Name ___________________________________________________ Date _____________________
Ecology and Ecosystems Part 1

1.	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)
2.	(a)	Define the terms species, population and community.
Species:	............................................................................................................
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Population:	............................................................................................................
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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)
3.	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)
4.	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)
5.	What is a community composed of?
A.	Habitats
B.	Populations
C.	Abiotic factors
D.	Biotic and abiotic factors
(Total 1 mark)

6.	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.
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(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)
7.	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)
8.	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)

9.	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)
10.	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.
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(1)
(ii)	both a secondary and tertiary consumer.
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(1)
(b)	Explain how the flow of energy in the food web differs from the movement of nutrients.
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(2)
(c)	Discuss reasons why the levels of a pyramid of energy differ in size.
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(2)
(Total 6 marks)
11.	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)

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.
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(1)
 
(b)	Describe the trend in the aquatic invertebrate flux.
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(2)

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

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

(3)