1.	Which of the following is the best definition of a population?
A.	A group of individuals that can interbreed and produce fertile offspring
B.	The number of individuals of the same species in a given area
C.	A group of species living and interacting with each other in a given area
D.	The total number of individuals in a given area
(Total 1 mark)

2.	The diagram below shows a simplified food web.
		
	What is the role of the snake in this food web?
A.	Primary consumer
B.	Secondary consumer
C.	Tertiary consumer
D.	Producer
(Total 1 mark)

3.	The graph below represents a sigmoid (S-shaped) population growth curve. Three sections of the curve are indicated (1, 2 and 3).
	In which of the sections is natality plus immigration greater than mortality plus emigration?
		
A.	1 only
B.	2 only
C.	1 and 2 only
D.	3 only
(Total 1 mark)

4.	Two different trees have been classified as Pinus pinea and Pinus nigra. Which of the following statements is correct?
A.	Both trees belong to the same class but a different genus.
B.	Both trees belong to the same family and same genus.
C.	The species name of both trees is Pinus.
D.	The family names are pinea and nigra.
(Total 1 mark)

5.	A collection of four animal specimens is observed and a dichotomous key is applied. Which specimen is an arthropod?
1.	Non-segmented body	.........................................	go to 2
Segmented body	.................................................	go to 3
2.	Body is not symmetrical	.....................................	specimen A
Body is symmetrical	...........................................	specimen B
3.	Jointed appendages present	................................	specimen C
Jointed appendages absent	.................................	specimen D
A.	Specimen A
B.	Specimen B
C.	Specimen C
D.	Specimen D
(Total 1 mark)

6.	Which of the following ecological units includes abiotic factors?
A.	A community
B.	An ecosystem
C.	A population
D.	A trophic level
(Total 1 mark)

7.	In the forest zone between Gabon and the Republic of Congo it is estimated that an epidemic of the Zaire strain of the Ebola virus (ZEBOV) killed nearly 5000 gorillas, significantly reducing the population. Which statement is supported by this information?
A.	Natality was greater than mortality.
B.	Mortality was equal to natality.
C.	Natality and immigration was greater than mortality and emigration.
D.	Mortality was greater than immigration and natality.
(Total 1 mark)

8.	If humans become infected with the Ebola virus it can have devastating effects. Strong, but not certain, evidence suggests that trading in animal products is the main reason for the spread of the Ebola virus to humans. Which statement about the precautionary principle is correct?
A.	In the absence of certainty about cause and effect, people should not be asked to stop trading in animal products.
B.	The burden of proof regarding a cause and effect relationship lies with scientists.
C.	Because it is a probable cause, trading in animal products should be banned because of the potentially devastating consequences.
D.	The precautionary principle is not relevant in this case.
(Total 1 mark)

9.	Which group of organisms in the carbon cycle converts carbon into a form that is available to primary consumers?
A.	Decomposers
B.	Saprotrophs
C.	Detritus feeders
D.	Producers
(Total 1 mark)

10.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Living organisms at every trophic level are part of the carbon cycle. Draw a labelled diagram of the carbon cycle to show the processes involved.
(9)
 
(b)	Explain, using an example of a food chain, how trophic levels can be deduced.
(4)
 
(c)	Explain methods that can be used to measure the rate of photosynthesis.
(5)
(Total 20 marks)

11.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Describe what is meant by a food chain using an example with four named organisms.
(4)
(b)	Outline how global warming may affect arctic ecosystems.
(5)
(c)	Explain how natural selection can lead to evolution using antibiotic resistance in bacteria as an example.
(9)
(Total 20 marks)

12.	The graph below shows the monthly mean values of terrestrial invertebrates from May 1997 to June 1998 in the northern hemisphere. The light line shows the biomass of invertebrates which are prey to forest birds (terrestrial invertebrate biomass). The darker line shows the invertebrates which lived in the stream and have moved to the forest (aquatic invertebrate flux or movement). The black bars on the horizontal line at the bottom show periods when trees have leaves and the white bars show periods of defoliation.
		
	[S Nakano and M Murakami. 2001. “Reciprocal subsidies: Dynamic interdependence between terrestrial and aquatic food webs.” PNAS. Vol 98, issue 1. Pp 166–170. Figure 1C. Copyright (2001) National Academy of Sciences, USA.]
 
(a)	State the mean terrestrial invertebrate biomass measured in August.
......................................................................................................................................
(1)

(b)	Describe the trend in the aquatic invertebrate flux.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(c)	Suggest the relationship between defoliation and the amount of terrestrial invertebrates in the forest.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(d)	Suggest a possible explanation for the pattern in aquatic invertebrate flux to the forest seen between the months of June and December.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 7 marks)

13.	(a)	Define the terms fundamental niche and realized niche.
Fundamental niche: .....................................................................................................
......................................................................................................................................
Realized niche: .............................................................................................................
......................................................................................................................................
(2)
 
(b)	Explain why the carnivores in an ecosystem tend to be fewer in number and have a smaller biomass than the herbivores in the same ecosystem.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(c)	Explain why carnivores tend to be more affected by biomagnification than organisms lower down the food chain.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(Total 7 marks)

14.	The introduction of alien species and the release of environmental pollutants are examples of human activities that have an impact on the environment.
(a)	Alien species may arrive in an ecosystem due to accidental or deliberate release.
State the impact of one named example of deliberate release.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(b)	Outline the effect of CFCs on the ozone layer.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
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......................................................................................................................................
(2)
(Total 4 marks)

15.	Competition between genetically similar species of birds may lead to changes of one or more characteristics. One characteristic that results from this kind of selection is differences in the beaks. Researchers studied the beak lengths of two species of warblers. The graphs below show the beak lengths of Pine Warblers (Dendroica pinus) and Yellow-throated Warblers (Dendroica dominica) from three geographically isolated areas in the USA.

	[Source: R Ficken et al. 1968. Evolution. Vol 27. Pp 307–314. Republished with the permission of Wiley-Blackwell.]
 
(a)	(i)	Identify the species with the shortest mean beak length.
...........................................................................................................................
(1)

(ii)	Determine the difference in the mean beak length of the two populations of Yellow-throated Warblers in Midwest and Delmarva.
...........................................................................................................................
(1)
 
(iii)	Compare the range of variation in beak length of the Yellow-throated Warblers in Midwest to the beak length of the Yellow-throated Warblers in Delmarva.
...........................................................................................................................
...........................................................................................................................
(1)
 
(b)	Suggest an advantage for the longer beaks of Yellow-throated Warblers in Delmarva.
......................................................................................................................................
......................................................................................................................................
(1)

(c)	Using the Yellow-throated Warbler as an example, outline the concept of allopatric speciation.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
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(3)
(Total 7 marks)

16.	Cadmium is a heavy metal that can be toxic to many species. In a study, the concentration of cadmium was examined in the tissues of three soil arthropods, Neobisium muscorum, Platynothrus peltifer and Notiophilus biguttatus. The shaded area of each graph indicates the time that the organisms were exposed to cadmium in their environment, while the unshaded area indicates the time when cadmium was not present in their environment.

	[Source: M P M Janssen. 1991. “Comparison of cadmium kinetics in four soil arthropod species.” Archives of Environmental Contamination and Toxicology. Vol 20. P 3.]
 
(a)	Identify the highest average concentration of cadmium found in P. peltifer.
......................................................................................................................................
(1)
 
(b)	Determine, with a reason from the data, which species is unable to eliminate cadmium.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(c)	(i)	State the species that accumulates the least cadmium.
...........................................................................................................................
(1)
 
(ii)	Suggest, with observations from the data, a reason why the species stated in (c)(i) accumulates the least cadmium.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)

(d)	Describe the possible effects of the presence of cadmium in food chains involving these arthropods.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 8 marks)

17.	(a)	Explain the concept of an ecological niche.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(b)	Distinguish between fundamental niches and realized niches.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 4 marks)

18.	(a)	Outline characteristics of a named biome.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)

(b)	Explain the factors that affect the distribution of animal species.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(Total 6 marks)

19.	What is a community composed of?
A.	Habitats
B.	Populations
C.	Abiotic factors
D.	Biotic and abiotic factors
(Total 1 mark)

20.	Which of the following are greenhouse gases?
I.	Oxides of nitrogen
II.	Carbon dioxide
III.	Methane
A.	I and II only
B.	I and III only
C.	II and III only
D.	I, II and III
(Total 1 mark)

21.	The population of white-tailed deer in Nova Scotia (Canada) suffered a significant decline in the late 1970s. Which of the following is most likely to have caused the decline?
A.	The population had depleted resources in the environment
B.	A decrease in hunting
C.	A decrease in predation
D.	Natality and immigration exceeded mortality and emigration
(Total 1 mark)

22.	

	What do all of the organisms in the diagram represent when considered together?
A.	A food chain
B.	A population
C.	A community
D.	An ecosystem
(Total 1 mark)

23.	The air in urban areas contains a variety of pollutants, including particles of solids and gases.
The table below shows the pH of rain in urban areas of New York and rural areas nearby.
The concentration of four air pollutants is also shown. The concentrations of gases are measured in parts per billion (ppb).

Area	Lead /
μg m–3	Nitrogen dioxide /
ppb	Nitrous oxide /
ppb	Sulfur dioxide /
ppb	pH of rain	
Urban	0.09	37.7	39.3	18.7	4.3	
Rural	0.04	6.2	0.5	2.3	4.2	
	[Source: Nature by Nature Publishing Group. Reproduced with permission of Nature Publishing Group in the format Journal via Copyright Clearance Center.]

(a)	(i)	Compare the acidity of rain in urban and rural areas.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)

(ii)	Compare the levels of atmospheric pollution in urban and rural areas.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)

	Tree planting has been suggested as a way of improving air quality in urban areas. The growth of Populus deltoides in urban and rural areas near New York was investigated. Trees were grown in pots containing the same type of soil in all areas. High levels of mineral nutrients in the soil ensured that lack of nutrients was not the limiting factor on growth rates. The growth of the trees above ground (shoot biomass) and below ground (root biomass) was measured after one year. The bar chart below shows the results for two rural areas (open bars) and four urban areas (filled bars).
		
	[Source: Nature by Nature Publishing Group. Reproduced with permission of Nature Publishing Group in the format Journal via Copyright Clearance Center.]

(b)	Outline the conclusions that can be drawn about the growth of Populus deltoides from the data in the bar chart.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(c)	Discuss whether the differences in growth rates of Populus deltoides between urban and rural areas could be due to
(i)	differences in the acidity of rain.
...........................................................................................................................
...........................................................................................................................
(1)

(ii)	differences in the concentration of air pollutants.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)

	The histograms below show the range of ozone exposure between May and September in urban and rural areas near New York.
		
	[Source: Nature by Nature Publishing Group. Reproduced with permission of Nature Publishing Group in the format Journal via Copyright Clearance Center.]

(d)	Compare the seasonal ozone exposures in urban, agricultural and forested areas.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
	The concentrations of ozone and the shoot growth of Populus deltoides were measured at eight sites. The results are shown in the scattergraph below.
		
	[Source: Nature by Nature Publishing Group. Reproduced with permission of Nature Publishing Group in the format Journal via Copyright Clearance Center.]

(e)	Using the data in the scattergraph and in previous parts of this question, suggest a hypothesis for differences in the growth of Populus deltoides between urban and rural areas. Give reasons for your hypothesis.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(Total 13 marks)

24.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	All organisms in an ecosystem are involved in the carbon cycle. Outline the roles of living organisms in the carbon cycle.
(8)
 
(b)	Explain how triose phosphate is produced and used in the chloroplasts of a plant.
(5)
 
(c)	Explain the conditions that are needed to allow a seed to germinate.
(5)
(Total 20 marks)

25.	The food web below shows some of the feeding relationships found between the organisms living in or near a river in England.

(a)	Identify an organism in the food web that is
(i)	an autotroph.
...........................................................................................................................
(1)
(ii)	both a secondary and tertiary consumer.
...........................................................................................................................
(1)

(b)	Explain how the flow of energy in the food web differs from the movement of nutrients.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(c)	Discuss reasons why the levels of a pyramid of energy differ in size.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 6 marks)

26.	(a)	(i)	State the name of the biome in which there is little precipitation and temperatures are very low.
...........................................................................................................................
(1)

(ii)	Outline the characteristics of the vegetation of this biome.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
 
(b)	Outline the consequences of the edge effect for small nature reserves.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(c)	Outline one example of biological control of invasive species.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 6 marks)

27.	Some organisms have adopted r-strategies and some have adopted K-strategies. Discuss the environmental conditions that favour each of these strategies.
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
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(Total 6 marks)

28.	(a)	Climograph A below shows a tropical steppe which is a form of grassland.

[© University of Wisconsin – Stevens Point. Used with permission.]
	Deduce, with a justification, the type of biome represented by climograph B.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)

(b)	Define indicator species.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(1)
 
(c)	Outline, with a named example, biological control of invasive species.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 6 marks)

29.	Outline either r-strategies or K-strategies.
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
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................................................................................................................................................
(Total 6 marks)

30.	What is a community?
A.	A group of organisms living and interacting in the same trophic level
B.	A group of populations living and interacting in a food chain
C.	A group of organisms of the same species living and interacting in an ecosystem
D.	A group of populations living and interacting in an area
(Total 1 mark)

31.	What are the units of a pyramid of energy?
A.	kJ m–2 yr–1
B.	kJ m–1 yr–1
C.	J m–3 s–1
D.	J m2 s–1
(Total 1 mark)

32.	What is a potential consequence of the rise in global temperatures on the Arctic ecosystem?
A.	Increased exposure to UV light
B.	Increased rate of decomposition of detritus
C.	Decreased success of pest species
D.	Increase in the ice habitat available to polar bears
(Total 1 mark)

33.	What can limit increases in population size?
I.	Decrease in prey
II.	Decrease in parasites
III.	Increase in predators
A.	I and II only
B.	I and III only
C.	II and III only
D.	I, II and III
(Total 1 mark)

34.	A poodle and a chihuahua are both dogs and classified as Canis familiaris. What conclusion can be made?
A.	They belong to the same genus but not the same species.
B.	They are the same species but not the same genus.
C.	They are different species but can interbreed.
D.	They belong to the same genus and are the same species.
(Total 1 mark)

35.	This question is about the food web below.
		
	[Source: http://cbc.amnh.org/crisis/foodweb.html. Center for Biodiversity and Conservation, American Museum of Natural History]
	What will happen to the sizes of the populations in the food web above if the sea otter disappears?
A.	Large fish increase and sea urchins decrease.
B.	Abalones increase and sharks increase.
C.	Sea urchins increase and kelps decrease.
D.	Sea stars decrease and sharks increase.
(Total 1 mark)

36.	Which gas will enhance the greenhouse effect if released into the atmosphere?
A.	Hydrogen
B.	Oxide of nitrogen
C.	Oxygen
D.	Nitrogen
(Total 1 mark)

37.	What do the graphs below show?

A.	Population in the United States is increasing at a higher rate.
B.	Infant death rate is high in both countries.
C.	Males live longer than females in both countries.
D.	Birth rate is higher in Mexico than in the United States.
(Total 1 mark)

38.	Which phylum does the plant below belong to?
		
A.	Angiospermophyta
B.	Bryophyta
C.	Coniferophyta
D.	Filicinophyta
(Total 1 mark)

39.	The grey partridge (Perdix perdix) is a species of bird that is found on farmland. Sparrowhawks (Accipiter nisus) and buzzards (Buteo buteo) are birds of prey that kill and feed on birds, including grey partridge. The number of grey partridges in a region of southern England was monitored from 1970 to 2004. The numbers of sparrowhawks and buzzards, seen from sampling positions during regular observation periods, were counted. The results are shown in the graph below.

	[Source: Watson, M et al. 2007. Journal of Applied Ecology. Vol 44. Pp 972–982. Reproduced with the permission of Wiley Blackwell.]

(a)	Outline the trends, over the period of time shown in the graph, in the number of grey partridges, buzzards and sparrowhawks.
Grey partridges: ...........................................................................................................
......................................................................................................................................
Buzzards: .....................................................................................................................
......................................................................................................................................
Sparrowhawks: ............................................................................................................
......................................................................................................................................
(3)
 
	The density of grey partridge (number per square kilometre) varied considerably in different areas within the study region. The graph below shows the correlation between the density of grey partridges and the density of birds of prey.
		
	[Source: The Journal of Applied Ecology by BRITISH ECOLOGICAL SOCIETY. Reproduced with permission of BLACKWELL PUBLISHING LTD. in the format Journal via Copyright Clearance Center]

(b)	(i)	Identify the correlation between the density of grey partridges and birds of prey.
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	Suggest a hypothesis to account for this correlation.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
	The highest density of birds of prey was found in areas used for recreational shooting. In these areas, other species of partridge were bred and released. Food and shelter were provided for the released birds. These measures tended to increase the number of both released and wild birds.
	The causes of death of grey partridge were investigated in one of the areas that was used for recreational shooting. The pie chart below shows the causes of death.

(c)	(i)	Calculate the percentage of deaths due to birds of prey.
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	Using the data provided, discuss the causes of the correlation between the density of grey partridges and the density of birds of prey.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
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...........................................................................................................................
...........................................................................................................................
(3)
 
(d)	Suggest a conservation measure that would be most likely to prevent the extinction of grey partridges from southern England.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(1)
(Total 11 marks)

40.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Plants are a diverse group of eukaryotic organisms. Describe the different characteristics of the bryophyta, filicinophyta, coniferophyta and angiospermophyta.
(9)
(b)	Plants store carbohydrate in the form of starch. Explain the reasons for starch being digested by the human digestive system.
(4)
(c)	Compare the structure of prokaryotic and eukaryotic cells.
(5)
(Total 20 marks)

41.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Describe the movement of energy and nutrients in an ecosystem.
(6)
(b)	Explain how sexual reproduction can eventually lead to evolution in offspring.
(8)
(c)	Using simple external recognition features, distinguish between the plant phyla bryophyta and angiospermophyta.
(4)
(Total 20 marks)

42.	The element arsenic (As) is not needed for plant growth and development. The accumulation of arsenic in the Chinese brake fern (Pteris vittata) was studied. Young ferns with five or six leaves were transplanted to soil contaminated with arsenic and were grown for 20 weeks in a greenhouse.
	The graph below shows the arsenic concentrations in leaves and roots of the Chinese brake fern during the 20 weeks after transplanting. Arsenic concentration is expressed as mg As kg–1 dry weight of plant.
		
	[Used with permission, from Journal of Environmental Quality. 2002. Vol 31. Pp 1671–1675.]

(a)	Using the data in the graph, describe the accumulation of arsenic in the Chinese brake fern.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
 
	The table below shows the total amount of arsenic accumulated by the Chinese brake fern, expressed as a concentration in the plant tissue and as a percentage of the arsenic originally in the soil.

Time / weeks	Arsenic concentration in fern / mg As kg–1	Percentage of original soil arsenic absorbed by fern	
0	2	0.00	
2	66	0.05	
4	221	0.15	
6	408	0.28	
8	1300	0.88	
12	5390	3.68	
16	13800	9.43	
20	37900	25.90	
	[Adapted from Sinton, L W et al. 1999. Applied and Environmental Microbiology. Vol 65, issue 8. Pp 3605–3613. Published by the American Society for Microbiology, 1752 N Street N.W., Washington, DC 20036, USA. Reproduced with permission.]

(b)	(i)	Assuming the mean rate of arsenic accumulation over the first 20 weeks continued, calculate how long it would take to remove all the arsenic from the soil.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	Using the data in the table, discuss the potential of using Chinese brake fern to remove all arsenic from contaminated soil.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(c)	Suggest one possible consequence of arsenic accumulation in plants for other organisms in the community.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(1)
(Total 7 marks)

43.	(a)	Outline three factors that affect plant distribution.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
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......................................................................................................................................
(3)
 
(b)	Outline a method used to correlate the distribution of plant species with an abiotic factor.
......................................................................................................................................
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......................................................................................................................................
(2)
(Total 5 marks)

44.	(a)	State one example of the accidental release of an alien species that has had a significant impact on an ecosystem.
......................................................................................................................................
......................................................................................................................................
(1)
 
(b)	Discuss the impact of alien species on ecosystems.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
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......................................................................................................................................
......................................................................................................................................
(3)
(Total 4 marks)

45.	Describe the distribution of tundra in the world today.
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
................................................................................................................................................
(Total 2 marks)

46.	Invasion of alien species has become a serious issue in most environments of the world.
This study of Nordic environments charts the presence of alien species over the last century.
Relative proportions of invertebrates, vertebrates and plants and fungi are indicated in each bar.

	[Reproduced with permission of the Nordic Council of Ministers.]
 
(a)	(i)	State the ecosystem in which the proportion of alien vertebrates is the greatest.
...........................................................................................................................
(1)
 
(ii)	Describe the general pattern of the numbers of alien species in terrestrial and marine ecosystems.
...........................................................................................................................
...........................................................................................................................
(1)
 
(b)	Suggest a reason why alien plant and fungi invasion is greatest in the terrestrial ecosystem.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(1)
 
(c)	Identify how invasion of marine waters by alien invertebrates might occur.
......................................................................................................................................
......................................................................................................................................
(1)

(d)	Discuss the impact of alien species on ecosystems.
......................................................................................................................................
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(3)
(Total 7 marks)

47.	(a)	List four factors that affect the distribution of plant species.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(4)

(b)	Describe one effect of plants on an abiotic factor in a pioneer community.
......................................................................................................................................
......................................................................................................................................
(1)
(Total 5 marks)

48.	(a)	State the name of a statistical method used to quantify changes in biodiversity.
......................................................................................................................................
(1)

(b)	Discuss reasons for conservation of biodiversity of a named ecosystem.
......................................................................................................................................
......................................................................................................................................
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(5)
(Total 6 marks)

49.	Population size is influenced by certain factors.
If I = immigration, E = emigration, N = natality, M = mortality and (N + M) = (I + E) = 0, which phase is this population in?
A.	Exponential phase
B.	Transitional phase
C.	Plateau phase
D.	Growth phase
(Total 1 mark)

50.	An animal has radial symmetry, a sac-like body with only one opening and tentacles with stinging structures. To which phylum does this animal belong?
A.	Annelida
B.	Cnidaria
C.	Mollusca
D.	Porifera
(Total 1 mark)

51.	Which of the following is a consequence of global temperature rise on arctic ecosystems?
A.	Increased rates of decomposition of detritus trapped in permafrost
B.	Decrease of geographical range of habitats for temperate species
C.	Decrease of pest species and increase of permafrost species
D.	Increase of geographical range of habitats for permafrost species
(Total 1 mark)

52.	Which of the following is a characteristic of platyhelminthes?
A.	Many pairs of legs
B.	Flat body
C.	Hard exoskeleton
D.	Presence of cnidocytes
(Total 1 mark)

53.	During aerobic cell respiration, oxygen is consumed and carbon dioxide is produced inside cells. This generates concentration gradients between respiring cells and the environment, which cause diffusion of oxygen and carbon dioxide. Both oxygen and carbon dioxide are soluble in water. As the temperature rises, water becomes saturated at a lower concentration of the gas.
	Laternula elliptica is a mollusc that lives on the sea bed in Antarctica. Its body temperature is always similar to that of the environment around it. To investigate the effect of temperature on Laternula elliptica, specimens were kept in temperature-controlled aquaria. The oxygen concentrations of water near the gills and in the body fluids were measured, at a range of temperatures from 0°C to 9°C. The graph below shows the mean results.
		
	[With kind permission from Springer Science+Business Media and the author.]
 
(a)	(i)	Outline the relationship between temperature and oxygen concentration in the body fluids in Laternula elliptica.
...........................................................................................................................
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...........................................................................................................................
(2)

(ii)	Suggest two reasons for the relationship.
...........................................................................................................................
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...........................................................................................................................
(2)
 
(b)	In its natural environment, Laternula elliptica buries itself in the mud on the sea bed.
In this investigation, it was found that above 6°C it is unable to bury itself. Suggest a reason for this.
......................................................................................................................................
......................................................................................................................................
(1)

	The world’s oceans can absorb large amounts of carbon dioxide. This process has been studied in the Pacific Ocean near Hawaii, by measuring carbon dioxide concentrations in the atmosphere and in surface water every month, from October 1988 onwards. The graph below shows the carbon dioxide concentration expressed as partial pressures (Pco2).

	[Source: Nature by Nature Publishing Group. Reproduced with permission of Nature Publishing Group in the format Journal via Copyright Clearance Centre.]

(c)	(i)	Describe the trends in atmospheric carbon dioxide concentration, shown in the graph.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(ii)	Suggest two reasons for the trends that you have described.
...........................................................................................................................
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...........................................................................................................................
...........................................................................................................................
(2)
 
(d)	(i)	Diffusion of carbon dioxide only occurs when there is a concentration gradient.
Deduce the pattern of carbon dioxide diffusion, between water and atmosphere, from 1988 to 2002.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)

(ii)	The graph provides evidence for the hypothesis that there will be no net diffusion of carbon dioxide between water and atmosphere by 2020. Explain this evidence.
...........................................................................................................................
...........................................................................................................................
(1)
 
	The concentration of carbon dioxide in the atmosphere is currently 385 ppm (parts per million).
Variations in the concentration of carbon dioxide in the atmosphere can be studied using ice-cores. An ice-core record covering the last 400 000 years has been obtained from Vostok in the Antarctic. The graph below shows the carbon dioxide concentrations that were measured at different depths in the ice. Atmospheric temperatures are also shown on the graph. These were deduced from ratios of oxygen isotopes. The upper line on the graph shows CO2 concentrations and the lower line shows temperature.

	[Source: Nature by Nature Publishing Group. Reproduced with permission of Nature Publishing Group in the format Journal via Copyright Clearance Centre.]
 
(e)	(i)	State the highest carbon dioxide concentration shown on the graph.
...........................................................................................................................
(1)

(ii)	State the highest temperature shown on the graph.
...........................................................................................................................
(1)
 
(f)	Using the data in the graph, deduce the relationship between atmospheric carbon dioxide concentration and temperature.
......................................................................................................................................
......................................................................................................................................
(1)
 
(g)	Using the data in this question, explain reasons for concern about the long-term survival of Antarctic species, such as Laternula elliptica.
......................................................................................................................................
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(3)
(Total 18 marks)

54.	The element arsenic (As) is not needed for plant growth and development. The accumulation of arsenic in the Chinese brake fern (Pteris vittata) was studied. Young ferns with five or six leaves were transplanted to soil contaminated with arsenic and were grown for 20 weeks in a greenhouse.
	The graph below shows the arsenic concentrations in leaves and roots of the Chinese brake fern during the 20 weeks after transplanting. Arsenic concentration is expressed as mg As kg–1 dry weight of plant.
		
	[Used with permission, from Journal of Environmental Quality. 2002. Vol 31. Pp 1671–1675.]

(a)	Using the data in the graph, describe the accumulation of arsenic in the Chinese brake fern.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
 
	The table below shows the total amount of arsenic accumulated by the Chinese brake fern, expressed as a concentration in the plant tissue and as a percentage of the arsenic originally in the soil.

Time / weeks	Arsenic concentration in fern / mg As kg–1	Percentage of original soil arsenic absorbed by fern	
0	2	0.00	
2	66	0.05	
4	221	0.15	
6	408	0.28	
8	1300	0.88	
12	5390	3.68	
16	13800	9.43	
20	37900	25.90	
	[Adapted from Sinton, L W et al. 1999. Applied and Environmental Microbiology. Vol 65, issue 8. Pp 3605–3613. Published by the American Society for Microbiology, 1752 N Street N.W., Washington, DC 20036, USA. Reproduced with permission.]

