Human Impact on the environment

Question 1

If trees are cut down from a forest with machinery, why could this increase the concentration of co2 in the atmosphere?

Answer 1

• Combustion of diesel fuel by machinery releases CO2 gas into the atmosphere
• Lack of trees means less photosynthesis to fix co2 (so less CO2 being used up
• Discarded plants/branches/leaves/debris gets decomposed by saprophytes

Question 2

What are the effects of human activities on the carbon cycle?

Answer 2

-Deforestation
-Climate change
-Global warming
-Ocean warming

Question 3

How does deforestation affect the carbon cycle?

Answer 3

•Increases the carbon dioxide content in the atmosphere:
removal of trees so less uptake of CO2 from the atmosphere due to less photosynthesis.
-Plants store carbon as biomass so burning the woody parts of trees releases carbon dioxide into the atmosphere.
-Forest is replaced by crops which store less carbon dioxide and when crops die, decomposers undertake decay, releasing carbon dioxide.
-Forest is often replaced with cattle that produce high levels of carbon dioxide and greenhouse gases such as methane.

Question 4

What is the cause of climate change and what is the reason?

Answer 4

-cause is thought to be the huge rise in atmospheric carbon dioxide levels and the rise in other greenhouse gases e.g. carbon dioxide, methane, nitrous oxides and water vapour.
-The two main reasons for the rise in carbon dioxide are combustion, the burning of fossil fuels releases carbon dioxide that was previously locked up and deforestation.

Question 5

How has carbon dioxide lead to global warming and what has this caused?

Answer 5

-CO2=important greenhouse gas, as it absorbs radiation from the Earth. If it accumulates in excess, it leads to global warming.
-resulted in increased frequency of extreme weather conditions, polar ice caps melting and an increased frequency of forest fires.
-Consequently, species distribution may change; plants and animals may be driven to extinction if they cannot find a suitable new habitat fast enough, which reduces biodiversity.
-In some regions, there may be increased crop yields, but pest populations may also increase.

Question 6

How does ocean warming link to CO2?

Answer 6

Oceans can store a lot of heat so there is a time lag between warming of the atmosphere (which Is linked to global atmospheric CO- levels) and the warming of the ocean.

Question 7

What does an increase in CO2 levels in water result in?

Answer 7

-CO2 + H2O= H2CO3
-this means increase in H+ so decrease in pH
-so water dissolved shells/skeletons

Question 8

What is agriculture particularly vulnerable to and what is it affected through

Answer 8

the impacts of climate change and is affected through changes in temperature, and timing and quantity of rain (Extreme events, such as droughts and floods are likely to be more frequent due to climate change)
-As global warming increases, fresh water will be critical to sustain food production and feed the growing human population.

Question 9

What are possible changes in farming practices due to climate change?

Answer 9

-Feeding cows high-sugar grasses with less cellulose to reduce the release of the greenhouse gas methane.
-Improving drainage to aerate water-logged and anaerobic soils. Re-instating meadows.
-Salt-tolerant crops to overcome rising sea levels.
-Keeping the soil healthy by using minimal preparation of land for growing crops (tillage) and cover crops like clover to protect and improve soils between crops
-Drought-resistant crops to tackle the low and fluctuating water supply
-Rotating crops to reduce pests and mineral depletion.

Question 10

What is carbon footprint?

Answer 10

the total amount of carbon attributable to the actions of an individual, a product or service over a period of one year

Question 11

How can we reduce our carbon footprint?

Answer 11

Recycling packaging material
•Driving less
•Using less air-conditioning and heating – insulating, clothing etc
•Choosing a diet low in animal protein, especially red meat
•Avoiding food waste – turn it into compost
•Planting trees

Question 12

What is the nitrogen cycle?

Answer 12

the flow of organic and inorganic nitrogen within the abiotic and biotic components of an ecosystem, where there is an interchange between nitrogenous compounds and atmospheric nitrogen.

Question 13

Why is nitrogen important to all living organisms?

Answer 13

-building blocks of nucleic acids- (DNA,RNA)
-amino acids for protein synthesis (nitrogen is in the NH2 amine group for protein synthesis)
-Nitrogenous bases in nucleotides (a,t,g,c,u)
-chlorophyll
-ATP is a nucleotide (contains adenine, ribose and 3 phosphate groups)

Question 14

How do plants and animals get nitrogen?

