Investigating Diversity Flashcards
What is variation in diversity?
The difference that exist between individuals within a species and between different species
What are 4 ways scientist can measure genetic diversity within a species or between didfernt species?
1) comparing the frequency of observable characteristics
2) comparing base sequences if DNA
3) comparing base sequences of RNA
4) comparing amino acid sequences
What is phenotypic variation within a species due to?
Genetic factors (differnt combination of alleles)
Environmental factors (competition for light and mineral ions in plants and diet in animals)
What do quantitative investigations of variation within a species involve?
1) collecting data from a random sample - it is representative of the whole population. To make sure it is representative your sample must be random to avoid bias and large in number
2) deciding how big a sample to collect - can use a running mean. You would continue sampling until a stable running mean is reached
3) random sampling of an area is done by dividing the area into a grid and randomly generating coordinates which specify where the sampling should take place
What is a running mean?
When you calculate the mean after very sample that you collect. You should notice that the mean varies a lot at the start of sampling but the variations reduce as you increase the number of repeats. Once the mean becomes roughly constant/stable this tells you that you have done enough repeats
What is standard deviation?
The spread of the values about the mean
Often written as:
How do you interpret standard deviations?
A smaller standard deviation tells us that the values are more closely clustered together and that the results have a small variation around the mean
A larger standard deviation tells us that the variation in the values is too high, the results have a larger variation around the mean
How do you interpret standard deviations?
A smaller standard deviation tells us that the values are more closely clustered together and that the results have a small variation around the mean
A larger standard deviation tells us that the variation in the values is too high, the results have a larger variation around the mean
How is standard deviation calculated?
How to report standard deviation?
Include:
Sample size
Mena
Standard deviation
Worked example for standard deviation:
