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Biology Revision 🌱 > Chapter 18 - Biodiversity and ecosystems > Flashcards

Chapter 18 - Biodiversity and ecosystems Flashcards

1
Q

what is biodiversity?

A

the variety of different species of organisms on earth or in an ecosystem

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2
Q

why is a high biodiversity important?

A

it makes sure the ecosystem is stable because different species depend on eachother for things like food and shelter
the loss of one species has a minor impact

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3
Q

2 human activities impacting biodiversity

A

deforestation

global warming

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4
Q

why has the population of humans increased so much? 2

A

development in medicine - stops people dying

development in farming - stops people starving

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5
Q

why does a higher number of humans have a larger impact on the environment?

A

we are demanding a higher standard of living
so we use more raw materials and more energy
raw materials are being used quicker than they are being replaced

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6
Q

4 main uses of land

A

building infrastructure
farming
mining
landfill

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7
Q

how is the growing population impacting land use?

A

the growing population needs more land for houses etc so we destroy habitats and affect biodiversity

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8
Q

how is waste impacting the air around us?

A

smoke and acidic gases can pollute the air, e.g. acid rain

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9
Q

how is waste impacting the land around us? 3

A

we use toxic chemicals for farming
we bury waste in landfill sites
nuclear waste is left underground

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10
Q

how is waste impacting the water around us?

A

sewage and toxic chemicals from industry pollutes lakes, rivers etc

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11
Q

how do people pollute the land in developed countries? 2

A

household waste

hazardous industrial waste

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12
Q

how does farming pollute the water?

A

weedkillers and pesticides are used which try to keep the crop healthy
these run off the fields into rivers and streams
they become part of food chains as animals ingest infected water
bioaccumulation - at each stage along the foodchain, more and more toxins build up in the animal

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13
Q

how are we affecting plant life in the water?

A

fertilisers and untreated sewage flow into rivers and streams
this leads to a build up of nitrogen
this stimulates algae and weeds to grow quickly
plants die because they are outcompeted

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14
Q

how are we affecting animal life in the water?

A

fertilisers and untreated sewage flow into rivers and streams
this leads to a build up of nitrogen
this stimulates algae and weeds to grow quickly
plants die because they are outcompeted
this leads to more decomposers
decomposers use up dissolved air in the water
the animals in the water now don’t have enough oxygen and can die too

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15
Q

2 ways in which the pH of water is tested

A

instruments used to show proportion of toxic chemicals

bioindicators (animals such as salmon that are only found in clean waterways)

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16
Q

how is acid rain formed?

A

fossil fuels burned
they contain sulfur impurities
the sulfur reacts with oxygen when it burns to form sulfur dioxide
acidic sulfur dioxide and nitrogen dissolve in rainwater to form sulfuric and nitric acids

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17
Q

effects of acid rain 3

A 
kills plantlife (trees, flowers etc)
if it soaks into the soil, it can destroy the roots of plants
can infect water ways, making them uninhabitable
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18
Q

why is acid snow worse than acid rain?

A

it will all melt in one go in the first meltwater of spring

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19
Q

why will ‘clean’ countries still be affected by acid rain?

A

the sulfur dioxide and nitrous oxides are carried high in the air by winds, infecting other countries

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20
Q

ways in which we have attempted to reduce the effect of acid rain

A

low sulfur diesel and petrols
strict emission levels
catalytic converters remove polluting gases

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21
Q

what has happened to the amount of acid rain over the past 40 years?

A

it has decreased

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22
Q

impacts of smoke on human health

A

particles breathed in and can damage cardiovascular system

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23
Q

how is smoke damaging our world?

A

the particles in smoke gather in the atmosphere

they reflect sunlight so less light reaches earth

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24
Q

what is smog?

A

a combination of chemicals and smoke that can be seen in the air

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25
Q

impact of sulfur dioxide on people

A

breathing difficulties

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26
Q

4 impacts of global warming

A

thermal expansion
changes in distribution of wildlife
changes in migration patterns
reduced biodiversity

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27
Q

problem of rising sea levels

A

extreme flooding and loss of habitats

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28
Q

process of global warming

A

gases in the atmosphere act like an insulating layer

they absorb the energy that would be reradiated out to space and reflect it back towards earth

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29
Q

what are the two main greenhouse gases?

A

carbon dioxide and methane

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30
Q

3 main reasons for deforestation

A

farming
rear cattle
to grow crops to be used as biofuels

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31
Q

what are the three ways in which deforestation increases CO2 levels in the atmosphere

A

less carbon dioxide taken in by the trees through photosynthesis
combustion = more CO2
decomposers release CO2 through respiration

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32
Q

why does deforestation reduce biodiversity?

A

habitats like forests contain a large number of species so when their habitats are destroyed there is an increased risk of them becoming extinct

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33
Q

how is peat made?

A

when plants that live in bogs die, they don’t fully decay because it is too acidic and there isn’t enough oxygen
over time, this builds up to form peat

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34
Q

what are bogs?

A

areas of land that are acidic and waterlogged

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35
Q

why are peat bogs so important?

