DP Biology Questionbank

Description

Overview of the essential ideas for this option.

C.1: Community structure is an emergent property of an ecosystem.

C.2: Changes in community structure affect and are affected by organisms.

C.3: Human activities impact on ecosystem function.

C.4: Entire communities need to be conserved in order to preserve biodiversity.

C.5: Dynamic biological processes impact population density and population growth.

C.6: Soil cycles are subject to disruption.

Directly related questions

• 17N.3.HL.TZ0.18: Discuss the causes and consequences of eutrophication.
• 17N.3.HL.TZ0.17b: Describe the relationship between Zooxanthellae and reef-building coral species.
• 17N.3.HL.TZ0.17a.ii: Outline a reason for organisms seldom occupying their entire fundamental niche.
• 17N.3.HL.TZ0.17a.i: Define fundamental niche.
• 17N.3.HL.TZ0.16c: Outline three issues arising from the release of pollutants into the environment.  
• 17N.3.HL.TZ0.15c: Hunting of M. gallopavo is currently regulated. Predict what would happen if the hunting...
• 17N.3.HL.TZ0.15b: State how the population of M. gallopavo may have been determined.
• 17N.3.HL.TZ0.15a.ii: Suggest factors that could account for the growth curve of the M. gallopavo population.
• 17N.3.HL.TZ0.15a.i: State the range of years when exponential growth of the M. gallopavo population occurred.
• 17N.3.HL.TZ0.14b.ii: Identify possible approaches to maintain the population of P. sandwichensis.
• 17N.3.HL.TZ0.14b.i: State the role of an indicator species.
• 17N.3.HL.TZ0.14a.iii: Suggest a method to limit the impact of F. silvestris on native species.
• 17N.3.HL.TZ0.14a.ii: Describe how invasive species such as F. silvestris can have a significant impact on native species.
• 17N.3.HL.TZ0.14a.i: Identify how the pattern in mammals is different from reptiles and birds.
• 17N.3.SL.TZ0.15: Explain reasons for differences in the realized niche and fundamental niche of an organism.
• 17N.3.SL.TZ0.14d: Explain the impact of plastic waste on Laysan albatrosses (Phoebastria immutabilis).
• 17N.3.SL.TZ0.14c: Outline how deforestation can affect the richness of biodiversity in an ecosystem.
• 17N.3.SL.TZ0.14b: State one reason mammals can continue to survive even if they are extinct in the wild.
• 17N.3.SL.TZ0.14a: Calculate how many species are classified as endangered due to hunting and trapping.
• 17N.3.SL.TZ0.13b: The sea star also eats the sea snails. Construct a food web to show the feeding relationships...
• 17N.3.SL.TZ0.13a: Compare and contrast the effects of the predators on the population of the mussels.
• 17N.3.SL.TZ0.12c: Explain how pesticides may undergo biomagnification in the lake.
• 17N.3.SL.TZ0.12b: Outline why a year is more suitable than a month for the measurement of energy flow.
• 17N.3.SL.TZ0.12a: Calculate the energy loss due to respiration in primary consumers in kJ m–2 y–1.
• 17M.3.HL.TZ2.17: Distinguish between tropical rainforest and taiga in terms of nutrient stores, nutrient flows and...
• 17M.3.HL.TZ2.15e: Explain how an excessive growth of algae on coral reefs can be controlled by top-down factors.
• 17M.3.HL.TZ2.15d: A coat of algae builds up on coral reefs as a consequence of eutrophication. Explain the...
• 17M.3.HL.TZ2.15c: When coral is bleached, certain organisms become more common in the ecosystem such as the...
• 17M.3.HL.TZ2.15b: State the trophic level of Zooxanthellae.
• 17M.3.HL.TZ2.15a: State the type of interaction that occurs between Zooxanthellae and reef-building corals.
• 17M.3.HL.TZ1.17: Discuss the factors affecting population growth that can result in an exponential growth curve.
• 17M.3.HL.TZ1.16b: The percentage of phosphorus in an ecosystem that is recycled per year is in most cases very...
