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A LEVEL BIOLOGY > 6 - Human Impact on the Environment (C1) > Flashcards

6 - Human Impact on the Environment (C1) Flashcards

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1
Q

What is the problem of land use change caused by?

A

Natural ecosystems, such as rain forests, have been used for urban development, raising livestock and farming, including growing biofuel crops

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2
Q

What are 3 examples of endangered species?

A
  • Black rhino - Orangutan - Bengal tiger
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3
Q

What is biodiversity?

A

The variety of life on the plant (species number and evenness)

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4
Q

How does pollution of inorganic chemicals cause extinction?

A
  • Industrial chemicals such as PCBs and pesticides are not biodegradable so accumulate through the food chain - Most of these pollutants are fat soluble and accumulate in body tissues
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5
Q

Why is manure and compost often added to soils?

A

To add nitrate to the soil

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6
Q

What is coppicing?

A

A technique whereby trees are cut down close to the ground and then left for several years to re-grow shoots

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7
Q

What is monoculture?

A

The simultaneous growth of a large number of crop plants of similar age and type within a defined area

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8
Q

What are some reasons for deforestation?

A
  • Land needed for agriculture - Land needed for road and housing development - For resources e.g. timber
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9
Q

What is selective cutting?

A

Cutting only some trees, leaving the others in place

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10
Q

What steps can be taken to improve the efficiency of forestry?

A
  • Planting trees optimum distance apart - Controlling pests and diseases
  • Cutting a similar number of trees each year for long periods of time, allowing the forest ecosystem to be maintained
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11
Q

What are advantages and disadvantages of coppicing?

A

+ Promotes regrowth and a sustainable supply of timber for future generations - Time consuming and labour intensive

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12
Q

What are advantages and disadvantages of selective cutting?

A

+ Helps maintain nutrients in forest soil + Minimises amount of soil washed into nearby waterways - Expensive - Time consuming - Some species won’t regrow as fast

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13
Q

What is long rotation time?

A

When many years are left between harvesting adjacent areas of forest

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14
Q

What are advantages and disadvantages of long rotation time?

A

+ Increases sustainability + Allows a variety of habitats to develop - Time consuming

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15
Q

What is replanting trees?

A

When all trees in the area are cut down at the same time

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16
Q

What are advantages and disadvantages of replanting trees?

A

+ Supplies resources for future generation - Care must be taken to ensure trees are being planted specific distances from other trees

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17
Q

What is regeneration?

A

The process by which new tree seedlings become established after forest trees have been harvested or died

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18
Q

What are advantages and disadvantages of regenerating trees?

A

+ Cheap, native plants that grow this way are likely to be well adapted to the area - Little control over spacing - May require some preharvesting operations to ensure regeneration

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19
Q

What do fishing exclusion zones do?

A

Prohibit fishing in certain areas and certain times of the year, allowing fish to reproduce

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20
Q

What do fishing quotas do?

A

Ensure only a certain mass of fish can be brought to land

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21
Q

What does increasing the fishing mesh size do?

A

Ensures young fish that are not yet sexually active are not caught

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22
Q

What are some methods of combatting over fishing?

A
  • Exclusion zones - Removing subsidies - Quotas - Reducing vessels and fishing time - Controlling mesh size - Eating non-traditional fish
23
Q

Why are diseases common on fish farms and why do treatments lead to environmental problems?

A
  • Fish are crowded together so diseases spread easily - Many treatments are toxic to other organisms - Antibiotics used may lead to antibiotic resistant bacteria developing
24
Q

What are benefits of fish farming?

A
  • Food security for expanding population - Employment - Makes fish more affordable
25
Q

Why does fish farming cause eutrophication?

A

High levels of protein in food of predatory fish, therefore large amounts of nitrogenous waste

26
Q

What are the 9 planetary boundary global processes?

A
  • Climate change
  • Biodiversity
  • Land use change
  • Nitrate and phosphate
  • Ozone
  • Acidification
  • Freshwater
  • Aerosol
  • Inorganic pollution
27
Q

What is meant by the term planetary boundary?

A

A threshold value for a global process that is affected by human activity. Crossing these boundaries could lead to abrupt or irreversible environmental changes

28
Q

What is the ozone problem?

A
  • Conc of ozone in the stratosphere has decreased, creating a hole in the ozone layer
  • Due to use of CFCs as aerosols
29
Q

What are consequences of the hole in the ozone layer?

A
  • More UV light penetrates atmosphere
  • UV light generates mutations in DNA and causes damage to living organisms
30
Q

What is an endangered species?

A

A species of plant or animal that is low in number and at serious risk of extinction

31
Q

Why is secondary succession often quicker than primary succession?

A
  • There is already an existing seed bank of suitable plants in the soil
  • Root systems undisturbed in the soil, stumps and other plant parts from previously existing plants can rapidly regenerate
  • The fertility and structure of the soil has already been substantially modified by previous organisms to make it more suitable for growth and colonisation
32
Q

How does non-contiguous populations cause animals to become endangered or extinct?

