40125142
Beschreibung
Karteikarten von Darcey Griffiths, aktualisiert more than 1 year ago
|
Erstellt von Darcey Griffiths
vor fast 2 Jahre
|
|
| Frage | Antworten |
| Why are humans a risk | Major destruction to habitats via: agriculture, urban development, deforestation, mining and environmental pollution Also: loss of hedgerows; pollution such as PCBs and oil; hunting and collecting; competition from domestic animals, drainage of wetlands. Biodiversity crisis is happening as species are deprived of biotic and abiotic factors- so reproduce less successfully- pop no.s decrease- in some cases- extinction |
| Extinction | Natural process- current rate of extinction underlies biodiversity crisis - fossil record shows normal background extinction rate= 10^-6y^-1 - so 1 species in a million becomes extinct- humans have been responsible for death of megafauna ( very large animals eg giant ground sloth)- and have increased extinction rates x1000 to x10,000 Geological evidence shows that mass extinction has happened x5- vast majority of species becomes extinct eg due to low global temp, dissolved O2 shortage in oceans/ ocean acidification- sixth is underway- human activity |
| Endangered species | IUCN (International Union for Conservation of Nature) assesses plants and animals and grades them on vulnerability to extinction rated based on numbers, rate of decline and distribution- eg EX- Extinct, EW- extinct in the wild, VU- vulnerable |
| why species are threatened - natural selection/ non contiguous pops | Natural selection- Individuals= less suited to prevailing conditions- less reproduction- human activities causes quicker habitat change than genetic mutation can take place Non contiguous pops- Total no. individuals can suggest no.s are insufficient to continue species but if groups are isolated- can't interbreed= lack of genetic diversity |
| why species are threatened- hedgerows, crop dates | Loss of hedgerows- separate fields/ provide habitat for insects, nesting sites for birds/ reptiles, food, varied light intensity and water availability - act as wildlife coridoors- species can pass into new areas- without=reduced herbivores/ other consumers- causes reduction at higher trophic levels Farmers often sow crops in Autumn not spring- plants are not right height for building nests- decrease pop |
| why species are threatened-overhunting, competition | Overhunting: Trophy hunting- some countries allow/ charge for privilege claim only old/sick is target Traditional medical practices- use animal parts, bush meat industry- primates/ others killed for food, overfishing, agricultural exploitation Also competition from introduced species- eg eating eggs, |
| why species are threatened-pollution | Oil- shipped worldwide in supertankers- some too big to enter a port- causes leakage- eg when ships run aground Oil floats prevents oxygenation of surface water- animals that break through surface- covered by oil layer/ oil can wash up on beach be ingested PCB's- (polychlorinated biphenyls)= artificial substances- accumulate in food chain- ingested in food containing animal product- are neurotoxins, carcinogens and hormone disruptors- so banned in UK |
| Conservation | Conservation=The protection, preservation ,management and restoration of natural habitats and their ecological communities to enhance biodiversity while allowing for suitable human activity Maintains genetic diversity both in wild/ captivity- many methods at local, national and international levels Habitat protection- protects species that live there- communities act as living gene banks- Official designation recognises local nature reserves- can be small or large national reserves International co-op- restrict trade eg whaling/ ivory |
| Conservation- gene banks | Endangered species are protected/ entered into breeding programmes eg specialised zoos/ botanical gardens- records of mating= kept so genetic diversity can be increased by deliberate choice of parents Sperm banks- stores genes of economically important animals/ threatened species- can be sent instead of animal itself for use eg in breeding programmes |
| Gene banks P2 | Seed banks-stocks of traditional/ vulnerable species- seeds degrade over time- periodically samples need to be thawed/ germinated- when needed- plants reproduce- next gen collected- protected by countries eg as food source in disaster Rare breed societies- maintain older, less commercial varieties for special characteristics eg wool production Species reintroduction- follow successful breeding programmes can be reintroduced to habitat- may need to be trained to fear predators, forage and find shelter before release |
| Conservation P3 | Education-eg from Global orgs for public awareness or gov bodies- advises gov and other groups who affect wldlife, publish, proposes eco managing schemes, establishes nature reserves Legislation- EU habitats Directive has published range of measures- eg protect habitats, enhancing biodiversity, preventing harmful practices Eco tourism- Responsible travel to natural areas to conserve environment and improves wellbeing of locals- helps employ locals/ give money back to communities, educate visitors abt environment/ culture, co-op w/ locals to manage natural areas and conserve |
