Distinguish between the mass extinctions evident in the fossil record and extinctions within historic times.

Evaluate the use of models for predicting climate change.

Tundra ecosystems are vulnerable to the effects of global warming. Discuss the response of two contrasting environmental value systems to the effects of global warming on the tundra.

fossil record extinctions occurred over relatively long timescales / over thousands to hundreds of thousands of years;
present day extinctions occurring over relatively short timescales / decades/hundreds of years;
extinctions within historic period largely attributable to anthropogenic / human causes eg over hunting / habitat loss / pollution / climate change;
past mass extinctions are linked to natural causes / eg meteorite impact / ice ages / extreme volcanic activity / changes in atmospheric composition;
current extinction is being more accurately recorded whereas in the past extinctions it is hard to see/identify species from fossils;

Award [1 max] for a named example or time of a mass extinction, eg K-T boundary (dinosaurs) / Triassic / Permian / Devonian / Ordovician;

Award [1 max] for a named example of a present day organism that has gone extinct due to human causes
eg Passenger pigeon;

Award [2 max] if only the fossil extinctions or only the recent extinctions are mentioned.

[4 max]

Explanation of models:
models are simplified representations of natural systems that enable predictions for change based on pre-existing data;
climate models are mathematical formulae/computer programmes that scientists/IPCC use to predict future changes in climate based on historic climatic data; [1 max]

Strengths:
provides information/range of scenarios to policy/decision makers;
allows predictions/extrapolations to be made based on wide input of historic data;
large quantities of data (from a variety of sources) can provide statistical certainty to predictions;
can provide relatively objective information to political/emotional/contentious issues;
can lead to greater understanding of complex relationships between environmental factors;
visualizes projected effects / eg images of projected changes in global average temperatures;
shows that some regions are more vulnerable than others / eg poles might undergo higher temperature increase than the Tropics;

Limitations:
conflicting results from different models can lead to uncertainty/confusion for policy/decision makers;
…and enable politicians to pick those that are most supportive to their cause;
approximations/simplifications are necessary and lead to uncertainties;
only a few experts/not all policy/decision-makers will fully understand the statistical limitations/reliability/application of models;
data used may be inaccurate as in-depth recordings have only been made recently;
data comes from many sources and instrumentation/methodologies may not be consistent/compatible;
models generally rely on assumptions that factors will operate in the way they have historically which may not always be valid;

Appraisal: Award [1 max] for a clear appraisal that is consistent with argument of response.
eg while models have significant limitations they are the best available means of planning appropriately for the future;
eg there is so much political manipulation in the current use of models that they are of very limited value;
[5 max] if no clear appraisal regarding relative strengths or weaknesses:
[3 max] if only strengths or only limitations are discussed.

[6 max]

Award [2 max] for clear definitions of the two chosen EVS.

Definition:
eg Ecocentric viewpoint is a nature-centred viewpoint with a minimum disturbance to the natural world;
anthropocentric viewpoint is a people-centred viewpoint with strong regulations about the environment;
technocentric viewpoint is a technology centred viewpoint with a strong emphasis on scientific analysis/market structures;
(accept equivalent definitions for their chosen value systems eg. deep ecologists / soft ecologists / environmental managers / cornucopians)

Responses should identify effects of GW on the Tundra and the responses to this effect of two different value systems (eg deep ecologists / soft ecologists / environmental managers / cornucopians). Broader categories can be accepted eg ecocentrics / anthropocentrics / technocentrics), but they should not be chosen in conjunction with narrower categories that they include eg ecocentrics & deep ecologists. Other than that, any two systems can be contrasted.

Any number of relevant and appropriate responses other than those given below should be credited, but do not credit responses from more than two environmental value systems.

Effect:
Melting of permafrost would cause the biome to disappear/reduce; [1 max]
Responses:
deep ecologists would consider this unethical per se;
cornucopians would consider it a chance to implement new modes of farming;
and they may search/exploit new resources now more easily accessed;
environmental managers would enforce legislations protecting the remaining habitat;
soft ecologists would call for the local and national community to take action; [3 max]

Effect:
Loss of biodiversity through competition by invasive species better adapted to the “improved” conditions; [1 max]
Responses:
deep ecologists would object to the infringement of biorights for the displaced species;
cornucopians would be optimistic that these new conditions will offer new resources to humans;
environmental managers would call for assigning endangered status to species and implement protection plan;
soft ecologists (might collaborate with EMs) to protect species through active involvement of locals; [3 max]

Effect:
Conditions becoming warmer / growing season longer / precipitation patterns changing (less snowfall, more rainfall); [1 max]
Responses:
deep ecologists believe in intrinsic importance of any process, thus would consider such change unacceptable;
they would advocate changes/simplification of lifestyles to reduce energy consumption/global warming;
cornucopians would call for investments in technology to help people survive in such conditions;
would see opportunities for exploiting a new frontier/new resources;
environmental managers would call for compensation to those who experience adverse effects due to these changes;
soft ecologists would advocate for small-scale adjustments in human settlements and/or work conditions to alleviate any issues arising from the changed conditions; [3 max]

Effect:
rising sea level reduces available land mass/habitat leading to loss of species/biodiversity; [1 max]
Responses:
deep ecologists would deplore the loss of intrinsic value in the ecosystem/species;
environmental managers would legislate to reduce production of greenhouse gases;
they may set up reserves to protect remaining populations;
technocentrics would invest in technology to mitigate for GW;
cornucopians would oppose any restrictions of human activities leading to GW; [3 max]

Award [1 max] for an explicit and valid conclusion.
Alternative points of equivalent validity, significance and relevance to those given, should be credited.
Award [4 max] if only one EVS discussed or if EVS are incorrectly identified.
Award [4 max] if only one or no effects of global warming are identified.
Otherwise, award [7 max] for marking points above, and [1 max] for a clear conclusion.

[8 max]

The candidates could clearly show the difference between fossil extinctions and historic ones using time. Most gained at least two marks here. Getting the other two marks was dependent on how much more they wrote. If they continued writing many gave examples for each extinction period or gave the reasons for the extinctions.

The question was poorly answered by most candidates. Most did give a definition for a model but linking the strengths and weaknesses to predicting climate change was more difficult. A few candidates gained full marks but most did not as the answers were too vague, or repeated.

The candidates really struggled with this question. Very few grasped the idea of naming an effect on the tundra and then stating how contrasting environmental value systems would respond. The most common response was to define the tundra but then ignore specific effects on the tundra and name generic effects. Candidates were stronger on how ecocentrics would respond than technocentrics. Many technocentric answers indicated a lack of understanding about the value system, with comments about destroying the environment being part of this value system.