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181 Cards in this Set
- Front
- Back
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Define Ecology. |
The study of living organisms within a habitat and their interactions with both biotic and abiotic factors. |
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Define Ecosystem |
A characteristic community of interdependent species interacting with the abiotic components of their habitat |
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Define habitat |
The place in which an organism lives, often containing a community of organisms |
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Define populations |
A group of interbreeding organisms of the same species occupying a particular habitat. |
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Define community. |
Interacting populations of two or more species within a particular habitat |
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Define environmental resistance |
Environmental factors that slow down population growth |
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Define biotic |
Living factors within the environment, e.g. pathogens and predators |
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Define abiotic |
Non- living environmental factors, e.g. air temperature, oxygen availability |
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Define niche |
The specific role and position a species plays within a particular ecosystem. |
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Define carrying capacity |
The maximum number of individuals a population can sustain within a particular environment |
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Define birth rate |
The reproductive capacity of a population (for bacteria, yeast or fungus say production rate) |
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Death rate |
Mortality rate |
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Define immigration |
The movement of individuals into a population of the same species |
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Define emigration |
The movement of individuals out of a population of the same species |
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Describe what an equilibrium species is. |
When populations are controlled within a stable habitat through competition |
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Describe the lag phase. |
Slow rate of reproduction. Period of intense metabolic a utility (such as protein synthesis). |
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What does the lag phase represent in sexually reproductive organisms? |
The time taken for individuals to reach sexual maturity. |
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What does the lag phase represent for yeast? |
The time taken for them to hydrate |
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Describe the exponential (log) phase |
Rapid increase in population numbers as more individuals are available for reproduction and there are no limiting factors to growth. |
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What happens at the end of the log phase? |
The species experiences environmental resistance |
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What environmental resistance will occur for bacteria in a flask? (3 examples) |
Availability for nutrients (e.g. glucose), toxic waste build up (e.g. ethanol in yeast), competition |
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What environmental resistance will occur for rabbits on a new island (4 examples) |
Completion for food, predators, parasitism and disease |
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Describe the stationery phase. |
Birth rate is equal to death rate. Factors are limiting any further growth. The population has reached its carrying capacity. |
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Describe the death phase. |
Environmental factors now result in death rate becoming great than birth rate, e.g. glucose running out in the nutrient broth. |
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Describe the lag phase. |
Slow rate of reproduction. Period of intense metabolic a utility (such as protein synthesis). |
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Give 3 density dependent factors |
Completion for food, disease and parasitism, toxic waste build up |
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Define density independent factors |
Factors that have an effect regardless of the size of the population (more likely to cause a population crash) |
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Name 2 density independent factors |
Natural disasters, sudden environmental changes (floods, fires, sudden temperature changes) |
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What the name for the equilibrium point of a species? |
The set point |
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What does the lag phase represent in sexually reproductive organisms? |
The time taken for individuals to reach sexual maturity. |
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What does the lag phase represent for yeast? |
The time taken for them to hydrate |
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Describe the exponential (log) phase |
Rapid increase in population numbers as more individuals are available for reproduction and there are no limiting factors to growth. |
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What happens at the end of the log phase? |
The species experiences environmental resistance |
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What environmental resistance will occur for bacteria in a flask? (3 examples) |
Availability for nutrients (e.g. glucose), toxic waste build up (e.g. ethanol in yeast), competition |
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What environmental resistance will occur for rabbits on a new island (4 examples) |
Completion for food, predators, parasitism and disease |