| Why conserve | Some ecosystems= especially at risk= vulnerable species - Ethics- each species represents particular combo of genes- has adapted to specific environment- uniqueness= valuable Agriculture/horticulture- animals used in these have been developed from those in wild- selective breeding increases genetic uniformity/ decreases rare alleles- breeders can neglect qualities eg resistance to temps/ disease- needs to be bred back to variety using wild plants/ sperm bank |
| Why conserve P2 | If environment changes- varied alleles can provide advantage- for species- those who carry will be selected to prevent extinction Potential medical use-plants used for antibiotics/ medicinal drugs - also- potential drugs not discovered - could be of immense value- can't afford to lose lants that could be needed. |
| Agricultural exploitation | Agricultural practices can conflict w/ maintaining habitats and biodiversity- efficiency and intensity of food production increases in relation to demand- eg development of fertiliser and pesticides - hedgegrows are removed for larger fields for machinery to prepare soil/ harvest Larger fields are used for monoculture (The agricultural practice of growing a single crop, breed or variety over a large area)- mixed crops= more microhabitats different, plants and so different animals- monoculture reduces species diversity |
| Monoculture effect on yield/ overgrazing | Same crop grown in same place for years= reduced yield as: roots= always same length- extract same minerals from same depth of soil- so intense cultivation increases inorganic fertiliser use, same crop= susceptible to same pests- increase in no so more insecticides, herbicides and fungicides needed Overgrazing causes unsustainable grassland-d - hooves compact soil- drive out air/ prevent water draining through- roots can't penetrate soil- grass can't grow |
| Deforestation | Deforestation= widespread as timber= used for building and fuel Felling/ removing trees damages other trees and organisms in the process, new roads are built for transfer of product, process causes lack of tree cover Consequences: -Soil erosion- (removal of topsoil which contains valuable nutrients)-tree roots bind soil together-deforestation on higher slopes of the valleys allows heavy rain to sweep topsoil down to flood plains below- leaves unfertile soil - Causes lowland flooding -Normally lower slopes, plants, humus and leaf litter soak up heavy rainfall- water only gradually released into soil-trees transpire returning water to atmosphere- without water evaporates from soil- reduces soil quality * |
| Deforestation P2 | *Evaporation returns water vapour to atmosphere slower than transpiration- deforested soil= wetter- Water fills soil's airspaces- O2 available to roots decreases Takes longer for wet soil to warm up- - germination and root activity= reduced- also cold/ damp- favours denitrifying bacteria- loses nitrates and so fertility -Less rainfall- water only returns to atmosphere by evaporation- slow- accelerates desrtification -Habitat loss/ less biodiversity - Reduces removal of CO2 from atmosphere by photosynthesis |
| Forest management- traditional | Traditional method= slash and burn- Small forest area= cut and burned- grow crops on soil fertilised w/ tree ash- when soil is no longer fertile-left to regenerate- sustainable only on small scale- effective for short-term agriculture, but= loss of biodiversity and more climate change. |
| Better forest management- coppicing | Coppicing- cutting down trees close to the ground and leaving them for several years to regrow- new shoots emerge from buds in stool- thicken- poles can be cut on rotation to produce timber of different widths - long rotation time increases sustainability- years between harvesting adjacent areas of the forest- variety of habitats develop- diverse |
| Better forest management- selective cutting | (Felling only some trees, leaving others in place)- Valuable on steep slopes as total removal of trees would leave soil vulnerable to erosion - SC helps maintain nutrients in soil/ minimises nutrients washed in nearby waterways How effectiveness is increased - planting trees optimum distance apart- too close- intra-specific competition - trees grow tall and thin - controlling pests and disease-healthier timber quality- fewwer trees cut as there is best use of land Cutting similar number of trees each year for long time allows ecosystem to be maintained- habitats left intact- species able to live |
| Preservation of native woodlands | Only 1% of UK is actually native woodland- need to preserve to maintain/ enhance biodiversity- need to plant more native species to give large range of habitats |
| Overfishing | (The rate at which fish are harvested exceeds the rate of reproduction)- - been increase in intensity and efficiency of overfishing eg technology development- / nets w/ small mesh catch young fish before they become sexually mature- fewer can reproduce- pop size decreases |
| Forms of fishing | Drift netting- pelagic fish live in surface waters- swim into a net suspended from floats stretched between 2 boats- but thousands of miles of nets can catch other species eg dolphins/ turtles Trawling- fish deeper in water are caught by large net dragged through water- catch whatever swims into it- equipment damages ocean bed- destroys habitats of molluscs/ other organisms |