Answer 14

-Plants and animals cannot use atmospheric nitrogen and so nitrogen enters the food chains when plants absorb ammonium or nitrate ions through their roots.
-Nitrogenous compounds then pass to consumers when they consume plants.

Question 15

By which processes do nitrates get taken up by plant roots?

Answer 15

-Facilitated diffusion
-Active transport

Question 16

What are two pathways that these ions can take when travelling through the cortex cells of a plant root?

Answer 16

Symplast – water & ions move through cytoplasm & plasmodesmata
Apoplast – water & ions move through the cell walls

Question 17

What are the 5 main processes in the nitrogen cycle?

Answer 17

-Ammonification
-Nitrification
-Nitrogen fixation
-Assimilation
-Denitrification

Question 18

What is ammonification?

Answer 18

Decomposers (saprotrophs and detritivores) result in the decay of dead plants and animals, faeces and urine into ammonium ions

Question 19

What is nitrification?

Answer 19

-The ammonium ions produced by decomposers are converted into nitrites and then nitrates by nitrifying bacteria. -Aerobic conditions are required for this process.
-Plants can then absorb these nitrate ions and incorporate them into amino acids, nucleotides and chlorophyll.

Question 20

What are the key nitrifying bacteria?

Answer 20

-Nitrosomonas convert ammonium ions to nitrites.
•Nitrobacter convert nitrites to nitrates .

Question 21

What is nitrogen fixation?

Answer 21

Nitrogen-fixing bacteria can directly fix nitrogen gas into ammonium ions.

Question 22

What are key nitrogen-fixing bacteria?

Answer 22

•Azotobacter free-living in the soil.
•Rhizobium found in root nodules of leguminous plants.

Question 23

What are rhizobium and what do they do?

Answer 23

-symbiotic bacteria found in root nodules of legumes, e.g. clover and pea plants.
-When nitrogen gas diffuses into the root nodule, rhizobium produces nitrogenase enzyme which catalyses the fixation of nitrogen gas into ammonium ions.
-These ammonium ions can then be converted into amino acids for use by the plant.
-However, nitrogenase is inhibited by oxygen.
-Therefore, Haemoglobin is present in root nodules to bind with the oxygen. -The presence of haemoglobin gives them a pink colour.

Question 24

Why can the relationship between the bacteria in the root nodule and the legume be classed as a symbiotic relationship?

Answer 24

Bacteria gain sugars from plant photosynthesis, plant gains nitrogenous compounds.

Question 25

What is assimilation?

Answer 25

-The formation of organic nitrogen compounds (e.g. amino acids) from inorganic nitrogen compounds present in the environment.

Question 26

What is denitfrication?

Answer 26

-Denitrifying bacteria (e.g. Pseudomonas) convert nitrate from the soil into nitrogen gas. -This is a problem as it removes useful nitrogenous compounds from the soil. -Anaerobic conditions are required for this and it occurs most often in waterlogged soils.

Question 27

What does rhizobium do?

Answer 27

Fix nitrogen gas into ammonium ions root nodules

Question 28

What does azobacter do?

Answer 28

fix nitrogen gas into ammonium ions in the soil

Question 29

What does nitrosomonas do?

Answer 29

Convert ammonium ions into nitrites in nitrification

Question 30

What does nitrobacter do?

Answer 30

convert nitrites to nitrates in nitrification

Question 31

What are human activities to aid the nitrogen cycle?

Answer 31

-Ploughing and drainage of soil to improve aeration -Cultivation in soils lacking nitrogen -Application of artificial fertilisers and manure to soil that will enable a greater yield of crop plants.

Question 32

What does ploughing and draining of soil do?

Answer 32

-improves aeration -this enables nitrifying bacteria to convert ammonium ions into nitrate and prevents denitrifying bacteria from completing denitrification.

Question 33

What does cultivation of legumes in soils lacking nitrogen do?

Answer 33

-Cultivation of legumes in soils lacking nitrogen so that Rhizobium will carry out nitrogen fixation within the plants and then when the plants die these nitrogenous compounds will enter the soil to be broken down by decomposers in ammonification.

Question 34

What do fertilisers contain?

Answer 34

Nitrates, potassium and phosphate

Question 35

What do crop fertilisers need?