(b)	(i)	Assuming the mean rate of arsenic accumulation over the first 20 weeks continued, calculate how long it would take to remove all the arsenic from the soil.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	Using the data in the table, discuss the potential of using Chinese brake fern to remove arsenic from contaminated soil.
...........................................................................................................................
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...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(c)	Suggest one possible consequence of arsenic accumulation in plants for other organisms in the community.
......................................................................................................................................
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......................................................................................................................................
(1)
(Total 7 marks)

55.	The following figure represents a terrestrial food web.

(a)	Identify the trophic level of the toad.
......................................................................................................................................
(1)

(b)	Outline a method that could be used to estimate the population of rabbits in this environment.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
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......................................................................................................................................
......................................................................................................................................
(4)
 
(c)	The Simpson diversity index is used to calculate the species richness in an ecosystem.
		D = 
	Define the terms N and n in the formula above.
N = ...............................................................................................................................
n = ................................................................................................................................
(2)
(Total 7 marks)

56.	Evaluate the use of indicator species in monitoring environmental changes.
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(Total 6 marks)

57.	(a)	Distinguish between fundamental niches and realized niches.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
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......................................................................................................................................
(2)
 
(b)	Outline the changes in species diversity and production during primary succession.
......................................................................................................................................
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......................................................................................................................................
(2)

(c)	Outline, using examples, the biogeographical features of nature reserves that promote the conservation of diversity.
......................................................................................................................................
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(3)
(Total 7 marks)

58.	Discuss international measures that would promote the conservation of fish.
................................................................................................................................................
................................................................................................................................................
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(Total 6 marks)

59.	This question is about the food web below
		
	What is the energy transfer level from the kangaroo rat to the weasel shown in the food web above?
A.	Three times greater than the energy transfer from the roadrunner to the bobcat
B.	Half the energy transfer from chaparral plants to the meadow mouse
C.	A quarter of the energy transfer from the quail to the bobcat
D.	Approximately the same as the energy transfer from the meadow mouse to the opossum
(Total 1 mark)

60.	What features distinguish Platyhelminthes from Annelida?

	Platyhelminthes	Annelida	
A.	segmented body	non-segmented body	
B.	non-segmented body	segmented body	
C.	bilateral symmetry	no bilateral symmetry	
D.	no bilateral symmetry	bilateral symmetry	
(Total 1 mark)

61.	(a)	Distinguish between fundamental niches and realized niches.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(b)	Describe a primary succession in a named type of habitat.
......................................................................................................................................
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(3)
(Total 5 marks)

62.	(a)	Label the levels of the trophic pyramid of energy shown below.

(3)

(b)	Discuss the impact of alien species on the environment.
......................................................................................................................................
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(3)
(Total 6 marks)

63.	Which taxa do Zerynthia rumina and Zerynthia polyxena share?
A.	They share the same class but not the same family.
B.	They share the same species but not the same class.
C.	They share the same class but not the same genus.
D.	They share the same family but not the same species.
(Total 1 mark)

64.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled graph showing a sigmoid (S-shaped) population growth curve.
(4)
 
(b)	Describe what is meant by a food chain and a food web.
(6)
 
(c)	Explain the relationship between rises in concentration of atmospheric gases and the enhanced greenhouse effect.
(8)
(Total 20 marks)

65.	Many factors affect the distribution of animal species including weather patterns. The mosquito Anopheles is a carrier of malaria, a disease that kills one to two million people annually. The eggs of the mosquito are laid in water and they hatch out as larvae before turning into adult mosquitoes. A study was undertaken to look at the influence of weather patterns on the incidence of bites on children. Being bitten increases the risk of catching malaria.
	The graphs show human biting rates (HBR) by Anopheles gambiae and Anopheles funestus and precipitation over the study period.

	[Adapted from J A Patz et al. 1998. “Predicting key malaria transmission factors, biting and entomological inoculation rates, using modelled soil moisture in Kenya.” Tropical Medicine and International Health. Vol 3. Pp 818–827. Reproduced with permission from Wiley.]
 
(a)	State the week number when the highest human biting rate (HBR) is found for A. gambiae.
......................................................................................................................................
(1)

(b)	Calculate the difference in peak HBR for A. gambiae and A. funestus for week 6.

......................................................................................................................................
(1)
 
(c)	Evaluate the effect of increased precipitation on HBR for both species.
......................................................................................................................................
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......................................................................................................................................
......................................................................................................................................
(3)
 
(d)	Suggest how predictions of global climate changes, such as predictions of precipitation patterns, could be used to help control malaria.
......................................................................................................................................
......................................................................................................................................
(1)
 
(e)	Suggest another factor which might affect the ecological distribution of mosquitoes.
......................................................................................................................................
(1)

(f)	Suggest a biological control that might be introduced to reduce HBR.
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......................................................................................................................................
(1)
(Total 8 marks)

66.	(a)	Earthworms are primary consumers that can be grown on household food waste such as fruit and salad leftovers. Outline their potential as an energy-containing food source for humans.
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......................................................................................................................................
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(3)
 
(b)	State the units used in a pyramid of energy.
......................................................................................................................................
(1)

(c)	Describe the effects of ultraviolet radiation on living tissues.
......................................................................................................................................
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(2)
(Total 6 marks)

67.	Discuss the role of ex situ conservation of endangered species.
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(Total 6 marks)

68.	What conclusion can be made from the following evidence from an analysis of DNA fragments?
		
A.	Both children are related to both parents.
B.	Child I is related to the man but child II is not.
C.	Both children are unrelated to either of the parents.
D.	Child II is related to the man but child I is not.
(Total 1 mark)

69.	The following diagram shows part of a food web from Yellowstone Park.
		
	What would be the short-term effects on the populations of the other species if the gray wolf were exterminated?

	Beaver	Moose	Elk	Aspen	
A.	Increase	Decrease	Increase	Increase	
B.	Decrease	Decrease	Decrease	Decrease	
C.	Increase	Increase	Decrease	Increase	
D.	Decrease	Increase	Increase	Decrease	
(Total 1 mark)

70.	Slime moulds (Acrasiomycota) are protoctists. They feed on decaying organic matter, bacteria and protozoa.
	Which of the terms describes their nutrition?
I.	Detritivore
II.	Autotroph
III.	Heterotroph
A.	I only
B.	I and II only
C.	I and III only
D.	I, II and III
(Total 1 mark)

71.	Why do food chains in an ecosystem rarely contain more than five organisms?
A.	Nutrients are recycled by the decomposers back to the producers.
B.	Nutrients are lost from the ecosystem when organisms die.
C.	The conversion of food into growth by an organism is not very efficient.
D.	Energy is recycled by the decomposers back to the producers.
(Total 1 mark)

72.	Several greenhouse gases occur in the atmosphere. Carbon dioxide (CO2) is one of them but so are methane (CH4) and oxides of nitrogen (NOx).
	Why are oxides of nitrogen classed as greenhouse gases?
A.	They trap some of the long-wave radiation emitted by the Earth’s surface.
B.	They prevent short-wave radiation from reaching the Earth’s surface.
C.	They dissolve in rainwater to produce acid rain.
D.	They are only produced by human activity whereas CO2 and CH4 are also produced naturally.
(Total 1 mark)

73.	Population growth, as shown by the curve below, is the result of changes in mortality, natality, immigration and emigration. Which of the following statements about population growth is correct?
		
