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A2 BIO UNIT3 > 3.6 Human Impact on the Environment > Flashcards

3.6 Human Impact on the Environment Flashcards

1
Q

Define endangered

A

Where a plant or animal species exists in such small numbers that it is in danger of becoming extinct

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2
Q

Define extinction

A

Where there are no more individuals of that species alive anywhere in the world, or no breeding pairs exist

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3
Q

Reasons for extinction

A
  • agriculture
  • urban development
  • forestry
  • mining
  • environmental pollution
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4
Q

What factors can cause a natural change in population?

A
  • volcanos, earthquakes
  • tsunamis
  • introduction of alien species
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5
Q

What is the IUCN?

A
  • international union for the conservation of nature
    —> assesses endangered species to see how close to extinction and produces Red List
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6
Q

REASONS FOR ENDANGERMENT: pollution

A
  • PCBs accumulate in food chains - neurotoxins, carcinogens and hormone disrupters - and still found in waste water in Wales
  • oil shipped globally in supertankers leading to accidental oil spillage meaning that water cannot be oxygenated, killing aquatic organisms, chilling birds to death, and poisoning organisms on shore
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7
Q

REASONS FOR ENDANGERMENT: loss of habitat

A
  • deforestation
  • drainage of wetlands
  • hedgerow loss
  • farmers often sow crops
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8
Q

REASONS FOR ENDANGERMENT: natural extinction

A
  • human activities change the habitat quicker than species can adapt leading to an accelerated extinction rate
  • organisms less suited to their habitat reproduce less successfully
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9
Q

REASONS FOR ENDANGERMENT: overhunting

A
  • trophy hunting
  • bush meat industry
  • over fishing
  • traditional medical practises
  • agricultural exploitation
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10
Q

REASONS FOR ENDANGERMENT: non-contagious populations

A
  • if groups are too isolated they cannot interbreed - each group would function as a separate population
  • too little genetic diversity to ensure a healthy population
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11
Q

REASONS FOR ENDANGERMENT: competition from introduced species

A
  • red squirrels outcompeted by grey squirrels
  • dodo driven to extinction as rats eat its eggs
  • signal crayfish invaded UK streams and are outcompeting native crayfish
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12
Q

Briefly list some methods of conservation

A
  • SSSI
  • CITES
  • gene and sperm banks
  • rare breed societies
  • species reintroduction
  • international organisations
  • ecotourism
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13
Q

Describe rare breed societies and their pros/cons

A
  • breed rare livestock to increase population
  • monitoring, gene bank, online educational resources
    —> ie Folly Farm saddleback pig

PROS: native rare species are well adapted, tourism, farming, soil fertility
CONS: introduction of new rare diseases, rare disease genes, risk of physical problems due to genetic bottleneck, decreased genetic diversity through generations

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14
Q

Describe species reintroduction and the pros/cons

A
  • intentional release of an organism into its natural environment to increase numbers
  • ie red kites in wales

PROS: restoring ecosystem, help fight climate change, increase biodiversity
CONS: harm other species, expensive, bottleneck, alters habitat for other organisms, disease, predators

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15
Q

Describe ecotourism and its pros/cons

A
  • low impact on natural habitat and conservation
  • Snowdonia
  • national parks

PROS: conservation, local economic growth, education
CONS: unsustainable development, green washing, disease

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16
Q

Describe methods of conservation and pros/cons

A
  • education ie WWF or RSPB
  • donation and awareness via charity
  • wildlife trust of south and west wales

PROS: prepares public, spreads awareness, responsibility, cheap and accessible
CONS: requires interest, charity relies on donation and interaction

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17
Q

Describe protecting habitats and the pros/cons

A
  • preserving natural habitats and species through SSSIs and SACs ie Gower

PROS: safeguard biodiversity, prevent disease, local economic success, ensure food and water security
CONS: human land use, climate change, invasive species, captive breeding, lack of local buy in

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18
Q

Describe gene, sperm and seed banks

A
  • sperm banks store genes of economically important animals and threatened species
  • seed banks maintain stocks of seeds to preserve genetic diversity
  • records of matings are kept so diversity can be increased by deliberate choice of parents

PROS: genetic diversity, food security, cost effective, long term storage, protect rare species, research
CONS: storage limitations, security, gene isolation, seeds degrade over time, high levels of protection

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19
Q

Describe international cooperations and legislation and the pros/cons

A
  • CITES: convention on international trade of endangered species - 184 countries signed up

PROS: promote sustainable trade, protect threatened species
CONS: huge fines if breach legislation

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20
Q

What is meant by monoculture?

