Grade 11 eost paper

1,964 views
1,649 views

Published on

Published in: Education, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,964
On SlideShare
0
From Embeds
0
Number of Embeds
10
Actions
Shares
0
Downloads
20
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Grade 11 eost paper

  1. 1. GURU CHARAN KUMAR/IB ESS 2012 End of Semester Test November 2012 Grade: 11 Subject: Environmental Systems & Societies Level: SL Paper: 1 Duration: 1hour 30 minutes Date: 21.11.2012 Maximum Mark: 80 Candidate Name: ______________________________ Subject Teacher: Guru Charan Kumar / Mesha Das Instructions to Candidates Section A: answer all of Section A in the spaces provided. Additional Material This question paper consists of 16 printed pages. Page 1 of 16
  2. 2. GURU CHARAN KUMAR/IB ESS 2012 Page 2 of 16
  3. 3. GURU CHARAN KUMAR/IB ESS 2012 SECTION A The graph below shows the interdependence of population size of two species of mites. Eotetranychus sexmaculatus serves as the food supply for Typholodromus occidentalis. 50 E. sexmaculatus 2500 E. sexmaculatus (prey) T. occidentalis (predator) 2000 40 1500 30 1000 20 500 T. occidentalis 1) 10 0 0 5 10 15 20 July 25 30 5 10 15 20 25 August 30 5 10 15 20 25 September 30 5 10 15 20 25 October 5 15 25 30 5 10 15 20 25 30 5 10 15 20 25 30 5 10 15 20 25 30 10 20 November December January February [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. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (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. ........................................................................................................................... (1) (ii) Determine when the difference in numbers between both populations is at a maximum. ........................................................................................................................... (1) (d) (i) Calculate the time lag between the maximums of both species in the period from October 5 through November 5. Page 3 of 16
  4. 4. GURU CHARAN KUMAR/IB ESS 2012 ........................................................................................................................... ........................................................................................................................... (1) (ii) Suggest a reason for this time lag. ........................................................................................................................... ........................................................................................................................... (1) (e) (i) Describe the role that negative feedback might play in this species interaction. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (ii) Explain why the global human population is less prone to negative feedback control than other organisms. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (3) (f) Outline two examples of feedback in global warming. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... Page 4 of 16
  5. 5. GURU CHARAN KUMAR/IB ESS 2012 ...................................................................................................................................... (2) (Total 14 marks 2) Figures 1 and 2 represent the food webs for two ecosystems. Figure 1. Terrestrial Grassland Sunlight Grass autotroph Inorganic material Decay and mineralization Herbivore heterotroph Death Carnivore heterotroph Figure 2. Marine Food Web Human Sperm whale Baleen whale Crabeater seal Small-toothed whale Leopard seal Elephant seal Seabird Fish Squid Carnivorous plankton Krill Herbivorous Page 5 of plankton 16 Phytoplankton
  6. 6. GURU CHARAN KUMAR/IB ESS 2012 [Source: Tudge, C (1991) Global Ecology, The Natural History Museum, pp. 112–113] (a) (i) State, giving three reasons, which of the food webs, Figure 1 or Figure 2, is likely to be more stable. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (3) (ii) Deduce what would happen to the ecosystem in Figure 1 if rabbits were removed. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (iii) Predict two changes that may occur if foxes were removed from the food web in Figure 1. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) Page 6 of 16
  7. 7. GURU CHARAN KUMAR/IB ESS 2012 Figure 3. Antarctic Marine Food Web Baleen whales Krill Fish Seals Penguins Squid [Source: Trudge C (1991) Global Ecology, The Natural History Museum, pp. 113] (b) In Figure 3, the size of the circle represents the relative biomass of each animal species within the food web. Identify which of the diagrams in Figure 4 below best illustrates what would happen to the food web balance in Figure 3, (i) if humans hunted for seals and fish. ........................................................................................................................... (1) (ii) if humans harvested krill. ........................................................................................................................... (1) (Total 9 marks) Page 7 of 16
  8. 8. GURU CHARAN KUMAR/IB ESS 2012 3) (a) Explain the 2 difference between an open system and a closed system. ........................................................................................................................... ........................................................................................................................... (2) (b) The first and second laws of thermodynamics suggest that energy is neither made or lost, merely transformed. Using a named ecosystem, outline how this occurs. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (c) (i) Explain how socio-political and economic pressures have caused or are causing the degradation of a named area of biological significance. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (3) Page 8 of 16 (Total 7 marks)
  9. 9. GURU CHARAN KUMAR/IB ESS 2012 4) a) Examine the diagram below. It is not intended to represent any particular ecosystem and the organisms are not shown to the same scale. Choose one of the organisms shown in the diagram. Write its name here ..................................................................................................... marsh plant aquatic invertebrate phytoplankton tree bird mammal aquatic plants amphibian midge larvae fish aquatic snail aquatic plant mussel [Source: Adapted from Adds, J et al. The Organism and the Environment, 2nd edition (1997), page 81] For the organism you have chosen, describe and evaluate a method for estimating its abundance. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... Page 9 of 16