A.	In phase I there is no mortality.
B.	In phase II mortality equals natality and immigration equals emigration.
C.	In phase II mortality and emigration are less than natality and immigration.
D.	In phase III mortality and emigration are less than natality and immigration.
(Total 1 mark)

74.	Which of the organisms A–D, identified by the key below, represents an Annelid?
1.	Shows bilateral symmetry	go to 2
Does not show bilateral symmetry	Cnidaria
2.	Has a segmented body	go to 3
Does not have a segmented body	go to 4
3.	Has jointed legs	A
Does not have jointed legs	B
4.	Has a shell	C
Does not have a shell	D
(Total 1 mark)

75.	To which group do sponges belong?
A.	Cnidaria
B.	Filicinophyta
C.	Porifera
D.	Mollusca
(Total 1 mark)

76.	The diagram below shows a population growth curve.
		
	At which time in the population growth curve does the population size begin to decline?
A.	Between the time marked 1 and 2
B.	During the time marked 2
C.	Between the time marked 2 and 3
D.	The graph does not show a time when population size declines
(Total 1 mark)

77.	The graph below shows variation in the concentration of CO2 in the atmosphere as measured at Mauna Loa in Hawai’i. The small inset graph shows the variations in CO2 during a one year period.
		
[Source: adapted from Dr P Tans, NOAA Earth System Research Laboratory]
	Why does the amount of CO2 fall between April and August?
A.	Seasonal increase in the rate of photosynthesis in the northern hemisphere forests
B.	Seasonal decrease in the rate of photosynthesis in the northern hemisphere forests
C.	Seasonal decrease in the rate of fossil fuel consumption
D.	Seasonal increase in the amount of CO2 dissolved in the oceans
(Total 1 mark)

78.	The scarlet cup fungus (Sarcoscypha coccinea) obtains its nutrition from decaying wood by releasing digestive enzymes into the wood and absorbing the digested products.
	Which of the following terms describe(s) the fungus?
I.	Autotroph
II.	Heterotroph
III.	Saprotroph
A.	III only
B.	II and III only
C.	I and III only
D.	I, II and III
(Total 1 mark)

79.	Below is a graph of atmospheric CO2 levels measured at Mauna Loa Observatory, Hawai’i.

[Source: adapted from Dr P Tans, NOAA Earth System Research Laboratory]

(a)	Explain the observed changes in atmospheric CO2 concentration from 1960 to 2005.
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(3)
 
(b)	Outline the precautionary principle.
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(2)
(Total 5 marks)

80.	(a)	Define the terms species, population and community.
Species:	............................................................................................................
	............................................................................................................
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Population:	............................................................................................................
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	............................................................................................................
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Community:	............................................................................................................
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(3)

(b)	Explain the shape of the pyramids of energy that are constructed by ecologists to represent energy flow in an ecosystem.
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(3)
(Total 6 marks)

81.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram showing the ultrastructure of a typical prokaryote.
(4)
(b)	Outline how three different environmental conditions can affect the rate of photosynthesis in plants.
(6)
(c)	Explain how the emission of gases, both naturally and through human activity, can alter the surface temperature of the Earth.
(8)
(Total 20 marks)

82.	(a)	Discuss the impact of an alien species on an ecosystem.
......................................................................................................................................
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(3)
 
(b)	Outline the temperature and vegetation characteristics of one major biome.
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(2)
(Total 5 marks)

83.	(a)	Define biomass.
......................................................................................................................................
......................................................................................................................................
(1)

(b)	Describe how biomass may be measured.
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(2)
 
(c)	Explain the biomass change in different trophic levels.
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(3)
(Total 6 marks)

84.	(a)	Define the terms gross production and net production.
Gross production: ........................................................................................................
Net production: ............................................................................................................
(2)

(b)	Using the table below, compare the characteristics of the following biomes.

Biome	Temperature	Moisture	Characteristic of vegetation	
Desert				
Tropical rainforest				
Tundra				
(3)
(Total 5 marks)

85.	(a)	(i)	State one example of a deliberate release of an alien species, including the name of the organism and where it was released.
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	Using the example from (a)(i), outline the reason for its release and the impact it had on the environment.
...........................................................................................................................
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(2)

(b)	Explain, using a named example, the cause and consequence of biomagnification.
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(3)
(Total 6 marks)

86.	The graph below shows variation in the concentration of CO2 in the atmosphere as measured at Mauna Loa in Hawai’i. The small inset graph shows the variations in CO2 during a one year period.
		
[Source: adapted from Dr P Tans, NOAA Earth System Research Laboratory]
	Why does the amount of CO2 fall between April and August?
A.	Seasonal increase in the rate of photosynthesis in the northern hemisphere forests
B.	Seasonal decrease in the rate of photosynthesis in the northern hemisphere forests
C.	Seasonal decrease in the rate of fossil fuel consumption
D.	Seasonal increase in the amount of CO2 dissolved in the oceans
(Total 1 mark)

87.	The scarlet cup fungus (Sarcoscypha coccinea) obtains its nutrition from decaying wood by releasing digestive enzymes into the wood and absorbing the digested products.
	Which of the following terms describe(s) the fungus?
I.	Autotroph
II.	Heterotroph
III.	Saprotroph
A.	III only
B.	II and III only
C.	I and III only
D.	I, II and III
(Total 1 mark)

88.	(a)	Define biomass.
......................................................................................................................................
......................................................................................................................................
(1)
 
(b)	Outline the effects of ultraviolet (UV) radiation on living tissues.
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(2)
(Total 3 marks)

89.	(a)	Describe the causes and consequences of a named example of biomagnification.
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(5)

(b)	Discuss conditions that favour K-strategies.
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(5)
(Total 10 marks)

90.	Seasonal changes of heterotrophic plankton biomass were measured in the western arctic Pacific during a one year period. The mesozooplankton, whose size is greater than 330 μm, was formed mainly by copepods. The microzooplankton, ranging from 10 to 200 μm, comprised mainly of ciliates and flagellates. Heterotrophic nanoflagellates (HNF), size range 2 to 10 μm, are organisms that feed on small flagellates and bacteria. The results are shown below.

	[Shinada, A et al. 2001. “Seasonal dynamics of planktonic food chain in the Oyashio region, western subarctic Pacific”. Journal of Plankton Research. Vol 23, issue 11. Pp  1237–1248. © Oxford University Press. Reproduced with permission.]
 
(a)	State the biomass of HNF found in this region in summer.
......................................................................................................................................
(1)
 
(b)	Calculate the percentage increase in mesozooplankton from summer to spring. Show your working.

......................................................................................................................................
......................................................................................................................................
(2)

(c)	Suggest how the seasonal changes cause the differences in biomass of heterotrophic plankton.
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(3)
(Total 6 marks)

91.	(a)	Outline the major differences in temperature and moisture that are characteristic of two named biomes.
......................................................................................................................................
......................................................................................................................................
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(2)

(b)	Explain, using a named example, the cause and consequence of biomagnification.
......................................................................................................................................
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(3)
(Total 5 marks)

92.	(a)	Outline the use of two named ex situ conservation measures.
......................................................................................................................................
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(4)

(b)	Discuss the environmental conditions that favour r-strategies and K-strategies.
......................................................................................................................................
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(5)
(Total 9 marks)

93.	Zoophobas morio is an insect. Its larvae feed on bat feces in caves in Guatemala. What type of organism is a Zoophobas morio larva?
A.	Autotroph
B.	Consumer
C.	Detritivore
D.	Saprotroph
(Total 1 mark)

94.	The diagram below shows some of the links in the carbon cycle.
		
	What processes are taking place at I, II and III?