• 17M.3.HL.TZ1.16a: Some scientists estimate that available phosphorus reserves in the Earth will be completely...
• 17M.3.HL.TZ1.15c: State the two components needed to calculate the biodiversity of an area.
• 17M.3.HL.TZ1.15b: Discuss two advantages of ex situ conservation measures. 
• 17M.3.HL.TZ1.15a: Zoos devote much effort to preserving and breeding elephants in captivity. Data for births...
• 17M.3.HL.TZ1.14e: Determine whether islands are open or closed ecosystems.
• 17M.3.HL.TZ1.14c: Indicator species may be affected by biomagnification. Discuss biomagnification using a named...
• 17M.3.HL.TZ1.14b: Define indicator species.
• 17M.3.HL.TZ1.13c: Distinguish between mutualism and parasitism, providing another example of mutualism and another...
• 17M.3.HL.TZ1.13b: The relationship between A. pallipes and B. italica is mutualistic. A. pallipes feeds on algae...
• 17M.3.HL.TZ1.13a: Describe the body length frequency of the B. italica worms collected in this study.
• 17M.3.SL.TZ2.17c: Researchers have argued that S. geminata is a keystone species in the corn agricultural system....
• 17M.3.SL.TZ2.17b: Discuss whether S. geminata might play a positive role in corn production.
• 17M.3.SL.TZ2.17a: State the impact of S. geminata on insect species diversity.
• 17M.3.SL.TZ2.16c: Outline the reason that parasite biomass occurs in both tertiary consumers and secondary consumers.
• 17M.3.SL.TZ2.16b: Compare and contrast the biomass in the different trophic levels.
• 17M.3.SL.TZ2.16a: Estimate the approximate amount of biomass represented by parasites in this ecosystem.
• 17M.3.SL.TZ2.14: Paramecium aurelia and Paramecium caudatum are single cell organisms. They were grown separately...
• 17M.3.SL.TZ1.16c: Discuss the advantages and disadvantages of in situ conservation methods.
• 17M.3.SL.TZ1.16b: Site A has a higher Simpson’s reciprocal index than Site B showing that its diversity is...
• 17M.3.SL.TZ1.16a: Calculate the diversity of site C. Working should be shown.
• 17M.3.SL.TZ1.15c: Evaluate the use of traps containing toxin as a means of cane toad control.
• 17M.3.SL.TZ1.15b: State the origin of cane toads.
• 17M.3.SL.TZ1.15a: Outline one consequence of introducing an alien species into an ecosystem.
• 17M.3.SL.TZ1.14: The Gersmehl diagram below shows the movement and storage of nutrients in a taiga...
• 17M.3.SL.TZ1.13c: State one limiting factor on Zooxanthellae which affects coral reef formation.
• 17M.3.SL.TZ1.13b: Describe the exchange of materials between the coral’s polyps and Zooxanthellae.
• 17M.3.SL.TZ1.13a: State the relationship between Zooxanthellae and coral reef species.
• 16N.3.HL.TZ0.18: Discuss how crop plants obtain the phosphorus that they need to grow and whether the supply of...
• 16N.3.HL.TZ0.17b: Explain how top-down factors control algal blooms.
• 16N.3.HL.TZ0.17a: State two bottom-up factors affecting algal blooms.
• 16N.3.HL.TZ0.16c: The number of plants in two fields of approximately the same size was counted. Compare and...
• 16N.3.HL.TZ0.16b: Outline how the edge effect can affect diversity in forests.
• 16N.3.HL.TZ0.16a: Describe one method that could have been used to estimate the population size of a given tree in...
• 16N.3.HL.TZ0.15d: Suggest changes in the management of the national park that could reduce the amount of...
• 16N.3.HL.TZ0.15c: Outline the effect of wind on the distribution of plastic pollution in this lake.
• 16N.3.HL.TZ0.15b: State two possible effects on organisms of microplastic pollution.
• 16N.3.HL.TZ0.15a: Predict one example of macroplastic pollution that is likely to be found in this lake.
• 16N.3.HL.TZ0.14: Cryptococcus neoformans and the closely related species Cryptococcus gattii are human fungal...
