IB ESS Exam Review Jeopardy Template

Topic 1: Foundations of ESS

Topic 2&3: Ecology & Biodiversity

Topic 4&5: Aquatic & Terrestrial Systems

Topic 6&7: Atmosphere & Climate Change

Topic 8: Humans & Resource Use

100

Distinguish between point and non-point sources of pollution with reference to named examples.

point source comes from a single source whereas non-point source comes from multiple/dispersed sources;
point sources more easily identifiable (than non-point source);
point sources are more easily managed (than non-point source);
e.g. point source such as a sewage pipe/factory smokestack/drainage ditch;
e.g. non-point source such as runoff of fertilizers and pesticides from agricultural land/soil erosion from improperly managed construction sites/oil and toxic chemicals from urban runoff/vehicle-exhaust emissions;

100

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

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

Note: Accept biome name as a named ecosystem. Examples must be given in context to the named ecosystem. Award 3 max if no ecosystem named.

100

Explain how the hydrological cycle influences climate around the Earth.

evaporation/evapotranspiration is higher at regions with higher insolation;
evaporation absorbs heat from the atmosphere (negative latent heat flux)…;
…water vapour carries (via convection currents/tropical cyclones) heat to higher latitudes/altitudes…;
…condensation of vapour releases heat (positive latent heat flux) to colder latitudes/altitudes…;
…stabilizing the heat deficit between Tropics and Poles;
condensation of vapour (as rising air cools) forms clouds…;
…leading to higher precipitation (e.g. in the Equatorial Belt) / snowfall (higher altitudes/latitudes);
oceans/inland waters effectively store heat (positive sensible heat flux) during periods of high insolation (day/summer)…;
…and release it back (negative sensible heat flux) during night/winter;
…thus ameliorating regional temperature differences (seasonal/diurnal);
overall, oceans warm the planet (by absorbing solar radiation)...;
…due to water’s high thermal capacity…;
water masses increase humidity of adjacent region (due to higher evaporation);
warm ocean currents transfer heat from equator to poles / cold ocean current absorb heat from atmosphere as they move from Poles toward Equator…;
…(warm currents) increasing temperatures in certain regions/e.g. Gulf Stream / (cold currents) decreasing temperatures in certain regions/e.g. Labrador current;
warm ocean currents also increase precipitation in coastal regions/e.g. Southwest Monsoon Current / cold ocean currents decrease precipitation in coastal regions/e.g. Peru Current…;
…(warm) due to increased evaporation during the summer (period of higher insolation)/e.g. monsoons in Bay of Bengal, which is helped by…;
…advection of vapor by prevailing onshore winds;
...(cold currents) due to cold air holding less moisture;
formation of ice / increased cloud cover increases albedo, thus may stabilize global warming (negative feedback) / reduce regional temperature;
melting of ice / reduced cloud formation decreases albedo, thus may contribute to global warming (positive feedback) / increase regional temperature;
increased evaporation may contribute to global warming, as water vapour is a greenhouse gas;
ocean acts as a carbon sink sequestering CO2, thus reducing global warming;

100

Outline the role of the greenhouse effect in regulating the temperature on Earth.

the principal greenhouse gases are carbon dioxide/CO2, methane/CH4, water vapour, nitrous oxide/N2O; (no credit for anthropogenic GHGs, like tropospheric ozone, CFCs, HFCs)
.…and are found in the troposphere;
sun light (visible/short wavelengths) pass through GHGs/reach the Earth and warm its surface;
warm Earth surface is re-radiating energy outward as infra-red radiation/heat; (no credit for “reflection” of light/heat)
GHGs are opaque to/absorb outgoing IR/long wavelength radiation;
much of the heat energy is therefore retained/raising the average temperature of the Earth surface (to 15 °C);

100

Explain how the growth in human population can affect local and regional water resources.