	I	II	III	
A.	photosynthesis	fossilization	combustion	
B.	cell respiration	fossilization	greenhouse effect	
C.	photosynthesis	decomposition	combustion	
D.	cell respiration	decomposition	greenhouse effect	
(Total 1 mark)

95.	Global warming threatens the survival of Arctic foxes. Which of the following factors could be involved?
I.	Competition with other fox species spreading north
II.	Reduction in numbers of prey species of Arctic foxes
III.	Decrease in oxygen availability to Arctic foxes
A.	I only
B.	I and II only
C.	II and III only
D.	I, II and III
(Total 1 mark)

96.	Which graph shows the sigmoid population growth curve?

(Total 1 mark)

97.	Ants, bees and wasps are classified in the same order. What can be deduced about these animals?
A.	They are classified in the same class.
B.	They are classified in different phyla.
C.	They are classified in the same family.
D.	They are classified in different kingdoms.
(Total 1 mark)

98.	Pseudolarix amabilis produces seeds but not flowers. Physcomitrella patens has leaves but not roots.
To which groups do they belong?

	Pseudolarix amabilis	Physcomitrella patens	
A.	coniferophyta	filicinophyta	
B.	filicinophyta	angiospermophyta	
C.	coniferophyta	bryophyta	
D.	angiospermophyta	coniferophyta	
(Total 1 mark)

99.	Limpets are small animals that feed on the green algae which grow on rocks on seashores.
Oystercatchers (Haematopus bachmani) are birds that feed on limpets.
		
	In a study on the north-west coast of the USA, where three limpet species are common (Lottia digitalis, Lottia pelta and Lottia strigatella), the limpets were protected from the oystercatchers by large wire cages. After two years the number of limpets in this area was compared with the number of limpets in an area without cages, where oystercatchers were present.

	[Source: Wooton, J T. 1992. “Indirect effects, prey susceptibility, and habitat selection: impacts of birds on limpets and algae”. Ecology. Vol 73. Pp 981–991.  Copyright by the Ecological Society of America.]
 
(a)	State the effect that the exclusion of the oystercatchers had on the total number of limpets per m2.
......................................................................................................................................
......................................................................................................................................
(1)

(b)	Construct a food web to show the feeding relationship between the three species of limpets, the oystercatchers and the green algae.

(2)
 
(c)	Suggest reasons for the difference in numbers of L. strigatella between the areas where oystercatchers were present and where oystercatchers were excluded.
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(3)

	There is evidence to show that both air and water temperatures have increased over a period of time. An investigation was undertaken to determine the effect this change in climate had on the populations of another species of limpet, Patella depressa, around south-west England.
The population of the limpet was recorded in many locations and around 30 years later, this study was repeated. The chart below compares the population in each of the locations.

	[Source: Burrows, M T et al. 2009. “Predicting the effects of marine climate change on the invertebrate prey of the birds of rocky shores: Predicting effects of climate change on invertebrates”. IBIS (Special Edition). Vol 145. Pp 40–47.]
 
(d)	On the map above label one location,
(i)	with the letter X, where the limpet population was abundant in the 1950s and occasional in the 1980s (1980–1984).
(1)
 
(ii)	with the letter Y, where the limpet population was abundant in both the 1950s and in the 1980s (1980–1984).
(1)

(e)	Outline, using the data, the overall trend in the limpet population from the 1950s to the 1980s (1980–1984).
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(2)
 
(f)	Suggest two reasons for the change in limpet population between the 1950s and the 1980s (1980–1984).
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(2)
(Total 12 marks)

100.	A colony of a marine diving bird, Brunnich’s guillemot (Uria lomvia), lives on the southern limits of the Arctic on Coats Island. Brunnich’s guillemots feed principally on Arctic cod (Arctogadus glacialis) which are characteristic of Arctic waters.
	The graph shows the changes in ice cover on Coats Island over a period of 19 years.
		
	[Source: Gaston, A et al. 2005. “Climate change, ice conditions and reproduction in an Arctic nesting marine bird: Brunnich’s guillemot (Uria lomvia L.)”. Journal of Animal Ecology. Vol 74. Pp 832–841. Reproduced with permission from Wiley.]
 
(a)	(i)	Outline the changes in ice cover shown in the data above.
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(2)

(ii)	Suggest one reason for the changes in ice cover.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
 
	At Coats Island, chick mass at 14 days was measured in most years between 1988 and 2002.
The scattergraph below shows the results, plotted against proportion of ice cover.

	[Source: Gaston, A et al. 2005. “Climate change, ice conditions and reproduction in an Arctic nesting marine bird: Brunnich’s guillemot (Uria lomvia L.)”. Journal of Animal Ecology. Vol 74. Pp 832–841. Reproduced with permission from Wiley.]

(b)	(i)	Outline the relationship between ice cover and the mass of 14-day-old chicks on Coats Island.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(ii)	Suggest reasons for the relationship.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(c)	Predict, with a reason, the change in the mass of chicks in the years ahead.
......................................................................................................................................
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......................................................................................................................................
(1)
(Total 8 marks)

101.	(a)	Outline one example of herbivory.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(b)	State the units used in a pyramid of energy.
......................................................................................................................................
(1)
 
(c)	Explain the small biomass of organisms in higher trophic levels.
......................................................................................................................................
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(2)
(Total 5 marks)

102.	(a)	Discuss the impacts of a named alien species introduced as a biological control measure.
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......................................................................................................................................
(3)
 
(b)	Outline the effects of ultraviolet radiation on living tissues.
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(2)
(Total 5 marks)

103.	How is energy passed from one trophic level to the next?
I.	Food
II.	Light
III.	Heat
A.	I only
B.	I and II only
C.	II and III only
D.	I, II and III
(Total 1 mark)

104.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled sigmoid population growth curve.
(4)
 
(b)	Outline the process of spermatogenesis in humans.
(5)
 
(c)	Explain the structure and function of the placenta during pregnancy.
(9)
(Total 20 marks)

105.	(a)	(i)	Define biomagnification.
...........................................................................................................................
...........................................................................................................................
(1)

(ii)	Outline a named example of biomagnification.
...........................................................................................................................
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...........................................................................................................................
(2)
 
(b)	Outline the characteristics of a tropical rainforest biome.
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(3)
(Total 6 marks)

106.	Discuss international measures that would promote the conservation of fish, including methods used to measure conservation of fish stocks.
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(Total 6 marks)

107.	The food web below shows a community in central France 24 000 years ago.

Which statement is a correct description of Ursus spelaeus?
A.	It is an omnivore which feeds on Lemmus lemmus.
B.	It is a producer preyed upon by Vaccinium oxycoccos.
C.	It is a top carnivore and a primary consumer.
D.	It is a decomposer and it competes with Rangifer tarandus.
(Total 1 mark)

