Topic 1
Topic 2
Surprise!
100

Outline two historical influences on the development of the modermn environmental movement.

For example: Rachel Carson — Author of Silent Spring (1962)
• Silent Spring documented/highlighted the problems caused by the widespread use of synthetic pesticides
• focus was placed on the activities of chemical companies
• explained impact of use of insecticides/pesticides on birds of prey
• led to widespread awareness among (American) public of environmental issues/bioaccumulation/biomagnification
• was a focal point for the social/environmental movements of the 1960s
• inspired many other environmentalists
• led to ban on DDT for agricultural uses
• inspired the formation of the US Environmental Protection Agency
• any other points

For example: Fukushima Daiichi nuclear disaster of 2011
• a natural disaster/earthquake/tsunami led to the biggest nuclear disaster since Chernobyl at Fukushima Nuclear Power Plant
• estimates vary about the number of people affected by the disaster/no direct deaths initially/over 600 deaths by workers/thousands with increased risk of cancers
• as the disaster was able to happen in a “developed” country like Japan, many societies concluded that nuclear power could not be “safe”
• this has led to increased public pressure to phase out nuclear power generation – e.g., Germany sped up plans to close nuclear reactors/over 90% of Italy voted against government plans to expand nuclear power/Switzerland also decided to phase out nuclear power
• any other points

100

Food chain: 

Savanna grassland --> antelope --> lion

State the trophic level of the lion. 

Secondary consumer; third trophic level; predator

100

Distinguish between zonation and succession. 

Then distinguish between primary and secondary succession.

Succession is the process of changes in a community or ecosystem over time, whereas zonation is the process of changes over an environmental gradient or space.

Primary- new land

Secondary- climax community --> disturbance --> pioneer --> intermediate --> climax

200

Outline the distinctive features of the anthropocentric environmental value system.

  1. a human responsibility to maintain the environment;
  2. concept of stewardship;
  3. sustainable exploitation of the environment;
  4. management/supervision of human activity;
  5. imposing sustainable practices through legislation;
  6. use of incentives/disincentives to regulate exploitation (compensations/taxes/fines etc.);
  7. public debate to reach consensual resolutions/pragmatic approaches;
  8. population control is of equal importance to management of resource use;

 

Note: Allow credit for any feature that distinguishes anthropocentrism form one or more alternative value systems.
Do not credit responses implying more cornucopian values e.g. Human supremacy / dominance over environment / only concerned with human benefit.

200

What are two criteria that the IUCN uses to determine if a species is endangered?

  • Criterion A (Population Reduction): A decline of ≥50% over 10 years or three generations, or a projected/suspected decline of ≥70% if the cause isn't understood/reversible, or extreme fluctuations.
  • Criterion B (Geographic Range):
    • Extent of occurrence (EOO) < 5,000 km² and severe fragmentation or continuing decline, OR
    • Area of occupancy (AOO) < 500 km² and severe fragmentation or continuing decline.
  • Criterion C (Small Population Size & Decline): Fewer than 2,500 mature individuals and a decline of ≥20% in 5 years or two generations, OR fewer than 250 mature individuals.
  • Criterion D (Very Small Population): Fewer than 250 mature individuals (often combined with Criterion B or C).
  • Criterion E (Quantitative Analysis): A probability of extinction in the wild of ≥20% within 20 years or five generations. 

A species only needs to meet one of these criteria (and its sub-conditions) to be listed as Endangered.

200

Outline the factors that lead to different environmental value systems in contrasting cultures. What are the three EVS'?

• cultural — some cultures place a high value on nature and thus have a more ecocentric EVS
• religious — some religions deify certain organisms/landscapes and thus have a more ecocentric EVS
• economic — some would argue that more economically wealthy societies tend towards a more technocentric/anthropocentric EVS
• socio-political — some would argue that a society with a strong social political movement would tend towards a more anthropocentric EVS
• experience/history — societies that have experienced anthropogenic disasters may become more prone to adopt ecocentric value systems

300

Compare and contrast biocapacity and ecological footprint. Use "ecological overshoot" in your answer.

Biocapacity is the ecosystem’s ability to provide resources and absorb waste (supply), while the ecological footprint is the amount of resources a population uses and waste it produces (demand). 

Both use the same units, but when the footprint exceeds biocapacity, it results in ecological overshoot.

300

Outline two transfers and two transformations of energy as it enters and flows through the first trophic level of a food chain.

