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
what are the two main gases biogas consists of
- methane
- CO2
explain how biogas is made
- decomposers such as bacteria and fungi are used to prodcue biogas
- from dead organic material like plants and waste from sugar factories
- this form of decay must take place anaeobically (without oxygen)
how is biogas stored and why
- it is stored as a gas
- to store as a liquid requires very high pressures to compress the gas
what makes biogas hard to store and dangerous
because it is stored as a gas
how soon does biogas have to be used
very soon after production
what can biogas be used for
- heating
- generating electricity
- cooking
- lighting
- refridgeration
describe the inlets and outlets of a biogas generator
- one inlet where the waste material goes in
- one outlet where digested material comes back out
- another outlet where the biogas comes out
give some advantages of biogas generators
- it is carbon neutral
- methane is a greenhouse gas so by using it as a fuel it contributes less to global warming
- waste material is made useful
- produces good fertilisers for crop
give some disadvantages of biogas generators
- expensive and time consuming to remove and add waste
- some require manual cleaning
- produces a bad smell from the waste material
- require insulations to retain optimal temp
do just abiotic factors change the environment
no - both abiotic and biotic factors contribute
what impact does environmental change in temperature have on animals
it changes the distribution of organisms
give some examples of what environmental changes can be
- seasonal (rainfall changes, temperature)
- geographical (soil structure, mountains)
- human interaction (pollution)
- water availiability
what does changes in temperature lead to
change in migration patterns
why do change in temperatures cause change in migration patterns
- days are warmer for longer so birds fly later in the year
- sea temps are warmer so aquatic animals migrate less
what can changes in water aaliability lead to
change in migration patterns and plant distribution within a habitat
what can changes in environmental gases lead to
changes in distribution of organisms
how do scientists determine levels of air or water pollution
use the absence or presence of certain linchen which are intoleratant to certain gases
what would you call a lichen
a bioindicator species
what is meant by the term bioindicator species
an organism which provides information about how unpolluted the environment is
what are the air quality bioindicators
- lichens = low amount of sulfur dioxide in the air
- no blackspot fungus on a rose = lots of sulfur dioxide
what do gardeners use compost for
fertilisers
state the conditions to produce compost quickly
- moist
- warm
- lots of oxygen
what are lichens sensitive to
sulfur dioxide
what is an invertebrate
an organism without a backbone
describe how freshwater invertebrates are used to monitor water quality
different species are found in different qualities of water
is a stream or river is polluted will there be more or less biodiversity
less
suggest why soil on mountainsides are poor for agriculture
- lack of nutrients as mineral ions dissolve and run off
- unstable soil
what is the decay required practicle
the effect of temperature on the rate of decay of fresh mild by measuring pH change