growing human populations result in increased need for water for domestic/drinking/cooking use;
Commercial development/industrialisation/factories increase water demand;
increasing food demand entails increased irrigation/water for crops/agriculture;
increasing populations may increase poverty and thus economic water scarcity;
areas/locations/countries that have physical water scarcity would be mostly affected;
…causing freshwater land resources (lakes, rivers) to dwindle / risking sustainability of freshwater- resources / depletion of aquifers;
…often resulting in conflict over access to water;
increased groundwater abstraction may lead to intrusion from salt water;
(increased) industrial effluents can cause water (toxic) pollution;
dam construction to meet higher demands of growing population can affect sustainability of that water source;
increasing populations can stimulate technological innovation and greater efficiency of water use / management;

200

Outline the differences between anthropocentric and technocentric value systems.

Anthropocentric [2 max]

a. Sustainable management is a duty of human societies / environmental manager;

b. Population control given equal weight to resource use;

c. Strong legal regulation by authorities / imposing environmental taxes, fees, compensations;

d. It is moral for human societies to benefit from natural capital;

e. Encourages debate to reach a consensual, pragmatic approach to solving environmental problems;

Technocentric [2 max]

f. believes technological developments can provide solutions to environmental problems;

g. provides an optimistic view of the role humans can play in improving the lot of humanity;

h. encourages scientific research in order to form policies and to understand how systems can be controlled, manipulated or changed to solve resource depletion;

i. sees a pro-growth agenda as necessary for society’s improvement / believes that economic growth can be sustained without environmental harm;

Note: any valid and exclusive characteristic of the given value system can be credited.

200

Outline how a positive feedback loop can impact an ecosystem.

positive feedback loops (destabilizing) amplify changes in an ecosystem;
feedback refers to the return of part of the output from a system as input so as to affect succeeding outputs;
this drives the system towards a tipping point where a new equilibrium is adopted;
this new equilibrium may be an alternative stable state / involve collapse of original system;
eg increased global temperatures are melting permafrost, leading to the release of methane;
...which is a greenhouse gas and leads to further increases in global temperatures;

Note: Candidates may gain full credit by illustrating the principles of positive feedback by means of a diagram or well-developed example. Credit should be allowed for this.

200

Explain how the process of succession leads to changes in productivity.

General:

GPP continues to increase throughout the successional stages due to increasing nutrient cycling / improved soil fertility/nutrients leads to greater productivity;
NP as a proportion of GP decreases throughout the stages due to increasing respiration from consumers/decomposers;

In primary succession/pioneer community:
Abiotic conditions are poor/nutrient levels are low so GPP is low;
NP of the community is high/NP as a proportion of the GP is high due to low consumption/respiration;

In intermediate stages:
Secondary productivity increases as consumers join food chain;
NP/increase in biomass of entire community slows due to consumption of GPP/increased respiratory losses by consumers;

In climax community/final stages:
Secondary productivity is at maximum as food chains are fully developed;
GPP is at maximum due to plant communities reaching carrying capacity;
No NP/biomass gains for community as a whole as all PP being consumed/lost to respiration

200

Outline the role of the atmospheric system in the distribution of biomes.

atmospheric/tri-cellular circulation (including Hadley, Ferrel & polar cells) creates patterns of climate that determine dominant vegetation types;
low pressure due to intense heating/high insolation at the equator causes / rising moist air in the tropics creates high precipitation giving rise to rainforests;
moving polewards (at high altitude), air cools, becomes denser and sinks forming a high-pressure zone / descending/dry air (20–30° latitude/tropics) creates water-limiting/arid conditions giving rise to deserts;
some of the air continues towards the poles to equalize temperature difference / atmosphere transfers heat from (sub-)tropics to mid-latitudes giving rise to temperate biomes;
descending/dry air (high latitude/polar regions) creates water-limiting conditions in tundra;
water vapour (from mid-latitudes/temperate regions) is transferred to high latitudes giving rise to heavy precipitation/snow in boreal forest;
water vapour is transferred from ocean surfaces overland generating freshwater aquatic systems;
prevailing winds/jet streams (blowing from high to low pressure) bring precipitation to a region, e.g. temperate rainforest in mountainous region/riverine/water-margin systems;
rain shadow effect of high mountains causes dry winds in the leeward side, resulting in arid or semi-arid biomes (e.g. Tibetan Plateau, Mongolian Gobi desert and steppes);
atmosphere may be responsible for shifting biomes due to global warming/climate change;

