1. The graph below shows the interdependence of population size of two species of mites. Eotetranychus sexmaculatus serves as the food supply for Typholodromus occidentalis.

[Source: C B Huffaker , (1958), Hilgardia , Volume 27, pages 343-383. Reprinted by permission of University of California Press.]

(a)Predict when the next population maximum of T. occidentalis will occur. Show your working.
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(2)

(b)Determine the numbers of both organisms on September 30.
T. occidentalis: ............................................................................................................
E. sexmaculatus: ......................................................... . ..............................................
(1)

(c)(i)Identify the five day period for which the rate of increase of E. sexmaculatus is at its maximum.
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(1)

(ii)Determine when the difference in numbers between both populations is at a maximum.
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(1)

(d)(i)Calculate the time lag between the maximums of both species in the period from October 5 through November 5.
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(1)

(ii)Suggest a reason for this time lag.
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(1)

(e)(i)Describe the role that negative feedback might play in this species interaction.
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(2)
2. Is the spraying of pesticides on a field an example of point or non-point source pollution? Explain your answer.
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(2)








3. The figure below contains an ancient Chinese proverb.

Proverb
If you are thinking a year ahead, sow seed
If you are thinking ten years ahead, plant a tree
If you are thinking a hundred years ahead, educate the people
Chinese poet Kuan Tzu 500 BC
(a)The poet Kuan Tzu could be seen as an ecocentrist or a technocentrist. Justify whether you think his views are ecocentric or technocentric.
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(4)
(b)Outline two factors which may affect someone's environmental philosophy.
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(2)
(Total 6 marks)
4. Below is a diagram from UNESCO showing relationships between development, the environment and health.
Sustainable development spirals

[Source: Sustainable development spirals, United Nations Environment Programme ]

(a)State, giving one reason, what kind of system feedback is illustrated by the descending spiral.
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(1)
(b)Discuss the meaning of the term sustainable development with reference to the diagram above.
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(2)

(c)Evaluate the strengths and limitations of the models shown in the diagram above.
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(2)
(Total 5 marks)

Mark scheme

1. (a)interval between 1st and 2nd peak is about 90 days and intervalbetween 2nd and 3rd peak is approximately 75 days; = 82.5 80 (± 4 days)/15 January + 80 days ≈ 20 April (± 5 days)2

(b)T. occidentalis: 7; (±1)E. sexmaculatus: 1550; (± 50)1Both needed for [1].

(c)(i)25 to 30 September; (±3 days)1
(ii)10 December; (±2 days)1

(d)(i)15 days; (±5 days)1
(ii)the predator population takes some days to take advantageof the increase in prey;availability of food facilitates reproduction of prey;predator cannot increase in number without access tofood and so must wait for increase in prey;1 max

(e)(i)the increase in prey leads to a corresponding increase inpredator which corrects the trend towards increase in prey;the decrease in prey leads to a corresponding decrease inpredator which corrects the trend towards decrease in prey;the periodic nature of the population curves indicates afeedback controlled interaction;2 max

2 (a) Non-point source as pollutant drains through soil into waterbodies [1]/mixes with other pollutants [1]; is untraceable toa particular source [1]/blown by wind over large area [1].
Allow marks for a reasoned argument for a point sourcee.g. a single nozzle spray and a contact pesticide [2]2 max







3. (a)This can be argued either way, although it is more probable thatKuan Tzu was an ecocentrist. Give credit for strong justification.
Ecocentrist becausethe proverb seems to be advising taking a long-term view;clearly advocates education and ecocentrism stresses importanceof self-reliant communities;through education people will arguably learn to value theenvironment and use resources sustainably;refers to "the people" and this perhaps suggests a lack of faithin elites/authorities;
or technocentrist becauseeducation will help lead to technological development;through technology we will find longer term solutions toenvironmental problems;we need to understand natural processes in order to control them;faith in the ability of people to overcome obstacles;4

(b)education - level and type will affect environmental awareness;economic conditions - will shape views towards environmente.g. short-term or long-term view;political context - will affect e.g. how groups in society areorganized/treated;cultural views - will affect predominant attitudes to theenvironment;religious view - holy texts/doctrine may dictate relationshipbetween people and creation/nature;2 maxAccept other reasonable answers.
[6]
4. (a)positive feedback because the effects of the problem make theproblem worse;1Award [0] if no reason is given for positive feedback.

(b)traditionally defined as development which meets the needs of thecurrent generation without compromising ability of future generationsto meet their own needs;but in this context it suggests development which has a positiverole in enhancing the environment;and