A

huge store of carbon and home to many unique animals, e.g. venus flytrap

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36
Q

why are peat bogs being destroyed?

A

the peat is cut up and used as a fuel or compost and the area is needed for farmland

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37
Q

why is peat non-renewable?

A

it is being used faster than it is being made

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38
Q

why does the sourcing of peat increase CO2 levels?

A

when peat is drained, it comes into contact with air nd microorganisms start to decompose it. when these organisms respire, CO2 is released

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39
Q

why are deforestation and methane levels linked?

A

the land which has been cleared by deforestation is often used for cattle farming and growing rice, both of which are a source of methane

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40
Q

why will there be more CO2 in the air as the oceans warm up?

A

carbon dioxide is less soluble in warm water so they are a less effective carbon sink

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41
Q

why will the distribution of animals change?

A

climate change may make some conditions more favourable for animals than others so for some their range will expand whilst for others it will shrink

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42
Q

how ill global warming impact migration patterns?

A

changing temperature and seasons

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43
Q

5 ways in which we are trying to maintain ecosystems

A

recycling
reduction of CO2 emission and deforestation
breeding programmes for endangered species
protection of rare habitats
reintroduction of hedges

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44
Q

problems with breeding programmes 2

A

must avoid inbreeding

many animals don’t reproduce easily or quickly

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45
Q

what are breeding programmes and why will they help?

A

animals are bred in captivity to ensure a species survives if they die out in the wild
they can then be released into the wild to boost or re-establish a population

46
Q

3 examples of rare habitats that are now becoming protected

A

coral reefs
heathland
mangroves

47
Q

what is being done to protect coral reefs

A

global warming is being tackled as acidic pH is the biggest threat here

48
Q

what is being done to protect heathland?

A

protecting it from developers and reestablishing its unique characteristics, e.g. letting ponies graze

49
Q

what is being done to protect mangroves?

A

salinity of water is being monitored

50
Q

why is it good that rare habitats are being protected?

A

helps to protect the species that live there, maintaining biodiversity

51
Q

why are people replanting hedgerows?

A

they provide a valuable habitat for a wide range of species in the UK

52
Q

how is costa rica benefiting from reduced CO2 emissions?

A

sustainable tourism

53
Q

what are countries doing to promote recycling? 3

A

encourage composting
companies are now recycling manufacturing waste
taxes on putting material in landfill

54
Q

4 arguments against maintaining biodiversity

A

it is expensive - to set up and maintain schemes
could affect peoples livelihoods - e.g. those working in the timber industry will struggle to find work
development is important
we must protect our food security against pests like foxes

55
Q

what are trophic levels?

A

the position of organisms in a food chaain

56
Q

what is trophic level 1?

A

producers, e.g. green plants and algae

57
Q

what is trophic level 2?

A

primary consumers, e.g. herbivores

58
Q

what is trophic level 3

A

secondary consumers - carnivores

59
Q

what is trophic level 4?

A

tertiary consumers - carnivores that eat other carnivores

60
Q

what is biomass?

A

the mass of material in living organisms

61
Q

how do decomposers work?

A

they secrete enzymes that break down the dead bodies into food molecules
these are diffused into the decomposer

62
Q

problem with measuring the dry biomass of an organism?

A

you have to kill it and dry it out first

63
Q

problem with measuring the wet biomass of an organism?

A

the amount of water in an organism varies throughout the day

64
Q

what happens to the amount of energy and biomass as you move up a trophic level?

A

it decreases

65
Q

why does the amount of biomass decrease as you go through trophic levels? 3

A

not all parts of organisms are eaten
some of the biomass is excreted, e.g. faeces
lots of biomass used to keep organism alive, e.g. respiration

66
Q

what is the incident energy?

A

sunlight

67
Q

why is biomass lost in faeces for a) herbivores and b) carnivores?

A

many herbivores don’t have the enzymes to break down cellulose so the food is excreted
carnivores can’t eat every bit of their prey, eg hooves

68
Q

how much of the suns energy that hits earth is used for photosynthesis?

A

1%

69
Q

why is biomass lost in waste?

A

plants and animals need glucose which they produce to stay alive - it supplies energy for the living processes in the body
some biomass is lost as carbon dioxide, heat and water - the waste products of respiration

70
Q

why will a more active animal transfer less biomass?

A

active, contracting muscles carry out a lot of respiration , which leads to the loss of lots of heat that would have been transferred as biomass

71
Q

why is biomass lost through temperature control?

A

mammals use lots of biomass in respiration in order to maintain a constant temperature

72
Q

how to calculate the efficiency of biomass transfer?

A

efficiency = biomass transferred to next level / biomass available at previous level x 100

73
Q

6 factors affecting food security

A 
increasing birth rates
changing diets 
new pests and pathogens
cost of agricultural inputs
conflicts
environmental changes
74
Q

what is food security?

A

having enough food to feed a population

75
Q

why is an increasing birth rate affecting food security?

A

there are more people to feed

76
Q

how can changing diets affect food security?

A

in developed countries, people often want to try new,exotic foods
they import them
this deprives local people of a traditional food source or drives up the price so they can’t afford it

77
Q

how can new pests and pathogens affect food security?

