3.6 Human Impcact On The Environment Flashcards
Define extinction
the complete loss of a species
Why would a species become endangered
Natural selection due to changing selection pressures
Non contiguous populations - populations which are too small with insufficient genetic diversity to ensure a healthy and viable increase in number.
Loss of habitat - eg deforestation
Over hunting by humans - overfishing
Competition from introduced alien species.
Pollution due to human activity- oil and PCB
Define conservation
the sensible management of the biosphere and enhancement of biodiversity locally
What are Examples of conservation methods
Habitat protection eg nature reserves, SSSI
International cooperation restricting trade eg CITES
Gene and sperm banks
Seed banks
Rare breed societies
Species reintroduction
International organisations eg WWFN
Legislation
Ecotourism
Define endangered species
A species considered to be in imminent danger of extinction.
How can gene pools be conserved in the wild
Through the establishment of protected areas, habitat restoration and legal protection of species.
Why is conserving gene pools important
Ensures the survival of species in their natural environment, maintains biodiversity.
Prevents the loss of potentially useful genes that could be used in medicine, agriculture or industry.
How are gene pools conserved in captivity
Captive breeding programmes
Seed banks
Zoos
What are the ethical reasons for conserving gene pools
Humans have the responsibility to protect other species, ensure their survival and prevent extinction caused by human activity.
It’s unethical to let species go extinct due to human activity.
Define agricultural explotiation
The increase in efficiency and intensity of food production in order to meet growing demands
What conflicts are caused between agricultural production and conservation
Demand for food production leads to habitat lost, deforestation, monoculture practices and reduced biodiversity
Define deforestation
Complete loss of trees in a defined area due to human activity
What are the consequences of deforestation
Soil erosion - nutrient losss
Lowland flooding
Desertification
Habitat loss
Decreased biodiversity
Climate change
How can we manage deforestation
Implementing sustainable replanting
Long rotation times
Coppicing - leaving a stump
Selective cutting
What is a monoculture and how does it reduce biodiversity
Reduces biodiversity by offering only one habitat. Growth of genetically identical crops in a large area.
What are the consequences to using monocultures
Depletes soil nutrients as plants extract minerals at the same depth increasing the need for chemical fertilisers
Why do monocultures increase pesticide use
Plants grow close together and are genetically identical making them vulnerable to the same pests and diseases
What is overgrazing and what are its harmful environmental effects?
Animals graze for too long, damaging the grasses. Exposes soil to erosion and compacts soil, reducing air spaces and inhibiting nitrogen fixing and nitrifying bacteria.
Water is unable to penetrate through compacted soil and grass growth is inhibited
What are the disadvantages to intensive fish farming
Rapid spread of disease and parasites due to high density of farmland increasing use of pesticides entering food chain
Pesticides then accumulate causing reduction in fertility at higher trophic levels
Nitrogenous waste pollution leading to eutrophication
Escaped farmed fish may carry disease and parasites to wild population
Farmed fish outcompete wild fish for resources if they escape
What toxic substances are in farmed fish
Methyl mercury
Dioxins
Pesticides
PCBS
What are methods to reverse decline in biodiversity
Organic farming
Set aside schemes
Replanting hedgerows
Legislations like environment act
How does organic farming increase biodiversity
Reducing chemical fertilisers and pesticides, allowing crop rotation and growing a variety of crops to provide different habitats
What is overfishing
capturing fish faster than they can reproduce impacting food chain
What fishing methods contribute to overfishing
Trawling
Drift netting
What is drift netting
A net suspended from floats stretched between two boats, thousands of miles of net is set and non target species are often caught eg dolphins
What is trawling
Weighted nets dragged across ocean floor.
This method catches everything and damages the ocean floor decimating habitats for miles
How to we preserve fish stocks
Regulate mesh size
Exclusion zones
Using lines not nets
Legislations limiting the size of fishing fleets or controlling number of days spent at sea
Fishing alternative.
How can science and technology contribute to sustainability
By predicting affects of human activity and develop sustainable alternatives to create countermeasures to harmful practises
Why is environmental monitoring essential for conservation
Tracks changed in ecosystems and predicts future impacts so countermeasures can be prepared or activities planned can be replaced with other less harmful consequences.
What are planetary boundaries?
A set of nine limits proposed by a group of environmental and Earth system scientists within which human activity can operate without risk of irreversible damage to the planet.
Why are planetary boundaries important
To prevent IRREVERSIBLE and abrupt environmental changes caused by human activities.
What are the 9 planetary boundaries
Biodiversity boundary
Climate change boundary
Nitrogen boundary
Land use boundary
Chemical pollution boundary
Fresh water boundary
Aerosol boundary
Ocean acidification boundary
Ozone boundary
What is the biodiversity boundary and has it been crossed
Relates to species extinctions and natural selection, change in habitats such as maurine and tundra
-has been crossed.
Effects of crossing biodiversity boundary
V Extinction disrupts ecosystems and reduces biodiversity
What causes the crossing of the climate change boundary
Increased greenhouse gas emissions eg CO2 due to human activity
Production and use of biofuels instead to prevent this.
What are the effects of crossing the climate change boudary
Disrupted ecosystems
Altered human plant and animal reproduction
What causes crossing of nitrogen boundary
Excess nitrogen from fertilisers lead to eutrophication in ecosystems
What are the effects of eutrophication
Algae blooms reduce oxygen levels harming aquatic organisms
What is the land use boundary
Involves land exploitation for farming and urbanisation, it can be avoided.
What is the fresh water boundary and can it be avoided
Ensures the availability of fresh water for ecosystems and human use. It can be avoided.
How can we ensure fresh water availability
Desalination
What causes chemical pollution and is it quantified
Caused by SO2 AND N oxides
It’s unquantified
What are the effects of chemical pollution
Acid rain damaging soil, water and organisms
What causes the aerosol boundary to be crossed
Air pollution from particulate matter eg soot, dust
What are the effect of crossing aerosol pollution
Poor air quality, harm to human health
What causes ocean acidification and can it be avoided
Burning fossil fuels increased co2 leading to acidification
It can be avoided
What are the effects of ocean acidification
Damages marine ecosystems eg coral reefs and fish farming
What causes ozone depletion and has the boundary been avoided
Causes by CFC emission
Boundary has been avoided due to Montreal protocol
How has ozone depletion boundary been avoided
International cooperation and banning of CFCS
What are the planetary boundaries that have been crossed
Biodiversity boundary
Climate change boundary
Nitrogen boundary
What are the planetary boundaries that are avoidable
Land use boundary
Fresh water boundary
Ocean acidification boundary
Ozone depletion boundary
What are the planetary boundaries that are unquantified
Aerosol boundary
Chemical pollution boundary
Explain how deforestation affects the planetary boundary for climate change
Deforestation reduces the uptake of carbon dioxide
Burning of trees puts carbon dioxide into atomosphere
Decay of waste tree material.
