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Biology Unit 2 > Human Impact on Biodiversity > Flashcards

Human Impact on Biodiversity Flashcards

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1
Q
  1. What does intensive farming involve?
A

Planting large areas with single crops (monoculture) and using inorganic fertilizers, pesticides and machinery to obtain as high a yield as possible, with maximum profit

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2
Q
  1. What is monoculture?
A

Growing a single crop eg arable crops like wheat

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3
Q
  1. What are the benefits of monoculture?
A
  • Allows more than one crop a year
  • Does not require much labour so reduces costs
  • Sowing and harvesting is simplified
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4
Q
  1. What are the alternatives to monoculture?
A

Polyculture and crop rotation

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5
Q
  1. What are the drawbacks of monoculture?
A
  • Reduces genetic diversity (fewer insects, less food sources, fewer habitats)
  • Requires use of fertilisers (which can lead to leaching)
  • Requires use of pesticides (expensive and pollute), as pests are a problem
  • Yields decline over time (due to nutrient depletion and disease)
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6
Q
  1. What is polyculture and what are its benefits?
A

GROWING SEVERAL CROPS AT ONCE. It leads to greater biodiversity, better soil fertility, fewer pests and pathogens BUT labour costs are greater

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7
Q
  1. What is crop rotation and what are its benefits?
A

PLANTING DIFFERENT CROPS FROM ONE YEAR TO THE NEXT in the same field. It conserves soil fertility and reduces build-up of pests specific to one crop.

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8
Q
  1. What are the negative effects of removing hedgerows?
A
  • You remove habitats and disrupt food chains, which reduces biodiversity
  • Often natural predators of pests are removed so a crop may be affected
  • Natural wildlife corridors are removed which reduces biodiversity
  • There is less shelter, so more exposure of soil to the elements. Leads to more soil erosion.
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8
Q
  1. Why, over the years, have many hedgerows been removed?
A

To free up land and allow farm machinery to operate

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9
Q
  1. What methods can be used to maintain hedgerows and their biodiversity?
A
  • Trim in Jan/Feb to avoid disrupting birds’ nests and to allow fruits to develop * Trim on a 2 year rotation - allows fruits to develop as a food source for birds and other creatures
  • Avoid removing native species in the hedge as they maintain biodiversity
  • Cut in an A shape to allow light to reach bottom of hedge - promotes more diversity of plant species
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10
Q
  1. What is a field margin or predator strip?
A

An area or margin around the field that the farmer leaves untouched so that there is more habitat space and more food sources for animals and also so that natural predators of pests are encouraged. Again, this will promote biodiversity.

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11
Q
  1. What is a pest?
A

A pest is any organism that damages a crop species causing economic damage.

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12
Q
  1. What is a pesticide?
A

A chemical used to control pests

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13
Q
  1. What are the problems associated with using pesticides?
A
  • They are often broad-spectrum, meaning they affect other species (non-target species) and not just the pest
  • They may cause pest resurgence by removal of natural predators of pests, allowing a secondary outbreak of the pests
  • They may cause bioaccumulation in food chains
  • They may persist in the environment and not get broken down (non-biodegradable)
  • Herbicides may kill plants apart from the weeds, which reduces food for other organisms and reduces biodiversity therefore
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14
Q
  1. What is BIOLOGICAL CONTROL?
A

Biological control of pests and diseases is a method of controlling pests and diseases in agriculture that relies on natural predation rather than introduced chemicals

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15
Q
  1. What is the main goal of biological control?
A

The goal of biological control is to reduce pest numbers to below the threshold of economic damage

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16
Q
  1. What makes a good biological control organism?
A
  • It should be able to reproduce rapidly in the area it is brought into
  • It should be specific to the pest
  • It should have good searching capacity, so that it can keep the pest at low numbers
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17
Q
  1. What are the advantages of biological control?
A
  • Often pest specific
  • No chemical pollution
  • No bioaccumulation
  • Maintains biodiversity
  • Often cheaper overall
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18
Q
  1. What is integrated pest management?
A

Combines the use of biological and chemical pest control

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18
Q
  1. What are the advantages of inorganic or artificial fertilizer?
A

Have known quantities of minerals such as nitrates, which lead to rapid growth of crop and therefore higher yield

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19
Q
  1. What problems are associated with artificial/inorganic fertilisers?
A
  • Rapid growth means the crop outcompetes other species that are slower growing and therefore this reduces biodiversity
  • Can lead to eutrophication if minerals leach into waterways
  • Leads to loss of soil structure and therefore soil erosion
20
Q
  1. What is organic fertiliser/ manure?
A

