Q1 [o/n 07] Lake Victoria is the largest tropical lake in the world. Until the 1960s it provided an
ecosystem with habitats for 500 species of small cichlid fish. They feed on algae (aquatic plants).
Prawns also feed on algae.
Nile perch were introduced into the lake. These fish are excellent food for humans, as well as providing
sport for tourists. The Nile perch eat cichlids.
Deforestation of the lake shore and pollution by humans caused eutrophication and resulted in a huge
reduction in cichlid numbers. However, the Nile perch are able to survive in poor quality water, even
when the oxygen level is low. As the cichlid population dropped, prawn numbers increased and Nile
perch now eat them.
(a) Define the term ecosystem. [2]
(b) Using information in the text above, state two reasons why Nile perch were introduced into Lake
Victoria.[2]
(c) Complete the table to identify at which trophic level each of the organisms named in the text are
feeding. algae cichlid fish human Nile perch prawn[3]
(d) Explain how eutrophication could have resulted in a reduction in the numbers of cichlid fish. [4]
Q2 O/N 03 (a) (i) Construct a food chain with four named organisms. [3]
(ii) Using appropriate biological terms, describe and explain the flow of energy through
your chosen food chain. [8]
(b) With reference to a suitable example for each, outline the need for conservation of
(i) a named species
and
(ii) a named habitat.
Q3 /O/N/06 In 2003, 25 000 square kilometres of Amazon rainforest were cut down and cleared. The
land was then used for agriculture, producing beef and soya beans for export. However, within three
years the land was no longer suitable for agriculture and had to be abandoned.
(a) (i) State the term used for cutting down and clearing areas of forest. [1]
(ii) Complete Table 3.1, to state different reasons why forests are cut down. The first
has been done for you.
Table 3.1 [2]
(iii) Outline and explain the likely effects of clearing forests.[6]
(b) Soya beans and beef produced on the land are both good sources of protein. Table 3.2
shows the nutritional content of products made from soya and beef.
Table 3.2
(i) Using data from Table 3.2, state and explain two reasons why soya sausages may be healthier than
corned beef as a major item in the diet. [4]
(ii) Soya beans are harvested from plants. Corned beef is produced from cattle that
have fed on grass.
Explain why it is more energy efficient for humans to eat soya products as a source
of protein than corned beef. Use the food chains involved to support your answer.[4]
[Total: 17]
Q 4 (O/N 2008)The freshwater mussel, Margaritifera margaritifera, is a mollusc which lives in rivers and
streams.
When the mussel reproduces, gametes are released into the water and fertilisation takes place.
The embryos, in the form of larvae, attach themselves to the gills of fish and develop there for a few
months.
The larvae then release themselves and grow in sand in the river, feeding by filtering food from the
water.
The number of mussels is falling due to human predation and the species is threatened with extinction.
(a) The mussel belongs to the group known as the molluscs. State two features you would expect the
mussel to have.[2]
(b) Explain how the species name of the freshwater mussel can be distinguished from its genus.[1]
(c) State the type of reproduction shown by the mussel.
Explain your answer. [2]
(d) (i) Fish gills have the same function as lungs. Suggest one advantage to a mussel
larva of attaching itself to fish gills.[1]
(ii) The mussel develops on the fish gills. Define the term development.[1]
(e) The mussel is threatened with extinction. Name another organism which is also
threatened with extinction and outline how it could be conserved. [3][Total: 10]
Q5(O/N 2008) Fungi are decomposers.
Why are they important in the food web?
A They provide food for snakes.
B They control the numbers of toads.
C They provide energy for plant growth.
D They release minerals essential for plant growth.
Q6 (O/N 2008)A single tree is food for a large population of caterpillars. Several small birds eat the
caterpillars. The small birds are eaten by a bird of prey.
Which is the pyramid of biomass?
Q7(O/N 2008) The diagram shows
part of the carbon cycle.
Which process is missing from the diagram?
A combustion
B photosynthesis
C respiration
D transpiration
Q8(M/J 2008)The wild dog is one of the smaller African carnivorous mammals. It has disappeared from
of the 39 countries where it used to live. Wild dogs hunt in packs, feeding on antelopes, which are
grass-eating mammals.
A conservation programme has been started to increase the wild dog population in South
Africa. Farmers are worried about numbers getting out of control because wild dogs breed at a very fast
rate. However, conservationists are not concerned because the lion is a natural predator of the dogs.
(a) Wild dogs are carnivorous mammals.
(i) Define the term carnivore. [1]
(ii) State one external feature which distinguishes mammals from other vertebrates. [1]
(b) (i) Suggest two reasons why numbers of African wild dogs are decreasing. [2]
(ii) Suggest what could happen to the species if numbers continue to decrease.[1]
(c) Using the information in the passage above, construct a food chain for a wild dog,
including its predator.
