Past paper notes

Question 1

identify some factors which may lad to an increase in water stress?

Answer 1

More affluent lifestyles such as more meant consumption and privet pools.

more intensive agreculture

increased population, and more water consumption per capita.

Question 2

for a 9 marker, what are some things you are going to want to keep in mind for the main body?

Answer 2

Using ESS terminology is key. Brainstorm terminology that will relate to the issue you are addressing.

Where does the point you make exist, not just between different economic classifications but in different ecosystems too.

Then when you have done that, consider the validity and relevance of it in different locations.

Examples are key.

Question 3

for a 9 marker, what is a good way to substantiate your conclusion?

Answer 3

Linking it back to the environmental value systems, as to who your conclusion applies and whether there are any exceptions to it.

Question 4

identify four ways in which solar energy reaching vegetation may be lost from an ecosystem before it contributes to the biomass of herbivores?

Answer 4

The plant could die and the energy is consumed by decomposers instead of herbivores.

The organic energy the solar energy is turned into through photosynthesis could be used for respiration and turned into heat which is re-emitted into the atmosphere.

Eaten by herbivor but not contributing to biomass, lost in faeces.

Solar energy is reflected by the leaf surface.

Question 5

When looking at concepts that messure biotic factors such as net producvity, what is somthing to keep in mind?

Answer 5

that is does not measure abiotic factors.

Question 6

Identify four characteristics of ecosystems that contribute to their resiliance?

Answer 6

biodiversity, a later stage in succession, well developed food webs, steady state equilibrium.

Question 7

what are three positive feedback loops which can be observed during the process of eutrophication?

Answer 7

excess input of nitrates/phosphates lead to rapid angle growth, this also means rapid turnover/ death rate of algae. They die and their decomposition releases more nitrates and phosphates.

Rapid algae growth reduces the light penetration and causes death of macrophytes. This means there is less shelter from predation for zooplankton which consume algae, and hence more algae growth.

Reduction in oxygen production from death of macrophytes causes the death of animals, death increases decomposition, decomposition produces oxygen levels more and kills more macrophytes.

Question 8

what are some methods to manage eutrophication?

Answer 8

Point source or non point source, organic or inorganic fertilisers, Education campaigns, buffer zones, waste/ sewage management. Phosphate free detergents. Domestic and agricultural waste.

Question 9

The soil systems include stores of inorganic nutrients, and identify two inputs to these storages and two outputs.

Answer 9

Inputs: decomposition recesses phosphates which are inorganic.
Weathering of parent rock
Fertiliser use

outputs:
Absorption by plants
Leaching

Question 10

what are some products that have toxic substances that come from SDW?

Answer 10

Battaries, flourecent lamps, tyres and cams

Question 11

what are some ways to manage SDW in order to conserve environments?

Answer 11

Recycling/re-use

reduction

promoting selective consumerism to want eco-friendly substances

collecting SDW in appropriate collection facilities

incineration

landfills with effective lining

sorting waste before entry to landfill

deep well injections.

Question 12

what is the pattern that has been occurring in the atmosphere that you will want to outline when addressing the atmosphere is a long answer question?

Answer 12

Stratospheric ozone has decreased and the production of tropospheric ozone has increased.

Question 13

how has the decrease in stratospheric zone affected biodiversity?

Answer 13

more UV reaches earth

which cuases mutations in DNA and cancer

possibly resulting in the death of organisms

also reduces plant growth by dmaging chlorophyll

affecting popualtions along the food chain.

Question 14

how has the increase in tropospheric ozone affected biodiversity?

Answer 14

in urban areas, it gives rise to photochemical smogs
that are toxic to humans and other organisms

also damages plan leaves reducing NPP of ecosystems

tropospheric ozone in a GHG contributing to global warming

resulting in the reduction of biodiversity.

Question 15

what are some factors which increase the resilience of an ecosystem?

Answer 15

greater genetic diversity

more complex food webs

establishment of keystone species

the larger size of the ecosystem increases resilience

strong negative feedback loops

a steady state equilibrium as in climax communities

Question 16

what are some components that illustrate that a forest is a system?

