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Science 3 > Biology b > Flashcards

Biology b Flashcards

0
Q

How does population affect the environment ?

A

Our increasing population puts pressure on the environment, as we take the resources we need to survive

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1
Q

Why is population rising ?

A

Modern medicine and farming methods mean less people are dying from disease and hunger

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2
Q

How does a higher standard of living affect the environment ?

A

People demand luxuries such as cars and computers. This uses up raw materials and energy for the manufacturing processes. This means lots of resources are being removed from the environment quicker

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3
Q

Why are many resources going to run out ?

A

They are being used up quicker than they are being replaced

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4
Q

What pollution affect water ?

A

Sewage and toxic chemicals from industry can affect the plants and animals in the water

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5
Q

What pollutants affect land ?

A

Toxic chemicals such as pesticides.
Nuclear waste is buried underground
Household waste is left in landfill sites

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6
Q

What pollutants affect the air ?

A

Smoke and gases released into the atmosphere. Greenhouse gases like carbon dioxide are considered the most dangerous

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7
Q

What four main human activities reduce land and resources ?

A
  1. Building
  2. Farming
  3. Dumping waste
  4. Quarrying
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8
Q

What is deforestation ?

A

The cutting down of trees

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9
Q

Why is deforestation done ?

A
  1. To provide timber

2. To clear land for farming

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10
Q

Why does so much land need to be cleared to grow crops ?

A

To provide food or grow biofuels such as ethanol

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11
Q

Why does deforestation mean more methane is released into the atmosphere ?

A
  • Rice grows in warm, waterlogged conditions which is ideal for microorganisms, which release methane
  • Cattle grown on the cleared land produce methane
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12
Q

Why is there more carbon dioxide in the atmosphere when trees are cut down ?

A
  • Some trees are burnt when the land is cleared which releases carbon dioxide
  • Microorganisms feeding on bits of dead wood release carbon dioxide through respiration
  • less carbon dioxide is removed from the atmosphere through photosynthesis because there are less trees
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13
Q

Why is a reduction in biodiversity a bad thing ?

A

It is seen as a lost opportunity. The animals and plants that have become extinct could have had many useful products

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14
Q

What are bogs ?

A

Areas of land that are acidic and waterlogged

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15
Q

What is peat ?

A

The remains of partly rotted plants builds up to form peat

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16
Q

How do peat bogs restrict carbon dioxide entering the atmosphere ?

A

The plants only partly rot, so the carbon is stored in the plants

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17
Q

Why are peat bogs destroyed ?

A
  1. The land is cleared for farming
  2. The peat is dried and used as a fuel
  3. Peat used as compost
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18
Q

What happens when a peat bog is destroyed ?

A

The peat starts decomposing so carbon dioxide is released. This adds to the greenhouse affect.

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19
Q

How can people reduce the influence of peat bogs on the environment ?

A

Buy peat free compost to reduce the demand for peat

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20
Q

Where is CO2 stored on earth ?

A
  • Oceans, lakes and ponds
  • Green plants as carbon compounds and photosynthesis removes it from the atmosphere
  • peat bogs
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21
Q

What balances the temperature of earth ?

A

The heat it gets from the sun and the heat radiated back out into space

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22
Q

What do gases in the atmosphere do ?

A

Act as an insulating layer. Thy absorb most of the heat and re-radiate it in all directions

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23
Q

How do the gases in the atmosphere help us ?

A

At night they keep heat in the atmosphere, otherwise it would be very cold

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24
Q

What are greenhouse gases ?

A

Gases in the atmosphere that absorb and emit heat

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25
Q

Which greenhouse gases are scientists worrying about ?

A

Carbon dioxide and methane

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26
Q

What is global warming ?

A

The gradual increase in temperature of earth because of greenhouse gases

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27
Q

How do sea levels rise ?

A

As the sea gets warmer it expands. Some water comes from ice caps melting

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28
Q

What can climate change do to the weather ?

A

Changes the weather patterns which can make it extreme. Hurricanes form in areas where water is over 27 degrees, so more hurricanes could occur

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29
Q

What could happen to plants and animals from climate change ?

A

The distribution of the animals could change due to alterations in migration patterns

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30
Q

Scientists are monitoring climate change, how do they make their readings useful ?

A

By covering a wide enough area and a long enough time scale

31
Q

What are biofuels ?

A

Fuels that are carbon neutral and are made using microorganisms

32
Q

What process makes biofuels ?

A

Fermentation

33
Q

What does yeast do in the fermentation process ?

A

Break down glucose into ethanol. Carbon dioxide and energy are by products

34
Q

Where is the glucose for fermentation sourced ?

A

Sugar cane juices or maize starch

35
Q

What is ethanol mixed with in countries like Brazil ?

A

Mixed with petrol to form gasohol

36
Q

What is biogas ?

A

A fuel made by the fermentation of waste material

37
Q

What makes up biogas ?

A

70% methane

30% carbon dioxide

38
Q

What waste material is used to make biogas ?