| Overfishing effects | Overfishing has an effect on rest of food chain- eg removes prey for bigger fish- can affect multiple trophic levels and disrupt food webs Also damages lives of fishermen- must be balance between catching enough fish to make a living but leave enough reproducing fish to replenish stocks |
| Methods to regulate fishing/ allowing breeding stocks to recover | - keep mesh size larger-young fish can swim through- reproduce- supported by legislation- can't sell fish of certain size - Quotas- certain mass of fish can be brought- but sometimes people fish above quota and throw dead fish back into water Exclusion zones- prohibited fishing at certain points of the year- allow fish to reproduce |
| Methods to regulate fishing/ allowing breeding stocks to recover p2 | Consumers can eat only fish certified by Marine Stewardship Council- ensures fish are taken from sustainable sources Legislation- controls size of fishing fleets/ no. days spent at sea Fish farming can reduce overfishing- where fish are intensively reared in ponds/tanks or nets; sea-fish are usually reared in large netted areas of the sea- reduces predation, maintains food supplies eg control plankton- |
| Fish farming pros and cons P1 | 😊Less fish need to be harvested from the wild, allowing fish stocks to replenish. 😊 Fish have been selected for high growth rates and therefore large size and increased yield. ☹ Excess fish food, egesta and excreta fall out of the nets and can cause eutrophication in the marine habitats. ☹ Parasites and diseases spread quickly through the overcrowded fish. ☹ Toxins eg methyl mercury, PCB's, dioxins and pesticides concs are bigger than w/ wild fish- but small conc- little effect |
| Fish farming pros and cons P2 | ☹ Prophylactic antibiotic use to keep fish healthy may lead to antibiotic resistance and using pesticides to control parasites will harm marine invertebrates. ☹ If farmed fish escape they could outcompete wild fish or interbreed with them, passing on the alleles for fast growth, pushing wild fish to extinction – some farmed fish have been engineered to be triploid to avoid this issue. ☹ The feed is often made from harvested wild fish |
| Sustainability and decision making | Environmental monitoring- describes/ assesses current state of environment- when repeated can see trends- make predictions Air quality monitoring- conc of air pollutants monitored because of health effects associated- air pollution is carried by wind- must account when monitoring pollution- can use lichens Soil monitoring- look at soil structure/ density , water holding/ drainage capacity, ph, organic particles, earthworms/ other organisms- lichen can show type/ severity of metal contamination |
| Sustainability and decision making- water quality monitoring | Looks at water aspects includes: -chemical- due to acid rain/ greenhouse gases - essential to monitor due to harmful effects- environmental oestregens in water has increased due to - can have feminising effect on aquatic organisms Biological- animals can act as indicator for water quality- eg decline in pop can indicate acid rain early- mosses for metal concs Microbiological- Bacteria and viruses monitored- especially in drinking water/ water for sport- many sewage treatement plants don't sterilise water they release so water going into rivers can have harmful bacteria/ pathogens |
| Environmental impact assesments | Statistical analyses of environmental monitoring data done by software packages- ensures data can contribute to environmental impact assesments= docs that predict environmental prospects of proposed project which has environmental risk eg road building |
| Environmental impact assesments p2 | Topics need to be addressed eg description of project, environment (pop, abiotic factors, human use, cultural history), effects of project, ways to avoid impacts- alternative methods- need collaborative thinking- lots of field views to get legal framework- data collection essential for decision to be made |
| Planetary boundaries | (Limits between which global systems must operate to prevent abrupt and irreversible environmental change)- regulates stability of planetary systems and interactions of air, land and sea- 9 global systems- each have a tipping point beyond which change to factor and response are not linear - each boundary has estimated value below which they can continue to operate without extreme responses- lots of research done for this- hope political, economic/ other decisions will use this knowledge to support the biosphere |
| Planetary boundaries- representation | Circular graph- within inner green circle= safe operating space- between this and outer red circle- increasing risk= 'zone of uncertainty'- Beyond red circle which represents planetary boundary- high risk- events unpredictable- diagram p110 |
| Climate change boundary p1 | 1 of 2 core boundaries- (Crossing this planetary boundary would drive the earth into a new and unpredictable state w/ severe consequences for the biosphere)- even if we stopped emissions - global temp would still rise for decades due to amount of greenhouse gases present- effects= wind, ocean currents, rainfall patterns and precipitation ,destruction of rainforest and weakened carbon sinks in tundra and ocean could accelerate the Earth’s warming and climate change |
