Topics 1 & 2
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
State two factors that are used to determine the conservation status of a species.
population size
rate of pop increase or decrease
degree of specialization
distribution
reproductive potential and behaviour
geographic range
habitat quality/fragmentation
trophic level
probability of extinction
State one transfer of matter occurring within the soil profile.
biological mixing by soil animals/earthworms
leaching or seepage
capillary action
drainage
percolation
infiltration
eluviation
absorption of minerals or water by living organisms
State a greenhouse gas other than CO2
Methane, water vapour, nitrous oxide, tropospheric ozone, CFCs, HCFCs or HFCs.
When measuring levels of pollution, state one advantage and disadvantage of using a biotic index compared with measuring the pollutants directly.
Advantage of using a biotic index:
• It shows the overall effect of pollution on the ecosystem, not just the concentration of one pollutant.
(Other acceptable answers: inexpensive, easy to collect data, indicates long-term/ cumulative pollution, organisms integrate effects over time.)
Disadvantage of using a biotic index:
• It may be less precise because species presence/absence can be influenced by factors other than pollution (e.g., temperature, flow rate, habitat).
(Other acceptable answers: requires taxonomic expertise, slower response time, does not identify the specific pollutant.)
Outline two historical influences on the development of the modern 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
Define habitat diversity, genetic diversity, and biodiversity.
Habitat diversity is the range of different habitats per unit area in a particular ecosystem or biome.
Genetic diversity is the range of genetic material present in a gene pool or population of a species.
Biodiversity is a broad concept encompassing the total diversity of living systems. Biodiversity includes the species, habitat and genetic diversity within an area. Biodiversity can also be defined as the amount of biological diversity per unit area.
Outline two conservation methods that could be used to reduce soil erosion.
contour ploughing with furrows following the contour lines/at right angles to the slope/to reduce run-off
terrace farming forms a series of steps in the hillside area/to prevent run-off
maintaining cover crops/plant roots/stubble/mixed agriculture/agroforestry to hold soil in place between harvesting
mulching consists of applying organic material over the exposed soil / preventing surface run-off
buffer strips/vegetative areas by watercourses to reduce run-off/water erosion
adding soil conditioners/lime/humus/organic material/fertilizers to increase root growth/hold soil together
wind reduction techniques, e.g. wind/shelter breaks to prevent wind erosion
avoid overgrazing/over-cropping/monoculture which degrades soil texture
zero/minimum tillage reduces soil agitation/potential for erosion
trickle/drip irrigation reduces run-off causing erosion
State two factors necessary for the chemical
formation of ozone in the troposphere.
Sunlight/UV light; and NOx/oxygen (atoms/ free radicals/molecules)/hydrocarbons/VOCs.
Identify two possible human influences, not related to climate change, that may cause the changes in water scarcity predicted for 2025.
Over-extraction of freshwater for agriculture, industry, or domestic use, reducing available groundwater and surface water supplies.
Pollution of freshwater sources (e.g., agricultural runoff, industrial waste, sewage), making water unsafe for use and effectively decreasing usable water availability.
Other acceptable answers include:
• population growth increasing demand for water
• poor water management or inefficient irrigation systems
• deforestation reducing infiltration and groundwater recharge
• construction of dams diverting water away from downstream users
• urbanization increasing water consumption and reducing natural recharge
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
Outline two ecosystem services in a named biome.
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 tropical rainforests…
...promotes ecotourism/recreation
high rate of photosynthesis in tropical rainforests…
...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
Compare and contrast the impact of two named food production systems on climate change.
Named food production system with description (e.g. Iowa corn production in mid-west USA is highly intensive, relying upon large machinery and inorganic nitrogen fertilizers); (e.g. rice-fish farming in China is a low-intensity system managed by human labour, with few chemical inputs).
Use of machinery vs human labour, dependency on fossil fuels; use of organic vs inorganic fertilizers, intensive energy needs of production of inorganic fertilizers/NOx released from use of inorganic fertilizers; animal vs plant production, animals require more land use due to position in food chain; types of greenhouse gases produced, e.g. both rice and animal production produce methane.
E.g. case study: Rice-fish farming in Thailand vs cattle farming in US. Both rice and cattle produce methane, a greenhouse gas. Inorganic fertilizers used in cattle farming release nitrogen oxides into atmosphere. Rice is fertilized naturally from fish faeces so has no direct impact on climate change. Cattle farming involves use of heavy machinery / fossil fuels not used in rice-fish farming. Rice farming produces food at lower trophic level so absorbs carbon dioxide.
