b6.1/2 monitoring and maintaining the environment and food security Flashcards
examples of environmental change
seasonal change
- average temp increase/decrease
- rainy/ hot seasons
geographic change
- land bridges sink(rising sea levels)
- habitat change
human causes change
- global warming
- intensive farming - causes deserts
deforestation
removing trees
for growing crops
decreases biodiversity
growing rice increases methane levels
trees aren’t being planted as fast as the rate of deforestation
trees cleared by burning
releases more CO2
peat bogs
areas of west land and pest is used as fuel or compost
burning peat increase CO2 levels (as peat is a carbon sink)
peat bogs carbon sink
decomposition cannot fully happen (acidic and not much O2)
advantages of monocultures
- cheap labour (machines used)
- high crop yield
- easy to take care of
disadvantages of monocultures
- easily affected by one disease
- soil is leached
- need fertilisers and pesticides
bioaccumulation
build up of absorbed chemicals in an organism over time
biomagnification
the increase in conc of these chemicals in each organism up the food chain
(organisms can’t breakdown / excrete chemicals as quick as they are absorbed)
eutrophication
the process by which a body of water becomes enriched in dissolved minerals that stimulate the growth of aquatic plant life (algae)
how eutrophication occurs
- sewage release / minerals from fertiliser leached into water
- algae in water have more nutrients for growth / reproduction eg nitrates
- algal bloom covers water surface
- less light in water plants cant photosynthesise and die
- algae run out of nutrients and also die
- bacteria decompose the plant / algae and respire the products using up O2 in water
- the water may become
anoxic and all animal life dies
global warming
gases trapped in Earths atmosphere eg CO2/ CH4
CO2 levels increases due to
industrialisation
- more cars / factories / combustion of fossil fuels
fluctuations of CO2 in UK because
- trees lose leaves - less photosynthesis - less CO2 taken in
- colder - enzymes aren’t at optimum - less photosynthesis
implications of global warming
- increase sea levels
- native animals can’t survive in habitat (extinct)
- drought
- food decreases
- increases competition for land/resources
white lemuroid possum
became almost extinct
cannot maintain body temp
so vulnerable to increases in temp
little terns
- vulnerable to high tides / storms (increase due to global warming)
- migrate to UK and nest above high tide
- affected by flooding due to stormy seas
coastal mangrove forests
- vulnerable to increase no. storms / typhoons
- these undermine the fine sediment they grow in
- seedlings can’t root
- nutrients are washed away
biodiversity
the variety of all life on earth
food security
when all people have access to consistent supplies of safe/ nutritious food to meet their needs for an active healthy life
biodiversity + food security
biodiversity must be protected to ensure food security due to variation preventing all food being wiped out by a certain disease
intensive farming
farming using machines/ chemicals to produce large yields quickly eg using fertilisers, pesticides, herbicides
what do fertilisers/ herbicides do
increase mineral content of soil
removed competition
hydroponics
plants grown without soil
+ production costs lower
+ minerals can be recycled
+ crops grown in areas where they normally wouldn’t
- high initial set up costs
ethics of intensive farming
- close confinement ^ rise of disease spreading
- lack of movement
- nature of pens /cages
- poor transportation/ slaughtering techniques
advantages of fish farming
- tank water quality can be monitored
- temp/oxygenation of water can be controlled
- the diet of fish is controlled by quality / quantity of feeding
- protected against predators (adults/young separated and separate from predators)
- pesticide are used to kill parasites
- selective breeding can improve quality
disadvantages of fish farming
- spread of disease more likely as are close together
- antibiotics used to treat disease might not break down and may be eaten by humans
- waste water contains high levels of organic material which causes eutrophication
- pesticides to kill parasites can be toxic to other species nearby
biological control
- controls pests without pesticides using natural predators
- most successful in controlled environments
- cause long term environmental problems