• 16N.3.SL.TZ0.14b: One pesticide used in killing mosquitoes was DDT. Considering its harmful effects,...
• 16N.3.SL.TZ0.14a: Outline the trend in the number of people with malaria during the period when the use of...
• 16N.3.SL.TZ0.13b: A calculation of Simpson’s reciprocal index was undertaken on each field with the following...
• 16N.3.SL.TZ0.13a: Compare and contrast the richness and the evenness of the two fields.
• 16N.3.SL.TZ0.12b: Referring to the climograph, explain reasons that the nutrient store in the litter layer of the...
• 16N.3.SL.TZ0.12a: Identify the ecosystem with the appropriate numeral from the climograph.
• 16N.3.SL.TZ0.11c: Describe how the distribution of Chthamalus and Balanus is affected when both are present.
• 16N.3.SL.TZ0.11a: Distinguish between a fundamental niche and realized niche.
• 16M.3.HL.TZ0.18: Evaluate the methods used to estimate populations of marine organisms.
• 16M.3.HL.TZ0.17d: Using microplastics as an example, outline the concept of biomagnification.
• 16M.3.HL.TZ0.17c: Outline the origin of microplastic debris in the marine environment.
• 16M.3.HL.TZ0.17b: Suggest a reason for the difference in ingested plastic in the diets of the Laysan Albatross in...
• 16M.3.HL.TZ0.17a: Suggest one reason for the Laysan Albatross ingesting indigestible plastic.
• 16M.3.HL.TZ0.16d: Explain why biomass continues to increase after the respiration levels plateau.
• 16M.3.HL.TZ0.16c: Explain the changes in biomass.
• 16M.3.HL.TZ0.16b: Outline the evidence from the graph that the area had plentiful rainfall.
• 16M.3.HL.TZ0.16a: Describe the change in biomass over the 100 year period.
• 16M.3.HL.TZ0.15b: Explain, with respect to the example of P. montenegrina, what is meant by realized niche.
• 16M.3.HL.TZ0.15a: Using graph A and graph B, compare and contrast the temperature ranges of the two species when...
• 16M.3.HL.TZ0.14c: Suggest one reason for ammonium levels in the interior of the forest being lower than the soil...
• 16M.3.HL.TZ0.14b: List two sources of the ammonium in the forest soils apart from deposition in rainfall.
• 16M.3.HL.TZ0.14a: Outline the procedure that was most likely used by the researchers to decide where to take the...
• 16M.3.SL.TZ0.16: Explain how alien species can affect community structure in an ecosystem.
• 16M.3.SL.TZ0.15c: Deduce two conclusions about PCBs that are supported by the data.
• 16M.3.SL.TZ0.15b: (i) Identify the predator with the least biomagnification of pollutants. (ii) Suggest a reason...
• 16M.3.SL.TZ0.15a: Outline how biomagnification occurs.
• 16M.3.SL.TZ0.14b: Outline how the type of stable ecosystem that will develop in an area can be predicted based on...
• 16M.3.SL.TZ0.14a: Primary plant succession has been observed in sand dunes adjacent to the northern end of Lake...
• 09N.3.SL.TZ0.21a: Discuss the impacts of a named alien species introduced as a biological control measure.
• 09N.3.SL.TZ0.20c: Explain the small biomass of organisms in higher trophic levels.
• 09N.3.SL.TZ0.20b: State the units used in a pyramid of energy.
• 09N.3.SL.TZ0.20a: Outline one example of herbivory.
• 10N.3.HL.TZ0.12: Discuss the role of ex situ conservation of endangered species.
• 10N.3.HL.TZ0.11b: State the units used in a pyramid of energy.
• 10N.3.HL.TZ0.11a: Earthworms are primary consumers that can be grown on household food waste such as fruit and...
• 10N.3.HL.TZ0.10f: Suggest a biological control that might be introduced to reduce HBR.
• 10N.3.HL.TZ0.10e: Suggest another factor which might affect the ecological distribution of mosquitoes.