Transfers: [3 max]

  1. solar/light energy absorbed by leaves/chlorophyll/chloroplasts/plants;
  2. stored as chemical energy in glucose/organic compounds/ATP;
  3. chemical energy transported around plant/moved from leaves to other plant organs;
  4. chemical energy in plant biomass eaten by herbivores/passed on to decomposers
  5. heat energy radiated from plant into atmosphere; 

 Transformations: [3 max]

  1. conversion of light to chemical energy in photosynthesis;
  2. conversion of chemical to heat energy in respiration / all metabolic processes release heat (heat loss);
  3. conversion of chemical to heat energy through decomposition;
  4. conversion of chemical energy to other forms of energy (e.g. kinetic in various metabolic process;
  5. conversion of solar energy to electric energy in the photosynthetic apparatus;
300

Describe how species diversity and population size influence the resilience of an ecosystem.

greater species diversity or greater population size usually leads to greater resilience

with more species, it is more likely others can take over the role or niche of any lost or declining species

more food chains or energy or biogeochemical pathways in an ecosystem provides redundancy, therefore greater stability

a variety of species is more likely to include those resistant to environmental change

larger populations provide greater storages that can last over periods of lower productivity

larger populations generally carry greater genetic diversity

larger populations of invasive species may lead to reduced diversity or resilience

lower populations are more prone to extinction after a disturbance (e.g. habitat fragmentation) or due to stochastic fluctuations

an ecosystem may be more resilient if there are many small populations of different species than one large population of a single dominating species

large populations of foundation or keystone species may be crucial for resilience of certain ecosystems (e.g. corals, kelp, beavers, elephants, pines, hemlock)

400

Outline two inputs and two outputs of a soil system.

Inputs

  1. Dead organic matter falling from plants (leaves, fruits) / animals (dead body/tissues, manure);
  2. Inorganic material/nitrates/phosphates/nutrients from decomposition of DOM;
  3. Inorganic matter from erosion/weathering of parent material/bedrock;
  4. Water through precipitation/irrigation/infiltration/urination;
  5. Nutrient addition via anthropogenic fertilisers;
  6. Organic matter/nutrients/minerals/dust by wind/water deposition;
  7. Nitrogen fixation by soil bacteria;

    Outputs

  8. Uptake nutrients by plants;
  9. Loss of nitrogen by denitrification (to atmosphere);
  10. Loss of water by plant uptake/evapotranspiration;
  11. Loss of matter/nutrients through soil erosion by wind/water;
  12. Loss of water via surface run off/evaporation;
  13. Loss of soluble nutrients through leaching;
  14. Water drainage/percolation to groundwater storage;
  15. Emission of CO2 from respiration of soil organisms;
  16. Methane (CH4) emitted from decomposition of DOM (anaerobic methanogenic bacteria);
400

Distinguish between the role of the jaguar as a keystone species and as a flagship species.


Markscheme

Keystone species: [1 max]
apex/top predator / integral to the food web/ecosystem;
Flagship species: [1 max]
popular/charismatic image / by protecting it, will help to protect the ecosystems/habitat/other species / used to raise funds for conservation; 

Note: Do not accept descriptions of just predators e.g. ‘controls population of primary consumers / eats organisms below it in the food web’.
Do not accept ‘top of food chain / balances the food chain’.

400

Describe biotic and abiotic factors with reference to a named ecosystem.

  1. abiotic factors are non-living physical factors;
  2. named example of ecosystem involving physical factors such as temperature/sunlight/pH/salinity/precipitation etc.;
  3. biotic factors are living factors;
  4. named example of ecosystem with biotic factors such as predation/herbivory/parasitism/ mutualism/disease/competition/producers/consumers/plants/animals etc.
500

Outline four ways in which ecological footprints (EFs) vary significantly by country.


Definition of EF [1 max]:

  1. The area of land and water required to sustainably support a defined human population at a given standard of living;
  2. The measure of EF takes into account the area required to provide all the resources needed by the population and the assimilation of all wastes;

    Aspects that will decrease EF in a country;

  3. Smaller populations use fewer resources/produce less waste (for total EF);
  4. Laws/education campaigns to promote recycling/reducing waste/using fewer resources;
  5. More productive biomes can absorb more waste per km2;
  6. Culture/EVS/lifestyles that promotes sustainability will use fewer resources/produce less waste;
  7. High level of technology/resources for more sustainable energy generation/waste disposal options;
  8. Low economic means so can’t afford resources;
  9. Low levels of industrialization so fewer resources used/less waste produced;
500

Describe one advantage and one disadvantage of vegetation (i.e., forests) as a carbon sink. Draw a labelled diagram to illustrate the flows of carbon between the vegetation and the atmosphere.

Advantage: Forests absorb and store large amounts of CO₂ through photosynthesis, helping reduce atmospheric carbon levels.


Disadvantage: Forests are vulnerable to deforestation, fires, and disease, which can release stored carbon back into the atmosphere.

500

Explain two reasons why the species within pioneer communities are more likely to be r-strategists than K-strategists.

r-strategists produce greater numbers or many offspring—fast population growth

r-strategists distribute themselves more widely or colonize more quickly

r-strategists mature quickly or reproduce earlier or establish themselves faster

r-strategists are better adapted to harsh or low-nutrient conditions ore less specialized niches

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