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Describe the changes that occur in the birth and death rates during demographic transition
Birth and death rates fall and then they both stabalise
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Describe the changes that occur in the size of the population during demographic transition
population increases and then stabilizes
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Calculate the percentage difference in average life expectancy for females compared to males
84-80/80 *100 = 5
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suggest one reason for the difference in the average life expectancy for males and females
males have a lower life expectancy as they are at risk from heart diseases and may be more likely to smoke.
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Which of the processes involves nitrification
r
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Describe another process carried out by microorganisms which adds ammonium ions to soil
amino acids are broken down to ammonium ions by saprobiotic microorganisms
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explain how ploughing would affect the fertility of the soil
fertility would be increased as more nitrate would be formed and less denitrification would occur
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suggest two ways in which crop rotation may lead to high crop yields
pests can't become established in the field. different concentrations of minerals would be added
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suggest appropriate units for gross productivity
energy/area/time
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explain the decrease in gross productivity as the woodland matures
Mature woodland trees will have more canopy which will decrease the amount of light reaching the lower layers. meaning smaller plants will have light as a limiting factor for photosynthesis. reducing gross productivity
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explain the increase in biomass during the first 20 years
first 20 years. the woodland is an extreme environment and so not many species could survive here. as plants decompose more minerals are added to the soil, and so it becomes more habitable. More animals are adapted to live here increasing diversity
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little increase in biomass after 100 years
net productivity = gross productivity decreases - respiratory losses increase
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suggest one reason for conserving woodlands
conserving habitats.
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explain what is meant by co dominant species
both genotypes are expressed in the phenotype
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why do male cats with a tortoiseshell phenotype rarely occur
gene is on the x chromosome which the males only have one of. can't be codominant
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how would selecting for polydactyly affect the frequency of homozygous genotypes
homozygous dominant increases. homozygous recessive decreases
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what measurements should the student have taken to determine the rate of photosynthesis.
time
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give two factors which should be kept constant during the investigation
intensity of light. time
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what would happen to the pH of the solution during the investigation
less acidic as CO2 is taken and oxygen is released.
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explain why the rate of photosynthesis was low
wrong wavelength and so was reflected back. less photosynthesis would occur.
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describe how acetylcoenzyme A is formed in the link reaction
hydrogen is removed from pyruvate and co2 released. addition of coenzyme a
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how does oxaloacetate enable the acetylcoenzyme a to bind to the enzyme
changes the shape of the active site. so it can bind to acetylcoenzyme a. Attaches to site other than active site putting pressure on the bonds there.
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how does production of succinyl coenzyme a control the rate of the reaction catalysed by citrate synthesase
produce NAD which is used in glycolysis
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why does converting pyruvate to lactate allow the continued production of ATP
provides enough energy for an ADP molecule and a phosphate molecule to combine
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lactate is converted to pyruvate why
prevents a build up of lactate in the muscles.
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suggest how climate change can cause an increase in soil salinity
increase in temperature. flooding by sea water
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explain why crop plants don't grow when soil salinity is 2% or higher
the soil will have a reduced water potential.
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explain why the fungus was isolated from the cucumber plants
different strains were representative of the population. Natural conditions were optimal for growth
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evaluate the effectiveness of the bacteria
least effective was s.plymuthica. least effective was more effective than no bacterium. no overlap of SE indicates results aren't due to chance
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why did they set up control a
comparison.
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suggest one way in which these bacteria could stimulate an increase in dry mass of cucumber plants
nitrogen fixing and so reduce infection. produce growth stimulating substance
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explain why they removed the weeds
prevents inter species competition. to prevent the weeds from passing on disease which could reduce productivity of cucumber
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explain how the caribbean species could have evolved
belonged to same species then seperated. seperate gene pools. environmental conditions. variation due to mutation. different reproductive success. change in allele frequency.
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mark- release- recapture
mark them in a way that wouldnt hinder chance for suvival. randomly distribute. another sample. no 1st * no 2nd / no marked in 2nd
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how the concentration of co2 in air changes
high conc of co2 linked with respiration at night. no photosynthesis in dark. net uptake of co2 greater than respiration. decrease in co2 with height.
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Other cards in this set

Card 2

Front

Describe the changes that occur in the size of the population during demographic transition

Back

population increases and then stabilizes

Card 3

Front

Calculate the percentage difference in average life expectancy for females compared to males

Back

Preview of the front of card 3

Card 4

Front

suggest one reason for the difference in the average life expectancy for males and females

Back

Preview of the front of card 4

Card 5

Front

Which of the processes involves nitrification

Back

Preview of the front of card 5
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