• 10N.3.HL.TZ0.10d: Suggest how predictions of global climate changes, such as predictions of precipitation patterns,...
• 10N.3.HL.TZ0.10c: Evaluate the effect of increased precipitation on HBR for both species.
• 10N.3.HL.TZ0.10b: Calculate the difference in peak HBR for A. gambiae and A. funestus for week 6.
• 10N.3.HL.TZ0.10a: State the week number when the highest human biting rate (HBR) is found for A. gambiae.
• 10N.3.HL.TZ0.8a(ii): Outline the conditions that favour denitrification.
• 10N.3.HL.TZ0.8a(i): State two nitrogen-fixing bacteria.
• 09N.3.HL.TZ0.11a(ii): Outline a named example of biomagnification.
• 09N.3.HL.TZ0.11a(i): Define biomagnification.
• 10N.3.SL.TZ0.3a: Label the levels of the trophic pyramid of energy shown below.
• 10N.3.SL.TZ0.2b: Describe a primary succession in a named type of habitat.
• 10N.3.SL.TZ0.21a: Distinguish between fundamental niches and realized niches.
• 10N.3.SL.TZ0.20e: Suggest another factor which might affect the ecological distribution of mosquitoes.
• 10N.3.SL.TZ0.20d: Suggest how predictions of global climate changes, such as predictions of precipitation patterns,...
• 10N.3.SL.TZ0.6c: Evaluate the effect of increased precipitation on HBR for both species.
• 10N.3.SL.TZ0.20b: Calculate the difference in peak HBR for A. gambiae and A. funestus for week 6.
• 10N.3.SL.TZ0.19a: State the week number when the highest human biting rate (HBR) is found for A. gambiae.
• 12N.3.SL.TZ0.21b: Water is one factor that affects the distribution of plant species. Outline three other factors...
• 12N.3.SL.TZ0.20b (ii): Using a named example, explain a consequence of biomagnification.
• 12N.3.SL.TZ0.20a: Explain the principal of competitive exclusion.
• 12N.3.HL.TZ0.11b (ii): Define the term biomass.
• 12N.3.HL.TZ0.11a: Define the term biomagnification.
• 12N.3.HL.TZ0.10e: Outline the concept of maximum sustainable yield in the conservation of fish stocks.
• 12N.3.HL.TZ0.10d: State two types of interactions that are most likely to occur among deep-water fish. 1....
• 12N.3.HL.TZ0.10c: Discuss the evidence in these data for a decline in the biodiversity of fish between the early...
• 12N.3.HL.TZ0.10b (ii): Suggest one reason for the difference in the abundance of fish at depths down to 2000 m between...
• 12N.3.HL.TZ0.10b (i): Compare the abundance of fish between the early period (1977 to 1989) and the late period (1997...
• 12N.3.HL.TZ0.10a : State the depth at which the maximum number of species per trawl were caught.
• 11N.3.SL.TZ0.19a: List two abiotic factors that affect the distribution of plant species. 1. ...
• 11N.3.SL.TZ0.16a: The diagram below shows the nitrogen cycle. Using the letter X, label where the process of...
• 11N.3.HL.TZ0.12: Discuss international measures that would promote the conservation of fish stocks.
• 11N.3.HL.TZ0.11d: Yellowstone National Park was the first national park in the world and is a designated biosphere...
• 11N.3.HL.TZ0.11c: Outline a method that could be used to sample the plant population shown in photograph B.
• 11N.3.HL.TZ0.11a: Identify, with a reason, the type of succession that has taken place.
• 10M.3.SL.TZ2.3b: Discuss reasons for conservation of biodiversity of a named ecosystem.
• 10M.3.SL.TZ2.21a: State the name of a statistical method used to quantify changes in biodiversity.
• 10M.3.SL.TZ2.20b: Describe one effect of plants on an abiotic factor in a pioneer community.  
• 10M.3.SL.TZ2.20a: List four factors that affect the distribution of plant species.
• 10M.3.SL.TZ1.28b: Discuss the impact of alien species on ecosystems.
• 10M.3.SL.TZ1.28a : State one example of the accidental release of an alien species that has had a significant impact...
