ESS PAPER 2
Define the term carrying capacity. (1m) - ANSWER...-the maximum number of
individuals/load of a species that can be sustainably
supported by a given area/habitat/environment
Identify three reasons why carrying capacity can be difficult to estimate. (3m) -
ANSWER...-Generally:
there are many different potential limiting factors for natural populations;
populations' needs may change through time due to genetic
changes/evolution;
environmental conditions may change eg climate change/introduced species;
it takes extensive/long-term study to identify a precise relationship between a
species and given environmental factor;
For human populations:
human populations exploit/depend upon a far greater range of different
resources than most other species;
(human ingenuity) humans are able to substitute one resource/material for
another;
variations in lifestyle/culture/economic status between human populations
mean different resources/amounts of resources are used/needed;
the importation of resources from other ecosystems/regions can offset a lack
of resources in an area;
technological developments cause changes in resources required/available
over time;
Identify two reasons why Uruguay has the biggest ecological footprint. (2m) -
ANSWER...-high usage of resources / high standard of living;
limited local vegetation/natural habitat/primary productivity to absorb CO2/wastes;
local food production is limited/unsustainable/poorly managed;
high usage of/dependence upon fossil fuels/high CO2 emissions / lack of
alternative/renewable energy sources;
unregulated/high production of industrial/domestic pollution/waste products;
meat-rich diet;
Define biodiversity. (1m) - ANSWER...-biodiversity is a broad concept encompassing
the total diversity of living
systems / biodiversity includes the species, habitat and genetic diversity
within an area / the amount of biological diversity per unit area;
With reference to Figure 2 identify three factors that could explain the high biodiversity
in Ecuador. (3m) - ANSWER...-close to the equator/high primary productivity/favourable
climate/high
,rainfall/insolation;
(Ecuador is in latitude of) tropical rainforest biome (which is a biodiversity
hotspot);
(greater species/genetic diversity due to) high habitat diversity/climatic
zones/biomes/range of coastal/lowland/forest systems;
active plate tectonics creating barriers to populations (and so encourages
speciation);
altitude variation on mountains (create zonation/diversity of habitats);
active plate tectonics enabling succession (from volcanic material/lava/
lahars etc);
large protected area/national park;
Describe a method that may have been used for collecting the tree data.(2m) -
ANSWER...-aerial photograph;
identify from the leaf canopy the different species seen;
OR
use quadrat sampling/sampling points along a transect;
identify and count all the different species seen in quadrats/along transect;
OR
collect live specimens of leaves/fruits/seeds etc from the unit area;
have them identified (in labs) using keys/expert botanists;
Outline two reasons for the differences in population size and density of ocelots at Site
A and B of Yasuni National Park as shown in Figure 4. (4m) - ANSWER...-traps in area
A may be more easily avoided/too obvious/have traces of
disturbance/be located in spots less used by ocelots/in area B be less easily
avoided/better hidden/cause less disturbance/be located close to ocelot
nests/hunting routes;
...causing trap-shy individuals in A/trap-happy individuals in B/overestimating
population in A/underestimating population in B;
population may be greater in site A because it provides greater quantity/quality
of resources/favourable factors eg food/shelter/water (or converse for site B ie
less food/shelter/water);
...leading to greater immigration of ocelots/more successful
reproduction/population growth in site A (or converse for Site B);
population may be lower in site B due to presence of more adverse factors eg
disease/competitors (or converse for site A ie less disease/competition);
...leading to less immigration of ocelots/greater death rate/lower fertility in site B
(or converse for site A);
population may be lower in site B due to higher levels of human disturbance (or
converse for site A ie less disturbance);
...leading to more emigration of ocelots/greater death rate/reduced
reproduction/loss of nesting sites in site B (or converse for site A);
Identify one human factor that contributes to photochemical smog. (1m) - ANSWER...-
(intensive) combustion of fossil fuels/organic matter/through high density
, traffic/urbanisation/industrialisation/forest burning/release of VOCs from
aerosols;
Identify one natural factor that contributes to photochemical smog. (1m) - ANSWER...-
