human influence on ecosystem Flashcards
(47 cards)
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
