Ecosystems Flashcards
What is an ecosystem
all the organisms living in a certain area and all the non - living conditions found there
why are ecosystems described as dynamic
changing all the time
what are biotic factors and abiotic factors and give examples
living features of an ecosystem: presence of predators or food
non living features of an ecosystem such as temp, rainfall
what is biomass
the mass of living material
describe how biomass is transferred between trophic levels
producers eaten by primary consumers then secondary consumers then tertiary consumers
how can you show biomass transfer and measure efficiency
food webs and food chains
what is a trophic level
a stage in a food chain that is occupied by a group of organisms
what are decomposers
organisms that break down dead or undigested organic material
how do you calculate efficiency
biomass transferred/ biomass intake x 100
what is gross productivity
rest of available energy
why is some available energy never taken in by the organism in the first place
plants can’t use all the light that reaches their leaves
some light hit parts of plant that cannot photosynthesise
some parts of organism aren’t eaten by predators
some parts of food are indigestible
when energy is lost to the environment during energy production what is this called
respiratory loss
what is net productivity
the total amount of energy available to the next trophic level
what are the relative energy transfer efficiencies between each trophic level
sun to prodcuer- 2-3%
producer to consumer- 5-10%
consumer to consumer- 15-20%
how can you measure the amount of energy in an organism
measure dry mass
what are the issues with using dry mass to measure amount of energy in an organism
consumers absorb energy from other sources than the producer, so difference between two calculated wouldn’t be accurate
how do farmers try and reduce energy loss in food chains
herbicides- kill weeds which compete with crops for resources
fungicides- kill fungal infections
insecticides- kill pests that damage crops
fertilisers- provide minerals for growth
rearing livestock- controlling their living conditions to ensure most energy is used for growth
draw a diagram of the carbon cycle
what processes are present in the carbon cycle
photosynthesis, decomposition, respiration, combustion, weathering
what happens to carbon in photosynthesis
absorbed by plants which carry out photosynthesis, carbon passed onto primary consumers when eaten by plants
what happens to carbon during decomposition
organisms die and are broken down by decomposers which secrete enzymes and absorb the products of digestion, processes is called saprobiontic nutrition
what happens to carbon during respiration
carbon is returned to air as all living organisms respire and produce CO2
what happens to carbon during combustion
if dead organic matter ends up in a place without decomposers it can be turned into fossil fuels, carbon is released when they’re burnt
what happens to carbon in volcanoes
rocks like limestone can be drawn into earths crust by movement of tectonic plates and they undergo chemical changes which is released into air via volcanoes
what happens to carbon during weathering
rocks broken down by rainwater,