• 10M.3.SL.TZ1.27b: Outline a method used to correlate the distribution of plant species with an abiotic factor.
• 10M.3.SL.TZ1.27a: Outline three factors that affect plant distribution.
• 10M.3.SL.TZ1.23c: Outline the consequences of releasing nitrate fertilizer into rivers.
• 10M.3.SL.TZ1.23b (ii): State the role of Nitrobacter in this cycle.
• 10M.3.SL.TZ1.23b (i): Draw an arrow to indicate where in the cycle Azotobacter plays a role.
• 10M.3.SL.TZ1.23a: Indicate the processes occurring at A and B.   A:...
• 10M.3.HL.TZ1.12: Evaluate the use of indicator species in monitoring environmental changes.
• 10M.3.HL.TZ1.11a: Identify the trophic level of the toad.
• 10M.3.HL.TZ1.10c: Suggest one possible consequence of arsenic accumulation in plants for other organisms in the...
• 10M.3.HL.TZ1.10b (ii): Using the data in the table, discuss the potential of using Chinese brake fern to remove arsenic...
• 10M.3.HL.TZ1.10b (i): Assuming the mean rate of arsenic accumulation over the first 20 weeks continued, calculate how...
• 10M.3.HL.TZ1.10a: Using the data in the graph, describe the accumulation of arsenic in the Chinese brake fern.
• 09M.1.SL.TZ2.22: The diagram below shows a population growth curve. At which time in the population growth...
• 09M.1.SL.TZ1.23: Population growth, as shown by the curve below, is the result of changes in mortality, natality,...
• 12M.3.SL.TZ2.21c: Define biomagnification.
• 12M.3.SL.TZ2.21b: State one example of biological control of an invasive species.   Invasive species: ...
• 12M.3.SL.TZ2.21a: Explain how living organisms can affect the abiotic environment during primary succession.
• 12M.3.SL.TZ2.20b: Research into a river ecosystem produced these approximate values: 25, 300, 6000 and 36 000 kJ...
• 12M.3.SL.TZ2.20a: Biotic factors involve the other organisms in the environment of an animal species. List two...
• 12M.3.SL.TZ2.18c (i): State the role of Rhizobium in the nitrogen cycle.
• 12M.3.SL.TZ1.21b: Explain how temperature and territory affect the distribution of animal...
• 12M.3.HL.TZ2.12: Explain, with examples, the use of specific indicator species and biotic indices to detect...
• 12M.3.HL.TZ2.11c: (i)  Describe the environmental impact of a named invasive alien species.   (ii)  State an...
• 12M.3.HL.TZ2.11a: Outline changes in species diversity during primary succession.
• 11M.3.SL.TZ2.20b: Distinguish between fundamental niches and realized niches.
• 11M.3.SL.TZ2.20a: Explain the concept of an ecological niche.
• 11M.3.SL.TZ2.18b: Explain the consequences of releasing raw sewage and nitrate fertilizer into rivers.
• 11M.3.SL.TZ2.18a: State one condition that favours denitrification.
• 11M.3.SL.TZ1.20a: Define the terms fundamental niche and realized niche.   Fundamental niche:...
• 11M.3.HL.TZ1.11b: Outline the consequences of the edge effect for small nature reserves.
• 11M.3.HL.TZ1.8b: State the role of Rhizobium and Nitrobacter in the nitrogen cycle.   Rhizobium:      ...
• 13N.3.SL.TZ0.21b.ii: Discuss three reasons for the conservation of biodiversity in rainforests.
• 13N.3.SL.TZ0.21b.i: State what \(N\) and \(n\) stand for in this formula.   \(N\):   \(n\):
• 13N.3.SL.TZ0.20b.ii: Outline the ecological changes that will occur on the island of cooled lava.
• 13N.3.SL.TZ0.20b.i: State the type of ecological change that will occur following the formation of an island from...
• 13N.3.SL.TZ0.19d: Evaluate the conclusion that there are trends in the distribution of plants along the transect of...
• 13N.3.SL.TZ0.19c.ii: Suggest a reason for this in community 17.
