3.4.7 Investigating diversity Flashcards
Give one technological advance that has helped to clarify evolutionary relationships.
E.g.
- Genome sequencing
- Comparing amino acid sequence
- Immunological comparisons
Why can observable characteristics be used as a measure of genetic diversity?
Different characteristics are controlled by different alleles.
How has the way in which genetic diversity is assessed changed over time?
- Early estimates were made by looking at the frequency of measurable/observable characteristics in a population.
- Nowadays, gene technologies are used to measure genetic diversity directly; these give more accurate estimates of genetic diversity than earlier techniques.
How is genome sequencing useful for clarifying evolutionary relationships?
- The entire base sequence of an organism’s DNA can be determined.
- The DNA base sequence can then be compared to another one, to see how closely related they are.
- Closely related species will have a higher percentage of similarity in their DNA base order.
How are amino acid sequence comparisons useful for clarifying evolutionary relationships?
- The sequence of amino acids in a protein is coded by the base sequence in DNA.
- Related organisms have similar DNA sequences and so similar amino acid sequences in their proteins.
How are immunological comparisons useful for clarifying evolutionary relationships?
- One type of antibody is added to isolated samples…
- …to find out which proteins will be recognised by that antibody.
- Similar proteins will bind to the same antibodies
Why do scientists look at a sample of a population, rather than the whole population?
- It would be too time-consuming or impossible to catch all the individuals in the group.
- Therefore, samples are used as models for the whole population.
Why does a population sample have to be chosen at random?
- To make sure the sample isn’t biased.
- To ensure any variation observed in the sample isn’t just due to chance.
What does the standard deviation of a data set tell us?
It tells us how much the value in a single sample varies. It’s a measure of the spread of values about the mean.