Outline why the Montreal Protocol may be considered the world’s most successful environmental treaty.
clear evidence of successful reduction in CFC use/ozone depletion/size of ozone hole
protocol prompted production of alternatives to replace CFCs allowing smooth phase-out
financial assistance was offered to assist in phase out of CFCs (Multilateral Fund)
demonstrated it was possible for governments to work multilaterally
led to changes in the behaviour of individuals and societies
very large number of signatories
secured binding environmental agreements/legal commitments with which countries/industries complied
there was a widespread/common acceptance/understanding of the effect of CFCs (among scientists/public/politicians)
ldentify two potential impacts of improved air quality on London and its population.
reduction in number of deaths due to air pollution / increase in life expectancy
reduction in asthma/chronic bronchitis/respiratory ailments/lung disease/reduction in heart disease
reduction in eye irritation/eye disease
reduction in healthcare costs
reduced heat island effect
reduced damage to buildings/monuments
reduced costs due to damage to monuments
reduction in damage to plant tissue / increase in photosynthesis/plant growth/primary productivity
increase in species diversity as high pollution levels have a detrimental effect on some species
improves visibility in absence of smog/particulate pollution
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)
Briefly describe a named protected area or nature reserve that you have studied and explain how it has been managed to protect its biodiversity.
Cocos Island, Costa Rica
protected areas may prohibit human activities which damage the habitat/threaten species (e.g. urban development/hunting) / protected areas provide a safe place/habitat for species to live
increase in size/number/coverage of protected areas may lead to:
more habitats protected/covered / more species are conserved
better support for higher trophic levels/top carnivores
increased distance from human activities/impacts / reduced edge effects
more genetic mixing/formation of corridors / increased chance of connecting corridors between the protected areas
(more people living close to protected areas leading to) greater engagement in conservation efforts / more local communities being involved in conservation / greater community involvement through education/raising awareness/greater familiarity
more opportunity for ecotourism which encourages continued/further conservation/financial investment into conservation
more financial support for conservation
any other points
Identify one climatic and one edaphic (soil) factor which affect the final climax community in an ecosystem.
Climatic:
amount of precipitation / insolation / (mean) temperature
limit primary productivity/rate of photosynthesis that will determine the available
biomass/food base/on which climax community will depend
Edaphic:
soil depth
mineral content/amount of N/P/K
soil compaction/aeration
soil particle size
balance between clay, silt and sand
percolation rate
soil pH
determine the particular vegetation types/plant species adapted to those
conditions that support the climax community
Identify one reduction strategy that the USA might use to achieve its projected change in CO2 emissions.
reduction of energy consumption/CO2 production through laws/taxes/education
use of alternatives to fossil fuels
CO2 removal though CCS
afforestation / reducing rates of deforestation
Describe four ways in which urbanization may influence processes in the hydrological cycle.
urban (paved) surfaces/reduced veg cover will lead to increase in run-off
…and thus increase stream-flow/flooding
urban (paved) surfaces/reduced veg cover will reduce infiltration of water into soils
…and thus reduce inputs to groundwater/aquifers/water table level
urbanization can increase heat/local temperature leading to greater evaporation/downwind precipitation
urbanization will reduce vegetation cover and thus reduce evapotranspiration/regional precipitation
urbanization will increase local water extraction reducing river flows/increasing outputs from groundwater storages/aquifers
urbanization may lead to increased emission of greenhouse gases/global warming /climate change that may result in multitude of changes in hydrological cycle e.g. increased melting of glaciers/shifting precipitation patterns/increased evaporation etc.
urbanization may lead to increased emissions of NOx/SOx leading to acid precipitation
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
Explain the causes, and the possible consequences, of the loss of a named critically endangered species.
Possible causes
habitat loss / deforestation
habitat degradation / pollution
narrowly distributed / endemic
poaching / overhunting
illegal trafficking of species
disease
small population size/gene pool / inbreeding
specialized niche
slow reproduction rate / specialized reproductive behaviour; high trophic level/top predator
low/negative cultural value
influence/competition/predation from invasive species
Possible consequences [4 max] include:
loss of an aesthetically attractive organism
loss of ethically significant life / breach of biorights
loss of biodiversity
increase in organisms upon which the species fed or competed with
decline in other organisms due to loss of food source
if keystone species, widespread impacts/cascade effects on food chains/ecosystem; economic costs from loss of ecosystem services provided by the species
economic costs from loss of tourism opportunities
social impacts on local culture as important/significant cultural loss
any other points
Explain two examples of soil degradation and the appropriate soil management strategies from a named farming system.