Answer 35

-Nitrate – nitrogen for amino acids, nucleic acids. -Potassium for stomatal opening -Phosphate for nucleic acids + ATP

Question 36

What is the process of eutrophication?

Answer 36

1.Fertilisers leach into watercourses, increasing levels of nutrients. 2.There is a bloom of algae, blocking out the light to plants below. 3. These plants die as they can't photosynthesis. 4. Decomposers such as bacteria and fungi decompose the dead organic matter. 5. As these bacteria respire aerobically they use most of the available oxygen. 6. This creates a biological oxygen demand (BOD). 7. Aquatic animals die due to lack of oxygen. 8. Anaerobic bacteria then flourish.

Question 37

How can high nitrate levels in waterways be overcome?

Answer 37

by- -Restricting the amount of fertiliser added to soil. -Only applying fertiliser when crops are actively growing so that it is readily taken up and does not remain in the soil. -Digging drainage ditches for minerals to concentrate in. This however has lead to a drop in invertebrate biodiversity and has reduced species diversity in nearby grasslands.

Question 38

What are endangered species

Answer 38

those that are at serious risk of extinction.

Question 39

What is extinction?

Answer 39

-when there are no living members of a species left. -It is a natural process

Question 40

What are the main threatens to species?

Answer 40

-Natural Selection -Non-contiguous Populations (LOSS OF HABITAT) -Deforestation -Drainage of wetlands -Hedgerow loss -Crop Sowing seasons -Overhunting -Competition from other introduced species -Pollution

Question 41

What is the explanation and an example of natural selection as a threat to species?

Answer 41

-Humans are changing environments faster than new mutations allow organisms to adapt -mutations in DNA can create new beneficial alleles needed for advantageous phenotype- this increases survival and reproduction so species can pass alleles to next generation (but mutation rate is too slow to respond) -Javan tiger

Question 42

What is the explanation and an example of non-contagious populations as a threat to species?

Answer 42

-If small populations are isolated from each other and are unable to interbreed there may not be enough genetic diversity to ensure a healthy population. -smaller isolated populations= smaller gene pool means fewer alleles -Black rhinos in Africa

Question 43

What is the explanation and an example of deforestation as a threat to species?

Answer 43

-Permanent removal of trees removes habitats. -Habitat=site of reproduction/feeding/shelter -Javan tiger

Question 44

What is the explanation and an example of drainage of wetlands as a threat to species?

Answer 44

-Wetlands are drained to allow agriculture or building. This destroys habitats -Large copper butterfly is now extinct in the UK.

Question 45

What is the explanation and an example of hedgerow loss as a threat to species?

Answer 45

-Removal of hedgerows which have separated fields for centuries removes breeding sites, feeding sites and wildlife ‘corridors’ which allow animals to move from one area to another Dormouse may face extinction in the UK

Question 46

What is the explanation and an example of crop sowing seasons as a threat to species?

Answer 46

-Sowing during autumn rather than spring means plants are unsuitable heights for birds to build nests -Skylark and lapwing are in decline.

Question 47

What is the explanation and an example of overhunting as a threat to species?

Answer 47

-For trophies, traditional medicine, ‘bush meat’, overfishing, agricultural exploitation -Pyrenean Ibex

Question 48

What is the explanation and an example of competition from other introduced species as a threat to species?

Answer 48

-Domestic animals and accidentally introduced animals predate or outcompete native species -Dodo, red squirrels in uk

Question 49

What is the explanation and an example of pollution as a threat to species?

Answer 49

-Pollutants kill organisms or make it more difficult for them to survive in their habitat -Oil spills, PCBs

Question 50

What is conservation?

Answer 50

the protection, preservation, management and restoration of natural habitats and communities; enhancing biodiversity whilst still allowing human activity

Question 51

What are conservation techniques?

Answer 51

-International cooperation -Gene banks -Legislation -Ecotourism -Protecting habitats -Education

Question 52

What does international cooperation do?

Answer 52

(e.g. restricting trade in ivory) -Helps prevent species becoming endangered/ extinction of endangered species

Question 53

What do gene banks do?

Answer 53

-Conservation of existing gene pools involves: -Breeding programmes in zoos & botanic gardens. -Re-introduction of species e.g. red kites. -Sperm banks. -Seed banks. (keeps rare alleles- may help organisms survival)

Question 54

What is legislation?

