5B- energy transfer and nutrient cycles Flashcards
what are producers
organism that produce there own food
what is biomass
chemical energy stored in plant
or mass of living material
how is energy transfered between organism
producers eaten by primary consumers then primary consumers eaten by secondary etc etc
how can bio mass be measured
in terms of carbon mass
measure dry mass- mass of carbon is 50% of this
how to collect dry mass
- dry sample of organiism in low heated oven
- weigh sample at regular intervals
- once weight becomes constant stop heating
how to find chemical energy from dry mass
- heat sample of dry biomass and enrgy released is used to heat a known volume of water
- change in temp can be used to calc chem energy
what is GPP
gross primary production
total amount of chemical energy converted from light energy by plants in a given area
what is NPP
NPP= GPP- R
Net production of consumers formula
N=I-(F+R)
what is net primary production
energy available for plants to grow and reproduce
how do insecticides wokr
kill insect pests whihc harm crops
so less biomass lost from crops so they grow larger increasing NPP
how do herbicides work
kill weeds so reduce competition for energy of sun for other plant and also kills habitat for pest
how do biological agents work
parasite liv/lay eggs on pests
pathogenic bacteria and virusses kill pests
how do farmers reduce energy lost via repsiration
keep animals in pens so movement restricted
keep animals in warm pens so less energy lost by generating body heat
what are saprobionts
decomposers which feed on remains of dead plants and there waste products allowing chemical elemnts to be recycled
what are saprobionts
decomposers which feed on remains of dead plants and there waste products allowing chemical elemnts to be recycled
explain saprobionts and extracellular digestion
saprobionts secrete enzymes and digest their food externally and then absorb the nutrients they need
during this organic compunds are broken down into inorganic ions
what is saprobiotic nutrition
obtaining nutrients from dead organic matter using extracellular digestion
what is mycorrihizae
fungi which forms symbiotic relatonship with plants
explain how mycorrhizae works
fungi are made up of thin strands called hayphae which connect to plants roots
these increase plants surface area helping plants absorb ions an duptake water
hyphae absorb organicn compunds like glucose from plants
What are the four stages of the nitrogen cycle
nitrogen fixation
ammonification
nitrification
denitrification
explain nitrogen fixation
nitrogen gas tuened into nitrogen containing compunds by bacteria
bacteria is found in root nodules of leguminous plants
forms mutualistic relationship with plant gives plant nitrogen compounds and plant gives them carbs
explain ammonification
nitrogen compounds from waste urine dead organisms turned into ammonia via saprobionts which goes on to form ammonium ions
explain nitrification
ammonium ions in the soil are changed into nitrogen compounds
nitrifying bacteria change ammonium ions into nitrites
then other nitrifying bacteria changes nitrites into nitrates
explain denitrification
nitrates in the soil are converted into nitrogen gas by denitrifying bacteria
happens under anaerobic conditions
explain the phosphorus cycle
1-phosphate ions released into soil by rocks via weathering
2-phos ions taken in to plants via roots
3-phos ions transfered through food chain as plants eaten
4-phos ions lost from animals by waste
5-plants animal die saprobionts break them down releasing phos ions for assimulation by plants
phosphate ion transfer in sea
weathering of rocks releases phosphate ions into sea then aquatic producers like algae takes it up then its passed onto birds like guano which produce phos ions as waste good fertilisers
how does removing animals reduce nutrients in area
animals eat grass etc and are taken away so they cannot decompose and replace the nutrients
what is artificial fertiliser
inorganic and contain pure chemicals like ammonium nitrate as powder or pellets
what is natural fertiliser
organic matter- could be manure , composted veg, crop residue or/ and sewage sludge
what is leaching in terms of fertiliser
when water soluble compounds in soil are washed away into nearby pomds and river
when is leaching most likely to occur
if fertiliser is applied just before heavy rainfall
which type of fertiliser leads to more leaching and why
artificial fertilisers as the inorganic ions are more soluble so excess minerals are not used straight away and more likely to leach off
natural fertilisers less liekly as they need to be decompsed before absorbtion by plants so release into soil more controlled
what is more likely to be leached and why phosphates or nitrates
nitrates as they are more soluble in water
what is eutrophication
1-mineral ions leached from fertilised feilds stimulate rapid growth of algae in rivers
2- large amounts of algae block light from reaching plants below
3-plants die as not able to photosynthesise
4-bacteria feed on dead plant increasing their population. this causes decreased oxygen as more aerobic respiration
5-fish and other animals die as their isnt enough oxygen dissolved in water
