organisation of an ecosystem: sampling & cycles TOPIC 7 (paper 2) Flashcards
why do scientists use sampling techniques
to study ecosystems by sampling a specific part of the habitat and using the data colleccted to draw conclusions about the ecosystem as a whole
give the two types of sampling techniques
- quadrats
- transects
what is a quadrat
a square frame of specific area (usually 1m^2) that can be made from wire, plastic or wood
suggest what quadrats can be used to do
- define a sampling area when measuring distribution of organisms
- study the distrubution of small organisms
- measure changes over seasons
why is it important to place the quadrat randomly within the sample area
to prevent bias in the results
what are the advantages of using quadrats
- keep the sample area constant
- allows comparison between sites
- generates valid results
what types of sampling do transects allow
systematic (regular)
what is a transect
a line (ie tape) across a habitat which is then used for sampling
when are transects used
- to study how the distribution of an organism changes in a habitat
- to determine if there is a correlation between an abiotic factor (ie pH, temp, salinity) and the distribution of an organism
- to collect large quantaties of data between 2 points
what are the two types of transects
- interrupted
- continuous
what are interrupted transects
quadrats are place a regular interval across the habitat being investigated
what are continuous transects
quadrats are placed adjacent to each other across the area of habitat being investigated
describe the water cycle
- percolation = water trickles through gaps in soils and rock
- run off = water flows across the surface of the ground
- traspiration = water vapour lost from plants directly into atmosphere
- evapouration = the sun heats the water to change state into vapour
- condensation = as moist air rises it cools and water vapour forms clouds
- precipitation = water droplets in clouds get heavier, then fall as rain, snow or hail
describe the carbon cycle
- respiration from humans / combustion of fuels releases carbon dioxide into the atmosphere
- the CO2 is then removed from atmosphere in photosynthesis
- these plants are then eaten and the animals die / plants die
- the animals respire to produce CO2 and repeats
- OR the dead matter is decayed and CO2 is released back into atmosphere/absorbed into ground by decomposers
what is meant by the term egestion
loss of feces which is broken down and produces carbon
what factors affect the rate of decay
- temperature
- water
- availability to oxygen
what is meant by the term decomposition
the breakdown of dead ORGANIC matter into smaller soluble molecules
what type of organisms carry out decomposition
decomposers
what type of organisms are decomposers
- bacteria
- fungi
- microorganisms
what does decomposition allow
- nutrients to be recycles (amino acids)
- nitrogen to be recycled
- carbon to be recycled
describe the process of decomposition
- fungi and bacteria involved in decay secrete specific enzymes into environment
- digestive enzymes (proteases, carbohydrases, lipases) break down dead organic matter
- the fungi & bacteria reasorb the nutrients by diffusion (amino acids, simple sugars, fatty acids, glycerol)
- fungi & bacteria use nutrients for own growth and respiration
what are the optimal conditions for decay
- warm
- moist
- oxygenated
what does anaerobic decay form
methane gas
how can anaerobic decay be used in inddustry
biogas generators which use the methane produced as a fuel
