7. Ecology Flashcards
1
Q
What is a habitat?
A
The place where an organism lives
2
Q
Examples of habitats?
A
- woodland
- grassland
- icecap
3
Q
What is a population?
A
All the organisms of one species living in a habitat
4
Q
Examples of populations?
A
- cattails
* wasps
5
Q
What is a community?
A
The populations of different species living in a habitat
6
Q
Example of a community?
A
all organisms within a pond
7
Q
What are biotic factors?
A
Living factors which can affect s community and therefore the distribution of organisms
8
Q
Examples of biotic factors?
A
- new predators arriving
- availability of food
- new pathogens
- competition between species
9
Q
What are abiotic factors?
A
Non-living factors which can affect a community
10
Q
Examples of abiotic factors?
A
- moisture levels
- light intensity
- temperature
- CO2 levels for plants
- wind intensity and direction
- O2 levels (aquatic)
- soil pH and mineral content
11
Q
What is an ecosystem?
A
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
12
Q
Examples of ecosystems?
A
- rainforest
- arctic
- aquatic
13
Q
What is the interdependence?
A
When organisms are dependant on other organism within their community to survive and reproduce
14
Q
What might organisms depend on others for?
A
- food
- shelter
- pollination
- seed dispersal
15
Q
What is a stable community?
A
One where all the species and environmental factors are in balance so the population remains fairly constant
16
Q
How is the population of yarrow estimated?
A
size = total area / area of quadrat x mean number of yarrow per quadrat
17
Q
How does eutrophication occur?
A
- Fertiliser released in pond
- Algae multiply rapidly
- Algae below surface can’t get light to photosynthesise
- Algae die
- Bacteria cause decay of algae
- Bacteria multiply - respiration causes decrease in CO2 and fewer algae photosynthesising
- Fish/organisms die
18
Q
What do field studies enable us to do?
A
Look at the distribution of organisms and the effects of environmental factors on this distribution
19
Q
Where do venus fly traps thrive?
A
Where nitrate ions are very low, because they can live in areas of boggy soil where nitrate ions are low and instead get their nitrate from their insect victims
20
Q
What are the sampling techniques used in field studies?
A
- random sampling - using quadrats, in areas where distribution is quite uniform
- systematic sampling - using transects, used to observe changes in distribution across areas of the habitat
21
Q
What type of sampling are quadrats used in?
A
Random sampling
22
Q
What type of sampling are transects used in?
A
Systematic sampling
23
Q
Where are quadrats used?
A
In places where distribution is quite uniform
24
Q
Where are transects used?
A
To observe changes in distribution across areas of the habitat
25
How could you measure how common an organism is in 2 or more sample areas?
Using quadrats, and comparing them
26
How could you study the distribution across an area?
By placing quadrats along a line known as a transect
27
What is random sampling?
A way of estimating - it should be logical, without bias to get an accurate reading that is representative of the area
28
What is the most common type of transect used?
A line transect
29
What do plants and animals compete for?
Light, space, minerals from soil (plants), food, mates and territory (animals)
30
What are the types of adaptation?
* structural
* behavioural
* functional
31
What is structural adaptation?
Features of an organism's body structure
32
What is behavioural adaptation?
The way an organism behaves
33
What is functional adaptation?
Processes within the organism
34
Examples of structural adaptation?
* fur colour
| * blubber
35
Examples of behavioural adaptation?
* huddling
* migration
* display
* avoiding the sun
36
Examples of functional adaptation?
* hibernating lowers metabolism which conserves energy
| * conserving water by producing very little sweat
37
What are the adaptations of a zebra?
* live in herds so it's hard for predators to detect them
| * run at speed of slowest member
38
What are the adaptations of a penguin?
* wings like flippers to help them swim
* spikes in mouth help swallow live prey
* huddle to keep warm while keeping eggs warm
* swap place so none are on the outside the whole time
* streamlined body helps catch prey and escape predators
39
What are the adaptations of a fennec fox?
