6.3.1 ecosystems Flashcards
what is an ecosystem
6.3.1(a)
all the living organisms and non-living conditions in an area
key word describing how ecosystems change over time
6.3.1(a)
dynamic
how are ecosystems dynamic
6.3.1(a)
-pathogens can arrive
-species may arrive or leave -imm or -emi gration
what are the 3 components of an ecosystem
6.3.1(a)
-habitat-physical location where organism lives
-population-all the organisms of one species
-community-all the populations of all the species living in an ecosystem
what is the role of each species in an ecosystem called
6.3.1(a)
niche
what is a biotic factor and name some examples
6.3.1(a)
living
eg-predation, competition and hunting
what is a abiotic factor and name some examples
6.3.1(a)
non-living
eg-light, temperature and pH
what are the 3 different types of dynamic changes an ecosystem can face
6.3.1(a)
-cyclic changes-changes repeat themselves in a predictable rhythm
-directional changes-they go in one direction and are irreversible
-unpredictable/erratic-dont have a particular direction and cant be predicted
How can biomass be calculated experimentally
6.3.1(b)
- collect sample of your species
2.dry it in an oven at 80 degrees to remove water then measure the dry mass - multiply dry mass to reflect dry mass of total population size.
what is a producer also known as
6.3.1(b)
photoautotroph
how do producers create their own energy
6.3.1(b)
using light energy from the sun however only a small amount is converted into biomass
what are the units for biomass
6.3.1(b)
energy per area of habitat per time
kj m-2 year-1
give 3 reasons all the light energy isnt converted to biomass in producers
6.3.1(b)
- light may not hit a chloroplast
2.it may be the wrong wavelength of light so be reflected
3.other factors eg-low CO2 may limit rate of photosynthesis
how can you calculate biomass efficiency
6.3.1(b)
biomass efficiency=biomass present in higher trophic level/biomass present in previous trophic level x 100
what is gross production
6.3.1(b)
total amount of energy used to form biomass
what is net production
6.3.1(b)
total amount of biomass after respiration
what is net production
6.3.1(b)
net production=gross production - respiratory losses
name 3 reasons why all the biomass isnt transferred from producers to consumers
6.3.1(b)
- some of the organism won’t be digested
Eg-may not be able to digest the cellulose cell wall of the plant
2.energy is lost through faeces and urine - energy is lost in respiration
how can you improve ecosystem efficiency
6.3.1(b)
simply food chains by removing competeing organisms
reduce respiratory losses
eg-reducing reliance on repsiration to keep them warm by having a heater
what is carbon fixation
6.3.1(c)
when producers take in CO2 for photosynthesis and use it to make organic carbon containing compounds
how do producers and consumers release CO2 back into the environment
6.3.1(c)
respiration
how are organic C containing compounds passed along the food chain
6.3.1(c)
when consumers eat producers
what is decomposition
6.3.1(c)
when producers and consumers die organic C containing compounds remain in waste matter when broken down by decomposers this releases CO2 back into the environment
what is combustion
6.3.1(c)
waste matter that isn’t decomposed is converted into fossil fuels which can be burnt to produce CO2
which nitrogen-fixing bacteria converts NO2 into NH3 which can be used immediately by the plant and where is it found
6.3.1(c)
rhizobium and is found in root nodules
which nitrogen-fixing bacteria converts NO2 into NH3 which dissolved in water in the soil to form ammonium ions and where is it found
6.3.1(c)
azotobacter and is found in soil
what conditions does nitrogen fixing bacteria take place under
6.3.1(c)
anaerobic-nitrogen fixation doesn’t require O2
what nitrifying bacteria do you need to convert ammonium ions into nitrite
6.3.1(c)
nitrosomonas
what nitrifying bacteria do you need to convert nitrite into nitrate
6.3.1(c)
nitrobacter
what conditions does nitrification occur under
6.3.1(c)
aerobic conditions as
-nitrifying bacteria need to carry out aerobic respiration
-O2 is used in nitrification
describe the process of ammonification
6.3.1(c)
nitrate is absorbed by plants then animals eats the plants to make N containg compounds
death and excretion returns nitrogen back to the soil
this waste is fed on by decomposers and is converted into ammonia which is released in water in the soil forming ammonium ions
what conditons does ammonification take place under
what is denitrification
6.3.1(c)
when denitrifying bacteria converts nitrate into nitrogen gas
what conditions does denitrification take place under
6.3.1(c)
anaerobic conditions
denitrifying bacteria carries out aerobic respiration
what is succession
6.3.1(d)
when an ecosystem changes from simple to complex through a series of seral stages
what is a pioneer species
6.3.1(d)
causes a change in the environment
makes it less hostile
enables other species to survive
reproduce asexually
what is an immediate community
6.3.1(d)
when shrubs and trees decompose they release nutriants into the soil making it less hostile
what is a climax community
6.3.1(d)
stable community which doesn’t experience succession
what is deflected succession
6.3.1(d)
when human activities eg-agriculture prevents a stable climax community from forming
what is plagioclimax
6.3.1(d)
community that is maintained by deflected succession
how do you calculate distribution
6.3.1(e)
-use systematic sampling eg-by placing quadrat and pre-determine intervals
how do you calculate abundance of a species
6.3.1(e)
-using percentage cover
-ACFOR scale
how can percentage cover be made more accurate
6.3.1(e)
using a point frame
how can you avoid bias
6.3.1(e)
use random sampling