local topography/high insolation/sunlight/low wind/thermal inversion;
Explain why the formation of photochemical smog may have harmful effects on the
environment of cities such as Santiago (Chile). (4m) - ANSWER...-reduced growth and
productivity of plants/reduces crop yields by damaging them;
leads to the reduction of the air quality/visibility/ambience within the urban area;
particulates/chemicals within the smog enter the lungs and irritate respiratory
system/cause respiratory disease/lung cancer;
particulates/chemicals within the smog may cause irritation of eyes/eye diseases;
the chemicals within the smog react with plastic/rubber causing it to perish/
become hard/inflexible;
tropospheric ozone (a secondary pollutant) is a greenhouse gas/contributes to
global warming/climate change;
smog pollutants reduce immune system of humans and animals (become more
susceptible to diseases);
(a) Describe the role of primary producers in ecosystems.(4m) - ANSWER...-producers
are plants that convert light energy into chemical energy by
photosynthesis;
photosynthesis/primary producers convert carbon dioxide and water into
glucose/sugar and oxygen;
this conversion/glucose forms the raw material of biomass/the basis of food chains;
producers (thereby) provide food for consumers/energy in a form that can be
passed along food chains;
the production of oxygen by producers is vital for the majority of ecosystems;
the absorption of CO2 maintains a balance of CO2 in atmosphere/reduces global
warming;
primary producers may alternatively generate biomass through chemosynthesis;
chemosynthetic bacteria use chemical energy to produce food without using
sunlight;
plants may also provide other resources/services for ecosystem eg habitats/soil
conservation/cycling of matter;
(b) Explain the potential impact of ocean acidification on environmental systems and
societies.(7m) - ANSWER...-ocean acidification is caused by increased CO2 levels in
atmosphere leading to
more CO2 absorbed into ocean;
the CO2 reacts with the water forming an acid (carbonic acid)/decreasing the
pH/changing pH from about 8.2 to 8.1;
macro-algae/seagrasses may benefit from higher CO2 conditions in the ocean;
some organisms are adapted to a narrow pH range/very sensitive to pH changes;
low pH/reduces ability of shelled organisms to maintain their shells/reduces
Define the term carrying capacity. (1m) - ANSWER...-the maximum number of
individuals/load of a species that can be sustainably
supported by a given area/habitat/environment
Identify three reasons why carrying capacity can be difficult to estimate. (3m) -
ANSWER...-Generally:
there are many different potential limiting factors for natural populations;
populations' needs may change through time due to genetic
changes/evolution;
environmental conditions may change eg climate change/introduced species;
it takes extensive/long-term study to identify a precise relationship between a
species and given environmental factor;
For human populations:
human populations exploit/depend upon a far greater range of different
resources than most other species;
(human ingenuity) humans are able to substitute one resource/material for
another;
variations in lifestyle/culture/economic status between human populations
mean different resources/amounts of resources are used/needed;
the importation of resources from other ecosystems/regions can offset a lack
of resources in an area;
technological developments cause changes in resources required/available
over time;
Identify two reasons why Uruguay has the biggest ecological footprint. (2m) -
ANSWER...-high usage of resources / high standard of living;
limited local vegetation/natural habitat/primary productivity to absorb CO2/wastes;
local food production is limited/unsustainable/poorly managed;
high usage of/dependence upon fossil fuels/high CO2 emissions / lack of
alternative/renewable energy sources;
unregulated/high production of industrial/domestic pollution/waste products;
meat-rich diet;
Define biodiversity. (1m) - ANSWER...-biodiversity is a broad concept encompassing
the total diversity of living
systems / biodiversity includes the species, habitat and genetic diversity
within an area / the amount of biological diversity per unit area;
With reference to Figure 2 identify three factors that could explain the high biodiversity
in Ecuador. (3m) - ANSWER...-close to the equator/high primary productivity/favourable
climate/high
,rainfall/insolation;
(Ecuador is in latitude of) tropical rainforest biome (which is a biodiversity
hotspot);
(greater species/genetic diversity due to) high habitat diversity/climatic
zones/biomes/range of coastal/lowland/forest systems;
