AQA A-level Biology - Topic 4 Already Passed

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AQA A-level Biology - Topic 4 Already Passed Define variation ✔✔Differences that exist between individuals In what ways can variation be caused? ✔✔It can be caused by genetic factors, such ... as alleles from mutations. It can also be caused by the environment, such as climate. Most variation is caused by a combination of genetic factors and environmental factors Why is it impossible to study a whole population? ✔✔Because it is too large and would take too long. Instead, scientists use a sample that is representative of the species' population Why should the sample taken be random? ✔✔So you can make sure that the sample isn't biased in any way. What could you calculate to look at variation between species? ✔✔The mean (average) What is standard deviation? ✔✔It tells you how much values in a single sample vary, by measuring the spread of values about the mean What does a large standard deviation mean? ✔✔That the values in the sample vary a lot What does a small standard deviation mean? ✔✔That the values in the sample varies little What can you use standard deviation to draw on a bar chart of mean values? ✔✔An error bar. You would draw it one standard deviation either side of the mean value. How is DNA stored in eukaryotic cells? ✔✔1) The DNA is lin [Show More]

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