Answer 54

-National & international laws protecting habitats and wildlife e.g. EU habitats preventing overfishing by imposing fishing quotas, preventing overgrazing -large net size that some mature fish out of the net- maintains breeding populations -limit size of boats/fishing and only certain times of the year

Question 55

What does ecotourism do?

Answer 55

aims to minimise the negative impacts of tourism by: -Contributing to conservation -Employing local people -Educating visitors -Cooperating with local people to manage area

Question 56

What is protecting habitats?

Answer 56

-Protecting a particular area, e.g. from urban development. -This includes National Parks, sites of special scientific interest (SSSI) e.g. Dunham Park.- maintains natural habitats for breeding

Question 57

What is education?

Answer 57

Public awareness campaigns on global or national scales e.g WWF, Countryside commission.

Question 58

Why is conservation of existing gene pools important?

Answer 58

-Ethical reasons: Each species is a unique combination of genes and alleles and so is therefore valuable. -Agriculture and horticulture: Breeds of animals and plants used in agriculture and horticulture have been selectively bred so may lack rare alleles that could be important in the future (e.g. disease resistance). Wild plants and animals can act as a gene bank for these alleles which animals and crop plants can be bred with. -Environmental changes: A large, varied gene pool increases the chance of a species surviving environmental change. -Potential medical uses: Plants and animals may have the potential to help in the development of new drugs or other medial tratmante hu niscosins habitats we allow this potential to be

Question 59

What is Re-introduction of species?

Answer 59

the reintroduction of an organism to its native habitat, an area from which it has been previously lost.

Question 60

What does reintroduction aim to do?

Answer 60

-re-establish a viable population of the species within its native habitat and can be a positive conservation strategy. -E.g. Introduction of beavers into UK, Wolves in Yellowstone national park, Siberian tiger introduction project.

Question 61

What factors must scientists consider if reintroduction to be successful?

Answer 61

-Habitat: The receiving habitat is suitable, the effect of species introduction on habitat or effect on biodiversity -Research: The resources and expertise are available for the establishment and protection of the reintroduced species -Consultation: This would occur between neighbouring landowners and local stakeholders, to make sure that the majority of those consulted do not oppose reintroduction -Correct individuals: A suitable disease-free donor population is identified, and the correct species is re-introduced

Question 62

Why can re-introduction into areas where there are no well-established populations can help?

Answer 62

•there are fewer predators •less intraspecific competition for food/ nest sites/habitats •less likely to pass on disease as fewer numbers (initially)

Question 63

Why could Illegal or unregulated re-introduction of species be a concern?

Answer 63

•Introduction of disease eg.TB in beavers •Destruction or loss of habitat and other effects on ecosystem •The wrong species would not be so well adapted

Question 64

What causes agricultural exploitation?

Answer 64

-There exists a conflict between agricultural production and conservation- After the second world war the government encouraged farmers to cultivate more land to maximise food crop yields.

Question 65

What changes to farming methods were introduced with wide envronemental implications?

Answer 65

-Removal of hedgerows to make larger fields -Monoculture -Overgrazing

Question 66

What does the removal of hedgerows to make larger fields do?

Answer 66

allows farmers to use larger machinery to plough the soil and harvest crops.

Question 67

What effect will removal of hedgerows to make larger fields have on biodiversity

Answer 67

reduces biodiversity by removing breeding sites, feeding sites and wildlife ‘corridors’ which allow animals to move from one area to another

Question 68

What is monoculture?

Answer 68

Single crops, e.g. maize, wheat, barley are grown in large fields.

Question 69

Why will monoculture have an effect on biodiversity?

Answer 69

as it only provides one habitat, reducing the number of different microhabitats that would be available in an area with mixed crops

Question 70

How does monoculture affect the concentrations of nutrients in the soil?

Answer 70

Roots grow to same length and extract the same minerals from the same depth of soil, reducing the concentrations of nutrients in the soil and increasing the use of inorganic fertilisers.

Question 71

When does overgrazing occur?

Answer 71

when plants are exposed to intensive grazing for extended periods of time

Question 72

What can over grazing lead to?

Answer 72

-soil erosion and desertification -Hooves of cattle compact soil, driving out air and preventing water drainage. -Roots cannot penetrate the soil and grass for grazing cannot grow.

Question 73

What is deforestation?