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Describe the stationery phase. |
Birth rate is equal to death rate. Factors are limiting any further growth. The population has reached its carrying capacity. |
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Describe the death phase. |
Environmental factors now result in death rate becoming great than birth rate, e.g. glucose running out in the nutrient broth. |
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Define density dependent factor |
Factors that have a greater effect the large the population size (more likely to slow down population growth rate) |
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Define intra-specific competition |
Competition between members of the same species |
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Define inter-specific competition |
Competition between members of different species |
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What type of competition is survival of the fittest? |
Intra specific |
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Explain the concept of niche. |
Only one species can occupy a particular niche within an ecosystem. One species will always outcompete the other. |
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Name 4 abiotic factors. |
Light intensity, amount of water and nutrients and temperature |
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Name 3 biotic factors |
Competition for resources , the amount of predator and disease |
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Define trophies levels. |
The feeding levels within an ecosystem |
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Explain why ecosystems rarely support more than 5 trophies levels. |
A lot of energy is lost, e.g. through respiration and excretion |
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Define photosynthetic efficiency |
It is a measure of the ability of a plant to absorb light energy |
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Explain why carnivores have a more efficient energy conversion than herbivores. |
Protein is more rapidly and easily digested that cellulose. A lot of cellulose is lost in the faeces of a herbivore. |
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Define gross ecological efficiency. |
It’s a meagre of how much energy is transferred from one trophies level to the next. |
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What’s the equation for gross ecological efficiency? |
Gross ecological efficiency= (energy in trophic level / energy in previous trophic level) x 100 |
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Why do aquatic organisms have a high ecological efficiency? |
They don’t regulate their own body temperatures and don’t use a lot of energy moving |
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Explain why birds and mammals have a low ecological efficiency. |
Birds and mammals maintain a high body temperature and so this used up a lot of energy |
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Define succession. |
The change in structure and species composition of a community over time |
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Describe primary succession. |
The introduction of plants (or animals) into areas that have not previously supported a community |
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Define secondary succession |
The reintroduction of organisms into a bare habitat previously occupied |
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What is each stage during succession when a particular communities dominated know as? |
A sere |
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Define pioneer species |
The first organism to colonise the rock (e.g. lichens) |
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What’s the equation for photosynthetic efficiency? |
(Energy incorporated into photosynthetic products/ total light energy falling onto the plant) x 100 |
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What do pioneer species do? |
They slowly erode the rock, the accumulation of dead and decomposing organic material leads to the formation of primitive soil. |
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Define a climax community. |
A stable, long lived community |
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Why doesn’t all light energy that falls into a plant get absorbed? (3 reasons) |
Wrong wavelength, reflected, transmitted straight through the leaf |
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Define gross primary productivity. |
The rate of production of chemical energy in organic chemicals by photosynthesis |
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Define net primary productivity |
Gross primary productivity minus the energy used by the price dx in respiration. |
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What is the equation for net primary productivity? |
Net primary productivity= GPP - respiration |
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Define biological productivity. |
The rate at which biomass accumulates in an ecosystem. |
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Define biomass. |
The dry weigh of organic matter comprising a group of organisms in a particular habitat. |
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Define secondary productivity. |
The rate at which consumers accumulate energy from assimilated food in biomass in their cells of tissues. |
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Explain why there’s a loss of energy from the food chain at each level. (3 reasons) |
Energy is egested molecules, energy lost as heat, energy remains in inedible parts of animals |
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Define photosynthetic efficiency |
It is a measure of the ability of a plant to absorb light energy |
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Explain why carnivores have a more efficient energy conversion than herbivores. |
