energy transfer/trophic Flashcards
define a producer
photosynthetic organisms that manufacture organic substance using light energy water and carbon dioxide
define a consumer
an organism that obtain their energy by feeding on other organisms
what is a saprobiont
organisms, usually bacteria that break down dead matter - they release valuable minerals and ions into the earth that can be absorbed by plants
define a food chain
describes a feeding relationship in which producers are eaten by primary consumers, which are then eaten by secondary consumers and so on tertiary lol
define a trophic level
each in the food chain
what is a food web
this states that animals are not reliant upon one food source. so are displayed with maby cross links between producers and consumers
define biomass
the total dry mass of living material
what is the best way to test chemical energy stores in biomass
bomb calorimetry
how does a bomb calorimeter work
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
why is not all of the sun’s energy converted into products of photosynthesis
- 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
define net primary productivity
the chemical energy store when losses to respiration have been taken into account
define gross primary productivity
the total quantity of the chemical energy store in the plant biomass given an area or volume
what is the equation of NPP
NPP = GPP -R
R = respiratory losses
what are some reasons that energy transfer from each trophic level is so small
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
what is the equation for effiiciency
energy available after transfer/ energy available before transfer x100
how can farmers increase productivity
- 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
what is the advantage of crops being grown in monoculture
this enables insect and fungal pests to spread rapidly this will limit the effect that pests have on productivity
what si the optimum concentration of CO2 for photosynthesis
0.4%
what is ammonification
where saprobionts feed on dead matter and faeces to releaser ammonia which in the soil will be an ammonium ion
what is nitrification
where ammonium ions are oxidised to nitrite ions. MUST BE IN PRESENCE OF O2. –>NO2-
nitrite ions are then oxidised to nitrate ions NO3-
define mycorrhizae
the symbiotic relationship between fungi and the roots of the plants
what is hyphae
long thin strands - which increase surface area and connect to the plants roots
what is the benefit for fungi in mycorrhizae relationships
obtain organic compounds from the plant such as glucose
what is nitrogen fixation
when nitrogen gas in the atmosphere is turned into nitrogen containing compounds which then goes onto form NH4+
define dentrifiction
when nitrates in the soil are turned into nitrogen that the plant cant use - N2 gas by denitrifying bacteria - this happens in anaerobic conditions
where does denitrifing bacteria live
water logged soil
because this is where there is a lack of oxygen -
where is phosphate used
DNA replication
ATP
how are phosphate ions released into the soil
weathering
how are phosphate ions taken into the roots
through the roots mycorrhizae
how are phosphate ions transferred through the food chain
as animals eat plants and are in turn eaten by other animals
how do plants receive phosphate ions again that is not through weathering
when plants and animals die saprobionts
are involved in digesting the dead matter and hence releasing phosphate ions into the soil for plant assimilation
what is the phosphorous cycle for aquatic animals
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
what are some environmental issues with fertiliser
- fertilisers can cause eutrophication
- some fertilisers are suited to rapidly producing plants - grass
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