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NATIONAL 4 AND NATIONAL 5 BIOLOGY
HOMEWORK
LIFE ON EARTH
UNIT 2: BIOTIC INTERACTIONS
HOMEWORK 1
1. (a) Explain what biotic factors are
(b) Give at least two examples of biotic factors
2. (a) State the definition of the term niche
(b) Describe the niche of an organism you have looked at in class
3. Copy and complete:
A food web with a
than one with
of organisms is more stable
. Changes in to populations have a
effect on an unstable ecosystem.
HOMEWORK 2
1. Explain which level of grazing maintains plant diversity
2. (a) Define competition
(b) Which resources could animals be in competition for?
(c) Which resources could plants be in competition for?
3. Describe the difference between intraspecific and interspecific
competition. Which type of competition is more intense?
NATIONAL 4 AND NATIONAL 5 BIOLOGY HOMEWORK
LIFE ON EARTH
Pollution
Homework 1
1. What does the word biodiversity mean?
2. Give 3 reasons why a high biodiversity is important.
3. Give 2 examples of natural disasters.
4. What effects have these natural disasters had?
Homework 2
1. Copy out the table and fill in the gaps:
environment
Main source
Example of
How to control
Of pollutant
pollutant
it
Air
Oil tankers/
nuclear power
stations
2. Name a harmful gas released from coal during burning.
3. Explain how this gas effects the environment.
Homework 3
1. List 3 things that organic waste includes
2. How does organic waste in a lake affect oxygen concentrations?
3. What happens to the animals in the lake due to organic waste?
4. What is an indicator species?
5. Give and example of an indicator species found in oxygen rich water
and oxygen poor water.
Homework 4
1. State the resources dense human populations require.
2. How does this demand on resources affect other organisms in the area?
3. Why is deforestation affecting the biodiversity?
4. What is the term used to describe an animal that no longer exists?
5. Give an example of an organism that is close to being killed out and
how this is happening.
NATIONAL 4 AND NATIONAL 5 BIOLOGY HOMEWORK
LIFE ON EARTH
UNIT 2: NATURAL SELECTION I & II
HOMEWORK 1
4. (a) State what is meant by a genetic mutation.
(b) State two factors that can increase the rate of a mutation.
5. (a) State what is meant by a neutral mutation.
(b) Give an example of an advantageous and disadvantageous mutation.
HOMEWORK 2
4. State what is meant by the term Natural Selection.
5. (a) Give the meaning of the term adaptation.
(b) Give an example of an adaptation in a named animal.
(c) Give an example of an adaptation in a named plant.
6. Give 2 examples of Natural Selection in action.
HOMEWORK 3
1. Give a definition of the term species.
2. The following list refers to stages in an evolutionary process.
1. Natural Selection
2. Mutation
3. Isolation
(a) The diagram below shows the stages in the process and its end
result. Copy the diagram and add numbers to the boxes to show the
order in which the stages would normally occur.
new species form
NATIONAL 4 AND NATIONAL 5 BIOLOGY
HOMEWORK
CELL BIOLOGY
FOOD, FARMING & FERTILISERS
HOMEWORK 1
1. Describe three changes which have taken place in agriculture since 1900.
2. a) What is a monoculture?
b) What would be an advantage to a farmer of the monoculture system?
3. Why do you think animal rights groups disagree strongly with ‘factory farming’?
HOMEWORK 2
1. Why are chemical fertilisers used by farmers?
2. State the three main chemical elements found in most fertilisers.
3. What is a ‘trace element’ as found in some fertilisers?
HOMEWORK 3
1. Give an example of an organic fertiliser.
2. Excess nutrients in aquatic ecosystems (often caused by fertiliser runoff from
farmland) causes algal blooms. What is the term for this process?
3. Write a sentence to describe what happens to dead algae in a pond using the words
‘bacteria’, ‘decomposition’ and ‘oxygen’.
HOMEWORK 4
1. DDT was banned in the UK in the 1980s. What effect did it have on the
environment which led to it being banned?
2. Give an example of an alternative method of pest control, not using chemical
pesticides.
3. The growing of genetically-modified crops divides opinion. State two known (or
potential) advantages and two known (or potential) disadvantages.