NATURAL ECOSYSTEMS AND HUMAN ACTIVITY
Ecosystem: The interaction of living organisms (biotic) in conjunction
with the physical environment (abiotic) components.
Biodiversity: The variety of species in an area.
Once ecosystem is destroyed, there is a very little chance of it returning
to the climax community. Only plagioclimax vegetation remains.
A Plagioclimax community is an area or habitat in which the influences
of the humans have prevented the ecosystem from developing further.
The ecosystem may have been stopped from reaching its full climatic
climax or deflected towards a different climax by activities such as:
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Cutting down the existing vegetation
Burning as a means of forest clearance
Planting trees or crops
Grazing and trampling by domesticated animals
Harvesting of planted crops
Characteristics of vegetation in the cool temperate climate zone:
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cone shaped trees / coniferous trees;
straight trunks;
spaced apart/ not close together;
sloping branches;
ground cover in foreground/ grass / bushes / shrubs / sedges
/rushes;
 some flowering plants;
 few species;
Adaptations:
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shallow roots – thin soils / soils frozen except for surface layer;
conical shape – to shed snow;
flexible branches – so don’t break under weight of snow;
flexible branches – so don’t break in strong winds;
evergreen leaves – as little energy to grow new leaves each year/
ready to grow in spring;
needle-like leaves – to reduce transpiration;
dark colour leaves – to absorb more sunlight;
cells / sap tolerant to severe cold – to survive winter
temperatures;
 thick bark – for frost protection;
Characteristics of tundra vegetation:
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small/ low-growing/ close to the ground/ stunted;
few nutrients in the soil;
close to warmth of soil; keeps plants from freezing;
roots (shallow) cannot penetrate the permafrost;
wind;
short roots;
shallow soils; frozen ground; permafrost;
some are dark in colour;
to absorb solar heat;
some plants are covered with hair/ fuzz;
to protect from wind; trap heat;
to keep plant warm; the warmer the plant the faster they grow;
some plants grow in clumps;
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to protect one another from the wind; cold;
some plants have dish-like (owtte) flowers;
follow/track the sun helping the plant stay warm;
plants grow quickly; are perennials; do not die in the winter;
short summers / growing season;
plants are able to grow under a layer of snow;
protects / insulates them during the winter;
have small leaves;
to retain moisture/ heat reduce transpiration;
seeds have thick coat;
to protect from cold temperatures / permafrost;
THE ATMOSPHERE AND HUMAN ACTIVITIES
Pollution in large cities
Air:
Causes
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increase in power stations;
increased traffic;
industry develops;
many people use wood; charcoal; dung for fuel;
these put smoke particles / diesel particulates into the air;
industry often little regulated so high volumes of pollutants;
nitrogen/ sulfur oxides / carbon monoxide given off by burning
fuel;
 lead from petrol engines;
Impacts
 particulates in air help create smog/ damage lungs;
 industry / vehicle emissions contribute to photochemical smog;
 may cause breathing difficulties / asthma/ bronchitis / heart
problems;
 CO causes headaches / fatigue;
 brain damage from lead;
Water:
Causes
 much rubbish not collected;
 gets into water courses;
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sewage system unable to cope with increased population;
many slum dwellers do not have toilets;
sewage not treated;
humans / animals defecate in water courses;
industries discharge waste into rivers;
detergents /washing clothes;
thermal pollution (from power stations);
example such as mercury;
Impacts
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water borne diseases such as cholera/ typhoid/ dysentery;
from human effluent;
used for drinking/washing food/ cooking utensils in water;
liquid stools likely to further infect water;
cholera causes dehydration;
industrial waste may contain poisons /heavy metals;
eating poisoned fish;
Strategies taken by governments to conserve fossil fuels:
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incentives for energy conservation; insulation;
introduce/ increase the use of alternative energy sources;
named example of an alternative energy source;
taxation to reduce use of fossil fuels / carbon tax;
encourage use of public transport;
encourage car sharing/ pooling;
encourage walking/ cycling; walk/cycle ways;
encourage/ subsidise hybrid/ solar powered cars;
afforestation/ biomass to provide an alternative energy source;
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promote recycling to reduce energy use;
research new energy related technologies;
education/ campaigns for conservation;
quotas on fossil fuels;