200

Evaluate the effectiveness of recycling as a waste management strategy

Effective [2 max]:

reduces waste going to landfill / reduces need for more land for landfill;
reduction in GHG/methane from landfill;
reduces need for incineration which adds to London’s air pollution;
reduces demand for extraction of new resources/reduces EF;
can contribute to green markets and create jobs;

Note: Do not accept only ‘reduces waste / less waste going into the environment (e.g. rivers/oceans)’.

Ineffective [2 max]:
currently a relatively low rate of recycling / not everyone is recycling effectively / requires change in lifestyle/behaviour / difficult to change behaviour;
recycling schemes can be quite expensive;
there may be a lack of recycling companies;
not all waste can be recycled;
recycling centres may need to be located outside the city (due to lack of available land), thereby increasing traffic/transport costs / recycling centres need infrastructure which may take up land (green space);
recycling (is end of pipe measure that) does not tackle problem of high waste production/over-exploitation of resources/over-consumption/consumerism;

Conclusion [1 max] needs to be balanced considering both sides of the argument for credit.

300

Outline two ecosystem services in a named biome.

Examples may include:

Tundra:
permafrost/glaciers in tundra;
…provides important storage in hydrological cycle;
ice in tundra provides reflective surface/increases planetary albedo;
…thus moderating global temperatures;
Wetlands:
decomposers/high productivity in swamps/wetlands;
…provides filtration of inorganic nutrients / water purification;
storage of water in wetlands;
…prevents flooding / provides ideal resting grounds for migratory birds;
Tropical rainforests:
high biodiversity in TRF;
…promotes ecotourism/recreation;
high rate of photosynthesis in TRF;
…maintains balance of O2/CO2 in atmosphere;
Boreal/temperate forests:
tree populations in boreal/temperate forests;
…prevent soil erosion on mountainsides;
forest canopies in forests;
…provide shade/shelter/habitat for diversity of species.

Note: Numerous valid examples can be credited, but to gain full credit (2 marks per service) candidates must identify relevant component of biome [1 mark] and outline the service it provides [1 mark] as in MPs above.
Be careful only to credit “services” (maintenance/establishment of favourable conditions) and not “goods” (consumable/harvestable/physical products).

Award [2 max] if no biome is identified. If more than one biome is given, credit only highest scoring biome addressed.

300

Explain how the shape of a population growth curve for a prey species may be influenced by the presence of a predator species.

Predation will lower growth rate...
...by increasing prey death rate / by reducing prey birth rate (includes egg predation);
Prey curve would flatten out sooner / become S-curve sooner…;
…as predation is a density-dependent limiting factor / adds to environmental resistance…;
…reducing prey carrying capacity;
Prey population number would decline…;
…leading to decline of predator population…;
…which would allow prey numbers to re-bound / prey growth rate bounce back;
…prey curve oscillate around carrying capacity / prey population be regulated by negative feedback / Lotka-Volterra/predator-prey system cycling;
Predation may prevent prey population crash (at overcrowded conditions)...;
...as predation would relax prey intraspecific competition;

300

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

Transfers: [3 max]

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

Transformations: [3 max]

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

Do not credit reflection of light (albedo), as energy does not enter 1st trophic level.