Protein is more rapidly and easily digested that cellulose. A lot of cellulose is lost in the faeces of a herbivore. |
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Define gross ecological efficiency. |
It’s a meagre of how much energy is transferred from one trophies level to the next. |
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What’s the equation for gross ecological efficiency? |
Gross ecological efficiency= (energy in trophic level / energy in previous trophic level) x 100 |
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Why do aquatic organisms have a high ecological efficiency? |
They don’t regulate their own body temperatures and don’t use a lot of energy moving |
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Explain why birds and mammals have a low ecological efficiency. |
Birds and mammals maintain a high body temperature and so this used up a lot of energy |
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|
Define succession. |
The change in structure and species composition of a community over time |
|
|
Describe primary succession. |
The introduction of plants (or animals) into areas that have not previously supported a community |
|
|
Define secondary succession |
The reintroduction of organisms into a bare habitat previously occupied |
|
|
What is each stage during succession when a particular communities dominated know as? |
A sere |
|
|
Define pioneer species |
The first organism to colonise the rock (e.g. lichens) |
|
|
What’s the equation for photosynthetic efficiency? |
(Energy incorporated into photosynthetic products/ total light energy falling onto the plant) x 100 |
|
|
What do pioneer species do? |
They slowly erode the rock, the accumulation of dead and decomposing organic material leads to the formation of primitive soil. |
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Define a climax community. |
A stable, long lived community |
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Name 3 factors that affect succession. |
Migration, competition and facilitation |
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Define mutualism. |
The interaction between two different species that is beneficial to both |
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Define commensalism. |
The loose interaction between organisms in which one benefits and the other is unaffected |
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How do primary and secondary succession differ? How do |
Secondary succession is much more rapid as soil is already present |
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How does grazing affect succession? |
Livestock such as sheep eat the grass and other plants |
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How does moorland management affect succession? |
Heather colonisation is controlled by burning |
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How does farming affect succession? |
Ploughing and growth of crops by monoculture stops trees and shrubs getting established |
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How does deforestation affect succession? |
Trees are cut down, which can cause erosion of the soil |
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Why doesn’t all light energy that falls into a plant get absorbed? (3 reasons) |
Wrong wavelength, reflected, transmitted straight through the leaf |
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Name two industries that affect succession |
Coal mining and quarrying of stone |
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How does urban development affect succession? |
Building new roads and buildings affects both plant and animal species |
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How has combustion led to an increase in carbon dioxide in the atmosphere? |
The burning of fossil fuels releases carbon dioxide that was previously locked up |
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How has deforestation led to an increase in carbon dioxide in the atmosphere? |
Less carbon dioxide is taken in from the atmosphere due to less photosynthesis |
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What can happen to the trees and the land after deforestation that can increase carbon dioxide in the atmosphere? |
When burning the woody parts of the trees carbon dioxide is released. The trees are replaced by crops which store less carbon dioxide or they are replaced by cattle which release methane. Parts of the tree left during deforestation also decompose releasing carbon dioxide. |
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Name 4 green house gases |
Methane, carbon dioxide, nitrous oxide, water vapour |
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Name 5 consequences of global warming. |
Icebergs melting leading to rises in sea levels, more extreme weather, extinction of plants and animals, decrease in ph of the oceans, increased frequency of forest fires |
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Decomposition of soil organic matter is leading to increased release of CO2 name 3 altered farming practices reduce this? |
Leaving crop residue on soil surface to reduce soil erosion, cover soil to protect it between crops, rotate crops to reduce pests. |
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Digestive activities of farm animals means there’s more methane in the atmosphere name 2 altered farming practices to reduce this? |
Reduce intake of meat and dairy, feed cows high sugar grasses and oats |
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Waterlogged and anaerobic soils due to deforestation means there’s more nitrous oxide in the atmosphere name an altered farming practices to reduce this? |
Improve drainage to aerate soils |
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Define gross primary productivity. |
The rate of production of chemical energy in organic chemicals by photosynthesis |
