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Wjec A Level Biology > 3.6 Human Impact On The Environment > Flashcards

3.6 Human Impact On The Environment Flashcards

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1
Q

What is extinction

A

It results in a loss of a species and decrease in biodiversity

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2
Q

What is an endangered species

A

A species that is seriously at risk of extinction

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3
Q

What is a natural reason for extinction to occur

A

Natural selection during evolution

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4
Q

What human impacts can cause species endangerment?

A

• habitat destruction
• pollution of the environment (PCBs oil and pesticides)
• over hunting/collecting by humans
• competition from domestic animals- introduction of alien species to an ecosystem may out-compete the native species
• monoculture
• building roads, houses and factories

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5
Q

What is conservation?

A

The sensible management of the biosphere and enhancement of biodiversity lovally

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6
Q

Why is conservation vital for maintaining biodiversity for the future?

A

It conserves existing gene pools in the wild and in captivity

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7
Q

How can conservation be achieved?

A

• habitat protection (nature reserves and SSSI)
• international cooperation restricting trade
• breeding programmes by zoo’s and botanic gardens
• sperm and seed banks
• reintroduction programmes eg red kits mid wales
• legislation to prevent overfishing, poaching, collecting birds eggs, picking wild flowers

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8
Q

What does it mean for the gene pool of that species is the species is conserved?

A

The gene pool is also conserved

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9
Q

What is a gene pool?

A

The total of all alleles for all of the genes in a population

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10
Q

Why are gene pools so important in the wild?

A

It maintains the genetic diversity of the species which is critical if the species is to survive changing environments as natural selection is dependent on variation in the species

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11
Q

Why are gene pools important in conservation and how is this done?

A

• captive breeding programmes - to maintain the genetic diversity of the stock to ensure the diversity of the species
• some organisms gave alleles that are useful to humans
- domestic animals and plants have wild relatives that may have useful alleles that could be bred back into domestic varieties (the point of sperm and seed banks - to be able to do this)
- many plants have medicinal properties and if they become extinct before investigation resource would be lost
• ethical reasons - uniqueness of each species is valuble

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12
Q

What is the tension between in agricultural exploitation?

A

The tension between an ever-increasing population to feed and so the need to produce more food and the need to conserve the environment and biodiversity

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13
Q

What is agriculture?

A

The means of producing food for human consumption in order to meet demands

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14
Q

What are 3 things agriculturalists have done to meet growing demand?

A

• created larger fields by removing hedges
• cultivated monocultures
• increased their use of fertilisers and pesticides

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15
Q

Why is removing hedgerows a problem?

A

They provide valuable habitats for wildlife and so their loss reduces biodiversity

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16
Q

Why is cultivating monocultures a problem

A

• only 1 type of habitat which reduces biodiversity
• reduces soil fertility- increases need for fertilisers
• plants grow very closely together and so are susceptible to the same pests and diseases which can pass around rapidly

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17
Q

What is a monoculture and why are they useful for agriculturalists?

A

It is the growing in large numbers of the same, genetically identical individuals in a given area
It allows farmers to grow crop that are easy to harvest mechanically

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18
Q

Why are fertilisers problematic?

A

Cause eutrophication of nearby water bodies as the excess leaches into rivers

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19
Q

Why are pesticides problematic?

A

They harm beneficial species as well as pests which causes them to decline in numbers

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20
Q

What is deforestation?

A

The complete loss of trees (due to human activity) in a defined area

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21
Q

What are the main concerns to do with deforestation?

A

The rate it is occuring
Trees are being cut down faster than forests can regenerate

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22
Q

What are the consequences of deforestation?

A

• habitat loss - reduced biodiversity
• desertification - soil becomes infertile and unable to sustain plant life
• lowland flooding
• increase in soil erosion which leads to nutrient loss
• climate change - less trees to absorb CO2

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23
Q

Why is forest management important?

A

It preserves natural woodland which enhances biodiversity

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24
Q

What does forest management involve?

A

Sustainable replanting and regeneration, protected areas to preserve species

25
Q

What are three ways trees can be harvested through forest management

A

Coppicing
Selective cutting
Long rotation time

26
Q

What is coppicing?

A

Tree trunks are cut at the base so new shoots grow from the stool which can be harvested at different diameters for different purposes

27
Q

What is environmental monitoring?

A

Physical and biological measurements that are made over a period of time

28
Q

Why is environmental monitoring required?

