Unit 20 : Human Influences on Ecosystems Flashcards
5 Ways that Humans have increased food production
- agricultural machinery to use larger areas of land and improve efficiency
- chemical fertilisers help crops grow better
- insecticides: a type of pesticide that kills insects
- herbicides: a type of pesticide that kills weeds
- selective breeding to improve production by crop plants and livestock
Define Large-Scale Monoculture
the continuous production of one type of genetically identical crop
4 Negative Impacts of Large-Scale Monoculture
- if a natural disaster occurs, the whole crop could be wiped out.
- if pests & diseases attack crops, they could harm them easily
- using large fields and pesticides reduces the variety of species. This hinders biodiversity.
- when insecticides are used persistently, the pests may eventually become resistant to them, reducing their effectiveness
3 Negative Impacts of Intensive Livestock Production
- welfare issues for the livestock
- diseases can spread easily among them
- waste can pollute land and waterways nearby
Define Biodiversity
the number of different species that live in an area
3 Reasons for Habitat Destruction
- increased area for food crop growth, livestock production, and housing
- extraction of natural resources
- freshwater and marine pollution
2 Effects of Habitat Destruction
- by altering food webs and food chains, humans can harm habitats
- deforestation
4 Effects of Deforestation
- reduced biodiversity/destroys habitats/extinction
- loss of CO2 fixation, thus increase in CO2, thus global warming
- soil erosion: tree roots cannot retain soil and go into rivers, making the water dirty & causing blockages, and the soil becomes less fertile
- flooding: 75% of water is usually absorbed by foliage, root systems or evaporates. after deforestation, water accumulates in valleys.
2 Pesticides that cause Pollution and how
- insecticides (kill insects): meant to kill insects which eat crops, but can kill other useful insects such as bees, which are pollinators, or by bioaccumulation
- herbicides (kill weeds): can be harmful to animals which eat the plants
3 Effects of Non-Biodegradable Plastics
- choke birds, fish and other animals
- fill up the animals’ stomachs so that they can’t eat food
- collect in rivers and get in the way of fish
5 Effects of Global Warming
- increase in the average temperature of the Earth
- methane from the burping of cows
- it started at the same time as humans began burning fossil fuels
- scientists believe fossil fuels are causing this – not proven yet
- it increased carbon dioxide and methane concentrations in the atmosphere, causing an enhanced greenhouse effect that leads to climate change
Define Eutrophication
a process in which nutrients build up in a water body, resulting in an increased growth of micro organisms that may decrease the oxygen in water.
Describe the process of Eutrophication
- fertilisers are put in soil by farmers.
- fertilisers with nitrates/detergents with phosphates leach into rivers and lakes after rain
- water plants grow more than usual
- they block sunlight and kill plants underneath
- they die and sink to the bottom
- bacteria/fungi decompose remains using the O2 and decreasing the O2 concentration
- fish and other creatures die from oxygen starvation
Define Sustainable Resources
one which is produced as rapidly as it is removed from the environment so that it does not run out
How can Forests be Conserved and Managed Sustainably
forests can be conserved using education, protected areas, quotas and replanting.
How can Fish Stocks be Conserved and Managed Sustainably
fish stocks can be conserved using education, closed seasons, protected areas, controlled net types and mesh size, quotas and monitoring
How is Water used and describe it’s supply
water is used to grow food, keep it clean, provide power, control fires, and drink. We get water constantly through rainfall, but we use the planet’s freshwater faster than it can be replenished
Describe Fossil Fuel’s supply
fossil fuels must be conserved as they will soon run out; therefore, they should be replaced with green energy
How can Water be Recycled
water from sewage can be returned to the environment for human use by sanitation and sewage treatment
How can Paper be Recycled
sent to special centres where it is pulped to make raw materials for industry
How can plastic be recycled
fossil fuels, bottles → fleece clothing
Why is Metal Recycled
mining takes a lot of energy, so recycling saves energy
5 Reasons why Species and Habitats need to be conserved
- organisms have value in themselves (ethical value)
- value to medicine (new molecules from exotic plants = new drugs)
- genetic resources are helpful to humans as well and are lost when species disappear (DNA for genetic engineering)
- each species has its role in its ecosystem; if it is removed, then the whole ecosystem could collapse
- the use of artificial insemination (AI) and in vitro fertilisation (IVF) in captive breeding programmes
How do Endangered Species become Endangered
climate change, habitat destruction, hunting, pollution and introduced species
How can Endangered Species be Conserved
they can be conserved by monitoring and protecting species and habitats, education, captive breeding programmes, and seed banks
4 Reasons for Conservation Programmes
- reducing extinction
- protecting vulnerable environments
- maintaining ecosystem functions by nutrient cycling and resource provision, e.g. food, drugs, fuel and genes
- increase biodiversity