• 13N.3.SL.TZ0.19c.i: Suggest a reason for this in community 1.
• 13N.3.SL.TZ0.19b: Analyse the graph to find whether species 45 has a broad or narrow realized niche.
• 13N.3.SL.TZ0.19a: State the grass species that is most abundant in plant community 1.
• 13N.3.HL.TZ0.12: Eight sub-species of tigers existed in 1950, but three of these former sub-species have now...
• 13M.3.SL.TZ2.20c: Outline one reason for the extinction of a named animal species
• 13M.3.SL.TZ2.20a: Explain the niche concept.
• 13M.3.SL.TZ2.19d: Suggest why adult feeding differs from instar larval feeding when predators are present.
• 13M.3.SL.TZ2.19c: Compare adult feeding to instar larval feeding.
• 13M.3.SL.TZ2.19a: Identify the primary food for all grasshoppers without predators.
• 13M.3.SL.TZ2.18a: State one soil condition that favours denitrification.
• 13N.2.HL.TZ0.3a: (i) Label the diagram to complete the food web for the organisms in the table above.  (ii)  ...
• 13M.3.HL.TZ1.11: Discuss how international efforts can contribute to the conservation of fish stocks.
• 13M.3.HL.TZ1.11c: Outline the biogeographical features of nature reserves that promote the conservation of diversity.
• 13M.3.HL.TZ1.1d: Discuss how an understanding of biomagnification could help these human populations reduce their...
• 13M.3.HL.TZ1.10c: Explain the large range of mercury concentrations seen in the piscivores.
• 13M.3.HL.TZ1.10b: Compare the levels of mercury found in herbivores (primary consumers) and detritivores.
• 13M.3.HL.TZ1.10a: State the trophic level of the fish that presents the least risk of mercury contamination for...
• 15N.3.HL.TZ0.12: Discuss, using three examples, how alien species have impacted ecosystems.
• 15N.3.HL.TZ0.11c: Explain how living organisms can change the abiotic environment during primary succession.
• 15N.3.HL.TZ0.11b: Outline how habitat corridors can aid conservation of biodiversity in a nature reserve.
• 15N.3.HL.TZ0.10f: Discuss whether the results for the Varied Tit and Coal Tit indicate competitive exclusion.
• 15N.3.HL.TZ0.10e: Suggest one reason why few Varied Tits were found far from trunk.
• 15N.3.HL.TZ0.10d: State how the distribution of birds changes with their size in the middle crown of the tree.
• 15N.3.HL.TZ0.10c: Compare how the Varied Tit and the Marsh Tit use the habitat in the upper crown of the tree.
• 15N.3.HL.TZ0.10b: Identify the section of habitat used least by the birds.
• 15N.3.HL.TZ0.10a: State the relative use of the habitat by the Great Tit in the upper crown of the tree close to...
• 15N.3.HL.TZ0.8c: Outline the process of nitrogen fixation by a named free-living bacterium.
• 15N.3.SL.TZ0.21b: Explain what is meant by the niche concept.
• 15N.3.SL.TZ0.21a: State the process where pesticides such as DDT become more concentrated at each trophic level.
• 15N.3.SL.TZ0.20b: Explain how living organisms can change the abiotic environment during primary succession.
• 15N.3.SL.TZ0.19d: Spiders and ground beetles are both predators. Discuss possible effects on other species...
• 15N.3.SL.TZ0.19c: Compare the changes in the range of ground beetles with the changes in the range of spiders.
• 15N.3.SL.TZ0.19b: Calculate the percentage of ground beetles that are below the zero shift.
• 15N.3.SL.TZ0.19a: State which taxonomic group shows the greatest median shift.
• 15N.3.SL.TZ0.17b: Outline the process of nitrogen fixation by a named free-living bacterium.
• 15N.2.SL.TZ0.3a: Identify the phases labelled X and Y. X: Y:
• 15M.3.SL.TZ2.18a: State the role of Rhizobium, Nitrobacter and Azotobacter in the nitrogen cycle. Rhizobium: ...
