7 Variation

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  • Created by: Naana
  • Created on: 26-03-15 16:02
What is interspecific variation?
When one species differs from another species
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What is intraspecific variation?
When members of the same species differ from each other
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What is sampling and why is it used?
Sampling involves taking measurements of individuals, selected from the population of organisms being investigated. If sample is representative, then measurements can be relied upon
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What might a sample not be representative?
Sampling bias-investigators make unrepresentative choices. Chance-individuals chosen may not be representative by pure chance
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How can we minimise the effects of chance?
1)By using a large sample size-more individuals selected so smaller the probability that chance will affect results (more reliable results) 2)Analyse the data collected using statistical tests-will determine how much chance has influenced data
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What causes genetic variation?
Mutations-sudden changes to genes and chromosomes may be passed on to next generation. Meiosis-Mixes up genetic material before it is passed on to gametes which as a result are all different. Fusion of gametes at fertilisation-random process which ad
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How do environmental influences cause variation?
Although genes set limits, the environment largely determines where within those limits an organisms lies e.g. height
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What are the types of variation and how are they represented as graph?
Variation due to genetic factors-represented as a bar chart or pie chart. Variation due to environmental influences- represented as a normal distribution curve (bell shaped curve)
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What is the mean of a normal distribution curve?
The measurement at the maximum height of the curve. It provides an average value which can be used to compare with other samples
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What is standard deviation?
A measure of the spread of values about the mean. The smaller the S.D the more reliable a set of results are
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Other cards in this set

Card 2

Front

What is intraspecific variation?

Back

When members of the same species differ from each other

Card 3

Front

What is sampling and why is it used?

Back

Preview of the front of card 3

Card 4

Front

What might a sample not be representative?

Back

Preview of the front of card 4

Card 5

Front

How can we minimise the effects of chance?

Back

Preview of the front of card 5
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