UNIT 2 section 1 Variation

what is varation

variation is = the difference that exists between individuals

Interspecific = variation that exists between different species

intraspecific= differences that occur within a species

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causes of intraspecific variation

Genetic - 
different alleles = versions of genes 
alleles make the genotype
different genotypes result in different phenotypes 

the phenotype of an indivdual is aslo affected by the enviroment 

genes and the enviromentvariation is a combination 
eg. someone may have the genes to grow 6ft , whether they do or not depends on envirmoental factors such as diet

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investigating variation

samples are used as as models for the whole population 
as its a model its improtant that it represents accurately 

random sampling = makes sure the sample isnt bias
random number generator
to ensure results arent due to chance it is important to anaylse results statistically

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mean = tells the average values collected in a sample
normal distrubution is symmetrical around the mean

standard deviation = how much the values in a sample vary , a measure of the spread of values around the mean 
values can vary a little or a lot 

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