• 15M.3.SL.TZ2.19b: Outline the relationship between area of foot and the force required to detach the limpet.
• 15M.3.SL.TZ2.19c: Smaller limpets can only be found at the back of crevices. Discuss the reasons for this.
• 15M.3.SL.TZ2.21a : Outline one example of biological control of a named invasive species.
• 15M.3.SL.TZ2.19a (i): State the force required to detach a limpet with an area of foot of 2 cm2 .
• 15M.3.SL.TZ2.19a (ii): State the smallest area of foot necessary to resist a force of 50 N.  ...................cm2
• 15M.3.SL.TZ2.19d: Limpets tend to live towards the high tide zone. State the method used to determine the...
• 17M.3.SL.TZ2.18: Explain the use of indicator species to assess the condition of the environment.
• 11N.3.SL.TZ0.19d: Discuss the difficulties of classifying organisms into trophic levels.
• 11N.3.SL.TZ0.19c: Distinguish between fundamental and realized niches.
• 11N.3.SL.TZ0.19b: State one example of secondary succession.
• 15M.3.HL.TZ1.10b: Describe the distribution of Bythotrephes during the day.
• 15M.3.HL.TZ1.10a: State the depth range showing the most Bythotrephes during the night.
• 15M.3.HL.TZ1.10c: Deduce the responses of Bythotrephes to temperature and light.
• 15M.3.HL.TZ1.10d: Explain the change in distribution of Bythotrephes between day and night in terms of its position...
• 15M.3.HL.TZ1.11a: Distinguish between the use of a quadrat and a transect in gathering field data.
• 15M.3.HL.TZ1.11b (i): State the change in species diversity and the change in production during primary...
• 15M.3.HL.TZ1.11b (ii): State one difficulty in classifying organisms into trophic levels.
• 15M.3.SL.TZ1.20b: The vegetation shown here has developed as a result of primary succession. Outline the changes...
• 15M.3.HL.TZ2.10d: Discuss the possible ecological relationships between E. coli and Cladophora.
• 15M.3.SL.TZ1.19a: Identify the most abundant animal type at the S. muticum site:      the control site:
• 15M.3.SL.TZ1.19b: Describe the impact of invasive S. muticum on the shoreline animal community.  
• 15M.3.SL.TZ1.20a: Describe how a transect can be used to investigate the distribution of plant species in this...
• 15M.3.SL.TZ1.21a: Explain the causes and consequences of biomagnification of a named chemical.
• 15M.3.HL.TZ2.12: Describe a named method for determining the size of fish populations and the challenges in...
• 15M.3.SL.TZ1.19c: Discuss possible reasons for the differences in the animal communities seen at the two sites.  
• 15M.3.SL.TZ1.21b: Explain the concept of niche.
• 15M.3.HL.TZ2.10a: Identify the site with the lowest average CFU of E. coli in the water samples.
• 15M.3.HL.TZ2.10b: Distinguish between the trends in the survival of E. coli on mat samples and in water samples...
• 15M.3.HL.TZ2.10c: Scientists formerly related the population of Cladophora to changes in phosphorous levels in the...
• 13M.2.SL.TZ2.3a: List two factors that could cause an increase in the size of an animal population. 1.      ...
• 13M.3.HL.TZ2.10b: Estimate the total percentage of time the gulls exposed to falcons spent flying and at rest in...
• 13M.3.HL.TZ2.11a: Distinguish between in situ and ex situ conservation.
• 13M.3.HL.TZ2.12: Explain the causes and consequences of biomagnification with reference to a named example.
• 13M.3.HL.TZ2.4b: Compare the effect that starvation had on both species of goby when no predator was present.
• 13M.3.HL.TZ2.4c (i): Describe the effect the predator had on the foraging of the gobies.
• 13M.3.HL.TZ2.10d: Predict, using the data in the pie charts for weeks 1 to 5 and weeks 6 to 10, if the use of...
• 13M.3.HL.TZ2.4a: Calculate the decrease in mass of food foraged by fed sand gobies when a predator was introduced,...
• 13M.3.HL.TZ2.4c (ii): Suggest a reason for the effect of the predator.
