State the role of an indicator species.

Describe how ingested plastics can cause problems to marine birds.

Sea urchins are destroying the giant kelp alga (Macrocystis pyrifera) marine forests of South East Australia. Suggest a reason that sea urchins might be an invasive species in this environment.

Identify possible approaches to maintain the population of P. sandwichensis.

A retreating glacier leaves an environment of lifeless glacial deposits, including sands and gravels. Retreating glaciers often offer suitable sites for primary succession.

State one abiotic factor that will determine the type of ecosystem in a succession.

The figure below shows the effects of soil pH on nutrient availability. Thicker bars indicate higher nutrient availability.

[Source: diagram drawn from Emil Truog, 1947, The Liming of Soils, USDA Yearbook of Agriculture 1943–1947,
and N.A. Pettinger, 1935, A Useful Chart for Teaching the Relation of Soil Reaction to the Availability of Plant
Nutrients to Crops, Virginia Cooperative Extension, Virginia Tech, and Virginia State University]

Identify which element is more available in strongly acid conditions.

State two bottom-up factors affecting algal blooms.

Identify the ecosystem with the appropriate numeral from the climograph.

Explain the impact of plastic waste on Laysan albatrosses (Phoebastria immutabilis).

State which species could be found in mildly polluted water.

Explain the factors that can contribute to the exponential growth phase in a sigmoid population curve.

Identify how the pattern in mammals is different from reptiles and birds.

Distinguish between fundamental niche and realized niche.

Suggest a method to limit the impact of F. silvestris on native species.

Predict one example of macroplastic pollution that is likely to be found in this lake.

A calculation of Simpson’s reciprocal index was undertaken on each field with the following results.

Evaluate these results.

A retreating glacier leaves an environment of lifeless glacial deposits, including sands and gravels. Retreating glaciers often offer suitable sites for primary succession.

Predict the process of succession that takes place on exposed bare ground as the glacier retreats.

A retreating glacier leaves an environment of lifeless glacial deposits, including sands and gravels. Retreating glaciers often offer suitable sites for primary succession.

[Source: climatica.org.uk]

Predict the process of succession that takes place on exposed bare ground as the glacier retreats.

The sea star also eats the sea snails. Construct a food web to show the feeding relationships between these five organisms in the ecosystem.

Outline what is meant by the edge effect.

A pyramid of energy represents the amount of energy taken in by each trophic level per unit time and per unit area. Discuss the advantages and disadvantages of the use of pyramids of energy as models of energy flow in an ecosystem.

Models are used as representations of the real world. Evaluate the use of food webs to represent ecological communities.

Define invasive alien species.

The map shows an area of the Pacific Ocean characterized by exceptionally high concentrations of plastics and other debris that have been trapped by the currents of the North Pacific Gyre.

Outline one consequence of marine plastic pollution.

Outline how the data could have been obtained.

Feed conversion ratio (FCR) is the mass of animal feed in kilograms required for farmed animals to produce one kilogram of edible mass. For example, the FCR for salmon is 1.2 and for chicken is 2.2. Deduce the implication of these ratios for sustainability.

Discuss how abiotic factors can affect the distribution of species in an ecosystem.

Outline one example of mutualism.

Explain the technique used to estimate the population size of a named species of organism that is able to move.

Explain how human activities could affect the phosphorus cycle.

Barnacles are sensitive to pollution. Outline how it might be possible to use these organisms as indicator species.

E. modestus is an invasive barnacle while the others are native species. Analyse the data to show how it supports this statement.

The garden snail, Helix aspersa, is a herbivore.

[Source: Sinan Önder /https://www.pexels.com/photo/animal-close-up-crawling-garden-243128/]

Explain how the population of snails in an ecosystem could be estimated by capture-mark-release-recapture, identifying the limitations in the method.

Compare and contrast the effects of the predators on the population of the mussels.

Indicator species may be affected by biomagnification. Discuss biomagnification using a named example of a pollutant.

The graph shows how the number of ant species found on isolated islands near New Guinea depends on the size of the island.

[Source: University of Windsor, The Theory of Island Biogeography. Available at:
http://web2.uwindsor.ca/courses/biology/macisaac/55-437/lecture9.htm.]

Explain the relationship between island size and number of ant species.

The image shows a Gersmehl diagram of tropical rainforest.

[Source: © International Baccalaureate Organization 2019]

Explain what this diagram indicates about nutrients in this type of ecosystem.

Sea otters are considered keystone species in this environment. Suggest how the presence of sea otters could affect the algae population.

Explain what information a pyramid of energy provides about an ecological community.

Describe how invasive species such as F. silvestris can have a significant impact on native species.

Using one example, outline biological control of an invasive alien species.

Explain what is meant by competitive exclusion, with respect to a named example of an invasive species.

Explain the consequences of biomagnification.

Cryptococcus neoformans and the closely related species Cryptococcus gattii are human fungal pathogens. The reproduction of these yeast species on increasing concentrations of pigeon droppings (PD) was examined to determine whether they occupy the same or different ecological niches. The results for reproduction are expressed as a percentage relative to the control.

Suggest how this experiment shows that pigeon droppings represent a realized ecological niche for C. neoformans and a fundamental (but not a realized) niche for C. gattii.

Explain how the levels of the Caesium (Cs) radioisotopes could have accumulated in the tissues of these fish.

Outline a named example of the captive breeding and reintroduction of an endangered animal species. 

Describe the distribution of C. montagui and S. balanoides barnacles in Butter Lump Bay.

Explain reasons for differences in the realized niche and fundamental niche of an organism.

Suggest factors that could account for the growth curve of the M. gallopavo population.

Hunting of M. gallopavo is currently regulated. Predict what would happen if the hunting regulations were removed.

Describe the relationship between Zooxanthellae and reef-building coral species.

Discuss the causes and consequences of eutrophication.

Compare and contrast food chains and food webs.

Commercial fertilizers are often applied to agricultural land. Discuss the use of fertilizers on crops and their effect on other ecosystems.

Outline three issues arising from the release of pollutants into the environment.

Outline three ways in which a named environmental disturbance can impact an ecosystem.

Explain how pesticides may undergo biomagnification in the lake.

The diagram shows the copper concentration (μg g^–1) in the seaweed Porphyra umbilicalis collected along the shoreline in Arklow, Ireland.

[Source: reprinted by permission from Springer Nature: Helgoländer Meeresuntersuchungen,
Problems in the assessment of heavy-metal levels in estuaries and the formation of a pollution index,
D L Tomlinson, et al., 33, issue 1, pages 566–575. Copyright 1980]

Explain how the copper found in these seaweeds could affect the birds living in Arklow town.

Explain biogeographic factors that increase the effectiveness of nature reserves.

Outline a method that could have been used in this study to measure the numbers of sea urchins per 0.25 m².