Label each organism with its trophic level.[4]
(d) It is important that the wild dog species is conserved.
(i) Explain the meaning of the term conservation. [2]
(ii) Outline the measures that could be taken to conserve a mammal, such as the wild
dog.[3]
(e) When wild dogs die, nitrogen compounds in their bodies may become available for plants. Outline
the processes that occur to make these nitrogen compounds in the
bodies of dead animals available for plants to absorb.[5] [Total: 19]
Q9(M/J 2008) Fig. 9.1 shows three species of zebra.
(a) Describe one method a scientist could use to show that the zebras shown in Fig. 9.1 are different
species.[1]
(b) Studies have shown that the hotter the environment, the more stripes zebras have.
(i) State the type of variation which would result in different numbers of stripes.[1]
(ii) Study Fig. 9.1. Suggest which species of zebra lives in the hottest environment.[1]
(c) Occasionally, zebras are born that are almost completely black. The change in
appearance is the result of mutation.
(i) State the term that is used to describe the appearance of an organism.[1]
(ii) Define the term mutation.[2]
(d) Tsetse flies attack animals with short fur, sucking their blood and spreading diseases.
Fig. 9.2 shows a tsetse fly. This fly is an insect, belonging to the arthropod group.
(i) State one feature, visible in Fig. 9.2, which is common to all arthropods.[1]
(ii) State two features, visible in Fig. 9.2, which distinguish insects from other
arthropod groups. [2]
(e) Scientists have discovered that zebras with more horizontal stripes attract fewer tsetse flies.
(i) Suggest why the stripes on the head and neck of the zebra would be an advantage when it feeds on
grass on the ground. [2]
(ii) Describe how a species of zebra could gradually develop more horizontal stripes.
[3][Total: 14]
Q10 O/N/07Lake Victoria is the largest tropical lake in the world. Until the 1960s it provided an ecosystem
with habitats for 500 species of small cichlid fish. They feed on algae (aquatic plants). Prawns also feed
on algae.
Nile perch were introduced into the lake. These fish are excellent food for humans, as well as providing
sport for tourists. The Nile perch eat cichlids.
Deforestation of the lake shore and pollution by humans caused eutrophication and resulted in a huge
reduction in cichlid numbers. However, the Nile perch are able to survive in poor quality water, even
when the oxygen level is low. As the cichlid population dropped, prawn numbers increased and Nile
perch now eat them.
(a) Define the term ecosystem. [2]
(b) Using information in the text above, state two reasons why Nile perch were introduced into Lake
Victoria. [2]
(c) Complete the table to identify at which trophic level each of the organisms named in the text are
feeding. [3]
(d) Explain how eutrophication could have resulted in a reduction in the numbers of cichlid fish.[4]
[Total: 11]
Q 11 /M/J/07 Fig. shows a female lion in a game reserve.
Fig.
(a) (i) State one feature, visible in Fig. which identifies the lion as a mammal.[1]
(ii) State one other feature, not visible in Fig. which distinguishes mammals from
all other vertebrate groups.[1]
(b) Study the eyes of the lion in Fig.
(i) Suggest and explain what the light conditions were when the photograph was
taken. [2]
(ii) Explain the importance of the eyes reacting to light in this way. [2]
(c) Scientists say that lions are unable to see in colour.
Suggest how a study of a lion’s retina would provide evidence for this statement. [1]
(d) The lion in Fig. was observing tourists nearby. It turned its head to see zebras
moving in the distance.Describe how the eyes of the lion would adjust to focus on the zebras.[3]
(e) The lion was photographed in a game reserve in Namibia.
Explain why the conservation of animals in game reserves is important.[3] [Total:13]
Q12 /M/J/07 Scientists are considering the use of a genetically engineered virus to kill a population of
the cane toad, Bufo marinus, which is growing out of control in Australia.
This virus will introduce a modified form of genetic material, responsible for hormone
production. The normal hormone causes the toads to mature in a similar way to hormones
causing puberty in mammals. The modified genetic material will prevent toads maturing,
leading to their death.
The toad was introduced into Australia because it eats scarab beetles, a pest of sugar cane
plants. Sugar cane is an important crop plant.
Animals such as crocodiles and dingos are predators of the toad, but the toad can kill them
by squirting a powerful toxin.
(a) Define the term genetic engineering.[2]
(b) State which part of the virus would carry the modified genetic material.[1]
(c) (i) Name the hormone that causes puberty in male mammals.[1]
(ii) State two characteristics that develop in a boy when this hormone is produced.[2]
First variant Question Paper
The toad population is increasing out of control. In terms of a sigmoid growth curve, it is in
the exponential phase.