• nocturnal to prevent dehydration
* big ears to hear predators and lose heat
* furry soles to stop feet burning on sand
40
What are the adaptations of dragonflies?
* fly fast to avoid predators
* female eggs have gel like substance to help stick to rocks
* most of weight is muscle for strong flying
41
What are the adaptations of great white sharks?
* rolls eyes back in socket at last minute before attack to protect self
* grow back teeth that fall out whilst making an attack
* streamlined for speed
* can detect drop of blood several in away by receptors in nose
42
Why do some birds like swallows migrate?
To move from areas of low resources to areas of high resources
43
Why do penguins huddle?
To conserve heat and shelter themselves from intense winds - decreases SA so less heat is lost
44
Why penguins have a streamlined shape?
Allows them to swim fast in order to catch prey and escape predators and travel long distances
45
Why do camels store fat in their humps?
Minimises heat trapping insulation throughout rest of body and get water and energy from respiration
46
What do camels produce little urine and sweat?
To conserve water
47
Why do cacti have spines instead of leaves?
To minimise SA to reduce water loss and defence against predators
48
Why do some desert plants have widespread roots?
To collect water from a larger areas, during rainy seasons
49
Why do mesquite trees have deep vertical tap roots?
To absorb water from deep down in the soil
50
Why do arctic foxes have a thick coat?
To maintain a consistent body temperature because it is insulating and traps warm air
51
Why do arctic foxes have a white coat?
Winter camouflage to hide from predators
52
Why do arctic foxes have small ears?
To prevent heat loss by minimising SA exposed to cold air
53
Why do arctic foxes have front facing eyes?
To catch prey and to sense distance and depth
54
Why do walruses have a small surface area to volume ratio?
To lose less heat to the surroundings
55
Why do walruses have a thick layer of blubber?
To insulate and help keep them warm in icy water
56
Why does the coral snake have a highly venomous bite?
To kill and paralyse prey
57
Why does the coral snake have red/yellow/black colouration?
Warning colouration
58
What are extremophiles?
Organisms adapted to live in extreme conditions
59
What extreme conditions do certain extremophiles live in?
extreme:
* temperatures
* salinity
* pH
* pressure
* nutrients
* O2 levels
60
What do some micro organisms have that allow them to survive hot volcanic vents, hot springs etc?
They have thermostable enzymes which don't denature at high temperatures
61
Features of ice fish?
* found in Antarctica
| * have no haemoglobin but enlarged heart and large blood vessels
62
Features of water bears?
• survive long periods of desiccation
63
Where do many tardigrades live?
In water
64
Where do you find tardigrades on land?
Where there's moss or lichen
65
What is the process of one organism feeding on another?
The food chain
66
What is cycling?
Where materials are recycled
67
What happens to the materials taken up from the environment by plants?
They are returned to the environment and recycled to provide building blocks for future organisms
68
What materials are cycled through the biotic and abiotic components of an ecosystem?
* carbon
* water
* nitrogen
69
Where is carbon present?
In all organisms
70
What is the carbon cycle?
The constant cycling of carbon
71
How does the carbon cycle work?
* plants and algae remove CO2 from the environment for photosynthesis
* this carbon is incorporated into the compounds (carbohydrates, fats, proteins) in plants and algae
* some of the CO2 is returned to the atmosphere when plants and algae respire
* algae and plants are eaten by animals -animals eat each other - carbon is incorporated into the compounds (carbohydrates, fats, proteins) that make up their bodies
* animals respire and release CO2
* when animals, plants and algae die detritus feeders and decomposers feed on their bodies
* CO2 is released when detritus feeders and decomposers respire
* combustion releases CO2
72
What are the different consumers in the food chain?
Producer -> primary consumer -> secondary consumer -> tertiary consumer
73
Example of a producer in the food chain?
Maize
74
Example of a primary consumer in the food chain?
Locust
75
Example of a secondary consumer in the food chain?
Lizard
76
Example of a tertiary consumer in the food chain?