A

Sludge waste from sewage works or sugar factories. Waste from keeping animals and kitchen scraps can also be used

39
Q

Where does the fermentation process take place ?

A

In a simple fermenter called a digester or generator

40
Q

Why do biogas generators need to be kept at a constant temperature ?

A

To keep the microorganisms respiring

41
Q

Why can’t biogas be stored as a liquid ?

A

It needs too high a pressure. This means it has to be used straight away for heating, cooking, or to power a turbine to generate electricity

42
Q

What can the byproducts of biogases be used for ?

A

Fertilisers

43
Q

What are the two types of biogas generators ?

A

Continuous

Batch

44
Q

How do batch generators, used to make biogas, work ?

A

They are manually loaded up with waste which is left to digest. The byproducts are cleared away at the end of each session

45
Q

How do continuous generators, which are used to make biogas, work ?

A

Waste is continuously fed in and biogas is produced at steady rate. continuous generators are more suited to large scale biogas projects

47
Q

What three things do biogas generators have ?

A
  1. An inlet for waste material
  2. An outlet for the digested material to be removed
  3. An outlet for the biogas
48
Q

Why are continuous biogas generators more expensive ?

A

Waste has to be mechanically pumped in and removed. The mechanics and upkeep is expensive

49
Q

Why do some biogas generators have to be insulated ?

A

Gas is produced best at 35 degrees Celsius. Generators in cold areas will need to be kept warm to maintain this

50
Q

Why are biogas generators situated away from homes ?

A

They smell and are usually close to where the waste is - which also smells

51
Q

Why is biogas better than fossil fuels ?

A
  • They are carbon neutral

* Doesn’t produce significant amounts of sulphur dioxide or nitrogen oxide

52
Q

How does the production of biogas mean less methane is released into the atmosphere ?

A

Untreated waste which is used as fertiliser gives of methane. By burning it as biogas, methane is not released

53
Q

Digested waste is produced when making biogas, how is this useful ?

A

It is a better fertiliser than undigested waste

54
Q

How does biogas improve the health of rural areas ?

A

It acts as a waste disposal unit. The waste would previously be lying around, this could cause disease or pollute water supplies

55
Q

What factors have to be considered when designing a biogas generator ?

A

Cost
Convenience
Efficiency
Position

56
Q

What three ways can humans increase the efficiency of food production ?

A
  1. Reducing the number of stages in the food chain
  2. Restricting the energy lost by farm animals
  3. Developing new food sources like mycoprotein
57
Q

Why do the amount of stages in a food chain need to be reduced ?

A

There’s less energy and biomass every time you move up a stage in the food chain

58
Q

Why is more food produce by growing crops as apposed to grazing animals ?

A

Only 10% of the food eaten by cattle becomes useful meat to eat

59
Q

Crops grow quicker and more can be grown, so why don’t we just grow crops ?

A
  • People need a variety of foods

* Some land is unsuitable for growing plants

60
Q

How do you restrict the energy lost by animals ?

A

Intensive farming. They are put in small pens close to other animals so they cannot move and are warm. This stops them wasting energy.

61
Q

Why do farmers want the animals to not waste energy ?

A

It makes the transfer of energy from the feed more efficient - so they put weight on quicker

62
Q

What is mycoprotein ?

A

Protein from fungi - used to make meat substitutes for vegetarians

63
Q

What is the main fungus used for mycoprotein ?

A

Fusarium

64
Q

How is the fungus grown in mycoproteins ?

A

In fermenters using glucose syrup as food.

65
Q

Why is the fermenter sterilised before Making fusarium ?

A

So other microorganisms don’t grow inside the fermenter

66
Q

Why is mycoprotein good ?

A
  • Cattle use up lots of space, fermenters aren’t as big
  • Good source of protein in developing countries
  • Efficient
67
Q

Why is the efficiency of food production important ?

A

It means food becomes cheaper and farmers get a higher standard of living

68
Q

What are the disadvantages of efficient food production ?

A
  • intensive farming is considered cruel
  • crowded farming conditions increases chances of disease
  • animals are given antibiotics which stops bacteria, increasing antibiotic immunity
  • power from fossil fuels used to keep animals warm
69
Q

What are food miles ?

A

The distance food travels from being grown to being on your plate

70
Q

Why are high ‘food miles’ bad ?

A
  • transportation uses fossil fuels

* expensive

71
Q

Why are fish stocks decreasing ?

A

Humans are fishing too much

72
Q

Why may some fish species disappear ?

A

Food chains are breaking down

73
Q

What is sustainable food production ?

A

Having enough food without using resources faster than they are being used up

74
Q

What are fish quotas ?

A

Laws put in place to limit the amount, size and species of fish being fished

75
Q

How are the sizes of fishing nets changing ?

A

The net size is increasing to:
• Allow younger,smaller fish to escape and reproduce
• Allow fish that I unwanted to escape

76
Q

What is fermentation ?

A

When yeast and bacteria break sugars down by anaerobic respiration

Science 3 (6 decks)

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