The number of organisms found in an area is affected by what?
environmental factors
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Random sampling uses a?
quadrat
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This method is typically used to compare what?
the number of organisms in different areas
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Used to sample what kind of organisms (2)?
plants
slow moving organisms
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STEPS
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Place a 1m squared _________ on the _______ at a _______ point in the area?
quadrat on the ground at a random point in the area
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We do this by dividing the area into a?
grid
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And using a random _____ _____?
number generator
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Then count?
the number of organisms within the quadrat
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________ and calaculate a ______?
Repeat multiple times and calculate a mean
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How do we calculate the mean?
total number of organisms
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number of quadrats used
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QUESTION
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Anna counted the number of daisies in 7 quadrats within her first sample area and recorded the values 18, 20,22,23,23,23,25.
Calculate mean.
154
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7
=22 daisies per quadrat
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We then repeat in the ______ area?
second
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And compare?
the two means
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Why do we place the quadrat lots of times?
since if we only place it once it may not be an accurate representation of the whole area
14 of 27
This gives you more?
valid results
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How do we calculate population size?
mean n.o of organisms x total area
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Why do we place the quadrat at random places?
to reduce bias
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TRANSECT
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This sampling technique measures the what ?
measures the distribution of a species across a habitat to see a change
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A transect is a?
tape measure
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STEPS
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Run the _____ in a ______ line across the area?
run the tape in a straight line
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Place the ________ along the line?
quadrat
21 of 27
And count?
the number of organisms in the quadrat
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Continue this by placing the quadrat at ______ ____?
equal intervals
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Then ?
repeat
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If it is difficult to count?
the number of individual species
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Then we calculate?
the percentage coverage
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We count the square if its?
over half covered
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Other cards in this set
Card 2
Front
Random sampling uses a?
Back
quadrat
Card 3
Front
This method is typically used to compare what?
Back
Card 4
Front
Used to sample what kind of organisms (2)?
Back
Card 5
Front
STEPS
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Place a 1m squared _________ on the _______ at a _______ point in the area?
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