  10. 10. GURU CHARAN KUMAR/IB ESS 2012 ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (5) (b) Explain why it might be important to know the abundance of the species of organisms in an ecosystem in assessing that ecosystem’s diversity. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (2) (c) State how you would attempt to identify an organism with which you were unfamiliar. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (2) (d) (i) Name and briefly describe an ecosystem of which you have made a special study. ........................................................................................................................... ........................................................................................................................... (1) (ii) Describe one human activity that might influence your chosen ecosystem. ........................................................................................................................... ........................................................................................................................... (1) (iii) State one abiotic factor that might be changed by this human activity. ........................................................................................................................... ........................................................................................................................... Page 10 of 16
  11. 11. GURU CHARAN KUMAR/IB ESS 2012 (1) (iv) Explain how this human activity might change the abiotic factor. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (v) Outline how you would measure changes in this abiotic factor. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (e) (i) Explain, with an example, what is meant by the term Trophic levels. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (ii) Explain how you would measure the changes in the species diversity of an ecosystem. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) Page 11 of 16
  12. 12. GURU CHARAN KUMAR/IB ESS 2012 (Total 20 marks 5) The following is a schematic diagram of an “ecotron”. This is a walk-in chamber with computer controlled climatic conditions for studying small communities representative of natural ecosystems. lighting airtight transparent ceiling irrigation system air outlet plant, animal and decomposer communities sensors air pump Scale: 1m [Source: modified from NERC www.cpb.bio.ic.ac.uk/ecotron/ecotron.html] (a) State whether this is an open, closed or isolated system. Give one reason for your answer. ...................................................................................................................................... ...................................................................................................................................... (1) (b) Identify and explain two ways in which the inputs to the system would differ from the outputs while communities are growing within the ecotron. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (4) (c) If a fall in temperature of the system is detected by the sensors, mechanisms will be automatically initiated to increase the temperature. State which kind of feedback this demonstrates. ...................................................................................................................................... (1) Page 12 of 16
  13. 13. GURU CHARAN KUMAR/IB ESS 2012 (d) (i) Outline how the second law of thermodynamics can explain the pyramid shape associated with most food chains including that found in the ecotron. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (ii) In this context, explain why food chains studied in the ecotron are generally limited to no more than three trophic levels. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (Total 10 marks) Page 13 of 16
  14. 14. GURU CHARAN KUMAR/IB ESS 2012 6) a) Define the term biodiversity. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (2) (b) Simpson’s diversity index is D = (i) N ( N 1) n( n 1) State what the symbol n represents in the above equation. ........................................................................................................................... ........................................................................................................................... (1) (ii) Suggest what a high D value indicates about an ecosystem. ........................................................................................................................... ........................................................................................................................... (1) (iii) Predict the effect on the value of D if the number of organisms of one species increased but the total number of organisms of all other species in an ecosystem remained constant. ........................................................................................................................... ........................................................................................................................... (1) (iv) Suggest one reason for a low D value in an ecosystem. ........................................................................................................................... ........................................................................................................................... (1) (c) (i) Outline a method for estimating plant biomass within a named ecosystem. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... Page 14 of 16
  15. 15. GURU CHARAN KUMAR/IB ESS 2012 ........................................................................................................................... (3) (ii) Outline a method for estimating the abundance of small mammals in a tundra environment. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (Total 11 marks) 7) The figure below shows the range of tolerance to temperature for a fish population. Lower limit of tolerance No organisms Zone of intolerance Upper limit of tolerance Few organisms Zone of physiological stress Abundance of organisms Optimum range Temperature Low Few organisms No organisms Zone of physiological stress Zone of intolerance High [MILLER, Living in the Environment, 7E. © 1992 Brooks/Cole, a part of Cengage Learning, Inc. Reproduced by permission. www.cengage.com/permissions] (a) (i) Outline what the figure above shows about fish density and temperature. ........................................................................................................................... Page 15 of 16
  16. 16. GURU CHARAN KUMAR/IB ESS 2012 ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (ii) Explain what is meant by a limiting factor in the context of the fish population in this lake. ........................................................................................................................... ........................................................................................................................... (1) (iii) State, giving a reason, whether temperature is a density-dependent or densityindependent factor in the regulation of fish populations. ........................................................................................................................... ........................................................................................................................... (1) (b) Temperature is an abiotic feature of an ecosystem. List four other abiotic factors of an ecosystem. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (2) (c) With reference to one abiotic factor you have named in (b), outline and evaluate a method for measuring this factor. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (3) (Total 9 marks) Page 16 of 16

×