Snake
77
What organisms break down waste products to recycle them?
Decomposers (bacteria and fungi) and detritus feeders (detrivores)
78
What is released when detrivores and decomposers respire?
CO2
79
What does combustion of wood and fossil fuels release into the atmosphere?
CO2
80
When carbon is incorporated into compounds in plants, algae and animals, what form does it take?
* carbohydrates
* fats
* proteins
81
What is the water cycle?
The changes to water when it evaporates into the air, condenses in clouds and then precipitates down to Earth
82
What is evaporation?
The process that occurs when water changes from a liquid to gas caused by heat
83
What is transpiration?
The passage of water vapour from a plant to the atmosphere
84
What is condensation?
The cooling of water in the atmosphere changing gas to a liquid
85
What is precipitation?
Water droplets fall from the atmosphere in the form of rain, sleet, snow or hail
86
What is percolation?
When water trickles through gaps in soil and rocks
87
What is run off?
Rainfall that is not absorbed by soil and travels to the ocean
88
What is the water cycle responsible for?
Distributing water across the earth through evaporation, condensation and precipitation
89
Where is water important?
* solvent - transport medium for solutes
* transpiration stream - column of water moved up the xylem
* osmosis - vital for uptake and movement of water
* expands on freezing - ice floats, insulating organisms in water below
* metabolic functions - required for photosynthesis, produced in respiration
* lubricant - synovial fluid
* support - amniotic fluid, buoyancy for large aquatic animals
* thermoregulation - evaporation of water cools us down, large bodies of water are thermostable
90
Why is water needed as a solvent?
As a transport medium for solutes
91
Why is water needed in the transpiration stream?
To move water up the xylem
92
Why is water needed for osmosis?
Vital for uptake and movement of water
93
Why is water needed to expand on freezing?
Ice floats, insulating organisms in water below
94
Why is water needed for metabolic functions?
Required for photosynthesis, produced in respiration
95
Why is water needed as a lubricant?
Synovial fluid - between joints
96
Why is water needed for support?
As amniotic fluid, and buoyancy for large aquatic animals
97
Why is water needed for thermoregulation?
Evaporation of water cools us down; large bodies of water are thermostable
98
What organisms help to decompose biological material?
* detrivores
| * decomposers
99
What are some examples of decomposers?
Bacteria and fungi
100
What are detrivores also known as?
Detritus feeders
101
Why is decomposition vital to the ecosystem?
It is vital for the recycling of materials
102
Examples of detrivores?
Woodlice and earthworms
103
What role do detrivores play in decomposition?
Starting the process of decay by breaking plant tissue into much smaller pieces
104
What effect do detrivores have by breaking plant tissue into smaller pieces?
They increase surface area for the action of decomposers
105
What do detrivores break into smaller pieces?
Plant tissue
106
What are decomposers (microorganisms)?
The bacteria and fungi that make things rot
107
What do decomposers (microorganisms) do?
Release enzymes into the dead animal or plant
108
What do enzymes released by decomposers do?
They break down large compounds into smaller soluble ones so they can be absorbed by decomposers
109
What comes first in the process of decomposition - microorganisms (decomposers) or detrivores?
Detrivores
110
What factors affect the rate of decay?
* temperature
* availability of water
* availability of oxygen
111
How do bacteria and fungi cause decay?
By secreting enzymes which break down biological material
112
What do microorganisms specifically release during decomposition?
* mineral ions
| * carbon dioxide
113
Why do dead animals and plants decay more quickly at higher temperatures?
* as temperature increases, rate of reaction increases - the enzymes secreted by decomposers work better at higher temperatures -> more energy -> more collisions between enzymes and substrates
* if temperature is too high enzymes will denature and decay will stop
114
Why do dead animals and plants decay more quickly when more oxygen is available?
detrivores and decomposers are causing this decay -> they need oxygen to respire
115
Why do dead animals and plants decay more quickly in moist conditions?