Answer 73

the removal of trees in an unsustainable way.

Question 74

What are reason for deforestation?

Answer 74

•Demand for timber as a construction material. •Wood used for fuel. • To make paper and cardboard packaging. •To clear the land for farming. •To improve transport infrastructure by building new roads. •Targeting high value trees e.g. teak and mahogany.

Question 75

What are consequences of deforestation?

Answer 75

Global climate change Destruction of habitats Soil erosion

Question 76

How does climate change affect deforestation?

Answer 76

-If trees are cut down less carbon dioxide is removed from the atmosphere by photosynthesis. -Felled trees will also increase the concentration of carbon dioxide in the atmosphere because:- •Combustion of trees releases carbon dioxide from biomass •Logs decompose and decomposers release CO2 •Fossil fuels burnt in transport of logs

Question 77

What causes soil erosion?

Answer 77

The removal of topsoil which contains valuable nutrients.

Question 78

What can the removal of trees in higher slopes lead to? (soil erosion)

Answer 78

-lowland flooding after heavy rainfall. -The topsoil in the sloped areas can also be swept away by the rain.

Question 79

How are transpiration and evaporation affected by deforestation?

Answer 79

-Evaporation from soil returns water more slowly to the atmosphere than transpiration does, leading to reduced local rainfall and accelerated desertification.

Question 80

How is oxygen in soil affected by deforestation?

Answer 80

- As the soil becomes wetter water fills the soil’s airspaces and the oxygen available for roots decreases.

Question 81

How is soil temperature affected by deforestation?

Answer 81

-It takes wet soil longer to warm up than dry soil, meaning these soils are cold. (soil temp reduced) -This reduces germination and root activity

Question 82

How is denitrifying bacteria affected by deforestation?

Answer 82

Cold, damp soil favours the growth of denitrifying bacteria so soils lose inorganic nitrogen compounds and so is less ‘fertile’.

Question 83

What is forest management?

Answer 83

-sustainable replanting and regeneration of forests.

Question 84

What other techniques can be employed for forest management?

Answer 84

-Coppicing -Selective cutting -Long rotation times -Planting trees optimum distances apart -Controlling pests and diseases

Question 85

What is coppicing?

Answer 85

-A tree trunk is cut but a ‘stool’ a few cm high is left. -New shoots emerge from the stool and grow into ‘poles’. -The poles can be cut on rotation to produce timber of different widths . -Coppiced plants can regenerate over long periods of time.

Question 86

What is selective cutting?

Answer 86

-Some of the larger trees are felled whilst others are left in place. -particularly useful on steep slopes and near rivers because on steep slopes the total removal of trees would leave the soil vulnerable to soil erosion, selective cutting helps maintain nutrients in the forest soil and minimise the amount of soil which is washed into rivers and other waterways.

Question 87

What are long rotation times?

Answer 87

Letting trees grow for a long period of time before cutting them down.

Question 88

What effect will a long rotation time have on the habitat diversity and associated biodiversity of an area?

Answer 88

It increases it as it provides more stable, long term habitats

Question 89

What does planting trees optimum distances apart do?

Answer 89

Reduces intraspecific competition which can lead to trees growing tall and thin and so producing poor quality timber.

Question 90

How does controlling pests and diseases help forest management?

Answer 90

Ensures trees grow well and produce high quality timber, this then means that fewer trees need to be felled and the best use is made of the land.

Question 91

Why is it important that native woodlands are preserved (controlling pests and diseases)?

Answer 91

Maintain and enhance biodiversity by preserving very old habitats and ensuring there is a wide range of habitats available

Question 92

Why is overfishing a problem?

Answer 92

because increased intensity and efficiency of modern fishing is having a highly negative effect on the populations of some marine organis

Question 93

What does using small mesh nets mean? (overfishing)

Answer 93

-means smaller, juvenile fish which are not sexually mature are unable to escape nets. -This reduces the future breeding population, over time this leads to fewer offspring and reduces genetic diversity.

Question 94

What are the effects of overfishing on other wildlife?

Answer 94

•Drift nets can catch non-target species such as turtles or dolphins •Trawling damages the sea floor habitat of organisms such as some molluscs - e.g. clams •Can catch organisms that are the prey of other species - e.g. catching capelin which is eaten by cod or krill which is eaten by some whales, seals, penguins squid and fish, which can affect whole food webs.

