Sampling Techniques To know how to use different sampling techniques.
Post on 05-Jan-2016
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Sampling TechniquesTo know how to use different sampling techniques
Adaptations
Sampling Biologists often want to find out what organisms are
present in an environment / what these organism do /where these organisms go etc…
Often it isn’t feasible to identify all the organisms present, so instead samples can be taken
Samples look at a small section, allowing us to predict what the whole is like – e.g. we couldn’t feasibly measure the height of every blade of grass, but we could look at a small sample grass and get an idea of what all the rest may be like
Sampling Techniques How can we sample this organism
Tagging – e.g. a few whales can be tagged and tracked, to give us an idea of where their migration routes are
Sampling Techniques How can we sample this organism?
Pitfall traps – e.g. a small trap can be set to collect a range of organisms within an area
Pit-fall trap
Sampling Techniques How can we sample organisms / areas?
Quadrat – e.g. a quadrat is thrown in an area, and the number of organisms within the quadrant are counted to give an estimate for a much larger area
Sampling Techniques Sampling is a good way to estimate population size – although
is not 100% accurate, if done properly it can give good estimates and is very time efficient!
Your task is to sample the number of daisies growing in the open and the number growing under trees
Do More Daisies grow in the open or under trees?
How long do you think it will take?
How many times will you have to do it?
How will you choose which part to sample?
What do you think you will
find out?
How are you going to
sample your daisies?
How will you
record your
results?
How will you make it safe?
Recording your Results
Design a table to collect your results in
This is usually
the thing you
change
These are usually the things you have measured
NEVER FORGET YOUR UNITS!!! (e.g. s, m, cm, N)
Use a PENCIL and RULER
Results
Number of Daisies
Sample 1
Sample 2
Sample 3
Average
In Open
Under Trees
Analysis Can you suggest reasons why the population sizes are
different? The daisies need a
variety of conditions to survive, including light – around the trees light is less abundant than out in the open field, so less daisies are able to grow there
There may also be less nutrients / water available allowing less daisies to grow in this area
Moving Quadrats are usually used for plants, but they can also
be used to estimate some animal population sizes (as long as these only move a little)!
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