Water is needed for metabolic processes
116
What type of process is the souring of milk?
Fermentation; takes places in the absence of oxygen
117
What do bacteria in pasteurised milk do?
Breakdown lactose to form lactic acid - which lowers pH so milk tastes sour
118
In the required practical, why will the pH of the milk fall?
Due to the production of fatty acids
119
In the required practical, what is used to speed up the process of fermentation?
Lipase
120
What is the difference between the model and the natural decay of milk?
* the model uses lipase -> pH decreases due to fatty acids
| * natural decay -> pH decreases due to lactic acid
121
What is cresol red?
An indicator that is purple in alkaline solutions but when pH drops below 8.3 it becomes yellow
122
What colour is cresol red in alkaline solutions?
Purple
123
When will the cresol red indicator turn yellow?
When pH drops below 8.3
124
Examples of organic material that can be composted?
* waste food
* vegetable peelings
* paper
* leaves/grass cuttings
125
What is released during the composting process?
Carbon dioxide from respiration
126
What is compost used for?
A natural fertiliser for plants or crops
127
What does composting do?
Recycles nutrients back into the soil, improving crop growth
128
How do farmers provide optimum conditions for rapid decay of biological matter?
* warmth - keep in the sun
* moisture - sprinkle water on if dry, cover in plastic cover to hold in moisture
* air - turn over compost with rake to keep aerated
129
What could happen if compost overheats?
Could cause methane to be produced instead of just carbon dioxide
130
Examples of where decay micro organisms are useful?
* compost
* gardeners putting manure on their roses etc.
* farmers decaying waste animal matter produced on farm
* sewage works
131
What is produced in anaerobic digestion?
Biogas
132
What is biogas?
A flammable mixture of gases
133
How is biogas formed?
When bacteria break down plant or animal waste material in anaerobic conditions
134
What is biogas composed of?
Mainly methane - it varies depending on what is put into generator and what bacteria are present
135
What does the composition of biogas depend on?
* what is put into the generator
| * which bacteria are present
136
What is the optimum temperature for bacteria in a biogas generator?
30*C
137
Why do biogas generators generate heat?
The reactions are exothermic
138
Inputs to biogas generators?
* animal dung
* farm waste
* garden waste
139
Outputs of biogas generators?
* methane for cooking, heating or refrigeration
| * slurry - can be used as fertiliser
140
Why do biogas generators work best in hot countries?
They work best at 30*C
141
Why are many biogas generators sunk into the ground?
For good insulation
142
Advantages of the floating draw biogas generator?
* easy construction
* easy to operate
* steady gas pressure produced
* reliable - well trialed technology
143
Disadvantages of the floating draw biogas generator?
* metal holder is expensive
| * metal holder may rust
144
Advantages of the fixed dome biogas generator?
* initial cost low
* well insulated
* long useful life - no moving or rusting parts
145
Disadvantages of the fixed dome biogas generator?
* gas pressure fluctuates
| * sealing of the gas holder is not always right
146
Which changes in the environment can impact the distribution of species within an ecosystem?
* a change in the availability of water
* a change in temperature
* a change in the composition of atmospheric gases
147
How may changes in the environment come about?
* naturally - seasonal, geographical changes
| * due to human activity
148
What is the general impact that humans have on the land?
More resources are used, more waste is produced
149
What happens if waste is not handled appropriately?
It may cause pollution of air, water and land
150
Why is there exponential growth of the human population?
* lack of predators
* advances in medicine
* increased efficiency of food production
* modern farming methods which increase productivity etc.
151
What is water pollution caused by?
* fertilisers
* toxic chemicals
* sewage
152
How do humans reduce the amount of land available for other animals?
By:
* building
* quarrying
* farming
* dumping waste
153
What happens when fossil fuels are burned?
Acidic gases and smoke are released and pollute the air
154
What can burning fossil fuels lead to?
Breathing problems, and the formation of acid rain
155
What is smog?
A haze of small particles and acidic gases that can be seen in the air in cities
156
What can smog be made of?
