2480946
Description
Mind Map by Lilac Potato, updated more than 1 year ago
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Created by Lilac Potato
over 9 years ago
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GCSE AQA Biology 2 Distribution of organisms
- The environment
- Habitat: The place
where an organism lives
- Distribution of an organism:
Where an organism is found
- Affected by environmental factors...
- Temperature
- Availability of water
- Availability of
oxygen/carbon dioxide
- Availability of nutrients
- Amount of light
- Temperature
- Ways to study it...
- Measure how common organism
is in 2 sample areas and compare
- Study how it
changes across area
- Measure how common organism
is in 2 sample areas and compare
- Affected by environmental factors...
- Habitat: The place
where an organism lives
- Quadrats
- Quadrat: Square frame enclosing
a known area e.g. 1m squared
- To compare how common
organism is in 2 sample areas...
- 1) Place quadrat on ground at random point in 1st sample area
- 2) Count all organisms within quadrat
- 3) Repeat steps 1 & 2 as many times as possible
- 4) Work out mean no. of organisms
per quadrat for 1st sample area
- 5) Repeat steps 1 to 4 in 2nd sample area
- 6) Compare the means
- 6) Compare the means
- 5) Repeat steps 1 to 4 in 2nd sample area
- 4) Work out mean no. of organisms
per quadrat for 1st sample area
- 3) Repeat steps 1 & 2 as many times as possible
- 2) Count all organisms within quadrat
- 1) Place quadrat on ground at random point in 1st sample area
- Quadrat: Square frame enclosing
a known area e.g. 1m squared
- Working out population size
- 1) Work out mean number of
organisms per metre squared
- 2) Multiply mean by total area
(in metres squared) of habitat
- 2) Multiply mean by total area
(in metres squared) of habitat
- 1) Work out mean number of
organisms per metre squared
- Transects
- Can use to find out how organisms
are distributed across an area...
- 1) Mark out line in area using tape measure
- 2) Collect data along the line by...
- a) counting all the organisms that
touch the line (that are being studied)
- b) using quadrats - can be placed next
to each other along line or at intervals
- a) counting all the organisms that
touch the line (that are being studied)
- 2) Collect data along the line by...
- 1) Mark out line in area using tape measure
- Can use to find out how organisms
are distributed across an area...
- Collecting environmental data
- Need to think about...
- Reliability
- Have to be repeatable and reproducible
- Use a large sample size
- Use random samples
- Have to be repeatable and reproducible
- Validity
- For results to be
valid they must...
- Be reliable
- Answer original question
- Be reliable
- Must control all variables - can find
out if difference in distribution is
caused by environmental factor or not
- For results to be
valid they must...
- Reliability
- Need to think about...
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