A

To monitor the effect, assess the effectiveness and measure the environment impact of conservation and re-introduction programmes

29
Q

Some aspects that are routinely monitored

A

• chemicals - pH, CO2, nitrates, ammonium
• biotic - animals and plants - especially ones sensitive to change
• radiation
• microbes- especially areas which are used for recreation which could be unsafe if levels become dangerous

30
Q

What is a plantery boundary

A

It defines a safe operating space for humanity

31
Q

What does the scientific research involved with planetary boundaries indicate?

A

That since the Industrial Revolution human actions have gradually becomes the main driver of global environmental ghange

32
Q

What could happen is 1 or more planetary boundary thresholds are exceeded

A

A possibility of abrupt and irreversible environmental change

33
Q

Biodiversity planetary boundary

A

• Crossed
• Extinction- natural selection
• Change of habitats effect indigenous species eg marine, tundra, coral reefs and coastal plains
• Biodiversity monitoring - gene banks
• Public awareness

34
Q

Climate change planetary boundary

A

• crossed
• greenhouse gases (CO2) and their sources
• effects the human population
• effects plant and animal populations
• rise in sea levels, rise in global temperature
• deforestation and weekend carbon sinks

35
Q

Ozone depletion planetary boundary

A

• avoided
• depleted in recent decades due to chemical pollutions from CFCs
• Montreal protocol 1987 - banned manufacture of CFCs found in propellants and refrigerants

36
Q

Aerosol planertary boundary

A

• unquantified
• aerosols are atmospheric polluants
• effect are complex

37
Q

Ocean acidification planetary boundaries

A

• avoidable
• owing to increased CO2 dissolving into oceans and forming carbonic acid
• organisms with calcium carbonate shells eg corals and molluscs can’t make shells in acid water
• knock-on effect on food chains and webs and could drastically reduce fish stocks

38
Q

Biochemical flows planetary boundary

A

• crossed
• concerns nitrogen and phosphorus cycles
• both fertilisers but up-take by plants leads to eutrophication

39
Q

Freshwater planetary boundary

A

• avoidable
• globally fresh water is becoming scarce because of modification of water bodies and land use change
• desalination of sea water could be an answer

40
Q

Land system change planetary boundary

A

• crossed
• describes land converted for human use eg for agriculture
• eg deforestation, livestock rearing and cultivation of biofuels crops
• represents the misuse of land resulting in too little food being produced

41
Q

What is overfishing?

A

Level of fishing where increased effort results in a declining catch

42
Q

Examples of overfishing

A

Drift netting
Trawling

43
Q

What is drift netting?

A

Use of massive nets and non-target species

44
Q

What is trawling

A

Weighted nets dragged along the floor of sea

45
Q

Ways to reduce impact of overfishing

A

• fish quotas
• reduce size of fishing fleets
• restricting season for fishing
• restricting mesh sizes for nets
• exclusion zones
• fish farming

46
Q

How does fish quotas reduce impact of overfishing

A

Limits how many of each species can be caught
Heavy fines are set

47
Q

How does reducing size of fishing fleets reduce impact of overfishing

A

Less boats out

48
Q

How does restricting season for fishing reduce impact of overfishing

A

Allows fish stocks have time to replenish

49
Q

How does restricting mesh sizes for nets reduce impact of overfishing

A

Smaller fish can escape and go on to breed

50
Q

How does exclusion zones reduce impact of overfishing

A

Fish populations will remain at sustainable levels

51
Q

What is fish farming

A

Isolating area of sea for the purpose of breeding and growing fish in managed conditions
Fish are fed, treated with chemicals then harvested

52
Q

The problems involved with fish farming

A

• addition of nutrients can lead to eutrophication
• overuse of antibiotics can cause resistance
• non-specific pesticides can leak out
• fish can be overcrowded which means diseases can spread rapidly
• fish in captivity may be GM for fast growth and larger sizes - will cause problems with wild stocks if they espace

53
Q

How is the provision of additional nutrients a problem of fish farming

A

It can lead to excess nutrients in the area leaking out and causing eutrophication
This causes oxygen depletion which can cause the fish to suffocate

54
Q

How is overuse of antibiotics a problem of fish farming

A

It can cause resistance in pathogenic bacteria

55
Q

How are non-specific pesticides a problem of fish farming

A

If they leak out they can affect the marine food chain

56
Q

How is fish being netted off and overcrowded a problem of fish farming

A

Diseases and pests can spread rapidly and easily

57
Q

How are fish in captivity maybe being genetically modified a problem of fish farming

A

They’re genetically modified for fast growth and larger sizes
If they escape and breed with wild stocks or compete with them for food it could push wild fish to extinction

58
Q

What is an SSSI

A

Site of special scientific intrest

Wjec A Level Biology (13 decks)

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