* sulphur dioxide
* nitrogen oxides
etc.
157
What are some pollutants from fuels that are in the atmosphere?
* sulphur dioxide
* particulate matter
* nitrogen oxides
158
How do fertilisers cause water pollution?
* fertiliser drains through soil into water so algae grow
| * when algae die the bacteria in the water increases and use the oxygen up, killing the fish
159
What is the process called that means fertiliser can cause water pollution?
Eutrophication
160
How do toxic chemicals cause water pollution?
Can pollute water and kill animals and plants, reducing biodiversity
161
How can sewage cause water pollution?
* can cause an increase in the number of bacteria in the water
* bacteria remove oxygen for respiration and organisms die
162
Where may land pollution come from?
* landfill
| * toxic chemicals from industry and households
163
Examples of some non-renewable energy resources that are being used up?
* uranium
* natural gas
* propane
* coal
164
Why is land pollution a problem?
* pest resurgence
* reduction in wild flower biodiversity
* persist in environment = long term damage
* affect top carnivore if persists in food chain
165
How can pest resurgence be caused by land pollution?
Land pollution may kill insects such as predators of the pest
166
How can reduced flower biodiversity be caused by land pollution?
Land pollution may kill wild plants which act as food plants for beneficial insects
167
When does bioaccumulation occur?
When toxic chemicals such as pesticides are taken up by predators in the food chain
168
How do toxins get passed in the food chain to cause bioaccumulation?
From the primary consumers to the secondary and tertiary etc.
169
Why does a toxin accumulate in larger amounts further down the food chain?
Organisms consume larger numbers of the organism below them in the food chain
170
What happens when acid rain reaches the earth?
It flows across the ground in surface runoff, enters water systems and sinks into the soil
171
How does acid rain occur?
* gases from combustion of fossil fuels are released into the atmosphere (e.g. sulphur dioxide, nitrogen dioxides)
* the wind spreads the acidic gases over 100s of miles
* acidic gases are dissolved in the rain and snow
* plants, animals and lakes are damaged by acid rain
172
What effects does acid rain have?
* makes waters acidic - increased aluminium in the water - killing aquatic animals
* damages forests - leaches mineral ions out of soil and aluminium is released into the soil - leaves damaged
173
How does acid rain affect aquatic animals?
* waters are made acidic
| * (toxic) aluminium in the water - enters lakes and streams - kills aquatic animals
174
How does acid rain affect forests?
* leaches essential mineral ions out of soil
* releases (toxic) aluminium into the soil
* leaves directly damaged
175
What is the meaning of biodiversity?
The variety of all the different organisms on earth, or within an ecosystem
176
Why is having high biodiversity important?
It ensures the stability of ecosystems - because it reduces the dependence of one species on another for food and shelter
177
How does global warming occur?
* energy from the sun is absorbed by earth
* normally the sun radiates the energy back out of the atmosphere
* greenhouse gases absorb the energy
* some energy is radiated back to earth
* results in global warming
178
What are the consequences of global warming?
* rising sea levels leading to habitat loss
* changes in distribution of organisms
* changes to migration patterns
* less biodiversity
179
How does global warming make sea levels rise and lead to habitat loss?
* sea warms and expands so sea level rises
* also makes ice melt so water trapped on land runs into the sea e.g. glaciers
* leads to flooding in low-lying areas
180
How does global warming cause changes to the distribution of organisms?
* some species become more widely distributed if they need warmer temperatures and can thrive over a larger area
* some species that need cooler temperatures have smaller ranges and can thrive over smaller areas
181
How does global warming cause a change in migration patterns?
animals (e.g. birds) migrate
• for example, birds in Africa moving back to summer breeding grounds earlier than before
182
How does global warming cause reduced biodiversity?
Some species may not be able to adapt to a change in climate - won't survive and become extinct
183
How does an increase in human population affect development and therefore land use?
Increased human population leads to increased development and there increased land use
184
What are the main reasons for deforestation?