ENERGY AND THE ENVIRONMENT
Formation of fossil fuels:
 millions of years ago;
 plants and animals or plankton or sea creatures died or fell to
bottom of sea;
 covered by (layers of) mud or sediment;
 this increased the temperature and pressure;
 this changed the animal and plant remains into crude oil;
Disadvantages of Renewables
 expensive to switch to non-renewables e.g. new plant and
machinery;
 investment / current contracts with e.g. oil companies;
 renewables transfer less energy;
 renewables are not constant;
 public opposition to change;
 location of renewable plants may be unpopular;
 country may not have suitable renewable sites e.g. tidal (inland
country), wind (low-lying land);
Disadvantages of Nuclear Power:
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lack of expertise (in some countries);
expensive to commission;
(some) countries have other (plentiful) source(s) of power;
e.g. geothermal power (Iceland)/ coal (Russia);
risk of nuclear accidents / explosions / leaks can contaminate
large areas;
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risk of terrorism;
expensive to decommission;
waste is highly toxic /radioactive/ dangerous;
waste is difficult to dispose of;
waste is costly to store;
waste remains dangerously radioactive for many / thousands
years;
equipment used in nuclear power stations becomes radioactive;
radioactivity can cause death/ cancers / leukaemia; mutations;
nuclear plant explosions have led to loss of public confidence/
support;
people unwilling to live near nuclear power stations;
visual pollution/ intrusion/ eyesore;
Fukushima disaster 2011 caused catastrophic damage to the
nuclear power plant;
Chernobyl explosion 1986 highly radioactive zone will be unsafe
for 100s of years;
Impact of oil pollution
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sea turtles / birds;
wetlands;
marine mammals / fisheries;
physical smothering;
chemical toxicity;
ecological changes;
indirect effects e.g. loss of habitat or shelter;
impact of clean-up process;
Minimising impact of oil spills
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floating booms;
detergent sprays;
dispersants;
skimmer ships;
controlled burning of surface oil;
AGRICULTURE AND THE ENVIRONMENT
Advantages of drip irrigation:
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sustainable; water conserved/ not wasted/less required;
water directed at roots;
most absorbed by plant;
fewer weeds (germinate);
less water lost by evaporation; surface runoff;
no wet leaves so fewer leaf diseases;
work can continue during watering; no risk of water-related
diseases;
 soil structure is not damaged from water falling on bare soil;
 insecticide/ fungicide use is reduced as they are not washed away;
 leaching reduced; risk of salinisation reduced;
MANAGING NATURAL HAZARDS
Protection measures taken during an earthquake:
Airports closed:
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runways covered with ash (several centimetres deep);
planes could not take off; reduced visibility;
planes cannot fly through ash clouds; danger of engine failure;
ash causes abrasion of engine parts; clogging of the fuel/ cooling
systems;
 ash concentrates in engines; turns into a kind of molten glass;
affects fuel
 flow; can cause engines to shut off;
People evacuated:
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danger of roofs collapsing; causing death;
health issues; volcanic ash (fine pulverised rock and gases) in
eyes /nose/ throat/ lungs;
death from burns / asphyxiation from ash inhaled in (hot, dense)
pyroclasticflow/ surge;
 danger from flowing lava/ volcanic bombs;
 disruption to water/ electricity supplies / transport;
Opportunities presented by volcanoes:
 lava / ash produces fertile soils (for farming); some of richest
agricultural lands in the world;
 family/friends live there/ have always lived
there/traditional/emotional attachment;
 shortage of land; job/ investments/cannot afford to move;
 risk not great enough to move;
 good forecasting/protection schemes;
 (volcanic) tourism/ scenery;
 health spas (hot springs);
 minerals (can be mined); e.g. copper/gold/ silver/ lead/ zinc /
mercury /molybendum
 valuable gems can be mined; e.g. diamonds / opals;
 (volcanoes provide) building materials; e.g. tuff/ hardened
volcanic ash;
 geothermal energy can be generated (in volcanic areas);
WATER AND ITS MANAGEMENT
Factors affecting choice of site of a dam:
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valley (in mountains, upland area);
narrow; deep/ steep sided; steep gradient;
natural lake;
wet climate;
high/heavy annual rainfall/ precipitation;
low evaporation rate;
(large) river; many tributaries;
few people/ settlements;
Social Disadvantages of dams:
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loss of (farm)land; valley floor; fertile;
loss of homes / villages;
loss of jobs / employment; income;
loss / disruption of ecosystems /wildlife/ deforestation;
people forced to move; communities destroyed;
archaeological/ historic / cultural heritage destroyed;