A
  • If groups of members of species are isolated, they can’t interbreed and each group functions as a separate population
  • There may be too little genetic diversity to ensure a healthy population, leading to extinction
33
Q

Why can a loss of hedgerows cause animals to become endangered or extinct?

A
  • Hedgerows provide a habitat for insects, birds and reptiles, and provide food
  • Vary light intensity and water availability for plants
  • Act as wildlife corridors, enabling animals to move from one area to another, helping to maintain biodiversity
34
Q

What are some examples of overhunting by humans?

A
  • Trophy hunting
  • Traditional medical practices
  • For food
  • Overfishing
35
Q

Why can oil spilt into water kill animals?

A
  • Oil floats and prevents oxygenation of surface water
  • Animals that break through the surface are covered by a film of oil. Animals such as birds are chilled to death as their feathers clump and can’t provide insulation
36
Q

What are some reasons why species are endangered or extinct?

A
  • Human activities are causing habitats to change faster than natural selection allows species to adapt
  • Non-contiguous populations
  • Loss of habitat: deforestation, drainage of wetlands, hedgerow loss, also farmers often sow crops in autumn rather than spring so plants are an unsuitable height for birds to build nests
  • Overhunting by humans
  • Competition from introduced species
  • Pollution
37
Q

What is conservation?

A

The protection and management of natural habitats and their ecological communities, to enhance biodiversity while allowing for suitable human activity

38
Q

How can species be conserved?

A
  • Nature reserves
  • Sperm banks
  • Education
  • Legislations
  • Ecotourism
39
Q

How do sperm banks work?

A

Store genes of economically important animals and of threatened species

40
Q

What is ecotourism?

A

Responsible travel to natural areas that conserves the environment and improves the well-being of local people

41
Q

What are reasons for species conservation?

A
  • Ethical reasons
  • Agriculture
  • If the environment changes, some alleles will provide an advantage to individuals, preventing the extinction of the species
  • Potential medical uses
42
Q

What is soil erosion?

A

The removal of topsoil, which contains valuable nutrients

43
Q

Other than CO2 production, what are consequences of deforestation?

A
  • Soil erosion
  • Deforestation of uplands causes lowland flooding
  • Destruction of habitats, reducing biodiversity
  • Less rainfall, as water only returns to the atmosphere by evaporation from the soil, not by transpiration, and evaporation is slow
44
Q

Why is raising fish rather than pork, poultry and beef better?

A
  • Fish convert their food into protein more efficiently
  • A greater proportion of fishes’ bodies are edible
  • Fish farming has a lower carbon footprint
45
Q

What are problems that fish farming causes?

A
  • Diseased fish: pesticides used to control fish parasites harm invertebrates
  • Pollution and eutrophication
  • Escaped fish outcompete wild fish for food, habitat and mates
  • Resource use: farmed salmon eat 3 times their bodyweight of other fish
46
Q

What are the 4 planetary boundaries that have been crossed?

A
  • Climate change
  • Biodiversity
  • Land use change
  • Nitrate and phosphate (biochemical flows)
47
Q

What is a biofuel?

A

A fuel made by a biological process, such as anaerobic digestion

48
Q

What are some concerns related to biofuel production?

A
  • ‘Food vs fuel’: land used to grow food is now used for crop production for biofuels, so less food is produced
  • Carbon emissions: European bioethanol production and use reduce greenhouse gas production
  • Deforestation occurs to grow biofuel crops
  • Reduction in water availability, as biofuel crops require a large volume of irrigation water
  • Combustion of biodiesel produces more nitrous oxide, a greenhouse gas, than fossil fuel
49
Q

What is the difference between the composition of biodiesel and petrodiesel?

A
  • Biodiesel contains less carbon and more hydrogen and oxygen than petrodiesel
  • Biodiesel releases less carbon particles and less carbon monoxide, but more nitrous oxide
50
Q

What planetary boundary has been avoided, which are avoidable and which are unknown?

A

Avoided: Ozone boundary

Avoidable: Ocean acidification, fresh water

Unknown: Aerosol use, inorganic pollution

51
Q

What are some reasons for the reduction in freshwater availability?

A
  • Changing landscapes: deforestation, draining wetlands and soil erosion influence the flow of fresh water
  • Agriculture consumes more fresh water than any other human activity
  • Water pollution e.g. eutrophication
  • Climate change: rising sea levels that contaminate freshwater
  • Increase in population due to increasing life expectancy
52
Q

What are some methods to increase freshwater availability?

A
  • Water conservation
  • Wastewater reclamation
  • Desalination: where minerals are removed from salt water producing fresh water
53
Q

What are some environmental problems caused by desalination? (removing minerals from salt water)

A
  • Brine (concentrated sodium chloride solution) is discharged, but is diluted before returning to ocean
  • Brine is denser than seawater so sinks and damages seabed ecosystem
  • Burning of fossil fuels to generate heat to run the desalination system
54
Q

What are atmospheric aerosols?

A

The microscopic particles put into the atmosphere by combustion of fuels, specifically diesel motor vehicles, and by creating dust from digging and quarrying

A LEVEL BIOLOGY (13 decks)

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