* to clear land for farming (e.g. cattle)
| * to grow crops for biofuel
185
What are the consequences of deforestation?
* less biodiversity - fewer habitats
* more carbon dioxide released into atmosphere - global warming
* fewer trees to 'lock up' carbon dioxide during photosynthesis - more in the atmosphere
* destruction of peat bogs leading to release of carbon dioxide
186
What are bogs?
Areas of land that are acidic and waterlogged
187
Why is there a lack of decay in bogs?
There is a lack of oxygen
188
How is peat formed?
When partly rotted plants in bogs build up to form a soil like material
189
Why are peat bogs often drained?
* so the area can be used as farmland
| * so the peat can be dried to burn as fuel or be sold as compost
190
What are the problems of peat bogs?
* draining peat means more air can get to it = more decomposition = microbes release carbon dioxide = global warming
* carbon dioxide is released when peat burns = global warming
* destroying bogs reduces habitats and therefore biodiversity
191
What are the general effects of rising sea surface temperatures and rising sea levels?
* people become displaced from their homes
* increased population density and demands on land
* river delta threatened - sea water moves upstream
* coral reefs bleached
* increased numbers of tropical storms
* warmer water temperatures - human health threatened e.g. cholera
192
What have scientists done to reduce negative effects of humans on biodiversity?
* breeding programmes
* protection and generation of rare habitats
* reintroduction of hedgerows in agricultural areas to increase biodiversity
* reduction of deforestation and and CO2 emissions by some governments
* recycling resources rather than dumping waste
193
Examples of breeding programmes that will reduce negative effects of humans on biodiversity?
In zoos, then releasing animals back into the wild without being humanised
194
Examples of rare habitats that can be protected to reduce negative effects of humans on biodiversity?
* marshlands
* heathlands
* coral reefs
* mangrove swamps
195
Examples of recycling instead of dumping waste that will reduce negative effects of humans on biodiversity?
Developing biodegradable plastic
196
What conflicting pressures are there which can affect how biodiversity is maintained?
* costs money
* can come at a cost to local people's livelihood
* may be conflict in protecting food security
* development can affect the environment
197
An example of how costs can affect how biodiversity is maintained?
Governments may pay farmers a subsidy to reintroduce hedgerows - costs money to check these programmes are being followed
198
An example of how other people's livelihood can affect how biodiversity is maintained?
Reducing deforestation means people employed in tree felling could be left unemployed and move away to find work - affecting the local economy
199
An example of protecting food security can affect how biodiversity is maintained?
Farmers may kill pests (locusts, foxes) to protect crops and livelihood so more food can be grown - affecting food chain and biodiversity
200
An example of how development can affect how biodiversity is maintained?
For housing development on the edge of towns or new agricultural land in developing countries - untouched land with high biodiversity used for development
201
How can indicator species measure pollution levels?
The presence/absence of certain organisms indicates how much pollution there is
202
What is the most common source of air pollution?
The combustion of fossil fuels
203
Example of an indicator species for air pollution?
Lichen
204
What are lichens?
Plants that grow in exposed places e.g. rocks, tree bark
205
How do lichens indicate the amount of pollution in an area?
* rainwater contains just enough nutrients to keep them alive
* air pollutants dissolved in rainwater can damage them and prevent growth
206
What is biomass?
The amount of dry biological matter (kg)
207
What is a carnivore?
An organism that eats meat - consumer
208
What is a herbivore?
An organism that eats producers (green plants)
209
What is a predator?
An organism which hunts for food (carnivores)
210
What is prey?
Organisms which are eaten by predators (herbivores or carnivores)
211
What is a producer?
A green plant
212
How is energy from the sun passed on through a food chain?
Radiation from the sun is the source of energy for organisms on earth. Energy is trapped by green plants and passed to animals in food chains
213
What is a trophic level?
A feeding level in a food chain
214
How can trophic levels be represented?
Using numbers - starting at level one with plants and algae
215
What are apex predators?