300

Outline the albedo effect and its role in regulating the Earth’s global temperature.

albedo is a measure of the reflectiveness of a surface / is greater from lighter-colored/smoother surfaces;
high albedo means that solar radiation is reflected away from a surface/reducing temperature / low albedo means that solar radiation is absorbed by a surface/increasing temperature;
oceans/ice/clouds contribute significantly to Earth’s albedo;
the balance between the albedo of the Earth’s surfaces involves feedback loops;
negative feedback loops reduce change (retain the balance in ratio of albedo) and maintain the global temperature;
e.g. rise of global temperature → increased evaporation → increased cloud cover → increased albedo and reflection of solar radiation → decrease in global temperature;
a change in the balance can result in a positive feedback loop which amplifies changes and results in a rise in the Earth’s global temperature;
e.g. rise in global temperature → increase melting in ice caps → decrease in albedo → increase in solar radiation absorption → rise in global temperature;

Note: Accept alternative feedback loops.

300

Outline how the ecological footprint (EF) of a human population is likely to change through the stages of the demographic transition model (DTM).

EF is likely to start off very small because of low population;
Footprint will be low because of subsistence food production/hunter/gathering;
It will then increase with increasing numbers/consumption/development of agriculture;
With industrialisation/commercialisation footprint is likely to increase with heavy use of fossil fuels;
Development of technology for alternative energy resources may reduce footprint;
Technological development in food production/transport may come to reduce footprint;
Reduced population growth/declining populations in MEDCs may tend to reduce overall footprint;
However, if greater consumerism/materialism/economic growth is still pursued footprint may continue to increase / per capita footprint increases can negate effects of decreased population;

400

Outline how the ecological footprint (EF) of a country can be measured.

EF is the area of land and water required to sustainably provide all resources at the rate at which they are being consumed by a given population;
find total amount of waste produced from food production/domestic activities;
find the total amount of food consumed;
find the total amount of water consumed by the population;
find the total amount of energy consumed / carbon (dioxide) emissions;
find the mean rate of productivity of local vegetation;
find the total availability of local water supply;
calculate the area of local vegetation/land required to absorb all waste and produce all food / (annual) total consumption rate plus waste emission rate divided by (annual) land productivity;
(If per capita rates are initially measured then) multiply per capita EF with population size;

400

Outline the mechanisms by which a terrestrial species may have evolved from an aquatic ancestor.

there was genetic variety in aquatic species / mutations accumulated over years;
certain features may have adaptation/advantage for terrestrial existence;
individuals with these features could colonize terrestrial habitat;
they would be more likely to survive/survival of the fittest/experience less competition (natural selection);
they produce offspring like themselves/feature will become more abundant;
individuals with feature may be unable to breed with others without feature/speciation occurs / reproductive/geographical barrier will give rise to new terrestrial species;

400

Outline two input processes and two output processes that occur to and from the soil system.

Inputs; [2 max]

water is added through precipitation/infiltration;
humus/detritus/organic molecules are added through leaf fall/death of organisms;
minerals are added when they dissolve in precipitation/percolating water;
minerals are added through weathering of parent rock;
usable nitrogen/nitrates/ammonia is added through nitrogen fixation/nitrification;

Outputs: [2 max]
water is lost through evaporation/plant uptake;
minerals are lost through leaching;
soil/minerals/nutrients lost through wind/water erosion;
minerals are taken up/absorbed by plants;
nitrates are converted/lost to nitrogen gas (by bacteria) through denitrification;

400

Explain the causes and effects of acid deposition on natural ecosystems.

Causes:
burning of fossil fuels releases NOx/SOx;
the sources of these are mainly coal-burning industries/transportation/electricity generation;
emissions from livestock/use & production of inorganic fertilizers also contribute;
volcanic eruptions can also cause acid rain/release oxides of N/S;
NOx/SOx react with water to form acid deposition;
this acid may be deposited locally as dry deposition or dissolve in air moisture and reach ground by wet precipitation;
nitrous oxides produce nitric acid / sulphur oxides produce sulphuric acid;
wind may carry primary pollutants causing ecological damage to be widespread.

Effects:
direct adverse effect of acidity on living organisms eg kills lichens / plankton / fish / soil microbiota;
causing leaf-fall/thinning of waxy cuticle/reduced immunity to disease/root damage in terrestrial plants;
leading to reduced primary production/plant growth;
indirect toxic effect by changing chemistry of soil/water;
eg increased solubility/leaching of plant nutrients/reduced soil fertility;
eg increased solubility/release of toxic metals/aluminium damaging fish/plants;
such toxic metals might undergo bioconcentration/biomagnification;
overall, may therefore cause loss of biodiversity/reduction in food chains/webs etc.