A

The agricultural practise of growing a single crop, breed or variety over a large area

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21
Q

How does monoculture lead to a decrease in yield?

A
  • roots are always same length so extract same minerals from same depth of soil
  • the same crop is always susceptible to the same pests
    —> both lead to increased use of fertilisers, herbicides, and fungicides
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22
Q

How does overgrazing by cattle deplete grassland?

A
  • hooves compact the soil driving out the air and preventing water draining through
  • roots cannot penetrate the soil so grass for grazing can’t grow
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23
Q

Define soil erosion

A

The removal of top soil which contains valuable nutrients

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24
Q

How does monoculture decrease biodiversity?

A
  • hedgerows removed for more land so habitat destruction
  • only one habitat provided by the one crop grown
  • less species diversity
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25
Q

Explain consequences of deforestation

A
  • soil erosion
    —> tree roots bind soil together so it becomes unstable when they’re removed
    —> deforestation on steep slopes of valleys allow heavy rain to sweep exposed top soil down to flood plains
    —> top soil is fertile and what remains is not suitable for growth
  • deforestation of uplands causes lowland flooding
  • loss of plants, foliage and trees means large volumes of water immediately reach soil - water evaporates from soil which is much slower than transpiration
    —> diminishes soil quality
    —> waterlogged soil promotes anaerobic denitrifying bacteria and stops nitrogen fixing bacteria - loses nitrates and therefore fertility
    —> soil too cold for seeds to germinate
    —> low O2 availability for roots
  • less rainfall accelerates desertification as water very slowly evaporates from soil into atmosphere
  • habitat loss and reduction in BD
  • increased atmospheric CO2
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26
Q

What is meant by coppicing?

A

Cutting down trees close to ground and leaving them for several years to regrow

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27
Q

Describe slash and burn

A
  • small scale management
  • set area of land on fire, grow crops in the fertile soil, leave after harvest and allow to regrow
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28
Q

Describe sustainable replanting

A
  • using coppicing
  • tree trunk cut to leave stool and new shoots emerge from bud in stool
  • poles can be cut for timber and they then regrow
  • long rotation time increases sustainability
29
Q

Describe selective cutting

A
  • used on steep slopes as total removal leaves soil very vulnerable
  • maintains nutrients in forest soil and minimises soil washed into nearby waterways
  • used intermittently on steep slopes
30
Q

Explain good forestry practise

A
  • planting trees the optimum distance apart - prevent intraspecific competition and poor timber growing
  • controlling pests and diseases reduces number of trees to fell and therefore reduces area of land impacted
  • cutting a similar number of trees each year to allow ecosystem to maintain BD even when timber removed
  • habitats protected
31
Q

Describe preservation of native woodlands

A
  • essential to maintain native woodland to enhance biodiversity
  • need to plant more native species to provide a variety of species
  • no alien species
32
Q

define overfishing

A

where the rate at which fish are harvested exceeds the rate at which they reproduce

33
Q

describe drift netting including -ves

A
  • net suspended in surface waters to catch palagic fish
  • fish swim into net
  • non-target species such as turtles or dolphins get caught in nets
34
Q

describe trawling including -ves

A
  • fish that live in deeper water and on sea bed are caught by a net dragged along sea bed
  • damaged ocean bed therefore damaged habitat
  • puts mollusc and clam populations at risk
35
Q

impacts of overfishing on other wildlife

A
  • implications along whole food chain
  • ie catching capelin removes food source from cod, decreasing their population
  • ie antarctic krill beign essential to the ocean food chain
  • balance must be struck between fishing to make a living for fishermen and ensuring there are enough fish left to be caught
36
Q

methods to regulate fishing

A
  • mesh size of net large enough for young fish to fit through to survive - supported by legislation
  • quotas on max number of fish to be caught
  • exclusion zones to prohibit fishing in certain areas at certain times of year
  • legislation controlling number of days at sea
  • legislation controlling size of fishing fleets
  • fish farming
  • consumers buying fish certified by Marine Stewardship Council which ensures sustainable fishing
37
Q

describe fish farming

A
  • breeding and growth of fish in managed enclosures where predation is limited and food supplies are maintained
  • ## abiotic factors regulated to be at optimum for the particular species
38
Q

what are the benefits of a fish-based diet as opposed to pork/beef etc?