Carnivores with no predators
216
What are decomoposers?
Microorganisms that break down dead plant and animal matter by secreting enzymes
217
What happens to the amount of biomass and energy in organisms as a food chain progresses?
It decreases throughout the chain
218
How much biomass is transferred from one trophic level to the one above?
10%
219
What are losses of biomass in the food chain due to?
* not all ingested material being absorbed (some faeces)
* some absorbed material lost as waste (CO2 and water in respiration)
* glucose used in respiration
220
Why do carnivores produce less waste than herbivores?
meat is easier to digest than vegetation, however some indigestible materials (fur, bones, teeth) become faeces
221
What happens when animals eat excess protein?
It cannot be stored and is broken down into urea and passed out in urine
222
How is biomass lost through movement?
some biomass used for respiration:
* movement uses energy
* muscles heat as they contract
223
Why do mammals need to eat more food than amphibians, reptiles and fish?
Mammals need to maintain a body temperature higher than their surroundings - more energy from respiration transferred as heat
224
What is extracellular digestion?
When decomposers break down dead animal and plant waste by secreting enzymes on it
225
Problem with pyramids of numbers?
Do not accurately reflect what is happening to biomass
226
Why does the number of organisms at each trophic level decrease?
A large amount of energy in the biomass of plants supports a smaller amount of herbivore biomass etc
227
How is the efficiency of a biomass transfer calculated?
biomass transferred to next level / biomass availible at previous level x100
228
An example to demonstrate how a pyramids of biomass is more useful than a pyramid of numbers?
1 oak tree could support lots of organisms, but it has a large biomass - showing energy loss throughout food chain
229
What are cyclic fluctuations?
When the numbers of predators and prey fluctuate in a regular pattern
230
Example of cyclic fluctation?
foxes and rabbits:
* more food (grass) - rabbit number increases
* more food for foxes - number increases
* rabbit number decreases
* no food for foxes so number decreases
* fewer foxes - rabbits increase
and so on
231
What is food security?
Having enough food to feed a population
232
What biological factors are threatening food security?
* increase in birth rate
* changing diets in developed countries
* new pests and pathogens
* environmental changes e.g. famine
* cost of agricultural inputs
* conflict
233
In general, how can the efficiency of food production be improved?
By restricting energy transfer from food animals to the environment
234
What farming methods can be used to minimise energy loss from food animals?
* limiting their movement
* controlling the temperature of their surroundings
* feed high protein foods to increase growth
* reduce number of stages in food chain
235
Advantages of intensive farming?
* lots of animals in a small space
* little food wastage
* minimum energy lost from heat loss or movement
* maximum weight gain
* cheaper eggs/meat
236
Disadvantages of intensive farming?
* chickens not able to behave naturally - debeaked
* large barns need heating and lighting
* chicken legs break - cannot hold own weight
* risk of disease - closely packed together
237
Advantages of free range farming?
* cattle behave naturally, less stressed
| * feeding on grass means no contamination
238
Disadvantages of free range farming?
* animals may take longer to gain weight as they are more active
* more land needed to provide grazing and hay
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Solutions to overfishing?
* larger mesh size
* bans on fishing during breeding season
* avoiding breeding grounds
* stricter quotas on amount and type of fish caught
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What fungus is useful for producing mycoprotein?
fusarium
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What is mycoprotein?
A protein-rich food suitable for vegetarians
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What do fermenters enable in mycoprotein production?
For microorganisms to be grown on an industrial scale
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How do fermenters obtain the maximum amount of product?
By reacting to changes and keeping conditions as stable as possible
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What is the role of oxygen in a fermenter?
* for respiration
* filtered to remove dust/microbes
* enters at base and bubbles through the liquid in the fermenter
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What is the role of the paddle stirrer in a fermenter?
* keeps microbes in suspension
| * maintains constant temperature so oxygen and food are evenly spread
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What is the role of the warm water outlet in a fermenter
• allows heat released from respiring microbes to leave the water-cooled jacket
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What is the role of the food inlet in a fermenter?
