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30 Cards in this Set
- Front
- Back
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Explain what is meant by a population/ecological niche |
Population is all the individuals of one species in a habitat at one time niche is feeding role/habitat role/abiotic factors |
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2 assumptions of mark-release-recapture |
Large population; marked individuals have time to distribute randomly/evenly; no births or deaths no change in population size; no migration; marking is not toxic |
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Give one factor that may increase birth rate/decrease in dirth rate |
Birth rate - Better nutrition/better health care of mother/more surviving to reproductive age; Death rate - sanitation/nutrition/healthcare/vaccination and disease |
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How can you tell that an abiotic factor has a large effect on a species? |
Large fluctuations in population |
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How can you determine that plants belong to the same species |
Breed together to produce fertile offspring; use of DNA and similar base sequence |
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Describe what happens to a chlorophyll molecule when it absorbs a photon of light |
Excited/electrons move to a higher eneryg level' molecule loses energy |
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Explain the rise in the amount of RuBP after CO2 is reduced. |
less combined with CO2 to produce less GP |
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Explain why CO2 was radioactivelly labelled |
Allows detection of carbon compounds |
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Explain what causes amount of radioactivelly labelled glucose to decrease when light is switched off. |
used in resp/stored as starch |
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Suggest an advantage to seaweed of having multiple pigments |
more wavelengths absorbed; more efficient photosyntehsis when some wavelengths not present |
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RuBP combines with oxygen to form phosphoglycate. Explain how production of phosphoglycate leads to reduction in rate of photosyntehsis |
Less RuBP combines with CO2 less GP produce; less TP less Co2 fixation; less RuBP regenerated |
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Suggest how CO2 conc could be increased in a glasshouse |
Co2 cylinders/manure/decaying organic material/heater |
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Describe what happens to pyruvate in anaerobic conditions and explain why anaerobic resp is advantageous to human skeletal muscle |
Forms lactate; oxidation of reduced NAD; regenerates NAD; re-used to oxidise more glucose/allow glycolysis to continue; produce ATP when oxygen in short supply |
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2 similarities between anaerobic resp in yeast and in muscle. 2 differences |
ATP produced; reduced NAD/pyruvate formed; glyolysis occurs/2 stage process; Ethanol vs lactate; Co2 released |
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Deduce order of electron carriers and epplain why. |
Reduced carriers cannot pass on electrons when inhibited |
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Suggest substrate for isolated mitochondria |
Pyruvate |
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2 reasons why % of energy transferred between consumers is low |
ENergy lost as heat due to respiration; muscle contraction; lost in faseces/food not eaten; excretion |
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Explain why food chains rarely have more than 5 trophic levels |
energy lost at each stage; little energy left at top/limited energy available |
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Explain why no tubers formed when photosyntehsis = respiration |
Little gain in biomass/loss in biomass; no excess for storage |
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Conc of insecticide that kills greenfly found to be higher in tissue of lady birds than that sprayed. Why? |
One lady bird eats many greenfly; can't be broken down/excreted and remains stored so bioaccumulation |
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Explain why pest not completely eliminated using: chemical control biological control |
Some not sprayed/washed off before has an effect; plant resistant; biological cant completely eliminate; as loss of pest = loss of control agent |
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Explain why pyramid of numbers is reverse pyramid while pyramid of biomass is normal |
Each one has many parasitic mites; total energy less than that of lower trophic level |
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What causes nitrogen input in an ecosystem? |
Nitrogen fixation/death of animals |
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Explain how farming practices might be responsible for the change in nitrate conc. |
Leaching/run off; excess fertiliser |
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Explain how carbon-containing compounds are used for growth by microorganimss |
Decompose; syntehsise structureal compounds; respiration releases energy for growth |
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Explain how digestion of insects helps the sundew obtain nitrogen compoudns |
Protein; digested to amino acids; which can be absorbed |
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Explain why mass of crop produced increases with fertilsier |
Replaces lost nutrients; nitrate for amino acid; more fertilsier more amino acid more growth |
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Explain why adding too much fertiliser has no effect on growth? |
Already enough nitrate/nitrate not limiting; something else limiting |
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Advantages and disadvanages of inorganic fertilsiser |
easy to apply/store/transport; can supply specific needs; releases nutrients quickly; easy to contorl mass enviromnetally damaging/uses supplies/does not add to soil structure/expensive/more readily leads to eutrophication |
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Explain why an allele that has a selective disadvantage may still be present? |
gene flow due to migration; mutation; could be recessive |