Named farming system: e.g. intensive corn (Zea mais) farming in Mid-West of USA.
Degradation + strategy: soil compaction managed by addition of organic matter/manure / reduced tillage.
Degradation: compaction leads to reduced drainage/oxygen levels in soil which reduces; ability of roots/crop to grow (and support crop).
Strategy: organic matter enhances the soil ecosystem which helps aerate soil / reduced tillage allows soil ecosystem to recover and aerate soil.
Degradation + Strategy: toxification of soil managed by reduced use of inorganic fertilizers/pesticides / bioremediation.
Degradation: excess use of liquid ammonia/fertilizers / pesticides can reduce range of soil microorganisms able to live.
Strategy: reduced use of chemical additives allows soil ecosystem to recover and provide ecosystem service of nitrogen fixation.
Degradation + Strategy: acidification of soil managed by addition of lime.
Degradation: acid precipitation in areas with soils that are naturally acidic, can quickly acidify the soil beyond normal levels.
Strategy: lime neutralizes the acid pH of the soil.
Degradation + Strategy: waterlogging of soil managed by addition of organic matter/sand/drainage systems.
Degradation: reduced organic content through overharvesting / elevated water table through over-irrigation / lack of use of organic fertilizers.
Strategy: improve soil drainage through addition of organic matter/drainage ditches/sub-surface pipes.
Degradation + Strategy: soil run-off/erosion managed by maintained plant cover all year / reduced grazing / wind breaks/stone walls / contour terracing/ploughing.
Degradation: caused by soil compaction / overgrazing / leaving land bare means soil may blow away in wind or wash away with rain.
Strategy: plant cover/reduced grazing/windbreaks/contour ploughing reduces ability of wind/rain to erode soil.
In 2016, the Earth’s atmospheric levels of carbon dioxide reached 400 ppm. Suggest the potential impacts of high levels of greenhouse gases on human societies in different locations.
increased mean global temperature causing increased use of A/Cs (especially in developed countries).
greater frequency/intensity of extreme weather events causing damage to infrastructure (especially in cities).
long-term changes in climate/weather patterns requiring cultural changes/adaptation in societies.
ocean acidification killing plankton/reducing fisheries (especially significant for coastal populations).
melting permafrost increasing productivity/arable land/water availability (for tundra populations).
decreased water availability/desertification leading to migration/relocation (especially for tropical populations).
biome shifts reducing/enhancing crop productivity (especially significant in crop-growing areas).
biodiversity loss reducing aesthetic value of ecosystems (significant for tourism-dependent societies).
disruption of ecosystem services causing increased flooding (particularly in high rainfall locations).
rise in sea level causing coastal erosion (especially significant to areas dependent on coastal tourism).
coastal inundation causing salinization of underground aquifers/soils (especially for coastal populations).
wider spread of tropical diseases (especially significant for previously sub-tropical areas).
Urban air pollution can become a problem as human populations develop. Evaluate urban air pollution management strategies at the three levels of intervention.
Level 1—altering human activity:
reducing transport e.g. promoting public transport/carpooling/regulating private vehicle use
using alternative/renewable energy sources / promoting availability of electric vehicles
development/use of more energy efficient appliances/housing / green architecture
Evaluations:
large investment required to facilitate public transport use/e-vehicle use
if electricity for transport comes from fossil fuels then simply moving the problem somewhere else
requires education/campaigns to overcome human intransigence to changing behaviours
prevents pollution right at source
Level 2—controlling release of pollutant:
use of catalytic converters on transport
use of scrubbers on industries
introduce legislation/regulation/for emissions/pollutant levels
Evaluations:
technological fixes can be very effective/easy to enforce
wealthy companies may simply budget for fines and continue to pollute
does not require change in human activities
Level 3—clean-up and restoration of damaged systems:
re-greening areas through tree planting/town parkland
liming of acidified urban water bodies
restoration of eroded architecture
medical treatments for consequent health conditions
Evaluations:
helps to maintain biodiversity/aesthetic value
only of short-term value / does not prevent ongoing damage to systems
can be very expensive processes