6.3.1 ecosystems Flashcards
examples of abiotic factors
- temp
- soil pH/type
- water availability
- oxygen availability
examples of biotic factors
- competition
- predation
- disease
define biomass
- the mass of living material
outline the biomass transfer
prod -> primary cons. -> secondary cons. -> tertiary cons.
as you go across trophic levels the energy available…
…decreases
define trophic level
- steps in a food chain
in plants, why cant they take in 100% of light energy?
- doesnt hit the parts of plant that can photosynthesis e.g chlorophyll in leaves
- wrong wavelength of light
- reflected
what are the parts of animals/plants that cant be eaten
- bones
- hair
- roots
how to calculate net. productivity
gross productivity - respiratory losses
how to calculate biomass efficiency
energy transferred / energy consumed
what are ways farmers can increase biomass
- herbicides/fungicides/fertilisers
- keep animals in a warm environment
- reduce movement
- feed them high protein food
outline the nitrogen cycle
- nitrogen fixation
- nitrogen fixing bacteria - Rhizobium + Azotobacter conert N2 g to NH3 to NH4+ in soil - ammonification
- saprobionts convert nitrogen compounds in waste and dead materials to NH3 -> NH4+ in soil - nitrification
- nitrifying bacteria
- nitrosomonas converts NH4+ ions into nitrites
- nitrobacter converts nitrites in nitrate ions - denitrification
- denitrifying bacteria converts nitrate ions to N2 g
what are saprobionts
- decomposers
- fungi / bacteria
- feed on waste and dead material
- secrete enzymes
what does aerating soil do to plants
- denitrifying bacteria only works in anaerobic conditions so unable to convert the nitrate ions into N2 g
what does lightning do
- causes N2 to be oxidised into nitrates in soil
define succession
- gradual change in a community of organisms over time
what is the difference between primary and secondary succession
primary
- no soil
- bare land
- no prev living organisms
secondary
- following a disturbance (earthquake/volcanic eruption)
- prev occupied
what is a pioneer species
- a group of interacting species that inhibit new land together
what is a climax community
- a community of species that live in a balanced way together
what is deflected succession
- not reaching climax community because :
- clearing an area for agricultural use
- animal grazing