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Sea levels are rising meaning cultivated land is inundated with salt water name an name altered farming practices to reduce this? |
Plant salt tolerant crops |
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Name 6 ways to reduce our carbon footprint. |
Recycle packaging material, drive less, use less air conditioning and heating, choose a diet low in animal protein, avoid food waste, plant trees |
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Name 3 reasons nitrogen is important to all living organisms. |
It’s important for making proteins (amino acids), nucleotides and chlorophyll |
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By which two processes are nitrate pins taken up through plant roots. |
Active transport and facilitated diffusion |
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Name two ways nitrate ions travel through plant roots. |
Apoplast (through the cell walls), symplast (through cytoplasm and plasmodesmata) |
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Define net primary productivity |
Gross primary productivity minus the energy used by the price dx in respiration. |
|
|
What is the equation for net primary productivity? |
Net primary productivity= GPP - respiration |
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|
Define biological productivity. |
The rate at which biomass accumulates in an ecosystem. |
|
|
Define biomass. |
The dry weigh of organic matter comprising a group of organisms in a particular habitat. |
|
|
Define secondary productivity. |
The rate at which consumers accumulate energy from assimilated food in biomass in their cells of tissues. |
|
|
Explain why there’s a loss of energy from the food chain at each level. (3 reasons) |
Energy is egested molecules, energy lost as heat, energy remains in inedible parts of animals |
|
|
Define photosynthetic efficiency |
It is a measure of the ability of a plant to absorb light energy |
|
|
Explain why carnivores have a more efficient energy conversion than herbivores. |
Protein is more rapidly and easily digested that cellulose. A lot of cellulose is lost in the faeces of a herbivore. |
|
|
Define gross ecological efficiency. |
It’s a meagre of how much energy is transferred from one trophies level to the next. |
|
|
What’s the equation for gross ecological efficiency? |
Gross ecological efficiency= (energy in trophic level / energy in previous trophic level) x 100 |
|
|
Why do aquatic organisms have a high ecological efficiency? |
They don’t regulate their own body temperatures and don’t use a lot of energy moving |
|
|
Explain why birds and mammals have a low ecological efficiency. |
Birds and mammals maintain a high body temperature and so this used up a lot of energy |
|
|
Define succession. |
The change in structure and species composition of a community over time |
|
|
Describe primary succession. |
The introduction of plants (or animals) into areas that have not previously supported a community |
|
|
Define secondary succession |
The reintroduction of organisms into a bare habitat previously occupied |
|
|
What is each stage during succession when a particular communities dominated know as? |
A sere |
|
|
Define pioneer species |
The first organism to colonise the rock (e.g. lichens) |
|
|
What’s the equation for photosynthetic efficiency? |
(Energy incorporated into photosynthetic products/ total light energy falling onto the plant) x 100 |
|
|
What do pioneer species do? |
They slowly erode the rock, the accumulation of dead and decomposing organic material leads to the formation of primitive soil. |
|
|
Define a climax community. |
A stable, long lived community |
|
|
Name 3 factors that affect succession. |
Migration, competition and facilitation |
|
|
Define mutualism. |
The interaction between two different species that is beneficial to both |
|
|
Define commensalism. |
The loose interaction between organisms in which one benefits and the other is unaffected |
|
|
How do primary and secondary succession differ? How do |
Secondary succession is much more rapid as soil is already present |
|
|
How does grazing affect succession? |
Livestock such as sheep eat the grass and other plants |
|
|
How does moorland management affect succession? |
Heather colonisation is controlled by burning |
|
|
How does farming affect succession? |
Ploughing and growth of crops by monoculture stops trees and shrubs getting established |
|
|
How does deforestation affect succession? |
Trees are cut down, which can cause erosion of the soil |
|
|
Why doesn’t all light energy that falls into a plant get absorbed? (3 reasons) |
Wrong wavelength, reflected, transmitted straight through the leaf |
|
|
Name two industries that affect succession |
Coal mining and quarrying of stone |
|
|
How does urban development affect succession? |
Building new roads and buildings affects both plant and animal species |
|
|
How has combustion led to an increase in carbon dioxide in the atmosphere? |
The burning of fossil fuels releases carbon dioxide that was previously locked up |
|
|
How has deforestation led to an increase in carbon dioxide in the atmosphere? |
Less carbon dioxide is taken in from the atmosphere due to less photosynthesis |
|
|
What can happen to the trees and the land after deforestation that can increase carbon dioxide in the atmosphere? |
When burning the woody parts of the trees carbon dioxide is released. The trees are replaced by crops which store less carbon dioxide or they are replaced by cattle which release methane. Parts of the tree left during deforestation also decompose releasing carbon dioxide. |
|
|
Name 4 green house gases |
Methane, carbon dioxide, nitrous oxide, water vapour |
|
|
Name 5 consequences of global warming. |
Icebergs melting leading to rises in sea levels, more extreme weather, extinction of plants and animals, decrease in ph of the oceans, increased frequency of forest fires |
|
|
Decomposition of soil organic matter is leading to increased release of CO2 name 3 altered farming practices reduce this? |
