Ecosystems – Exam Questions (Biology Study Guide, Practice Questions &
Answers)
The efficiency of energy transfer between trophic levels limits the number of organisms in a
particular ecosystem.
(a) Outline how the percentage efficiency of energy transfer between producers and herbivores
can be estimated - ANS ✔✔1 herbivore / primary consumer, energy x 100 ; producer energy
Plus any 3 of the following: 2 (a sample of) producers collected ; 3 (a sample of) herbivores
/primary consumers collected; 4 5 6 7 (collected from) the same area ; (measure) biomass / dry
mass (of individual or population) ; energy content calculated of producer and herbivore ; use of
calorimeter / described;
Suggest three ways that farmers can maximise the efficiency of the transfer of energy up food
chains from primary consumers to humans. - ANS ✔✔animals = primary consumers 1 keep
animals, warm / indoors ; 2 reduce animal movement ; 3 feed animals high, protein / energy,
food ; 4 vaccination / (routine) antibiotics, for animals ; 5 selective breeding / genetic
engineering, for improved animals ; 6 slaughter just before, mature / full size ;
Define the following terms:
> producer
> consumer
> trophic level - ANS ✔✔producer (leaves / plants) fix carbon / photosynthesise / make food /
autotroph(ic) / convert light energy to chemical energy / convert inorganic, C / CO2, to organic
molecules ; consumer (bird) eat / derives energy from / feeds on , other organisms or
heterotroph(ic) ; trophic level stage / position / place / level , in a food , chain / web
Most of the minerals in a peat bog are held within the living plants at all times, not in the soil.
• Plants like bog cotton and bog asphodel recycle the minerals they contain.
• The leaves of these plants turn orange as the chlorophyll within them is broken down.
• Minerals such as magnesium ions are transported from the leaves to the plants' roots for
storage.
, > Describe one similarity and two differences in mineral recycling in a peat bog and in a
deciduous forest - ANS ✔✔similarity chlorophyll breaks down / leaves change colour ;
differences (bog) minerals stay in plant / (forest) minerals in soil ; ora decomposers / fungi /
bacteria , not, present / active in bog ; ora for forest
) In Ireland in 2002, two well-preserved Iron Age human bodies were found in peat bogs.
Despite having been dead for over two thousand years, the bodies had not decomposed. They
still had skin, hair and muscle. Suggest why these bodies had not decomposed - ANS
✔✔decomposers / named decomposers, not, present / active ; waterlogging reduces, air /
oxygen ; acidity / low pH , stops (decay) enzymes working
) Suggest two reasons why the large scale removal of peat from bogs for use in gardens is
discouraged by conservation groups. - ANS ✔✔bog / habitat / ecosystem, takes a long time to
form / hard to replace ; loss of, biodiversity / rare species ;
Briefly describe the steps that must occur for plant protein to be converted to animal protein in
the farmer's sheep - ANS ✔✔1 (sheep / animals) ingest / consume / eat / feed on (grass /
plants) ; 2 digest / hydrolyse , (protein) to amino acids ; 3 amino acids move into , blood / cells ;
4 synthesis of proteins / translation
Suggest a crop she could plant that would allow process F to occur and explain how this would
add nitrate to the soil - ANS ✔✔legume / any named leguminous plant ; 2 Rhizobium / nitrogen-
fixing bacteria (in root nodules) ; 3 idea of converting nitrogen gas / N2 , into , compounds /
ammonium / ammonia / amino acids / protein (in plants) ; 4 plants ploughed in / plants left to
decay / ref B / ref C / ref D
The sheep on this farm belong to a rare breed called Greyface Dartmoor. The Rare Breeds
Survival Trust (RBST) gives advice on looking after these sheep and keep records to monitor the
breeding of these sheep, in order to maintain a healthy population. Why is the continued
existence of rare breeds of farm animals desirable? - ANS ✔✔1 genetic resource / gene bank /
have (different) alleles ; 2 for , genetic engineering / genetic modification / artificial selection /
selective breeding / described ; 3 if conditions change / in the future ; 4 example of useful trait ;
5 to maintain , biodiversity / genetic diversity / (large) gene pool ;
Answers)
The efficiency of energy transfer between trophic levels limits the number of organisms in a
particular ecosystem.