108.	Which diagram shows the flow of energy through a community with three trophic levels?

(Total 1 mark)

109.	According to the precautionary principle, what should happen if there are fears that eating a food might cause a health problem?
A.	People should be warned about the possible health problem.
B.	The company producing the food should be warned about the possible health problem.
C.	People who have fears about the food should test it to see if it causes a real health problem.
D.	The company producing the food should test the food to prove that it does not cause a health problem.
(Total 1 mark)

110.	If natality is slightly larger than mortality, and immigration is much larger than emigration, what will happen to the size of a population?
A.	It will increase
B.	It will decrease
C.	It will fluctuate up and down
D.	It will remain constant
(Total 1 mark)

111.	In the hierarchy of taxa, what is in a family?
A.	A group of classes
B.	A group of genera
C.	A group of orders
D.	A group of phyla
(Total 1 mark)

112.	Methane produced by anaerobic bacteria contributes substantially to atmospheric methane concentration. These bacteria are found in a variety of habitats. Some live inside the cytoplasm of larger unicellular organisms and are known as endosymbionts. In marine sediments, endosymbionts living in the cytoplasm of a group of unicellular organisms, known as ciliates, can contribute up to 90% of methane production.
To see if endosymbionts in freshwater sediments had the same effect on methane production a one-year study was carried out in Holland. The graph below shows the rate of methane production by untreated sediment samples and sediment samples treated to kill the ciliates containing endosymbionts. The standard deviations are indicated by bars. The total number of ciliates is also indicated by circles.

[Source: AHAM van Hoek, et al., Acta Protozoologica, (2006), 45, pages 215–224]

(a)	State what the standard deviation indicates.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(b)	State the maximum number of ciliates and the month in which the maximum occurs.
.....................................................................................................................................
(1)
 
(c)	Compare the methane production in the untreated and treated samples.
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(2)

(d)	Deduce, with reasons, whether the endosymbionts in the ciliates are responsible for the methane produced by the sediment samples.
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(2)
 
(e)	Explain how methane and other greenhouse gases cause global warming.
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(2)

	Models predict global warming will cause sea temperatures to rise by approximately 2°C by 2100. An investigation was carried out to study the effect of slight increases in temperature on the ability of Antarctic marine molluscs to carry out basic activities essential for survival.
	The graph below shows the effect of temperature on the percentage of limpets (Nacella concinna) able to right themselves after being turned over.

[Source: LS Peck, Frontiers in Zoology, (2005), 2:9]
 
(f)	Outline what the two parts of the scientific name Nacella concinna refer to.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(g)	State the relationship between temperature and the percentage righting in N. concinna.
.....................................................................................................................................
.....................................................................................................................................
(1)

(h)	Estimate the percentage change of N. concinna able to right themselves when the temperature is raised from 0°C to 2.5°C.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(i)	At present, the maximum summer temperature in the normal Antarctic environment of this organism is 1°C. Suggest what might be the effect on the survival of this organism if the predicted rise in sea temperature due to global warming occurs.
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(2)
(Total 13 marks)

113.	(a)	Outline the effect of light intensity on the rate of photosynthesis.
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(2)
 
(b)	Identify which phyla of plants fit each of the brief descriptions below.

(i)	Evergreen woody plant; leaves are shaped like needles; seed-producing with reproductive structures in cones.
Phylum:	....................................................................................................
 
(ii)	Underground stem that bears roots and leaves called fronds; spores develop in spore cases called sporangia located on the underside of fronds.
Phylum:	....................................................................................................
(2)
(Total 4 marks)

114.	(a)	Explain the consequences of releasing raw sewage into a river.
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(4)

(b)	Outline the habitat of methanogens.
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(2)
(Total 6 marks)

115.	The timing of breeding in tree swallows (Tachycineta bicolor) was studied in the United States and Canada from 1959 to 1991. Figure A represents the mean egg laying date for each year. The date is indicated as number of days after January 1st. Figure B shows the correlation between mean May temperature (°C) and mean laying date over the same period.

[Source: www.pewclimate.org/docUploads/final%5FObsImpact%2Epdf]
 
(a)	Identify the year with the earliest mean egg laying date.
.....................................................................................................................................
(1)

(b)	Outline the relationship between mean laying date and mean May temperature.
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(1)
 
(c)	Evaluate the evidence for global warming using figures A and B.
.....................................................................................................................................
.....................................................................................................................................
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(2)
 
(d)	A change in mean laying date may increase competition with another species.
 
(i)	State the competitive exclusion principle.
...........................................................................................................................
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(1)
 
(ii)	Apply the competitive exclusion principle to a change in mean laying date for the tree swallow.
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(2)
(Total 7 marks)

116.	(a)	Define the term biomagnification.
.....................................................................................................................................
(1)
(b)	Outline one example of biomagnification.
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(3)
(Total 4 marks)

117.	(a)	Outline the temperature, moisture and vegetation characteristics of any one biome.
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(3)

(b)	Discuss ecological arguments for the preservation of biodiversity.
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(4)
(Total 7 marks)

118.	Which group of organisms in the carbon cycle converts carbon into a form that is available to primary consumers?
A.	Decomposers
B.	Detritus feeders
C.	Producers
D.	Secondary consumers
(Total 1 mark)

119.	Which phylum does an animal belong to, if it has stinging tentacles and a mouth, but no anus?
A.	Annelida
B.	Cnidaria
C.	Porifera
D.	Platyhelminthes
(Total 1 mark)

120.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled graph showing a typical sigmoid growth curve.
(4)
(b)	Outline the consequences of an increased greenhouse effect on arctic ecosystems.
(6)
(c)	Explain how natural selection leads to evolution.
(8)
(Total 20 marks)

121.	(a)	State one example of a microbial photoautotroph and a microbial chemoautotroph.
Photoautotroph : .........................................................................................................
Chemoautotroph : .......................................................................................................
(1)
 
(b)	Draw and label the nitrogen cycle.
(5)
(Total 6 marks)

122.	The timing of breeding in tree swallows (Tachycineta bicolor) was studied in the United States and Canada from 1959 to 1991. Figure A represents the mean egg laying date for each year. The date is indicated as number of days after January 1st. Figure B shows the correlation between mean May temperature (°C) and mean laying date over the same period.

[Source: www.pewclimate.org/docUploads/final%5FObsImpact%2Epdf]
 
(a)	Identify the year with the earliest mean egg laying date.
.....................................................................................................................................
(1)
 
(b)	Outline the relationship between mean laying date and mean May temperature.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(c)	Evaluate the evidence for global warming using figures A and B.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
 
(d)	A change in mean laying date may increase competition with another species.
 
(i)	State the competitive exclusion principle.
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	Apply the competitive exclusion principle to a change in mean laying date for the tree swallow.
...........................................................................................................................
...........................................................................................................................
(2)
(Total 7 marks)

123.	(a)	Define gross production.
.....................................................................................................................................
(1)

(b)	Outline the characteristics of a desert biome.
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(3)
(Total 4 marks)

124.	(a)	Outline the factors that affect the distribution of animal species.
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(5)

(b)	Discuss the environmental conditions that favour r-strategies.
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(4)
(Total 9 marks)