* allows nutrients to enter at a controlled rate
| * this ensures that microbes are kept at correct stage of growth
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What is the role of the steam inlet in a fermenter?
• raise temperature of contents to optimum
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What is the role of the pH/temperature probe in a fermenter?
* CO2 would alter pH and then affect activity of enzymes in microbes
* ensure the conditions remain constant
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What is the role the outlet - harvest line - in a fermenter?
• enables product to be harvested
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How long does the fermenter run in mycoprotein production?
Six weeks
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What conditions is mycoprotein grown in?
* aerobic
| * temperature no higher than 35*C
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What does the fungus in mycoprotein production require?
Glucose for respiration
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How is temperature controlled in the making of mycoprotein?
A cooling water jacket
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Why does temperature need to be controlled in mycoprotein production?
* aerobic respiration produces heat
| * if temperature goes above 35*C
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What happens to the waste gases produced in a fermenter during mycoprotein production?
Leave the fermenter at the top (such as CO2)
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What happens to the mycoprotein after it is removed from the fermenter?
* heated to break down substances that would otherwise cause kidney problems
* dried in centrifuge
* flavourings added
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How does temperature control in a fermenter differ to that in a biogas generator?
Fermenter - above 35*C and growth slowed - AEROBIC
Biogas generator - needs to be above 30*C - ANAEROBIC fermentation
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In terms of minerals, what does mycoprotein lack?
Iron
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How does genetic engineering help to treat diabetes?
A genetically modified bacterium produces human insulin which is used when purified
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What two cells are used to produce human insulin from bacteria?
* human cell with insulin gene in DNA
| * bacterium cell with ring of DNA (a plasmid)
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How is human insulin produced from genetically modified bacteria?
1. insulin gene cut out of DNA by restriction enzyme
2. plasmid taken out of bacterium and split open by enzyme
3. insulin inserted into plasmid using enzyme
4. plasmid taken up by bacterium
5. bacterium multiplies and grown in fermenter
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What does a restriction enzyme do?
Recognises specific sequences of DNA and cuts it at these points
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What happens to DNA after is has been 'cut' using a restriction enzyme?
One of the DNA strands is left with unpaired bases - a sticky end
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What is a sticky end?
When DNA has been cut by restriction enzyme and one of the DNA strands is left with unpaired bases
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What is the plasmid of a bacterium taken out using during genetic engineering?
The same restriction enzyme as the insulin gene - leaving the same sticky ends
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Where can genes be transferred to in genetic engineering?
* bacteria
| * plants
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How are GM crops created?
New genes transferred to crop plants
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When are genes transferred in GM crops?
At an early stage of development
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Why are genes transferred so early in GM crops?
So that the organism develops with the desired characteristics
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An example of a GM crop?
Golden rice
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How is golden rice engineered?
* genes involved in beta-carotene production are obtained from other species
* then they're introduced to the white rice genome
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What is the benefit of golden rice?
Increased vitamin A content (25 times)
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Arguments for GM crops?
* higher crop yields
* resistant to herbicides
* reduces pesticide use
* safe for human consumption
* help developing world
* preserves habitats
* better shelf life
* produces plants better for harsher habitats
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How do GM crops reduce pesticide use?
Some crops resistant to viruses and insect pests
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How do GM crops preserve habitats?
Less land needed for agriculture
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Arguments against GM crops?
* effect on wild flowers and insects
* mainly benefits large GM companies
* unknown long term health risks
* affect wild life
* increasing yields won't help developing world
* cross contamination
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Why might GM crops affect wildlife?
Weeds killed could be a source of food for animals
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Why might cultured meat slow down the rate of global warming?
* less methane produced by cows
| * less deforestation to cater for grazing
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Describe how mycoprotein is produced
* the fungus fusarium is grown in a fermenter
* in aerobic conditions
* it needs glucose
* mycoprotein is harvested and purified