active plate tectonics creating barriers to populations (and so encourages
speciation);
altitude variation on mountains (create zonation/diversity of habitats);
active plate tectonics enabling succession (from volcanic material/lava/
lahars etc);
large protected area/national park;
Describe a method that may have been used for collecting the tree data.(2m) -
ANSWER...-aerial photograph;
identify from the leaf canopy the different species seen;
OR
use quadrat sampling/sampling points along a transect;
identify and count all the different species seen in quadrats/along transect;
OR
collect live specimens of leaves/fruits/seeds etc from the unit area;
have them identified (in labs) using keys/expert botanists;
Outline two reasons for the differences in population size and density of ocelots at Site
A and B of Yasuni National Park as shown in Figure 4. (4m) - ANSWER...-traps in area
A may be more easily avoided/too obvious/have traces of
disturbance/be located in spots less used by ocelots/in area B be less easily
avoided/better hidden/cause less disturbance/be located close to ocelot
nests/hunting routes;
...causing trap-shy individuals in A/trap-happy individuals in B/overestimating
population in A/underestimating population in B;
population may be greater in site A because it provides greater quantity/quality
of resources/favourable factors eg food/shelter/water (or converse for site B ie
less food/shelter/water);
...leading to greater immigration of ocelots/more successful
reproduction/population growth in site A (or converse for Site B);
population may be lower in site B due to presence of more adverse factors eg
disease/competitors (or converse for site A ie less disease/competition);
...leading to less immigration of ocelots/greater death rate/lower fertility in site B
(or converse for site A);
population may be lower in site B due to higher levels of human disturbance (or
converse for site A ie less disturbance);
...leading to more emigration of ocelots/greater death rate/reduced
reproduction/loss of nesting sites in site B (or converse for site A);
Identify one human factor that contributes to photochemical smog. (1m) - ANSWER...-
(intensive) combustion of fossil fuels/organic matter/through high density
, traffic/urbanisation/industrialisation/forest burning/release of VOCs from
aerosols;
Identify one natural factor that contributes to photochemical smog. (1m) - ANSWER...-
local topography/high insolation/sunlight/low wind/thermal inversion;
Explain why the formation of photochemical smog may have harmful effects on the
environment of cities such as Santiago (Chile). (4m) - ANSWER...-reduced growth and
productivity of plants/reduces crop yields by damaging them;
leads to the reduction of the air quality/visibility/ambience within the urban area;
particulates/chemicals within the smog enter the lungs and irritate respiratory
system/cause respiratory disease/lung cancer;
particulates/chemicals within the smog may cause irritation of eyes/eye diseases;
the chemicals within the smog react with plastic/rubber causing it to perish/
become hard/inflexible;
tropospheric ozone (a secondary pollutant) is a greenhouse gas/contributes to
global warming/climate change;
smog pollutants reduce immune system of humans and animals (become more
susceptible to diseases);
(a) Describe the role of primary producers in ecosystems.(4m) - ANSWER...-producers
are plants that convert light energy into chemical energy by
photosynthesis;
photosynthesis/primary producers convert carbon dioxide and water into
glucose/sugar and oxygen;
this conversion/glucose forms the raw material of biomass/the basis of food chains;
producers (thereby) provide food for consumers/energy in a form that can be
passed along food chains;
the production of oxygen by producers is vital for the majority of ecosystems;
the absorption of CO2 maintains a balance of CO2 in atmosphere/reduces global
warming;
primary producers may alternatively generate biomass through chemosynthesis;
chemosynthetic bacteria use chemical energy to produce food without using
sunlight;
plants may also provide other resources/services for ecosystem eg habitats/soil
conservation/cycling of matter;
(b) Explain the potential impact of ocean acidification on environmental systems and
societies.(7m) - ANSWER...-ocean acidification is caused by increased CO2 levels in
atmosphere leading to
more CO2 absorbed into ocean;
the CO2 reacts with the water forming an acid (carbonic acid)/decreasing the
pH/changing pH from about 8.2 to 8.1;
macro-algae/seagrasses may benefit from higher CO2 conditions in the ocean;
some organisms are adapted to a narrow pH range/very sensitive to pH changes;
low pH/reduces ability of shelled organisms to maintain their shells/reduces
