energy transfer/trophic

Question 1

define a producer

Answer 1

photosynthetic organisms that manufacture organic substance using light energy water and carbon dioxide

Question 2

define a consumer

Answer 2

an organism that obtain their energy by feeding on other organisms

Question 3

what is a saprobiont

Answer 3

organisms, usually bacteria that break down dead matter - they release valuable minerals and ions into the earth that can be absorbed by plants

Question 4

define a food chain

Answer 4

describes a feeding relationship in which producers are eaten by primary consumers, which are then eaten by secondary consumers and so on tertiary lol

Question 5

define a trophic level

Answer 5

each in the food chain

Question 6

what is a food web

Answer 6

this states that animals are not reliant upon one food source. so are displayed with maby cross links between producers and consumers

Question 7

define biomass

Answer 7

the total dry mass of living material

Question 8

what is the best way to test chemical energy stores in biomass

Answer 8

bomb calorimetry

Question 9

how does a bomb calorimeter work

Answer 9

a sample of dry material is weighed and then is burnt in pure oxygen within a sealed chamber.
- the bomb is surrounded by a water bath
- the heat of the water will rise

measure the initial temp and the final temp to calculate the energy change

volume of water must be known too

Question 10

why is not all of the sun’s energy converted into products of photosynthesis

Answer 10

• 90% of the suns rays are reflected back into space by clouds and dust and or absorbed by the atmosphere
• not all wavelengths can be absorbed by pigments
• a factor such as low CO2 may limit the rate of photosynthesis

Question 11

define net primary productivity

Answer 11

the chemical energy store when losses to respiration have been taken into account

Question 12

define gross primary productivity

Answer 12

the total quantity of the chemical energy store in the plant biomass given an area or volume

Question 13

what is the equation of NPP

Answer 13

NPP = GPP -R

R = respiratory losses

Question 14

what are some reasons that energy transfer from each trophic level is so small

Answer 14

some parts of the organism are not consumed ( bones)
- some parts are consumed but are excreted as faeces and therefore is energy lost
- heat lost in respiration

Question 15

what is the equation for effiiciency

Answer 15

energy available after transfer/ energy available before transfer x100

Question 16

how can farmers increase productivity

Answer 16

• movement is restricted - therefore less respiration - therefore less heat energy lost
• the environment is heated in order for them to not use stores of fat or ATP for shivering - conserving energy
• predators are excluded so they will not be hunted

Question 17

what is the advantage of crops being grown in monoculture

Answer 17

this enables insect and fungal pests to spread rapidly this will limit the effect that pests have on productivity

Question 18

what si the optimum concentration of CO2 for photosynthesis

Answer 18

0.4%

Question 19

what is ammonification

Answer 19

where saprobionts feed on dead matter and faeces to releaser ammonia which in the soil will be an ammonium ion

Question 20

what is nitrification

Answer 20

where ammonium ions are oxidised to nitrite ions. MUST BE IN PRESENCE OF O2. –>NO2-

nitrite ions are then oxidised to nitrate ions NO3-

Question 21

define mycorrhizae

Answer 21

the symbiotic relationship between fungi and the roots of the plants

Question 22

what is hyphae

Answer 22

long thin strands - which increase surface area and connect to the plants roots

Question 23

what is the benefit for fungi in mycorrhizae relationships

Answer 23

obtain organic compounds from the plant such as glucose

Question 24

what is nitrogen fixation

Answer 24

when nitrogen gas in the atmosphere is turned into nitrogen containing compounds which then goes onto form NH4+

Question 25

define dentrifiction

Answer 25

when nitrates in the soil are turned into nitrogen that the plant cant use - N2 gas by denitrifying bacteria - this happens in anaerobic conditions

Question 26

where does denitrifing bacteria live

Answer 26

water logged soil
because this is where there is a lack of oxygen -

Question 27

where is phosphate used

Answer 27

DNA replication
ATP

Question 28

how are phosphate ions released into the soil

Answer 28

weathering

Question 29

how are phosphate ions taken into the roots

Answer 29

through the roots mycorrhizae

Question 30

how are phosphate ions transferred through the food chain

Answer 30

as animals eat plants and are in turn eaten by other animals

Question 31

how do plants receive phosphate ions again that is not through weathering

Answer 31

when plants and animals die saprobionts
are involved in digesting the dead matter and hence releasing phosphate ions into the soil for plant assimilation

Question 32

what is the phosphorous cycle for aquatic animals

Answer 32

weathering of rocks will leach phosphate ions into the sea - this is taken up by aquatic producers such as algae and is passed along the food chain.
the waste produced by sea birds is guano - guano returns a significant proprtion of phosphate ions to the soils particularly in coastal areas

Question 33

what are some environmental issues with fertiliser

Answer 33

• fertilisers can cause eutrophication
• some fertilisers are suited to rapidly producing plants - grass

Question 34

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