Variation
A mind-map to help with the basics of variation. Hope this helps :)
- Created by: Suterfamily
- Created on: 22-05-14 09:47
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- Variation
- Causes of variation
- Environmental factors
- Plant growth is affected by the amount of minerals available in the soil.
- Identical twins are genetically identical - they have the same alleles, so any differences between them will be due to the environment.
- The appearance (phenotype) of an individual is also affected by the environment.
- The fur colour of Himalayen rabbits is affected by temperature.
- Be careful when drawing conclusions about the cause of variation.
- Scientists draw conclusions based on the information they have until new evidence challenges, i.e. overeating & antioxidants.
- Variation is often a combination of genetic and environmental factors.
- No two individuals are exactly alike.
- Genetic factors
- You inherit your genes from your parents, this means genetic variation is inherited.
- All members of a species have the same genes.
- But individuals within a species can have different versins of these genes - alleles.
- The alleles an organism has make up its genotype.
- Different genotypes result in variation in phenotype - the characteristics displayed by an organism, i.e. eye colour.
- The alleles an organism has make up its genotype.
- But individuals within a species can have different versins of these genes - alleles.
- Variation exists between all individuals.
- Interspecific - the variation that exists between different species.
- Intraspecific - the differences that occur within a species.
- Environmental factors
- Investigating variation
- Standard deviation
- When all the values are similar the graph is steep so standard deviation is small.
- When all the values vary a lot the graph is fatter so standard deviation is large.
- The standard deviation tells you how much the values in a single sample vary.
- Describe data
- General trend
- Specific data
- Draw conclutions
- mean value = average
- Can be used to tell if there is variation between samples.
- To study variation you've got to sample.
- Has to random
- Not biased
- To ensure variation isn't by chance.
- Analyse results statistically.
- Has to random
- Bell-shaped graph = normal distribution.
- Standard deviation
- Causes of variation
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