ecosystems Flashcards
what is an ecosystem?
a;ll the organisms living in a certain area and all the non living conditions found there - abiotic and biotic factors
its a dynamic system as it is changing all the time
what are some abiotic and biotic factors that affect the ecosystem of a rock pool?
biotic factors
many organisms in a rock pool feed on seaweed so competition over this food source can limit the population size of the ecosystem
abiotic factors
tides change the temperature and salinity of an ecosystem- only some organisms can tolerate these conditions
what are some abiotic and biotic factors that affect the ecosystem of a playing feild?
biotic factors
large amounts of producers attract large numbers of organisms that use them as a food source
abiotic factors
rainfall and sunlight affect the growth of producers in the ecosystem
what are some abiotic and biotic factors that affect the ecosystem of a large tree?
biotic factors?
insects such as caterpillars can use the leaves of a tree as a source of food, if they remove all the leaves- defoliation they can dlow growth of the tree or cause its death
abiotic factors
drought conditions can negatively impact the growth of a tree and can even cause death
how does energy enter an ecosystem
energy enters an ecosystem through photosynthesis by producers convderting sunlight energy to chemical energy that can be used by other organisms
how is biomass transferred between trophic levels?
energy/biomass is transferred through living organisms in an ecosystem when organsism eat other organisms - producers are eaten by primary consumers and so on
energy locked up in things than cannot be eaten such ass bones and faeces gets recylced back into the atmsphere by decomposers
what is the equation for efficiency of biomass transfer?
biomass transferred/ biomass intake x 100
how is biomass lost between trophic levels?
organisms use energy in respiration for movement and heat - respiratory loss
parts of biomass produced such as feaces and bones cannot be eaten so energy
indegestible parts eaten pass through organism and come out as waste- faeces.
how is energy lost between light and plants?
plants cannot use all light energy that reaches the leaves as some is the wrong wavelength, some is reflected and some pass straight through the leaves
some light hits parts of the plant that do not photosynthesise
what is net productivity?
the amount of enrgy that is available to the next trophic level
gross productivity - respiratory loss
how can you measure the transfer of energy between trophic levels?
calculate the difference between the amount of energy in each trophic level
measure the dry mass of an organism and multiply by the size of the population
the biomass indicates how much energy is stored so difference in biomass shows energy transferred
what are the issues of measuring energy transfer?
consumers might have taken in energy from sources other than the producer measured
how do human activities increase the energy transfer in plants and in animals?
farmers use methods to increase productivity by increasing the enrgy transfer through an ecosystem
in plants
using herbiicides to reduce competition so crops receive more enrgy
insecticides to kill insects that kill or damage ctops so less biomass is lost
fertilisers used so growth is not limited by abiotic conditions
in animals
1 keep animals, warm / indoors ;
2 reduce animal movement ;
3 feed animals high, protein / energy, food ;
4 vaccination / (routine) antibiotics, for animals ;
5 selective breeding / genetic engineering,
for improved animals ;
6 slaughter just before, mature / full size ;
what is nitrogen fixation?
when nitrogen gas in the atmosphere is turned intp ammonia by bacteria such as rhizobium (in root nodules) and azotobacter (in soil)
what kind of relationship does rhizobium have witha plant?
mutualistic relationship
it provides the plant with nitrogen compounds and the plant gives rhizobium carbohydrates(energy)