| Climate change boundary P2- biofuels | (A fuel made by a biological process eg anaerobic digestion rather than by geological processes eg long term heat and compression that formed fossil fuels) CO2 that biofuels release on combustion have only been recently removed from the atmosphere- growing more biofuel crops removes CO2 from atmosphere again- useful in reducing use of fossil fuels which release CO2 laid down millions of years ago- but growing them contrasts land needed for agriculture and requires lots of irrigation |
| Biofuels p2 | Also fossil fuels are used for transport- so target is 25% of worlds transport to use biofuels by 2050- 1st gen biofuels made w/ sugars and veg oil in arable crops- extracted- 2nd gen made from cellulose and lignin from woody crops- harder to extract |
| Cimate change boundary- biofuel concerns | social, economic, technical concerns- less food to eat or export/ energy crops often grown in monoculture sustainable biofuel production relies on sustainable planting/ efficient technical systems Deforestation to grow biofuel crops leads to soil erosion/ biodiversity loss Reduction in water availability- biofuels require irrigation water Combustion of biodiesel produces more nitrous gas NO2 than fossil fuel |
| Bioethanol | Commonest biofuel- aims to reduce greenhouse gases- used to mix 15% w/ petrol in most cars- made by fermenting carbs in sugar or starch crops Stages of production: *Plant material crushed - stored starches digested w/ carbs to release sugars * Sucrose crystallised out leaving molasses- rich in glucose and fructose *Glucose and fructose fermented by yeast to produce mixture containing ethanol * Mixture heated by burning fibrous waste from initial plant, - material and pure ethanol is distilled- diagram p112 |
| Biodiesel | Widely used biofuel- made from veg oils including soya, rapeseed and palm oil- can be made from algae- crops are grown for long chain fatty acid content- acids are reacted w/ an alcohol common= methanol to produce methyl linoleate (biodiesel) mathanol+ linoleic acid---> methyl linoleate+ water |
| Biodiesel P2 | contains less carbon and more hydrogen than petrodiesel- 60% of Carbon emissions- also produces less carbon particles/ carbon monoxide but more nitrous oxide- pure biodiesel can be used in cars but usually mixed |
| Biogas | Mixture of gases comprises of 60% methane and 40% CO2 made by bacterial digestion of biodegradagble waster materialseg animal and human waste or energy crops- occurs in 3 main stages- last is anaerobic- |
| Biogas stages | 1) Macromolecules in the waste are aerobically digested by amylases, proteases and lipases to sugars, amino acids and glycerol 2)Acetogenesis= aerobic process- produces short chain fatty acids especially ethanoic acid- carbon monoxide and hydrogen gas are produced as O2 is used up 3) methanogenesis- anerobic C6H12O6---> 3CH4+3CO2- solid material left is dried- used as biofuel or fertiliser biogas produced industrially or naturally at landfills-can be tapped off- used as fuel |
| biosphere integrity boundary | 2nd core boundary- crossed-describes biodiversity loss and extinctions. The cause is increased demand for food, water and natural resources. These are increasing in intensity and the boundary has been crossed. Habitats are being lost rapidly, e.g. coral reef bleaching caused by ocean acidification and rising temperatures-organisms work together eg mineral recycling/ absorbing CO2 but humans cause rapid habitat change- marine, tundra, coral reefs and coastal plains are of major concern need to monitor to see which species should be prioritised for gene banks- also need education reduce activity causing biodiversity loss |
| Land System Change Boundary | This describes land converted for human use, e.g. deforestation for agriculture. Globally, this is approaching red- also deforestation to make biofuels- Urban development= important factor- land for biofuels contradicts need for agriculture- also land that could be used for crops for locals is used for crops for export- 2015 data suggests- already been crossed- to reverse farming should be concentrated to most productive areas/ global reduction in meat consumption- reduce land under cultivation |
| Biochemical Flows boundary | Biogeochemical flows= recycling of minerals through biotic and abiotic components of ecosystem- cycles- eg carbon, sulphur, phosphorus and nitrogen-essential for maintaining availability of elements in ions absorbed and transmited through web- intense use of fertilisers= boundaries for nitrogen and phosphorus= crossed so cycles= no longer self sustaining- pollution eg eutrophication damages ecosystems- reduce fertiliser use and has been attempts to transfer nitrogen fixing genes to crops- not yet done |
| Ozone depletion boundary | Ozone depletion The ozone protects the earth from UV radiation from the sun. Halogenated hydrocarbons eg CFC's alter the equilibrium of ozone and O2 in usually in the stratosphere (3O2<----> 2O3) In the stratosphere ultraviolet light causes CFCs to release chlorine as free radicals; free radicals break down ozone. The use of CFCs in aerosols and refrigeration has been reduced globally, reversing the depletion of the ozone layer- started as ozone reached tipping point hole in layer over antartica and the ozone absorbs UVB- ultraviolet radiation- strongly absorbed by DNA and skin so cancer increased- only boundary where crossing has been deliberately avoided by action following international agreement |