(a) Outline how the percentage efficiency of energy transfer between producers and herbivores
can be estimated - ANS ✔✔1 herbivore / primary consumer, energy x 100 ; producer energy
Plus any 3 of the following: 2 (a sample of) producers collected ; 3 (a sample of) herbivores
/primary consumers collected; 4 5 6 7 (collected from) the same area ; (measure) biomass / dry
mass (of individual or population) ; energy content calculated of producer and herbivore ; use of
calorimeter / described;
Suggest three ways that farmers can maximise the efficiency of the transfer of energy up food
chains from primary consumers to humans. - ANS ✔✔animals = primary consumers 1 keep
animals, warm / indoors ; 2 reduce animal movement ; 3 feed animals high, protein / energy,
food ; 4 vaccination / (routine) antibiotics, for animals ; 5 selective breeding / genetic
engineering, for improved animals ; 6 slaughter just before, mature / full size ;
Define the following terms:
> producer
> consumer
> trophic level - ANS ✔✔producer (leaves / plants) fix carbon / photosynthesise / make food /
autotroph(ic) / convert light energy to chemical energy / convert inorganic, C / CO2, to organic
molecules ; consumer (bird) eat / derives energy from / feeds on , other organisms or
heterotroph(ic) ; trophic level stage / position / place / level , in a food , chain / web
Most of the minerals in a peat bog are held within the living plants at all times, not in the soil.
• Plants like bog cotton and bog asphodel recycle the minerals they contain.
• The leaves of these plants turn orange as the chlorophyll within them is broken down.
• Minerals such as magnesium ions are transported from the leaves to the plants' roots for
storage.
, > Describe one similarity and two differences in mineral recycling in a peat bog and in a
deciduous forest - ANS ✔✔similarity chlorophyll breaks down / leaves change colour ;
differences (bog) minerals stay in plant / (forest) minerals in soil ; ora decomposers / fungi /
bacteria , not, present / active in bog ; ora for forest
) In Ireland in 2002, two well-preserved Iron Age human bodies were found in peat bogs.
Despite having been dead for over two thousand years, the bodies had not decomposed. They
still had skin, hair and muscle. Suggest why these bodies had not decomposed - ANS
✔✔decomposers / named decomposers, not, present / active ; waterlogging reduces, air /
oxygen ; acidity / low pH , stops (decay) enzymes working
) Suggest two reasons why the large scale removal of peat from bogs for use in gardens is
discouraged by conservation groups. - ANS ✔✔bog / habitat / ecosystem, takes a long time to
form / hard to replace ; loss of, biodiversity / rare species ;
Briefly describe the steps that must occur for plant protein to be converted to animal protein in
the farmer's sheep - ANS ✔✔1 (sheep / animals) ingest / consume / eat / feed on (grass /
plants) ; 2 digest / hydrolyse , (protein) to amino acids ; 3 amino acids move into , blood / cells ;
4 synthesis of proteins / translation
Suggest a crop she could plant that would allow process F to occur and explain how this would
add nitrate to the soil - ANS ✔✔legume / any named leguminous plant ; 2 Rhizobium / nitrogen-
fixing bacteria (in root nodules) ; 3 idea of converting nitrogen gas / N2 , into , compounds /
ammonium / ammonia / amino acids / protein (in plants) ; 4 plants ploughed in / plants left to
decay / ref B / ref C / ref D
The sheep on this farm belong to a rare breed called Greyface Dartmoor. The Rare Breeds
Survival Trust (RBST) gives advice on looking after these sheep and keep records to monitor the
breeding of these sheep, in order to maintain a healthy population. Why is the continued
existence of rare breeds of farm animals desirable? - ANS ✔✔1 genetic resource / gene bank /
have (different) alleles ; 2 for , genetic engineering / genetic modification / artificial selection /
selective breeding / described ; 3 if conditions change / in the future ; 4 example of useful trait ;
5 to maintain , biodiversity / genetic diversity / (large) gene pool ;
