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Sec 4 Pure Bio > Our impact on the ecosystem (Ecology) > Flashcards

Our impact on the ecosystem (Ecology) Flashcards

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1
Q

Why the use of natural resources needs to be controlled and regulated

A
  • used everyday
  • depletion results in environmental damage
  • mostly irreversible
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2
Q

Types of natural resources

A
  • Renewable

- Non-renewable

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3
Q

Renewable natural resources

A
  • can be replaced via natural cycles (as long as not overused)
  • e.g. air, water, soil, wildlife
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4
Q

Non-renewable natural resources

A
  • cannot be replaced once used

- e.g. fossil fuel, minerals

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5
Q

Deforestation

A
  • clearing of forests
  • makes land available for agricultural, urban development
  • wood (raw material)
  • usually cleared faster than replaced
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6
Q

Effects of deforestation

A
  1. Soil erosion
  2. Flooding
  3. Desertification
  4. Climate changes
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7
Q

Soil erosion (Deforestation)

A
  • forests leafy canopy protects topsoil (most nutrients here) from direct impact of rain
  • retain water thru absorption by roots
  • w/o, top soil easily washed off by heavy rain
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8
Q

Flooding (Deforestation)

A
  • resultant of soil erosion
  • rise in water lvl
  • increase chances of flooding
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9
Q

Desertification (Deforestation)

A
  • w/o leafy canopy, sunlight falls directly onto ground
  • water evaporate
  • create desert-like condition
  • unsuitable for plant growth
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10
Q

Climate changes (Deforestation)

A
  • less plants, less CO2 removed frm atmosphere via photosynthesis
  • CO2 greenhouse gas, traps heat
  • warmer climate
  • mosquitoes example
  • disrupts water cycle
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11
Q

Uncontrolled fishing practices

A
  • impt food source
  • population increase, demand increases
  • uncontrolled and unregulated fishing practices leads to reduced aquatic biodiversity
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12
Q

Dredges (uncontrolled fishing practices)

A
  • destroy coral reefs and

- organisms living on sea bed

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13
Q

Drift nets and trawlers

A
  • catch ,marine life indiscriminately
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14
Q

Cyanide fishing

A
  • kills corals and other reef organisms
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15
Q

Effects of uncontrolled fishing practices

A
  • destruction of marine habitat

- decrease and extinction of certain fish populations

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16
Q

Pollution

A
  • process where harmful substances added to environment
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17
Q

Water pollution

A
  • contamination of water bodies
  • discharge of untreated sewage into water bodies
  • excessive use of fertilisers and insecticides
  • dumping of inorganic waste material into water bodies
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18
Q

Sewage

A
  • waste materials frm homes and industries
  • untreated sewage may contain disease-causing bacteria, result in epidemic of water bodies
  • e.g. cholera outbreaks (caused by bacteria in untreated sewage)
  • untreated sewage contain phosphates and nitrates, can lead to eutrophication
19
Q

Define epidemic

A
  • outbreak of disease

- affects large population of humans in a given period

20
Q

Chemical fertiliser

A
  • contain phosphates and nitrates
  • used to increase crop yield
  • excessive use can lead to eutrophication
21
Q

Eutrophication

A
  • excessive nutrients washed into waterbody
  • increase growth of algae, water plants
  • form a layer above water
  • submerged plants die due to lack of sunlight
  • bacteria grow rapidly , use up dissolved O2 as decomposing dead plants
  • anoxic environment, other organisms die
22
Q

Inorganic waste

A
  • include poisonous metals (e.g. mercury)
  • pesticides
  • harmful to humans
23
Q

Mercury poisoning (1971 Minamata)

A
  • plastic factory discharged waste water containing mercury in to Minamata Bay
  • mercury absorbed by water weeds
  • weeds eaten by fish
  • fish caught contained high conc of mercury
  • villagers ate the contaminated fish, suffered frm mercury poisoning
24
Q

Insecticides

A
  • DDT
  • inorganic compounds, non-biodegradable
  • DDT cannot be broken down and excreted, stored in fatty tissues of consumers
  • can be passed along food chains
  • conc increase along tropic level (biomagnifciation)
  • results in bioaccumulation of DDT in top consumers
25
Q

DDT effect on birds

A
  • insects die, laced with DDT
  • birds eat
  • shells of egg too thin, cannot hatch eggs
  • unable to reproduce enough
26
Q

Bioaccumulation

A
  • chemicals not excreted, accumulate in bodies of consumers

- within trophic lvl

27
Q

Biomagnification

A
  • chemicals passed along food chain
  • conc in bodies on final consumers
  • across trophic lvls
28
Q

Define conservation

A
  • protection
  • preservation
  • of natural resources in environment
29
Q

Define biodiversity

A
  • range of species

- present in particular ecosystem

30
Q

Reasons for conservation

A
  1. Scientific value
  2. Maintenance of balanced ecosystem
  3. Maintenance of biodiversity
  4. Economic importance
  5. Food source
  6. Preservation of natural scenery and wildlife
31
Q

Scientific value (Reasons for conservation)

A
  • study of fossils , diversion of species

- insight on evolution

32
Q

Maintenance of balanced ecosystem (Reasons for conservation)

A
  • deforestation

- disrupts carbon and water cycle

33
Q

Maintenance of biodiversity

A
  • discovery of fauna and flora
  • medicinal value
  • prevent extinction
  • maintaining large gene pool
34
Q

Economic importance

A
  • raw materials for industrial use

- e.g. wood

35
Q

Food source

A
  • e.g fish

- main human food source

36
Q

Conservation measures

A
  1. Environmental biotech
  2. Conservation of forests
  3. Conservation of fishing grounds
37
Q

Environmental biotechnology

A
  • use of biological sciences
  • provide environmentally-friendly solutions (reducing pollution)
  • e.g. wastewater treatment process
38
Q

Wastewater treatment process

A
  1. Channelled into water reclamation plants
  2. Primary settling tank
  3. Aeration tank
  4. Final settling tank, treated water discharged into sea
39
Q

What happens to sludge from primary settling tank

A
  • removed from primary settling tanks
  • treated in anaerobic digesters
  • dewatered and disposed into soil container
  • removed from final settling tanks
40
Q

Primary settling tank

A
  • heavy solids settle
  • bottom of tank
  • removed as sludge
41
Q

Aeration tank

A
  • partially treated wastewater
  • mixed with bacteria
  • organic pollutants broken down into harmless substances
42
Q

Final settling tank

A
  • bacteria removed
43
Q

Conservation of forests

A
  • laws to regulate logging
  • reforestation
  • designating lands for forests reserves
  • research, improve quality and productivity of forests
44
Q

Conservation of fishing grounds

A
  • banning use of drift nets, trawlers, dredges
  • using nets of certain mesh size
  • limit no. of ships in fishing ground at certain time
  • raising endangered fish in hatcheries b4 releasing into wild

Sec 4 Pure Bio (13 decks)

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