dam may break; endanger life;
dam may cause/ increase earthquakes;
visual pollution;
noise during construction;
Water-related diseases
Examples: bilharzia, cholera, typhoid, dengue, diarrhoea, dysentery
Controlling malaria
Eradication of parasite
 drugs to prevent malaria from being caught; e.g. chloroquinine;
larium; which kill parasites / plasmodium in blood;
 vaccines being developed following trial results;
Eradication of vector
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kill female mosquito;
sterilise male mosquito;
drainage of mosquito breeding grounds;
pour oil/ salt/ polystyrene beads on breeding waters to suffocate
larvae;
biological control using carnivorous fish;
insecticides (pyrethrum) used to spray indoor surfaces /pesticides;
cover water storage areas /wells;
sloping roofs on buildings;
empty water collected in tyres / empty bottles;
Protection from vector
 repel mosquito with;mosquito/bed nets;insect repellents;
 accept references to vaccination using new vaccine (RTS,S, or
Mosquirix);
Water supply in urban and rural areas
Urban areas…
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have more wealth/ developed; more money from taxes /rates;
water pipes are easier/ cheaper to build;
public taps / standpipes / bottled water for sale;
piped household water (in dwelling, plot or yard);
water is more likely to be treated;
chlorination/ filtration/ro (reverse osmosis);
sewage treatment;
sanitation/ separation of clean drinking water and sewage
disposal;
 easier to put pressure on politicians /officials to improve
infrastructure;
Comparing MEDCs and LEDCs
 greater domestic use in MEDCs;
 example of domestic use; e.g watering garden, drinking, cooking,
cleaning.
 greater industrial use in MEDCs;
 example of industrial use; solvent, coolant, etc.
 greater availability of water in MEDCs;
 higher standard of living/ higher incomes in MEDCs;
 greater wastage/ leakage in MEDCs;
Water consumption per person is likely to increase in the future
because…
 need for more food and therefore irrigation in LEDCs;
 developing countries increasing standard of living;
 developing countries increasing industrialisation;
Human population
Push and pull factors
Pull:
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temperature / climate;
low-lying / fertile land;
natural resources;
political stability / national policies;
availability of jobs / high wages;
Push:
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(extreme) climate;
mountainous / highland land;
dense vegetation;
conflict / political instability / national policies;
OCEANS AND FISHERIES
Bycatch: unwanted fish/species caught during fishing for different
species / capture of non target species;
Bycatch should be monitored for:
 for sustainable management of fisheries;
 high level of mortality in bycatch;
 to understand the effects of fishing on each fish species;
Sustainable management of fisheries
Advantages of protected areas
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allows fish stocks to recover;
repopulates other parts of the reef;
maintains biodiversity / prevent extinction;
maintains tourism;
maintains jobs;
maintains revenue from tourism;
Restrictions to prevent overfishing
 restricted number of fishing days; limits the overall catch /
protects fish stocks;
 introduce a quota / limited number of fishing licences; limits the
overall catch / protects fish stocks;
 closed season; allows species to reproduce / protects fish stocks /
limits the overall annual catch;
 size of boat; limits the distance travelled by boats / prevents the
use of factory ships / limits daily catch;
 type of fishing gear; only sustainable methods allowed, e.g. pole
and line for tuna / only target species harvested / reduces
bycatch;
 larger mesh size; allows juvenile fish to escape / protects fish
stocks / reduces bycatch;
 smaller net size; limits the overall catch / protects fish stocks;
 marine protected areas; protects vulnerable ecosystems / limits
the overall catch / protects fish stocks;
El Nino
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El Niño warmer sea surface temperatures in mid-Pacific;
warm air rises near Peru;
so rainfall in Peruvian desert;
warm sea water is nutrient poor / prevents cold nutrient rich
water reaching coast;
 so less fish are caught / fisheries decline;
ROCKS AND MINERALS AND THEIR EXPLOITATION
Why open-cast mining has greater environmental impact than deep
mining:
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larger area of land cleared of natural vegetation;
so more habitat lost (in open cast mining);
more dust / noise / visual pollution;
more polluted surface drainage;
After mining activity has terminated:
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making waste piles safe from collapse by re-profiling;
creating soil;
planting with herbs to absorb toxic substances;
tree planting;
use as landfill;
use as a lake or reservoir;
Additional notes:
 Deep shaft mining: tunnel roof supported by pit props