🩶 3.4 Topic 4 - 3.4.7 Investigating diversity Flashcards
What are 3 technologies that have been useful for clarifying evolutionary relationships?
Genome sequencing, comparing amino acid sequences and immunological comparisons.
What does genome sequencing determine?
It determines the entire base sequence of an organisms DNA.
What is the sequence of amino acids in a protein coded for by?
The base sequence in DNA.
What technologies have changed the way in which genetic diversity is assessed?
Gene technologies.
_ _ _ _ _ _ _ determine different characteristics.
Alleles.
What does a wide variety of each characteristic in a population indicate?
a high number of different alleles - so a high genetic diversity.
What do similar proteins bind to?
The same antibodies.
What will different alleles of the same gene have? What will they also produce?
Slightly different DNA base sequences.
Slightly different mRNA base sequences and may produce proteins with slightly different amino acid sequences.
What does comparing the DNA base sequences of the same gene in different organisms in a population allow scientists to find out?
How many alleles of that gene there are in that population.
As different alleles will also produce slightly different mRNA base sequences, what does this mean?
That they may produce proteins with slightly different amino acid sequences, sp these can also be compared.
What is variation?
The differences that exists between individuals. There is variation between species and within species.
What are two types of factors which cause variation within a species?
Genetic factors and environmental factors.
How can genetic factors cause variation within a species?
Different species have different genes, which causes variation between species.
Individuals of the same species have the same genes, but different alleles causing variation.
What are examples of environmental factors which cause variation within a species?
Climate, food and lifestyle.
What do you have to sample to study variation?
A population.
As same data will be used to draw conclusions about the whole population, the sample has to be random, why?
So that it accurately represents the whole population and that any patterns observed are tested to make sure they are not due to chance.
You can use the _ _ _ _ to look for variation between samples.
Mean.
What is the mean?
The mean is an average of the values collected in a sample.
What is the formula you use to find the mean?
Total of all the values in your data/the number of values in your data.
What distribution does a bell-shaped graph show? why?
A normal distribution - this is because most samples will include values either side of the mean.
A normal distribution is _ _ _ _ _ _ _ _ _ _ _ about the mean.
Symmetrical.
What does standard deviation tell you about?
It tells you how much the values in a single sample vary.
Standard deviation is a measure of what?
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 most of the sample data is around the mean value, so only varies a little.
What does a graph which is steep tell you about the standard deviation?
That the values are similar and close to the mean so therefore the SD is small.
What does a graph which is wide tell you about the standard deviation?
That the values vary a lot so therefore the SD is large.
What bars can you draw with standard deviation?
Error bars.
What do error bars do with standard deviations?
Error bars extend one SD above and one SD below the mean. This means that the total length of the error bar is twice the SD.
On an error bar what does the longer the bar mean?
Means the larger the SD is and the more spread out the sample data is from the mean.
Early estimates of genetic diversity were made by looking at …
… the frequency of measurable or observable characteristics in a population.
What do alleles determine?
Different characteristics.
A wide variety of each characteristic in a population indicates …
… a high number of different alleles - a high genetic diversity.
What gene technologies have now been developed that allow us to measure genetic diversity directly?
- Different alleles of the same gene will have slightly different DNA base sequences. Comparing the DNA base sequences of the same gene in different organisms in a population allows scientists to find out how many alleles of that gene there are in that population.
- Different alleles will also produce slightly different mRNA base sequences, and may produce proteins with slightly different amino acid sequences, so these can also be compared.
What can new technologies be used to give and compare?
- More accurate estimates of genetic diversity within a population or species.
- The genetic diversity of different species to be compared more easily.
