July on
At all times
At all times
From May on
-
From May on
From May on
The table above gives information about the use of four different fertilisers on some types
of flowering plant.
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2a) At which times of the year should rose plants be given fertiliser A?
2b) How many types of plant can be given fertiliser B during June?
2c) How many types of plant can be given fertiliser C during July?
2d) How many different types of fertiliser can be correctly used on fuchsia plants during the
six-month period from April to September?
2e) Which fertiliser should be used on dahlia plants in August?
2f) on which TWO types of plant can fertiliser D be used in June?
2gi) Fertiliser C has a mineral ratio (N:P:K) of 15:15:30 and fertiliser D has a mineral ratio
(N:P:K) of 10:30:20. Draw TWO pie charts to show these ratios.
2gii) In a 100kg bag of fertiliser C, how many kilograms would be N?
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Homework 9
The Nitrogen Cycle - Homework
Certain elements (substances found in nature) are used again
and again day after day by different living organisms for
different purposes. We refer to the repeated use of an
element as CYCLING.
Nitrogen (N) is needed by plants and animals to make PROTEINS.
Proteins are part of muscles in humans and seed stores in plants.
Nitrogen is present in large amounts in the air we breathe but
humans cannot get it this way. We get our protein from eating
plants.
3) Which element is needed to make proteins?
4) What do plants and animals use proteins to make?
5) Where can’t humans get their nitrogen from?
6) Where do we get our nitrogen from?
Special plants called legumes can get nitrogen out of the soil
and turn it into proteins which we can eat. Examples of legume
plants are peas and beans. They are very important in the
nitrogen cycle.
7) What type of plants can convert nitrogen in the soil into protein?
8) Give two specific examples of a plant that can do this.
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How do animals get protein?
11) How is nitrogen returned to the air to complete the cycle?
12) What do we call the group of organisms that break down protein
waste?
13) How is protein lost from animals?
14) What is the chemical symbol for nitrogen in the air?
15) Why is the process above called a cycle?
9) What
do we call
bacteria
that can
take
nitrogen
from air
and turn
it into
useful
nitrates?
10) Plants
can take
up these
nitrates
and turn
them into
protein.
BONUS QUESTIONS
16) What could a farmer do if he wanted to increase the amount of
nitrogen in his soil naturally?
17) What would he add if he didn’t mind being inorganic?
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Homework 10
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Homework 11
Behavioural responses help animals and plants to survive. This means they are more likely to
live and have babies themselves.
Describe what the following animals might do under the given environmental conditions;
Animal
Condition
Response (what it
does)
Woodlouse
Light
Dog
Getting too hot in the
Hide under some leaves
sunshine
Human
Cold hands playing in
the snow
Pig
Gets too hot since it
cannot sweat
Horse
Gets whipped by the
rider in a race
Trout
A fisherman splashes
in the water near the
fish
Clownfish
Sees a big fish coming
to eat it
Rabbit
Sees a fox
Hedgehog
Is in the middle of the
road when a car is
coming
Possum
A hawk flies overhead
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