Note: Do not credit biomagnification except in the explicit context of releasing heavy metals. And do not credit impacts of ocean acidification or impacts on limestone/urban infrastructure which are beyond the limits of this question.
Award [5 max] if either causes or effects are not included in response.

400

Using examples, evaluate two solid domestic waste disposal strategies as methods to mitigate climate change.

Strategy:

increased reusing/recycling/reduction of resource use;

Advantage:
recycling/reducing/reusing prevents release of GHGs through landfill/incineration;
recycling/reducing/reusing prevents release of GHGs in production of further materials;

Disadvantage:
involves sorting and transportation costs;
requires challenging behavioural changes;

Strategy:
incineration / use for energy production / combustion/oxidation of methane;

Advantage:
waste can be used to produce heat or electricity / this could replace the energy produced using coal or other fuels;
CO2 produced has lower greenhouse equivalent than methane;

Disadvantage:
there is some air pollution associated with incineration;
reduction in local property value/peoples’ negative perception;

Strategy:
collection of methane from landfills;

Advantage:
Can be burnt as fuel (CO2 has lower greenhouse equivalent);

Disadvantage:
requires sophisticated equipment not accessible to LEDCs;
would promote further use of landfills instead of decommissioning;

Strategy:
composting;

Advantage:
replacing production of inorganic/artificial fertilizers which contributes to climate change;

Disadvantage:
sorting costs;
produces methane;

Note: Award [4] max per waste disposal option (1 max for named strategy, 2 max for advantage, 2 max for disadvantage) Credit can be given for just naming a strategy (i.e. recycling/incineration/composting) but no credit for ‘landfills’ unless methane collection is added.

500

Evaluate the use of an environmental impact assessment (EIA) to ensure the sustainability of a new development project.

Definition [1 max]

sustainability is the use and management of resources that allows full natural replacement of the resources exploited / full recovery of the ecosystems affected by their extraction and use / so that future generations may also use them;

Pros [4 max]

a. EIA provides to decision-makers the relevant information on the current situation (baseline study);
b. identifies/predicts the possible environmental impact before the onset of a project;
c. suggests the possible management strategies that would mitigate/prevent any adverse effects of a project;
d. holds policy-makers/entrepreneurs accountable for any decision they will eventually make (in follow-up assessment);
e. takes into consideration social and economic impacts as well/e.g. social acceptance, deterioration of property value/life quality;
f. may be effective in stopping a potentially harmful project;

Cons [4 max]

g. may not prevent the implementation of a project, even if it has severe negative impacts;
h. requires technical expertise that might not be available in all countries/situations;
i. if funded by the enterprise developing the project, it might be biased;
j. in most countries, the legal/regulatory framework is not well established / lack of standards/official training for practitioners;
k. some environmental factors/impacts may not be readily quantified / e.g. life/landscape quality / may fail to properly study some environmental factors;
l. may not include socio-economic impacts;
m. it may be more profitable for an enterprise to pay a fine for ignoring EIA’s precautions;
n. may delay the implementation of a project due to time consuming procedure.

Conclusion [1 max]

Despite the shortcomings of an EIA, becoming a legal requirement for major projects has reduced the adverse environmental impacts/resulted in higher social responsibility of enterprises / Even a “perfectly” implemented EIA may not guarantee the future sustainability of a project, as environmental conditions may change (e.g. climate change).

500

Explain the ways in which species diversity and an abundance of plant and herbivore species will increase the resilience of an ecosystem.

