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QUESTION 8 The table shows the daily energy input and output for a typical leaf. Incident sunlight Evaporation Heat loss (radiation) Reflection of sunligh Transmission of sunlight Calculate the daily net energy stored by the leaf. (A) 0.8kJ (B) 5.0kJ (C) 36.2kJ (D) 73.5kJ
QUESTION 16 The figures show the original distribution zone of Species I and some possible distribution zones of Species I after the introduction of Species I1. Species II has a competitive advantage over Species I; however it does not tolerate areas of lower rainfall. Before After possible distribution zones ~ D removed from the ecosystem original distribution zone / Rainfall Rainfall Temperature Temperature Which of the following would be an accurate prediction of the new distribution zone for Species 1? (A) Zone A i.e. no change to the distribution (B) Zone B i.e. reduced distribution within the original zone (C) Zone C i.e. new distribution outside the original zone (D) Zone D i.e. complete removal of the species from the ecosystem
QUESTION 25 (4 marks) The following simplified energy-flow diagram provides the gross productivity figures for producers and herbivores in an ecosystem. plant respiration (including heat) herbivore respiration 16 MJ/m?/year 20 MJ/m?/year Producers i Higher CRESVQESS trophic levels decomposition decomposition 8 MJ/m?/year (waste and death/decay) 5 MJ/m?/year a) Determine the net productivity for the producers and herbivores in this ecosystem. [2 marks] Producers: Netproductivity=___ MJ/m?/year Herbivores: Net productivity=___ MJ/m?/year b) Contrast the outputs of energy for the two trophic levels in the diagram. [2 marks]
QUESTION 2 (5 marks) Two species of Paramecium single-celled microorganisms were grown for 4 days in test tubes with a fixed amount of algae added to each tube daily as their food source. The life span for each species ranges from 4—6 hours. Test tubes 1 and 2 each contained a single species and test tube 3 initially contained both species. Live Paramecium population after 4 days (per mL) T w0 T e s w0 a) Identify and describe the ecological principle that relates to these observations. [2 marks] b) Explain the results of the experiment. [3 marks]
QUESTION 3 In ocean food webs where phytoplankton is in the first trophic level the second trophic level of zooplankton often has a higher biomass than the phytoplankton at any given time. Which explanation would account for this? (A) (B) © (D) The zooplankton are also able to photosynthesise. Different phytoplankton species are preying on each other. Carnivores in the third trophic level have increased their consumption of zooplankton. The phytoplankton multiply much faster than zooplankton but their lifespan is shorter.
QUESTION 8 The place where an organism lives is called its (A) niche. (B) habitat. (C) community. (D) environment.
QUESTION 20 A keystone species is defined as a species that (A) 1s the top predator in an ecosystem. (B) 1s a major producer in an ecosystem. (C) has a unique and crucial role in an ecosystem. (D) directly influences all species in an ecosystem.
QUESTION 22 (3 marks) Describe two ways carbon is transformed and one way it is transferred as it cycles through the biotic components of an ecosystem.
QUESTION 24 (5 marks) The diagram is a hypothetical biomass pyramid for a community. Secondary consumers 76 kg Primary consumers 1520 kg Producers 15200 kg Not to scale a) Contrast the efficiency of the biomass transfers between each level of the pyramid. [3 marks] b) Explain the difference in biomass transfer efficiency identified in Question 24a). [2 marks]
QUESTION 7 What 1s used directly by plants for protein synthesis? (A) nitrite NO (B) mnitrate NOy~ (C) ammonia NH; (D) atmospheric nitrogen N
QUESTION 18 The competitive exclusion principle applies to different species occupying the same (A) niche. (B) habitat. (C) environment. (D) trophic level.
QUESTION 2 (4 marks) This 1s a biomass pyramid for a grassland community. Not to scale a) Calculate the percentage energy transfer between the first two trophic levels. Show your working. [2 marks] b) Explain the loss of biomass between trophic levels. [2 marks]
QUESTION 4 (1 mark) Define keystone species.
QUESTION 14 This figure shows an energy pyramid for a hypothetical ecosystem. Decomposers Second order consumer = 16 276 kJ/m?/year = 201 kJ/m?/year First order consumer = 2494 kJ/m?/year Primary producers = 36 380 kJ/m?/year The trophic level transfer efficiency of primary producers to herbivores in this situation would be (A) 0.6%. (B) 6.9%. Q) 7.4%. (D) 44.7%.
QUESTION 15 The figure below shows a model of two species populations species A and species B competing for the same resource over time. 160 140 Species A — - N o Species B 100 Population density Qo o Time (dimensionless) Identify the response that describes the relationship between the two species over time. (A) species A competitively excludes species B (B) species B competitively excludes species A (C) there is no competitive exclusion coexistence occurs between species (D) either species competitively excludes the other based on population densities
QUESTION 28 (5 marks) The figure below shows a model of ecological niche occupation by species A—E. : T :_¢§ Species D - ‘© 2 | ® % © . m = 2 Z 2 3 Cool Warm Niche axis 2 — Temperature a) Identify which two species are occupying the same ecological niche. [1 mark] b) Species A and B have a common ancestor. Which diversification pattern would have occurred between species A and species B for them to occupy these niches? [1 mark] The table below shows the frequencies of genotypes and phenotypes for a particular trait in a generation of species E. Genotype (% frequency) Phenotype (% frequency) TT (0) Tt (100) tt (0) Phenotype 2 (0) c) Predict the next generation’s genotype and phenotype frequency. Which type of inheritance pattern is represented for Phenotype 17 Phenotype 1 (100) [3 marks]
QUESTION 9 An ecological niche refers to (A) a group of organisms competing for the same resources. (B) the role and space that an organism fills in an ecosystem. (C) all organisms occupying a physical space close enough to interact with each other. (D) the largest population of a particular species that can be supported by an ecosystem.
QUESTION 14 An energy pyramid for an aquatic ecosystem is shown (values are in kJ m secondary consumers 410 primary consumers 3400 producers 21 600 Transfer efficiency between producers and primary consumers is closest to —2 y’). Not to scale (A) 5% (B) 10% (C) 12% (D) 16%
QUESTION 22 (2 marks) Describe two ways bacteria assist matter to cycle through ecosystems.
QUESTION 2 (4 marks) The diagram shows feeding relationships for an Australian ecosystem. a) Use the data to explain why dingoes are a Keystone species. [2 marks] b) Predict the effect a drastic reduction in the number of dingoes would have on the termite population. Justify your response. [2 marks]
![Question-Image](https://examinsightsimages.syd1.cdn.digitaloceanspaces.com/Biology/Biology_2023_Paper_2_Question_2.webp)
Difficulty: A
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Paper 2
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2023
QUESTION 9 (7 marks) The graphs show the findings of an experiment investigating the competitive exclusion principle. Two species of protozoa (P. aurelia and P. caudatum) were grown separately and together under identical conditions. Grown separately Grown together 300 250 300 250 P. aurelia lia N S o N S Oo one sens seni e deen esce cesses sees ous sere serenrenbennnaeesnewesuaed 150 100 100 50--—/ 2s = -- P caudatum Population density (cells/mL) a S Population density (cells/mL) 50 Fe i a o+ P. caudatum 0 5 10 15 20 10 20 Time (days) Time (days) a) Identify the population density of P caudatum on day 10 when grown separately. [1 mark] b) Compare the growth of P. aurelia in the two graphs. [3 marks] c) Use the data to explain the competitive exclusion principle. [3 marks]
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