Question 95

What are controls that can be used to reduce the impact of overfishing?

Answer 95

-Impose quotas on catches so only a certain mass of fish can be landed. -Ensure mesh sizes of wets are large enough to let young fish escape. -Enforcement of exclusion zones. -Legislate size of fishing fleets and number of days at sea. -Encourage consumers to eat sustainably sourced fish

Question 96

What additional proves can imposing quotas on catches so only a certain mass of fish can be landed?

Answer 96

Too many fish are still caught but those over quota are discarded

Question 97

Why is it important to ensure mesh sizes of nets are large enough to let young fish escape?

Answer 97

To ensure the young fish can grow and become sexually mature and then reproduce

Question 98

What areas and what times of year should fishing boats be unable to fish? (Enforcement of exclusion)

Answer 98

in areas where fish breed (breeding grounds) and during (spawning) the breeding season

Question 99

What can fish farming be used to do?

Answer 99

-to overcome the problem of overfishing but can cause other problems. -It is used for species such as salmon and trout in the UK.

Question 100

Where are fish bred and grown to maturing in fish farming?

Answer 100

grown to maturity in enclosures in ponds, lakes, estuaries or in tanks on land.

Question 101

What are advantages of fish farming rather than traditional livestock?

Answer 101

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

Question 102

What are fish farm problems?

Answer 102

-Diseased Fish -Pollution -Resource use -Environmental Toxins -Environmental degradation

Question 103

Why are diseased fish a fish farm problem?

Answer 103

Salmon farms often have a high density so can easily transmit disease. -Large amounts of antibiotics and pesticides have to be used to keep the fish healthy. -The pesticides used can harm other organisms such as marine invertebrates. -Escaped fish can also pass parasites and other infections to wild populations.

Question 104

What is pollution a fish farm problem?

Answer 104

Effects the ecological balance of waterways, waste from fish farms can get into water around the fish pens and lead to eutrophication

Question 105

Why is resource use a fish farm problem?

Answer 105

Farmed fish can eat a large amount of food, which is often other fish, this is inefficient.

Question 106

Why are environmental toxins a fish farm problem?

Answer 106

Environmental toxins e.g. PCBs and pesticides are more concentrated in farmed fish than in wild fish.

Question 107

Why is environmental degradation a fish farm problem?

Answer 107

Local environment can be damaged e.g. shrimp industry leading to salinisation of soil and groundwater leading to destruction of mangroves.

Question 108

What were planetary boundaries designed to do?

Answer 108

-to define a ‘safe operating space for humanity’. -Scientists believe that once human activity has passed certain thresholds (planetary boundaries), there is a risk of ‘irreversible and abrupt environmental change’.

Question 109

What does research indicate about global environmental change?

Answer 109

that since the Industrial Revolution, human actions have gradually become the main driver of global environmental change.

Question 110

What is the definition of a planetary boundary?

Answer 110

A safe operating level for a global process (that humans effect) under which any damage is reversible

Question 111

What are the planetary boundaries that have been crossed?

Answer 111

-Biodiversity boundary -Climate change boundary -Nitrogen Boundary -Land use boundary -Fresh Water Boundary -Ocean acidification boundary -Ozone boundary -Chemical pollution boundary -Aerosol boundary

Question 112

how has the biodiversity boundary been crossed?

Answer 112

-Human activity has caused environmental changes to happen too fast for natural selection to produce organisms that are adapted to this changing environment- As a result, many species have become extinct. -Habitat change in regions such as tundra (temperature rises) and marine environments (pollution of oceans with acid, oil and sewage)- has caused concern and biodiversity has been significantly reduced in these regions. •Coral reef bleaching and coastal plain submersion due to rising sea levels are also reducing biodiversity.

Question 113

How can we do to help the biodiversity boundary?

Answer 113

-Monitoring biodiversity, collecting materials for gene banks, raising public awareness to reduce human behaviour that has generated biodiversity loss

Question 114

How has the climate change boundary been crossed?

Answer 114

-Greenhouse gases are continually being added to the atmosphere. -This is causing an increase in global temperature, climate change, rise in sea levels

Question 115

What can we do to help the climate change boundary?

Answer 115

-The production of biofuels – these fuels are made by biological processes. -As the growth of biofuel crops takes in CO2 from the atmosphere, the release of CO2 when they’re burnt has less impact – carbon neutral. -Biofuels can be made by anaerobic digestion of plant material.