| Ocean acidification boundary | This is owing to increased CO2 dissolving into oceans as hydrogen carbonate releasing hydrogen ion. Hydrogen carbonate ions break don to carbonate ions and hydrogen ions. More H+= lower ph. H20 + CO2 --->H2CO3---> H+ + HCO3- - Low ph- calcium carbonate leaches out of mollusc/ coral shells and arthropod skeletons- vulnerable to physical/ chemical attack CaCO3+H+ --->Ca2+ + HCO3- - This has a knock-on effect to food chains and webs, and could drastically reduce fish stocks. This boundary could be avoidable (reduction in fossil fuel combustion ) but is approaching amber |
| Fresh water use boundary | (Fresh water=Fresh water has a low conc of dissolved salts eg <0.05% w/v- sometimes called sweet water- not salt water)- many organisms eg most higher plants and mammals need this- not yet quantified. Globally, fresh water is becoming scarce because of modification of water bodies and land use change. Desalination of sea water may ease the situation- usually occurs naturally on surface- ice sheets, ice caps glaciers, icebergs, ponds, bogs, lakes and rivers- mainly from precipitation- not always drinkable |
| Fresh water availability has decreased- why? | -Changing landscapes-eg draining wetlands, deforestation and soil erosion- affects flow of fresh water and so water cycle -Agriculture- strain on local fresh water source damages ecosystem- may use water pumped from underground aquifers but will not be refilled in future -Increased demand as people move to warm climates- if there's not fresh watter locally needs to be imported -Water pollution- eg eutrophication- makes itt unsuitable for use- eg cyanobacteria causes algal bloom when high nitrate conc- releases neurotoxins - Increased pop/ increased use |
| How climate change alters fresh water availability | Glaciers melt- fresh water initially increases- but may be flooding- availability decreases--- drought Thermal expansion of ocean water- raised sea levels- contaminates fresh water in coastal regions Semi arid and arid areas are vulnerable due to rain- their water source- occurs over short space- already disrupted |
| Provision of fresh water | Several methods for increasing availability of fresh water - Water conservation- eg suggested non food crops (eg biofuels and cotton) shouldn't be irrigated -Water efficiency -Wastewater reclamation for irrigation and industrial use - Urban runoff-/ storm water capture- recharging groundwater - Drip irrigation systems- reduce water volume used for irrigation of food crops as water containing fertiliser is dripped directly into roots of individual plants - Desalination |
| Desalination | (The removal of minerals from saline water)- - leaves slt and recycled wastewater- doesn't rely on rain- can have high energy use- so maybe expensive- but may be solution for dry areas unless its poor , far from sea or high elevation |
| Methods desalination | Solar stills distill seawater using heat from sun- saltwater converted entirely- no air pollution or warm awtaer discharge to endager local lakes/ rivers Reverse osmosis- seawater seperated from fresh by fine selectively permeable membrane - water expected to move by osmosis from fresh to seawater- but pressure applied to seawater- moves against water potential gradient across membrane- requires energy- most use fossil fuels or nuclear power - but some use waste heat to generate steam as drive for process. |
| Environmental problems from desalination | Brine (Concentrated sodium chloride solution) is discharged- potential environmental impact of such high salt concentration is avoided by diluting the brine before returning it to the ocean- Brine is denser than seawater because of its high solute conc- sinks and damages seabed ecosystem Burning of fossil fuels to generate heat to run system |
| Atmospheric aerosol loading boundary | Aerosols are microscopic particles put into atmosphere by fuel combustion and by creating dust from digging and quarrying- atmospheric pollutants. Their effects in the atmosphere are complex and they have yet to be quantified. - Worsens respiratory issues eg PM10 10 um in diameter forms aerosol and lodges in lungs when inhaled Deposition on leaves reduces light absorption for photosynthesis so crop yields are reduced Sulphates in aerosols reflect sunlight provide some cooling effect but some particulates eg soo absorb sunlight- reradiate- increase warming Aerosols= so variable unable to suggest planetary boundary yet |
| Introduction of novel entities boundary | These are emission of toxic and longlived substances, such as heavy metals, radioactive materials and synthetic organic pollutants. These can cause reduced fertility and genetic damage, e.g. DDT dramatically reduced bird populations. These have yet to have a quantified boundary. Some substances eg DDT and PCB- so toxic- banned widely- some chemicals may interact and have additional harmful impact- aerosols- boundary not identified |
Möchten Sie mit GoConqr kostenlos Ihre eigenen Karteikarten erstellen? Mehr erfahren.