• 13M.3.HL.TZ2.10a: State which activity decreased in weeks 1 to 5 as a result of exposure to the falcons.
• 13M.3.HL.TZ2.11b: The Atlantic cod is considered in many countries to be endangered due to overfishing. Describe...
• 13M.3.HL.TZ2.11d: Outline one reason for the extinction of a named animal species.
• 13M.3.SL.TZ1.21a: Discuss the difficulties of classifying organisms into trophic levels.
• 13M.3.HL.TZ2.10c: Compare the behaviour of the gulls exposed to falcons with the control group over the period of...
• 13M.3.SL.TZ1.18b: Explain the consequences of releasing raw sewage and nitrate fertilizer into rivers.
• 13M.3.SL.TZ1.19a (i): State the most ruderal species.
• 13M.3.SL.TZ1.19a (ii): Species number 4 has a ruderalism value of 29.  State the stress-tolerance value and...
• 13M.3.SL.TZ1.19b: Analyse the change of species over time.
• 13M.3.SL.TZ1.21b: Explain the cause and consequences of biomagnification, using a named example.
• 11M.2.HL.TZ2.4a (ii): Identify an organism in the food web that is both a secondary and tertiary consumer.
• 11M.2.HL.TZ2.4b: Explain how the flow of energy in the food web differs from the movement of nutrients.
• 11M.2.HL.TZ2.4a (i): Identify an organism in the food web that is an autotroph. 
• 11M.3.HL.TZ2.10b: Determine, with a reason from the data, which species is unable to eliminate cadmium.
• 11M.3.HL.TZ2.10c (i): State the species that accumulates the least cadmium.
• 11M.3.HL.TZ2.10a: Identify the highest average concentration of cadmium found in P. peltifer.
• 11M.3.HL.TZ2.11c: Outline, with a named example, biological control of invasive species.
• 11M.3.HL.TZ2.10d: Describe the possible effects of the presence of cadmium in food chains involving these arthropods.
• 11M.3.HL.TZ2.10c (ii): Suggest, with observations from the data, a reason why the species stated in (c)(i) accumulates...
• 11M.3.HL.TZ2.11b: Define indicator species.
• 11M.3.SL.TZ1.20c: Explain why carnivores tend to be more affected by biomagnification than organisms lower down the...
• 11M.3.SL.TZ1.21a: The introduction of alien species and the release of environmental pollutants are examples of...
• 12M.3.HL.TZ1.10a (ii): Deduce the tank in which the level of mercury accumulation in Daphnia was lowest.
• 12M.3.HL.TZ1.10c: Using the data, suggest reasons for the relationship between phosphorus concentration in the...
• 12M.3.HL.TZ1.12: Discuss the advantages of in situ conservation of endangered species, using examples.
• 12M.3.HL.TZ1.11b: Define biomass.
• 12M.3.HL.TZ1.10a (i): Deduce the tank in which the quantity of algae was highest.
• 12M.3.HL.TZ1.10b: Outline the relationship between phosphorus concentration in the water and the accumulation of...
• 12M.3.HL.TZ1.11a: In a grassland ecosystem, the amount of energy captured by the photosynthetic organisms was 100...
• 12M.3.SL.TZ1.7a: Estimate the difference between the lowest and highest rates of release of CO2 from the soil in...
• 12M.3.SL.TZ1.7c (i): Describe the relationship between rates of nitrogen addition and release of CO2 from soil in the...
• 12M.3.SL.TZ1.7b: Suggest one process occurring in tree roots that could cause the release of CO2 from the soil.
• 12M.3.SL.TZ1.7c (ii): Suggest a reason for this relationship.
• 12M.3.SL.TZ1.7d: Compare the effects of the nitrogen addition treatments on the hardwood and softwood areas of the...
• 12M.3.SL.TZ1.17b: Denitrification is part of the nitrogen cycle. Outline the conditions that favour denitrification...
• 10N.3.SL.TZ0.22b: Discuss the impact of alien species on the environment.
• 09N.3.HL.TZ0.12: Discuss international measures that would promote the conservation of fish, including methods...