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biology > ch 15 human influences on the environment > Flashcards

ch 15 human influences on the environment Flashcards

1
Q

we have changed many environments to suit our needs. state 3 of needs.

A

(any three)
- food or crops
- building materials
- fuel
- space for living, industrial activities and leisure facilities
- space for waste disposal

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2
Q

famers need to control the environment to ____ from crop plants and livestock.

A

maximize the yield

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3
Q

the use of ____ and ____ provides the right conditions for plants to grow.

A

greenhouse ; polythene tunnels

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4
Q

light factor

A
  • glass for building the greenhouse –> allow sufficient natural light in for photosynthesis
  • additional lighting –> provides a ‘longer day’ during winter
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4
Q

carbon dioxide factor

A
  • burning of fossil fuels
  • increases the amount of carbon dioxide which is a raw material for photosynthesis –> rate of photosynthesis can be increased
  • raises the temperature when the external temperature is too low
  • produces water vapour which maintains a moist atmosphere and so reduces water loss by transpiration
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5
Q

heat factor

A
  • glass walls of greenhouse
  • short wave radiation entering is absorbed and re-radiated as longer wave radiation which cannot leave easily and heats the greenhouse
  • maintains optimum temperature for photosynthesis even in cold days
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6
Q

soil ions factor

A
  • applying fertilizers
  • growing crops in hydroponic culture –> extra minerals can be taken up and used to make proteins/other compounds for growth
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7
Q

soil pH factor

A
  • adding lime to acidic soils
  • making soil pH suitable for mineral uptake and plant growth
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8
Q

soil structure factor

A
  • ploughing fields to break up compacted soil
  • adding manure to soil –> ensure good aeration and draining for better uptake of mineral ions and water
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9
Q

when the crops and livestock are sold, the ____ goes with them and is lost from the ____.

A

nitrogen in the protein ; farm ecosystem

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10
Q

what are the two main types of fertilizers?

A

organic fertilizers, inorganic fertilizers

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11
Q

what are organic fertilizers made of?

A

faeces of a range of animals mixed with straw

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12
Q

what are inorganic fertilizers?

A

inorganic compounds carefully formulated to yield a specific amount of nitrate when applied.

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13
Q

state 2 examples of inorganic fertilizers.

A

potassium nitrate, ammonium nitrate

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14
Q

list the advantages of organic fertilizers.

A
  • contains humus which can improve soil texture
  • less soluble in water so less likely to be washed away
  • less expensive
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15
Q

list the disadvantages of organic fertilizers.

A
  • less soluble in water so more difficult to be absorbed
  • time is needed for the decomposition to be complete before nutrients are available to plants
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16
Q

list the advantages of inorganic fertilizers.

A
  • very soluble in water so easier to be absorbed
  • more readily to be used by the plants
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17
Q

list the disadvantages of inorganic fertilizers.

A
  • no humus so cannot improve soil texture
  • very soluble in water do more likely to be washed away
  • more expensive
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18
Q

what is another way to replace lost nitrates?

A

grow a legume crop.

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19
Q

legumes have ____ in root nodules on roots.

A

nitrogen-fixing bacteria

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20
Q

nitrogen-fixing bacteria convert ____in soil to ____.
some ____ are passed to plants to make ____.
at the end of season, crop is ploughed back into soil.
____ convert ____ in ____ to ____.
____ is oxidized to ____ by ____.
available for absorption by next year’s crops.

A

nitrogen gas ; ammonia/ammonium ions
ammonium ions ; proteins

decomposers ; nitrogen ; proteins ; ammonia
ammonia ; nitrate ; nitrifying bacteria

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21
Q

what are pests?

A

pests are organisms that reduce the yield of crop plants or stock animals.

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22
Q

pest can harm yield of crops in two ways:

A
  1. lower the amount by reducing growth
  2. affecting the appearance or quality of a crop, making it unsuitable for sale
23
Q

____ –> kill weeds
____ –> kill insects
____ –> kill fungi
____ –> kill molluscs

A

herbicides
insecticides
fungicides
molluscicides

24
Q

define crop rotation.

A

planting a different type of crop each year.

25
Q

list the advantages of using pesticides to kill pests.

A
  • initially very effective
  • easy to use
  • used with almost all crops
26
Q

list the disadvantages of using pesticides to kill pests.

A
  • pests can develop resistance through mutation and natural selection
  • bioaccumulation
  • not specific
  • disrupt food chain
  • expensive (needs reapplication)
27
Q

explain the effects of DDT.

A
  • DDT is extremely persistent and it is fat soluble, so it is easily stored in living tissue
  • when it is passed along the food chain through feeding, its concentration increases –> biomagnification –> because each organism in the food chain eats many of the organisms at the lower trophic levels
  • finally the concentration of DDT reaches a toxic level which may kill the organisms at high trophic level of the food chain
28
Q

explain why pesticides are persistent.

A
  • cannot be broken down / decomposed easily
  • are stored in fatty tissues where the amount build over time –> bioaccumulation
29
Q

name the characteristics of an ideal pesticide.

A
  • control the pest effectively
  • be biodegradable (no toxic products are left in the soil or on crops)
  • be specific, only the pest is killed
  • not accumulate in organisms
  • be safe to transport and store
  • be easy and safe to apply
30
Q

define biological control.

A

it involves using another organism, rather than a toxic chemical, to reduce the number of a pest.