Leaving crop residue on soil surface to reduce soil erosion, cover soil to protect it between crops, rotate crops to reduce pests. |
|
|
Digestive activities of farm animals means there’s more methane in the atmosphere name 2 altered farming practices to reduce this? |
Reduce intake of meat and dairy, feed cows high sugar grasses and oats |
|
|
Waterlogged and anaerobic soils due to deforestation means there’s more nitrous oxide in the atmosphere name an altered farming practices to reduce this? |
Improve drainage to aerate soils |
|
|
Define gross primary productivity. |
The rate of production of chemical energy in organic chemicals by photosynthesis |
|
|
Sea levels are rising meaning cultivated land is inundated with salt water name an name altered farming practices to reduce this? |
Plant salt tolerant crops |
|
|
Name 6 ways to reduce our carbon footprint. |
Recycle packaging material, drive less, use less air conditioning and heating, choose a diet low in animal protein, avoid food waste, plant trees |
|
|
Name 3 reasons nitrogen is important to all living organisms. |
It’s important for making proteins (amino acids), nucleotides and chlorophyll |
|
|
By which two processes are nitrate pins taken up through plant roots. |
Active transport and facilitated diffusion |
|
|
Name two ways nitrate ions travel through plant roots. |
Apoplast (through the cell walls), symplast (through cytoplasm and plasmodesmata) |
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Describe ammonification |
Decomposers result in the decay of dead plants, animals and organic waste into ammonium ions |
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Describe nitrification |
Ammonium ions produces by decomposers are converted into nitrites and then nitrates by nitrifying bacteria |
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What conditions are needed for nitrification? |
Aerobic conditions |
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What does nitrosomonas do? |
Convert ammonium ions into nitrites |
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What does nitrobacter do? |
Convert nitrites into nitrates |
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Define net primary productivity |
Gross primary productivity minus the energy used by the price dx in respiration. |
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Describe nitrogen fixation. |
Nitrogen gas is fixed into ammonium ions. |
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Where is azotobacter found? |
Free living in the soil |
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Where is rhizobium found? Why can |
In the root modules of leguminous plants |
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Why can the relationship between the bacteria in the root module and the legume be classified as a symbiotic relationship? |
The plant gains nitrogenous compounds and the bacteria gain sugars |
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Describe assimilation |
The formations of organic nitrogen compounds from inorganic ones |
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Describe denitrification |
Bacteria convert nitrates from the soil into nitrogen gas |
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What is the problem with denitrification? |
It removes useful nitrogenous compounds from the soil |
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What conditions are needed for denitrification? And give an example of where it occurs |
Anaerobic conditions, it occurs most often in waterlogged soils |
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What does pseudomonas bacteria do? |
Convert nitrates into nitrogen gas |
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What is the equation for net primary productivity? |
Net primary productivity= GPP - respiration |
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Define biological productivity. |
The rate at which biomass accumulates in an ecosystem. |
|
|
Define biomass. |
The dry weigh of organic matter comprising a group of organisms in a particular habitat. |
|
|
Define secondary productivity. |
The rate at which consumers accumulate energy from assimilated food in biomass in their cells of tissues. |
|
|
Explain why there’s a loss of energy from the food chain at each level. (3 reasons) |
Energy is egested molecules, energy lost as heat, energy remains in inedible parts of animals |
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How does ploughing and drainage of soil affect the nitrogen cycle? |
It improves aeration, enabling nitrifying bacteria to convert ammonium ions intro nitrate and prevent denitrification |
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How does the cultivation of legumes in soil lacking nitrogen aid the nitrogen cycle? |
Rhizobium will undergo nitrogen fixation, then when the plant dies these nitrogenous compounds will enter the soil to be broken down by decomposers in ammonification |
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Name three compounds fertilisers contain. |
Nitrates, potassium and phosphates |
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Why do plants need nitrates? |
For amino acids and nucleic acids |
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Why do plants need potassium? |
For stomatal opening |
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Why do plants need phosphates? |
For nucleic acids and ATP |
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What is the cause of eutrophication? |
Fertilisers leaching into watercourses causing a bloom of algae to grow |
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Name three ways high nitrate levels in waterways can be overcome. |
Restricting the amount of fertiliser, only applying fertilisers when crops are actively growing and digging drainage ditches |
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How does digging drainage ditches affect biodiversity? |
It leads to a drop in invertebrate biodiversity |