(d) (i) 1. Sketch a sigmoid growth curve using the axes below.
2. Label the axes (units are not needed).
3. Label the exponential phase of the curve.[4]
(ii) Suggest one limiting factor, other than viruses or predators, that could stop the
toad population rising.[1]
(e) (i) Construct a food web for the organisms named in this question.[2]
(ii) Complete the table by writing each of the organisms you used in the food web in
the correct column.
carnivore herbivore producer[3][Total : 16]
Q13 O/N/03FFig. 13.1 shows part of a river into which sewage is pumped. The river water flows from W
to Z, with the sewage being added at X.
Fig. 13.1
Some of the effects of adding sewage to the river are shown in Fig. 3.2.
Fig. 13.2
(a) Describe the changes in the levels from W to Z of
(i) nitrates;
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................2]
(ii) suspended solids.
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................2]
(b) Suggest why the level of oxygen
(i) drops at X;
..................................................................................................................................
...............................................................................................................................1]
(ii) increases again towards Z.
..................................................................................................................................
...............................................................................................................................1]
(c) Suggest two reasons why levels of algae drop
(i) when sewage is added to the river;
1. ...............................................................................................................................
2. ...........................................................................................................................[2]
(ii) towards Z.
1. ...............................................................................................................................
2. ...........................................................................................................................[2]
(d) A farm at Z used herbicides on the field next to the river.
Suggest why this could cause further problems in the river.
.........................................................................................................................................
.....................................................................................................................................[1]
[Total : 11]irst vari
ant Question Paper
Q 14 M J/03 The seaweed, Caulerpa taxifolia, lives in tropical oceans but is now also found in the
Mediterranean sea, where it grows at twice the rate of local seaweeds. As a result, the local
seaweeds are becoming rare.
Although not poisonous, Caulerpa produces a chemical in its cells that makes it inedible to
Mediterranean herbivores, such as sea urchins. They do not feed on it and their numbers are
decreasing. Carnivorous fish populations have also decreased by up to 50 %.
Marine conservationists are very concerned. At first they used chlorine to kill Caulerpa but
are now considering the introduction of tropical sea slugs (herbivorous molluscs). Caulerpa
is part of their natural diet.
(a) The seaweed, Caulerpa taxifolia, is named using the binomial system.
Explain the term binomial system.
.........................................................................................................................................
.........................................................................................................................................
.....................................................................................................................................[2]
(b) (i) Suggest why the local seaweeds are becoming rare.
..................................................................................................................................
...............................................................................................................................2]
(ii) Sea urchins are herbivores. Define the term herbivore.
..................................................................................................................................
...............................................................................................................................1]
(iii) Suggest why the populations of carnivorous fish have decreased by up to 50%.
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................2]
(c) Suggest why using chlorine to kill Caulerpa might not be a good idea.
.........................................................................................................................................
.....................................................................................................................................[1]
(d) (i) Suggest why conservationists are concerned about the effects of Caulerpa on
other organisms in the Mediterranean.
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................2]
(ii) Explain how the introduction of herbivorous sea slugs from the tropics could be
effective in re-establishing a balanced ecosystem.
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................2]
(iii) Outline the possible dangers of introducing tropical sea slugs.
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................2]
[Total : 14]
Q 15 MJ 04 Table 15.1 shows data for human life expectancy for six countries.
Table 15.1
(a) Human life expectancy worldwide has increased between 1982 and 1999.
(i) State the countries in Table 15.1 that show this trend.
...............................................................................................................................1]
(ii) Suggest two reasons why life expectancy is increasing worldwide.
1. ...............................................................................................................................
2. ...........................................................................................................................[2]
(b) A person suffering from AIDS tends to have a reduced life expectancy.
State the country, from Table 15.1, that has developed the most serious AIDS problem
since 1982. Use data from the table to explain your choice.
country .............................................................................................................................
explanation .......................................................................................................................
.....................................................................................................................................[2]
(c) HIV, the cause of AIDS, can be transmitted sexually. Many sexually transmitted
diseases, such as gonorrhoea, can be treated with antibiotics.
(i) Explain why HIV cannot be controlled with antibiotics.
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................2]
(ii) Name a type of contraception that is used to prevent the transmission of HIV during
sexual intercourse. Explain how it prevents HIV from being transmitted.
type of contraception ................................................................................................
explanation ...............................................................................................................
...............................................................................................................................2]
(iii) Describe one other way, other than sexual intercourse, by which HIV can be
transmitted.
..................................................................................................................................
..................................................................................................................................
..................................................................................................................................
...............................................................................................................................3]
[Total: 12]