Diversity:

a greater diversity of plant and herbivore species would mean there are more species to take over the role of any that would be lost/creates a more complex food web;
a wider variety/diversity set of plant species will support a wider range of herbivores/increase habitat diversity;
a wider variety/diversity of plant species will be able to exploit a wider range of abiotic conditions;
more plant species/greater plant diversity will be more likely to include species that will survive a change in conditions;
a wider variety/diversity plant species will increase interspecific competition resulting in evolution of more species;
a wider variety/diversity of herbivorous species will support a wider range of predators;
a wider variety/diversity of herbivore species will occupy a wider range of niches adding to the complexity of the system;

Abundance:
a greater abundance/larger populations of plant species means greater primary productivity which supports a greater abundance/larger populations of herbivores;
a greater abundance/larger populations of plant species is less likely to become extinct from the ecosystem;
a greater abundance/larger populations of herbivores will support a greater abundance/larger populations of predators;
a greater abundance/larger populations of herbivores will be less likely to become extinct in the ecosystem;

500

Evaluate management strategies for reducing the impact of agricultural pollution on an aquatic ecosystem.

Answers may demonstrate:

understanding concepts & terminology of agricultural pollution; inorganic fertilizers; organic run-off/slurry; persistent pesticides; biomagnification; erosion; spraying; biological control; buffer zones; organic fertilizers; eutrophication; mud-pumping; re-introduction of aquatic species; levels of pollution management etc.
breadth in addressing and linking different forms of agricultural pollutants with effective management strategies to protect or clean-up different aquatic ecosystems.
examples of different pollutants; agricultural practices; management strategies; aquatic systems etc.
balanced analysis evaluating advantages and disadvantages of management strategies employed to reduce impacts of agricultural pollution.
a conclusion that is consistent with, and supported by analysis and examples given e.g. The most effective management strategies are those that prevent pollutants being released in the first place e.g. replacing inorganic with organic fertilizers, but this is not always the most economically feasible for farmers.

500

To what extent are food production systems impacted by anthropogenic (human-caused) changes to the atmosphere?

Answers may include:

understanding concepts and terminology of food production systems; subsistence; commercial; intensive; extensive; terrestrial; aquatic; acid rain; global warming; climate change; precipitation patterns; hazardous weather events; inundation; ocean acidification; ozone depletion; tropospheric ozone; photochemical smog;
breadth in addressing and linking a wide range of anthropogenic impacts on the atmosphere’s composition and temperature with their associated impacts (both positive and negative) on a wide range of food production systems in different environments/regions.
examples of named impacts on named food production systems in named locations and societies due to named anthropogenic influences on the atmosphere.
balanced analysis evaluating the extent to which anthropogenic impacts on the atmosphere do or do not influence food production systems either positively or negatively.
a conclusion that is consistent with and supported by analysis and examples given, e.g. There are a wide range of anthropogenic influences on the atmosphere that impact both terrestrial and aquatic food production systems and although some impacts may positively affect productivity, the great majority tend to reduce it.

500

To what extent is the use of solid domestic waste (SDW) as an energy source beneficial to a society?

Answers may include:

understanding concepts and terminology types and sources of SDW; increasing trend (overpopulation); consumerism; methods of SDW disposal (landfill, incineration, recycling, composting); strategies for managing SDW including zero-waste programmes; energy production, e.g. trash to energy systems; environmental indicators; sustainability; pollution – air, atmosphere, water;
breadth in addressing and linking disposal of SDW to climate change and pollution; impact on resource use and exploitation; perspectives from EVSs; range of perspectives from a societal and cultural angle; differences due to development level; energy security;
examples could include different countries’ strategies; examples of sustainability plans for cities; examples of impact of incineration or landfills; examples of climate change goals and integration;
balanced analysis could include a range of societies challenges; a variety of perspectives from an EVS angle; contradiction of energy production needs and reduction of resource use; contrast of MEDCs to LEDCs;
a conclusion that is consistent with, and supported by, analysis and examples given e.g. the use of SDW as an energy source can be very beneficial for a city in reducing its waste disposal needs and greenhouse gas emissions however it can lead to a reduction in impetus to reduce waste production and therefore resource use as the society becomes dependent on the waste as an energy source;