Manure is an organic mixture of straw, faeces and urine from the farm

21
Q
  1. What are the advantages of using organic fertiliser/manure?
A
  • It is broken down and released slowly into the soil by decomposers, so this slow release of nitrates will be used for growth by crops/plants
  • It helps to improve soil structure by adding humus
  • Less leaching into waterways occurs (less chance of eutrophication)
  • As it is readily available on the farm, it is cheap
  • Good soil bacteria are built up, as well as beneficial invertebrates like earthworms
22
Q
  1. What disadvantages are there with organic fertilisers?
A
  • They are bulky and need to be spread in large amounts to be beneficial for growth * They smell bad
  • They may contain things like fungal spores or weed seeds
22
Q
  1. What is slurry?
A
  • An organic fertiliser made from a mixture of water and animal waste from the animal houses.
23
Q
  1. Why do farmers drain their land?
A

To increase the amount of land they can use for agricultural purposes

24
Q
  1. What are the disadvantages of using slurry?
A
  • It reduces biodiversity as it removes the soil organisms (remember, detritivores and decomposers)
  • It causes soil to lose crumb structure and leads to soil erosion.
  • It can leach into waterways and reduce oxygen concentrations (decreases BOD)
25
Q
  1. What are the disadvantages of this?
A

Areas of wetland containing rare flora and fauna are removed, therefore biodiversity is reduced

26
Q
  1. What then has to happen to this land to make it usable?
A

It will be ploughed and re-seeded following drainage

27
Q
  1. What is eutrophication?
A

Eutrophication is the nutrient enrichment of waterways by inorganic ions from fertilizers and sewage

28
Q
  1. What are the main mineral ions causing eutrophication?
A

Nitrates and phosphates

29
Q
  1. How does eutrophication lead to oxygen depletion in water?
A
  • The nitrate and phosphate ions cause excess growth of algae which form algal blooms on the water
  • These block out light so the plants below them die and eventually so do the algae
  • Decomposers break down the dead material but use up oxygen in the process, thereby lowering oxygen levels for fish and invertebrates
30
Q
  1. How can farmers prevent this from happening?
A
  • Do not apply fertilizer before periods of heavy rain
  • Do not apply fertilizer on land sloping downwards towards a river
  • Have closed periods when you’re not allowed to apply fertilizer and only apply to prior to a period of rapid growth
  • Alter the nutrient content of fertilizer for each crop
  • Legislation eg European Nitrates Directive
31
Q
  1. Where does organic pollution of waterways come from?
A

Sewage, slurry, silage effluent

32
Q
  1. What is BOD?
A

This is the biological oxygen demand of the water and it is a measure of usage of oxygen in the river

33
Q
  1. What would cause BOD to suddenly rise?
A

A sudden influx of sewage or slurry would cause a surge in numbers of saprobiotic bacteria, which then would cause an increase in oxygen usage. As a consequence, oxygen levels would drop in that area of the river.

34
Q
  1. What would it tell us, if a sample of water from a river gave a high BOD value?
A

It would tell us that the river has been polluted with something organic, like sewage or slurry

35
Q
  1. What is an INDICATOR SPECIES?
A

Invertebrate species that can be used to indicate water quality

36
Q
  1. What are the characteristics of polluted water?
A

Polluted water will tend to have a small number of different species (but each one may still be present in large amounts)

37
Q
  1. What are the characteristics of water with low pollution levels?
A

Cleaner water will have a higher diversity of species with no single species becoming overly abundant

38
Q
  1. What is an ASSI?
A

Area of Special Scientific Interest (the area is managed to promote biodiversity)

39
Q
  1. What is a SAC?
A

Special Area of Conservation (the area is given special protective status)

40
Q
  1. What is a BAP?
A

Biodiversity Action Plan (quite often involves local polices and activities)

41
Q
  1. What is DAERA?
A

The Department of Agriculture, Environment and Rural Affairs

42
Q
  1. What is the Northern Ireland Priority habitat and species list?
A

A list of priority habitats and species that are most important in terms of needing to be conserved

43
Q
  1. In the carbon cycle, what two main processes put carbon back into the air?
A

Combustion and respiration

44
Q
  1. In the carbon cycle, what main process takes carbon out of the atmosphere?
A

Photosynthesis

45
Q
  1. What processes are putting this cycle out of balance and increasin carbon dioxide levels in the atmosphere?
A

Emissions from combustion of fossil fuels and deforestation

46
Q
  1. What is global warming mainly attributed to?
A

The “greenhouse gases”, dioxide, nitrous oxides (from denitrification and car exhausts) and methane (from livestock and decomposition of organics matter)

47
Q
  1. What is the greenhouse effect?
A

This is how heat energy gets trapped by the layer of greenhouse gases that form in the atmosphere around earth. It leads to global warming i.e. temperature rises

48
Q
  1. What does global warming cause?
A
  • Due to drier conditions, loss of habitats like wetlands which are important for biodiversity
  • Rising sea levels resulting in loss of shoreline species; loss of salt marshes and associated species
  • Acidification of oceans leading to loss of coral reefs
  • Loss of arctic ice sheets, leading to loss of species like polar bears
  • Extinction of some species unable to adapt to changing climate and environment
  • Changes in distribution of species eg mosquitos moving northwards

Biology Unit 2 (5 decks)

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