human influence on ecosystem Flashcards
how humans have increased food production
- agricultural machinery
- chemical fertilisers
- insecticides
- herbicides
- selective breeding
agricultural machinery
to use larger areas of land + improve efficiency
chemical fertilisers
the mineral ions increase nutrients in soil so plants grow larger + produce more fruit, increasing yield
insecticides
kill unwanted insects that can damage the plants
agricultural machinery
to use larger areas of land + improve efficiency
herbicides
kill unwanted weeds to minimise competition for minerals, soil, water, sunlight
selective breeding
animals + crops that produce high yield are bred together to produce larger amounts of animals + crops that produce high yield
advantages of intensive livestock production
- less land needed for large amounts of food
- food can be produced all year-round in controlled
environments - lower production cost so lower selling price
- lower labour requirement
chemical fertilisers
fertilisers with mineral ions increase nutrients in soil so they grow larger and produce more fruit, increasing yield
disadvantages of intensive livestock production
- use herbicides which may cause eutrophication
- ethical issues due to cruel treatment of animals
(stress due to high density + restricted movement) - habitats destroyed to make land available
- disease can spread rapidly
advantages of large scale monocultures of crop plants
- allow use of specialised machinery + techniques
leading to higher yields + efficiency - managing one type of crop makes pest control +
harvesting simpler so overall management easier
disadvantages of large scale monocultures of crop plants
- low biodiversity as natural crops have variety of
coexisting species while monos have one species - pest population increases as increasing amount of
food - disease can spread rapidly
biodiversity
number of different species that live in a given area
insecticides
kill off insects and pests that may cause damage to plants
3 reasons for habitat destruction
- increase land area for housing + crops + livestock
- extraction of natural resources
- freshwater + marine pollution
increasing land area
as population increases demand for food + housing increases so clear habitats such as forests
extracting resources
- wood, stone, metals
- trees cut down to get wood (destroys forests)
- land cleared to mine for metals + stones
herbicides
kill off unwanted weeds to minimise competition with other species for minerals, soil, water, and sunlight
marine pollution
- disposing waste + oil spills + littering causes pollution that harms / kills marine organisms
- eutrophication if fertilisers enter waterways
humans have negative impacts on habitats through
altering food chains and food webs
6 ill effects of deforestation
- biodiversity loss
- extinction
- loss of soil
- minerals washed away + regrowth difficult
- flooding
- increased CO2 in atmosphere
loss of soil
no roots to hold the soil together so soil eroded by rain
mineral loss + regrowth difficult
no trees so minerals are unused get washed away into waterways making regrowth very difficult due to lack of nutrients
flooding
topsoil easily washed away without trees causing flash floods + landslides
effects of untreated sewage on aquatic ecosystems
- feeds bacteria that remove dissolved oxygen causing death of marine organism (eutrophication)
- degrade the habitat
- contain pathogens that harm organisms
effects of excess fertilisers on aquatic ecosystems
causes algal blooms which die + feed bacteria leading to eutrophication
effect of non-biodegradable plastics on marine organisms
- animals try to eat plastic (toxic)
- get caught (injuries + death)
- break down to release toxins to surroundings
- broken down particles are ingested, entering + altering food chains
- remain in environment for a long
effect of non-biodegradable plastics on terrestrtrial organisms
- animals may choke on it
- release toxic substances
- cover plants + block light, preventing photosynthesis
- remain in environment for long time
- toxic if ingested
- enter food chain
sources + effects of pollution of
the air by methane
sources:
- keeping livestock
- melting polar ice (trapped methane)
effects:
- enhanced greenhouse effect
- climate change
sources + effects of pollution of
the air by CO2
sources:
- burning fossil fuels
- increasing population
effects:
- enhanced greenhouse effect
- global warming
process of eutrophication
- runoff fertilisers enter waterways
- increased availability of nitrates + other ions
- increased growth of producers (algal bloom)
- increased decomposition after death of algae
- increased aerobic respiration of decomposing bacteria
- they use up (reduce) dissolved oxygen in water
- death of marine organisms
sustainable resource
one which is produced as rapidly as it is removed from the environment so that it does not run out
some resources can be
conserved + managed sustainably
reasons organisms become extinct/endangered
- climate change
- habitat destruction
- hunting
- overharvesting
- pollution
- introduced species
climate change leads to
- natural disasters
- ocean acidification + rising sea levels
habitat destruction
species lose natural home + resources
hunting
reduces population + genetic diversity
overharvesting
affect reproductive patterns + genetic diversity
pollution
contaminate habitats causing health difficulties + death
introduced species
- competition for resources
- may bring diseases native species are susceptible
to
5 ways to conserve endangered species
- monitoring + protecting habitats
- education (spread awareness)
- captive breeding (establishing populations in
controlled environments) - seed banks (secure facility preserves genetic
diversity, protecting from extinction) - international agreements
4 ways to conserve forests
- education (spread awareness)
- protected areas that restrict human activities
- quotas (limit deforestation activities)
- replanting helps restore forest + biodiversity
7 ways to conserve fish stocks
- education (spread awareness)
- closed seasons help them reproduce undisturbed during peak breeding seasons
- protected areas provide safe habitats
- controlled net types reduce overfishing
- quotas limit + prevent overfishing
- monitoring
- international agreements + permits + fines
4 reasons for conservation programmes
- maintaining/increasing biodiversity
- reduce extinction by preserving habitats
- protect vulnerable ecosystems
- maintain ecosystem functions (nutrient cycling + provision of resources
use of artificial insemination (AI) in captive breeding
allows many offspring to be produced without need for convenient intercourse
use of in vitro fertilisation (IVF) in captive breeding
allows gametes with known alleles to be used in ensuring the next generation remains biodiverse
risks of reduced population - reduced genetic variation
- more susceptible to diseases
- higher extinction risk
- reduces adaptability
- expression of harmful recessive traits due to
inbreeding - reduced fertility / reproductive success