Answer 16

individuals of trees are the component of the system

these components are interdependent

it has flows/transfers of matter and energy between storages.

components carry out transformations
e.g photosynthesis/ respiration

it is an open system exchanging matter and energy with surroundings.
e.g absorbtion of solar energy

it has feedback mechanises to maintain equilibrium.

Question 17

What are the ways you can estimate the abundance of organisms in an ecosystem?

Answer 17

quadrats can be used for the sampling of organisms on the ground
need to be randomly distributed with in area

totals estimated by multiplying mean of sales by total area

mark-realise- recapture/ lincoln index
individuals can be caught using your traps.

bird populations can be estimated by aerial photography or bird song recordings

bars and histograms proportional to the total population are to be drawn.

Question 18

with refrence to named examples, distingush between a primary and secondary pollutant?

Answer 18

A primary pollutant, such as oil from an oil spill, is a pollutant that is active immediately as it is released into the environment, and directly impacts that environment. Oil spills suffocate fish and other marine organisms. A secondary pollutant is a substance, such as oxygen molecule, which undergoes chemical reaction, such as being exposed to UV, to become a pollutant, in this case, tropospheric ozone.

Question 19

what are some extra things to think about when looking at organic waste and differentiating its affects in a terrestrial ecosystem vs an aquatic one?

Answer 19

On land, organic waste, such as cattle manure or compost, releases nitrates and phosphates and other nutrients when it decomposes and therefore acts as a fertiliser. It is similar to the natural organic waste in a terrestrial system so may not be a pollutant.

Organic waste, from agricultural runoff or domestic sewage can be discharged into aquatic systems. Increases turbidity and reduces the light penetration, reducing PP. Its decomposition requires high BOD, reducing Co2 availability which negatively impacts aquatic life.

Organic waste may contain some substances which should not be consumed by aquatic organisms and leads to their death if they do. Organic waste will become dispersed in the water and may suffocate some fish. Can pollute drinking water sources for humans and animals.

Question 20

with reference to hydropower, explain why this renewable resource may not be sustanible?

Answer 20

hydropower is renewable because the water flow is replenished by the water cycle (this is bringing the question out, which gets you a mark).

building of dams will inhibit the migration of fish reducing their populations.

involve the use of non-renewable building materials

construction/maintenance involves heavy use of fossil fuels/GHG

reduced downstream flow through riverine populations

the reduced downstream flow will threaten associated terrestrial systems dependent on water flow such as floodplains

building access roads for recreational activity may lead to habitat fragmentation.

may increase water scarcity through increased evaporation rates.

Question 21

give different examples of how changes in the hydrological cycle give rise to different biomes.

Answer 21

In certain tropical regions, there is high transpiration/precipitation allowing for higher productivity which gives rise to tropical rainforests.

in other tropical regions evaporation exceeds precipitation leading to water-limited and little vegetation growth conditions such as the desert.

in polar regions, large proportions of water are frozen which lead to it being unavalible to plants s tundra.

in mid latitudes there is moderate precipitation allowing moderate plant growth of tempretate forests and grasslands.

in regions where water inputs exceed outputs and promote the rise of the water table, water accumulates in the soil to form a wetland or aquatic system.

Question 22

explain how the atmosphere plays a role in maintaining life-supporting temperatures over the earth’s surface 7 marks.

Answer 22

The atmosphere allows for the greenhouse effect, which is where GHG (such as C02) traps longwave radiation from leaving the atmosphere inorder to insulate the earth. This ensures the earth is habitable by living organisms.

Cloud reflects in comping solar radiation to help keep temperatures down.

Most heat is radiated to the equator, the tricellular model and convection currents help to distribute this heat to different latitudes.

Winds may contribute to oceanic currents that transfer heat.

Question 23

with reference to four different qualities of soil, outline how each one can contribute to high primary productivity.

Answer 23

particle size affects water retention - more water for plants to do photosynthesis increases productivity.

Nutrient status- a lot of organic matter and humus will help plants grow.

Air space - makes sure roots can absorb co2 needed for photosynthesis.

PH, neutral to slightly acidic.