31
Q

list methods of biological control.

A
  • natural predator of the pest
  • herbivore that feeds on weeds
  • parasite of the pest
  • pathogenic microorganism to control pest population
  • sterile pest males
  • using pheromones
32
Q

state the advantages of using biological control.

A

no poisonous and harmful effect to human and wildlife.

33
Q

state the advantages of fish farming.

A
  • water quality is carefully monitored
  • temperature and oxygen levels of the water can be monitored and controlled
  • diet of the fish is controlled
  • fish are protected against predators
  • pesticides are applied to kill parasites
  • selective breeding programmes are used to improve the quality of fish
34
Q

state the disadvantages of fish farming.

A
  • potential for the spread of diseases is greater than normal –> animals are too close together
  • antibiotics used to treat diseases may not have been degraded when fish are eaten by humans
  • cause pollution problem –> animals’ faeces and food pellets –> cause eutrophication
  • pesticides are toxic to other non-harmful species
35
Q

define pollution.

A

the contamination of the environment by harmful substances that are produced by the activities of humans.

36
Q

name the 4 major air pollutants.

A
  1. carbon dioxide
  2. methane
  3. carbon monoxide
  4. sulphur dioxide
37
Q

why has the concentration of carbon dioxide in the atmosphere has increased by 30% over the last 100 years?

A
  • increased burning of fossil fuel
  • cutting down of tropical rain forest –> less carbon dioxide is being absorbed by plants
38
Q

define the greenhouse effect.

A
  • short-wavelength IR radiation from the sun strikes the planet
  • some short wave-length IR radiation is absorbed and some is reflected as longer wave radiation
  • greenhouse gases absorb the longer wave radiation and re-emit some of this long-wavelength radiation towards the earth
  • escape of IR radiation from the earth is prevented –> increase global temperature
39
Q

give examples on the effects of global warming.

A
  • polar ice caps melts and sea lvels rises
  • change in ocean currents
  • change in global rainfall pattern
  • change in ecosystem
  • pests may become more abundant
40
Q

methane is produced when ____ larger organic molecules to release energy.

A

microorganisms ferment

41
Q

state the most significant sources of methane.

A
  • decomposition of waste at landfill
  • fermentation in rumen (stomach) of rabbit
  • fermentation by bacteria in rice paddy field
42
Q

when is carbon monoxide formed?

A

formed when substances containing carbon are burned in a limited supply of oxygen (incomplete combustion)

43
Q

what are the characteristics of carbon monoxide?

A
  • toxic yet colourless, odourless, tasteless
  • binds to haemoglobin more strongly than oxygen
  • person may lose consciousness and eventually die as a result of a lack of oxygen reaching cells
44
Q

where are sulphur dioxide and nitrogen oxides formed?

A

formed from the burning of fossil fuels.

45
Q

sulphur dioxide and nitrogen oxides will form ____ when combined with water droplets in air.

A

acid rain

46
Q

what are the harmful effects of acid rain?

A

kill plants and animals, depletion of minerals in soil, reaction with carbonates and other ions in stone.

47
Q

patterns of lichen growth can be used to monitor the level of pollution by ____.

A

sulphur dioxide

48
Q

what are the problems caused by deforestation?

A
  • global warming and climate change
  • ‘slash and burn’ method adds to the carbon dioxide in the atmosphere and contributes to global warming
  • deforestation removes trees, which would otherwise be absorbing carbon dioxide for photosynthesis
  • destruction of habitats and reduced biodiversity
  • reduced soil quality
  • soil is exposed due to lack of tree cover –> soil erosion
  • many undiscovered drugs and crop plants will be lost with deforestation
49
Q

what substances do industrial and agriculture sewage contain?

A
  • nitrate from fertilizers
  • organic waste
  • detergent
50
Q

nitrates from fertilizers

A
  1. inorganic fertilizers are applied to soils –> rich in nitrates
  2. rainwater dissolve nitrates
  3. nitrates are leached into waterways
  4. level of nitrates rises rapidly –> eutrophication
  5. algae reproduce rapidly –> algal bloom
  6. light is cut off from submerged plants –> plants cannot photosynthesise and die
  7. bacteria decay the dead plants and algae –> releasing more nitrates to the water and the cycle starts again
  8. bacteria reproduce and use up oxygen for respiration
  9. water becomes anoxic and all life in the water die
51
Q

why is the nitrate problem more severe in hot water?

A
  • heat evaporates water and nitrates are more concentrated
  • increased enzyme activity under high temperature
52
Q

why is the nitrate problem less severe in moving water?

A
  • nitrates are rapidly diluted
  • water is continually being re-oxygenated
53
Q

water pollution by organic waste

A
  • it occurs when untreated sewage is released into waterways
  • decayed by bacteria and fungi –> oxygen is used up in respiration
  • water becomes deoxygenated –> fish and other animals die
54
Q

define indicator species.

A

it can be used to indicate different levels of water pollution.

55
Q

at the point of polluting outlet –> low in ____ level –> because bacteria ____ the organic material –> only species ____ can survive.

A

oxygen level ; decompose ; adapted to such conditions

56
Q

as the water moves away from the outlet –> water becomes ____ as it mixes with the ____ at the ____ –> more species of ____ can survive.

A

oxygenated ; oxygen ; surface ; ‘clean water animals’

biology (4 decks)

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