A
  • fish convert their food into protein more efficiently
  • a greater proportion of fishes’ bodies are edible
  • fish farming has lower carbon footprint
39
Q

main disadvantages of fish farming

A
  • diseased fish: large numbers stocked so high doses of antibiotics are used to keep fish healthy. pesticides are also used which are known to be harmful to marine invertebrates like molluscs
  • pollution: eutrophication from excretion, waste food and fertiliser
  • escaped fish: farmed fish have been selected for very rapid growth so can out-compete wild fish. also can transmit parasites to wild fish. farmed fish interbreeding with wild fish can also set up fast-growing populations which drive fish to extinction
  • environmental toxins are more concentrated in farmed salmon than wild salmon
  • environmental degradation: the shrimp industry in particular has been blamed for the salination of soil and ground water and the destruction of the mangroves that protect coastal communities
40
Q

Define planetary boundaries

A
  • limits between which global systems must operate to prevent abrupt and irreversible environmental damage and ensure a safe operating space for humanity
41
Q

What is meant by a core boundary?

A
  • a boundary that when crossed will drive the earth into a new and unpredictable state with severe consequences for the biosphere
42
Q

Describe the climate change boundary

A
  • one of the two core boundaries & has been crossed
  • Kyoto protocol 1997 and Paris agreement 2016
  • green house gases, increasing temps etc
  • leading to increasing biofuel use
43
Q

Describe the use of biofuels including +/-

A

Biofuel: a fuel made by biological processes such as anaerobic digestion as oppose to geological processes

  • growing biofuel crops reduces atmospheric CO2 concentrations
  • conflicts with the use of land for food production
  • large volumes of water used for irrigation
  • combustion of biodiesel produced more NO2 than fossil fuels
  • deforestation to grow crops —> soil erosion and BD loss
44
Q

Describe the production of bioethanol

A
  • plant material crushed and stored starches are digested by carbohydrates to release sugars
  • sucrose is crystallised out leaving mollases (lots of glucose and fructose)
  • glucose and fructose fermented by yeast to produce ethanol mixture
  • mixture heated by burning fibrous waste and pure ethanol is distilled
45
Q

Describe the production of biodiesel

A

Methanol + linoleic acid —> methyl linoleate + water

—> produces lots of NO2

46
Q

Describe biogas production

A
  • macromolecules in waste material aerobically digested by amylases, proteases, and lipases
  • acetogenesis is an aerobic process that produces short chain fatty acids like Ethanoic acid
  • methanogensis splits glucose and solid material left is dried and used as biofuel

—> produced naturally but contributes to global warming when left to escape into atmosphere ( methane and carbon dioxide)

47
Q

Describe the biosphere integrity boundary

A
  • second core boundary, also crossed
  • human activity has caused environmental changes to happen too quick for natural selection to enable adaptations, leading to endangerment and extinction
  • marine habitats are particularly impacted - ocean pollution, DDT pesticide, impacts on trophic levels
48
Q

Describe the land system change boundary

A
  • boundary crossed
    -deforestation increase through expansion of farming and livestock rearing
  • large forest areas cleared to grow biofuel crops
    —> too little food produced for growing populations
  • global reduction in meat consumption would reduce the land under cultivation
  • use of genetically engineered plants
49
Q

Describe the biogeochemical flows boundary

A
  • cycling of minerals through biotic and abiotic components of an ecosystem
  • essential in maintaining availability of ions through food webs
  • agricultural fertilisers used so intensively that the boundaries for nitrogen and phosphorus have been exceeded
    —> leads to pollution like eutrophication further damaging ecosystems
50
Q

Describe the ozone depletion boundary

A
  • oxygen and ozone exist in equilibrium
  • CFCs alter the equilibrium to favour the breakdown of ozone leading to holes in the ozone like in Antarctica
  • 1987 Montreal protocol banned CFC production
  • hole has decreased by 20% since and is expected to be fully repaired by 2040
51
Q