A

this can result in lack of crops produced and lead to widespread famine

78
Q

how do environmental changes affect food security?

A 
flooding = crops drown = no food
drought = no water = no crops
79
Q

how can the changing price of agricultural inputs affect food security?

A

in developing countries, the expense of farming means some people can’t afford it, so they grow no food and starve

80
Q

how can conflict affect food security?

A

people can’t access food and water and often, infrastructure such as water pipes are destroyed

81
Q

what is sustainable fish production?

A

maintaining fish stocks at a level where fish can continue to breed

82
Q

how can fish production be conserved? 2

A 
fishing quotas (there are limits on the number of and species of fish that can be fished in certain areas)
net size (using a bigger mesh size means young fish can escape and breed)
83
Q

what is sustainable food production?

A

producing food in ways that supplies the whole population and can continue to for many years

84
Q

3 ways of making food production sustainable?

A

taking care of fishing in oceans so fish supplies don’t run out
maintaining soil quality so plants grow well consistently

85
Q

how is biotechnology helping in food production?

A

genetically modified crops are being developed to give better yields or more nutritional value

86
Q

3 advantages of GM crops

A

pest resistance
more nutritional value
grow in difficult areas

87
Q

3 disadvantages of GM crops

A

poor soil is one of the main reasons why crops fail and GM crops won’t change this
people can’t afford the seeds
there is enough food, people just don’t have the money to buy it - poverty needs to be tackled first

88
Q

what is mycoprotein?

A

it is a high protein meat substitute for vegetarians

89
Q

process of creating mycoprotein

A

the fungus fusarium is grown on relatively cheap glucose syrup
aerobic conditions were provided in fermenters
the biomass is then harvested and purified to produce mycoprotein, which is a pale yellow solid that can be shaped and flavoured

90
Q

2 disadvantages of fishing quotas

A

if fishermen have caught too much, they throw it back into the sea. But by then it is dead anyway
may affect their income and food security

91
Q

what do farmers often do to increase the growth of livestock and why?

A

they feed animals to animals

this protein rich diet improves growth

92
Q

why would it be most efficient if humans lived off plants?

A

there would only be two phases in the chain so less energy would be wasted

93
Q

why does limiting movement of livestock increase efficiency?

A

they don’t use their muscles much
this reduced respiration
so less energy is lost

94
Q

why does keeping animals in a temperature controlled environment improve efficiency?

A

they don’t have to use much biomass to respire and keep warm so less biomass is lost

95
Q

process of fish farming

A

they are caught and live in cages
they are fed high protein meals
they have restricted movement
because of this, they grow and mature very rapidly

96
Q

why are fish being specifically bred?

A

for fast growth

97
Q

disadvantages of farming animals in factories 4

A

disease spreads quickly
ethics - is it right to restrict growth?
there are concerns about the high-protein food they are fed
they need constant monitoring - expensive

98
Q

how is the farming of cattle, fish and chickens made more efficient?

A

they are farmed in factories in specially monitored conditions

99
Q

why are intensive farming methods used?

A

there has been an increase in demand for cheap meat products

100
Q

why are the conditions that animals are kept in in factories not that bad?

A

outside, they are subjected to all the elements and many choose voluntarily to move into a barn

101
Q

how can bacteria be modified to produce human insulin?

A

a plasmid is removed from a bacterium
the insulin gene is cut from a human chromosome using a restriction enzyme. The cut leaves one of the bases unpaired, which is called the sticky end
the plasmid is cut open using the same enzyme, leaving the same sticky ends
the plasmid and insulin gene are mixed
ligase (an enzyme) is added to join the two sticky ends together to make recombinant DNA
this is inserted into the bacterium
the bacterium multiplies under carefully controlled conditions

102
Q

what does a restriction enzyme do?

A

it recognises specific sequences of DNA and cuts the DNA at these points
the cut leaves one of the DNA strands with unpaired bases, this is called the sticky end

103
Q

what is recombinant DNA?

A

when an enzyme joins two sticky ends together

two different bits of DNA stuck together

104
Q

how do seasonal changes impact the distribution of organisms?

A

in temperate parts of the world, many factors, such as temperature, change between seasons. Some organisms will migrate to find more favourable conditions

105
Q

how do geographical changes impact the distribution of organisms?

A

many plants and animals have adaptations that enable them to survive in specific conditions, so will move when the conditions aren’t favourable (e.g. soil pH)

106
Q

negative impacts humans have on the environment 3

A

global warming and climate change
acid rain
pollution

107
Q

positive impacts humans have on the environment 3

A

preserving rain forests
reducing pollution and monitoring pH
conservation measures (e.g. replanting hedgerows)

108
Q

what are organisms doing as a result of global warming?

A

relocating to cooler and higher areas

109
Q

what are the three things that affect the distribution of an organism?

A

seasonal changes
human impacts
geographical changes

110
Q

what has happened to dartford warblers as a result of climate change?

A

in the 1900s, they lived in southern europe

as temperatures have increased, they have moved into england and wales

111
Q

what do scientists predict will happen to many bird species in Europe by the end of the century?

A

they will have moved out of Europe or will become extinct

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