Question 116

How has the nitrogen boundary been crossed?

Answer 116

•Denitrification due to waterlogged soils. •Use of agricultural fertilisers leading to eutrophication.

Question 117

What can we do to help the nitrogen boundary?

Answer 117

-Planting fields of legumes to increase nitrogen fixation. -Ploughing soil to improve aeration and prevent anaerobic conditions.

Question 118

How has the land use boundary been crossed?

Answer 118

-Deforestation to allow for farming and urban development has led to a conflict between the need to grow food and the need to grow biofuels and protect natural habitats

Question 119

What can we to help the land use boundary?

Answer 119

-Changing farming practices to concentrate it in the most productive areas. -Reducing consumption of meat would reduce land being cultivated.

Question 120

How is the freshwater boundary avoidable?

Answer 120

-Many organisms must have access to fresh water to live. -The fresh water boundary would be crossed if organisms do not have enough fresh water to survive. -Only 2.5% of water on earth is fresh water, it is important as it only contains a low concentration of dissolved salts. -The decrease in supply of freshwater is due to changing landscapes, agriculture, increased demand from humans, water pollution and climate change.

Question 121

What can we do to help the fresh water boundary?

Answer 121

-Water conservation (not irrigating non-food crops), water efficiency, waste water reclamation and drip irrigation systems. -Desalination is an important technology that removes minerals from salt water to produce fresh water.

Question 122

How is the ocean acidification boundary avoidable?

Answer 122

-The pH of the oceans is decreasing due to dissolving carbon dioxide forming carbonic acid which releases hydrogen ions. -Low pH leads to mollusc, coral shells and arthropod exoskeletons softening, making them vulnerable. -Gill structure in fish is also affected by low pH and their functioning is damaged.

Question 123

What can we do to help the ocean acidification boundary?

Answer 123

Reduction in the burning of fossil fuels

Question 124

How has the ozone boundary been avoided?

Answer 124

-Chloro-fluorocarbons (CFCs) favour the breakdown of the ozone. -CFCs were widely used in spray cans, solvents, refrigerator coolants and manufacture of food and drink containers. -This resulted in the thinning and development of a ‘hole’ in the ozone layer. -The use of CFCs in spray cans was banned in 1978. The ozone layer is now recovering naturally.

Question 125

Why is the pollution boundary unquantified? (so variable we cannot suggest a boundary)

Answer 125

-Organic pollutants, radioactive materials, nanomaterials and micro-plastics. -These could all interact with each other and produce harmful effects.

Question 126

Why is the aerosol boundary unquantified?

Answer 126

•Atmospheric aerosols are the microscopic particles put into the atmosphere by combustion of fuels and by creating dust from digging and quarrying- these can lead to respiratory problems and cause death from lung disease. •Sulphates in aerosols reflect sunlight, providing a cooling effect, but other particulates reradiate it, increasing warming.

Question 127

What are non-contagious populations?

Answer 127

Populations that are separated from one another and so are unable to interbreed

Question 128

What are wetlands?

Answer 128

Distinct ecosystems that are inundated by water, either permanently or seasonally, where oxygen-free processes prevail.

Question 129

What is monoculture?

Answer 129

Growing a single type of crop, e.g. wheat, in a large field.

Question 130

What is soil erosion?

Answer 130

Removal of topsoil (the fertile soil which is suitable for crop growth)

Question 131

What is coppicing?

Answer 131

-Young tree stems are repeatedly cut down to near ground level, known as a stool. -New growth emerges and after a number of years, the coppiced tree is harvested and the cycle begins anew.

Question 132

What is Ecotourism?

Answer 132

-Tourism directed towards exotic, often threatened, natural environments, intended to support conservation efforts and observe wildlife.

Question 133

What is fish farming?

Answer 133

Breeding and growth of fish to maturity in managed enclosures in e.g. lakes and estuaries

Question 134

What is a hedgerow?

Answer 134

-A rough or mixed line of wild shrubs and occasional trees, typically bordering a road or field. -Often removed in intensive farming to make manoeuvring of large machinery easier, but provides an important habitat for many species

Question 135

What is a meadow?

Answer 135

An open habitat, or field, vegetated by grass and other non-woody plants