Describe the ocean acidification boundary

A
  • in 17th century pH of ocean was 8.16 and now 8.03
    —> 30% increase in H+ conc making it much more acidic now
  • increased CO2 in atmosphere leading to increased dissolved in ocean, therefore lower pH
  • leaches CaCO3 out of shells making them softer, leading to organisms being more vulnerable to chemical and physical attack
  • gill structure and function of fish damaged by low pH
52
Q

Describe the reasons for decrease in fresh water availability

A
  • changing landscapes ie draining wetlands, soil erosion etc
  • increased agriculture
  • increased demand as people move to warmer climates with low levels of fresh water (ie Florida)
  • water pollution
  • climate change
  • increase in population via greater life expectancy
  • increase in water use (domestic, aesthetic etc)
53
Q

How can fresh water availability be increased?

A
  • water conservation
  • water efficiency
  • wastewater reclamation
  • urban runoff and storm capture
  • drip irrigation
  • desalination
    —> brine (high in salt) discharged
    —> brine sinks and damages sea beds
    —> burning fossil fuels to provide energy
54
Q

Describe the atmospheric aerosol loading boundary

A
  • microscopic particles put into atmosphere by combustion of fuels
  • exacerbates respiratory problems resulting in death by lung disease
    —> PM10 lodges in the lungs increasing chances of lung cancer
    —> PM2.5 fits into capillaries and travels around body increasing chance of multiple cancers, and increased likelihood of death by CVD
  • deposition on leaves reduces light absorption therefore decreasing crop yield
  • sulphate reflect heat leading to cooling, but some particles reradiate heat which makes it warmer
55
Q

Describe the novel entities boundary

A
  • increasing use of new tech and materials
  • organic pollutants, radioactive materials, plastics, nano material etc
  • some chemicals are widely restricted due to their toxicity ie DDT and PCB
  • difficult to quantify the levels when the boundary is not yet defined
56
Q

What conclusions can be drawn about world fishing stocks since 1974?

A
  • overfished have increased, fully fished have increased, underfished decreased
  • fish stock decreasing which might lead to extinction due to unsustainable fishing
  • overfished have plateaud since 2007
57
Q

Why are farmed fish more susceptible to infection by lice than wild fish and why is eliminating lice a problem?

A
  • closely packed so lice can easily spread from fish to fish
  • cannot be easily killed as they’re resistant to pesticides
58
Q

Explain why it is importantly that farmed fish don’t escape

A
  • competition with wild for things like food, and would likely outcompete wild
  • reproduce with wild which decrease genetic diversity therefore diluting gene pool which can lead to extinction
  • spread of disease to wild fish also leading to extinction
59
Q

Two advantages of beaver reintroduction

A
  • restores biodiversity and reduces flooding
  • beavers from similar environments enable population genetics to be maintained & also better adapted to the environment
60
Q

Two reasons why people may be concerned about illegal and unregulated introduction of beavers

A
  • habitat loss due to flooding if beavers don’t adapt
  • introduce disease that impacts native beavers or other native organisms, leading to decreased biodiversity
61
Q

Two factors scientists have to consider when planning reintroduction of species

A
  • correct species for the habitat
  • resources available for their protection and establishment
62
Q

Explain how deforestation can directly impact the climate change boundary

A
  • trees absorb CO2 so chopping them decreases uptake
  • increased atmospheric CO2
  • combustion of trees releases CO2
  • decay of plant material also releases CO2
63
Q

Explain why more species have become extinct recently

A
  • human activity has caused environments to change at much quicker pace than animals can adapt
  • natural selection takes place over thousands of years
  • cannot adapt quick enough to new environments and so animals become endangered, then extinct
64
Q

How might biodiversity loss be delayed using conservation methods?

A
  • seed banks
  • legislation like CITES
  • restricting deforestation and habitat destruction
  • SSSIs and natural parks
65
Q

Why does the location of nest sites of reintroduced species need to be kept secret?

A

People steal chicks

66
Q

What is meant by an SSSI?

A
  • special site of scientific interest
  • protected from development and other changes
67
Q

Causes of species extinction

A

Pollution
Habitat loss
Climate change
Natural selection

68
Q

Name of the biological process involved in forest regeneration

A

Secondary succession

69
Q

Describe and explain the process of forest regeneration

A
  • presence of seeds
  • pioneer species return and alter conditions, encouraging other organisms
  • seral stages begin
  • climax community reached

A2 BIO UNIT3 (8 decks)

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