Ecology: organisation of an ecosystem Flashcards
what do food chains represent?
Feeding relationships within a community
what is biomass?
the total mass of living material
what does a producer do?
synthesis molecules and makes glucose through photosynthesis
how can we determine the distribution of species in an ecosystem?
using transects and quadrats
what is random sampling used for?
compare the number of different organisms in different areas
how do we do ‘random sampling’?
what is the equation to find total population size?
how do we investigate a factor (e.g light intensity) on the distribution of different plant species?
what is the median?
- the middle set of values but first order the set of numbers from lowest to highest
- if we have an even set of numbers the median is the central 2 numbers and then we find the mean of the central 2 numbers
- e.g 5,6,7,8,8,9, central= 7,8 median=7+8=16/2
*median= 8
what is the mode?
number which appears the most
what does the carbon cycle do?
returns the carbon from organims to the atmosphere as carbon dioxide to be by plants in photosynthesis.
describe the carbon cyles what happens?
- plants and agae take in carbon dioxide from atmosphere in photosyntheis
- plants an algae respire some co2 is released back into atmosphere
- plants and algae are eaten by animals which also respire so co2 released into atmosphere
- all plants + animals die –> these are waste products and dead remains which are broken down by decomposing microognisms and which respire to release rest of co2 to atmosphere
- but if microognism are in anarobic conditions they will turn into fossil fuels and go through combustion by humans to release co2
why are decomposing microogismins( bacterial or fungi) important?
they cycle materials through an ecosystem and returns carbon dioxide to the atmosphere and release mineral ions to the soil
describe what happnes in the water cylcle?
- energy from the sun causes water to evaporate + transpiration from the ocean
- water vaper condenses to from clouds
- water in clouds precipitates- which includes rain,snow,hail
- some water hits the groud and evaporates and some water passes through rocks to form aquifers
- some water forms rivers or streams whihc go back into the ocean
what does the water cycle do?
provides fresh water for plants and animals on land before draining into the seas
how is compost made?
by microogimsim decomposing plant material
why is compost needed for farmers?
compost is used as a natural fertiliser for growing garden plants or crops as it is rich in minerals needed for plants growth
what are the factors which effect decomposition?
- temeprature
- water
- availiability of oxygen
how does tempertaure affect the rate of decay of biological material?
warm temperature is good as decomposing uses enzymes to break down plant material and this works faster in the heat but if too warm enzymes will denature
how does water affect the rate of decay?
decomposistiion as works fatser when plants materials are moist as the chemical reactions in decay need water
how does oxygen affect the rate of decay?
decomposing microoginism carry out anarobic respiration which need a good supply of oxygen but if no oxygen carry out anarobic respiration which release methan= biogas
what is biogas?
the microoginims go through anarobic respiration and produce methane
anarobic decay
what is biogas used for?
biogas genertaors are used to produce mthan gas for as a fuel
how can we investigate the effect of tmnepertaure on the rate of decay on fresh milk by meausring the PH channge? name the variables
independant= tmperature
depednant= time taken for soloution to ceome yellow
control= volume of lipase, milk sodium carboante, cresol red
the graph for the experiment: here
which environmental changes affect the distribution of species in an ecosystem?
- temperature
- availaibility of water
- composition of atmospheric gases
these may be seasonal geographic or caused by human interaction.
