What four types of evidence can be compared to investigate genetic diversity within or between species?
- Frequencies of measurable or observable characteristics
- DNA base sequences
- mRNA base sequences
- Amino acid sequences of encoded proteins
AQA A-Level Biology - (7402) · 3.4.7
Revise AQA A-Level Biology - (7402) specification point 3.4.7, Investigating diversity, with free active-recall flashcards. Flip through the set or review every question and answer below.
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What four types of evidence can be compared to investigate genetic diversity within or between species?
Why are observable characteristics indirect evidence of genetic differences?
Characteristics can also be influenced by the environment.
How has gene technology changed investigations of genetic diversity?
It has enabled a shift from inferring DNA differences through characteristics to directly comparing DNA sequences.
What does greater sequence similarity generally suggest about the relationship between organisms?
They are more closely related and share a more recent common ancestor.
Why can DNA and protein sequence comparisons reveal different levels of variation?
Different DNA base sequences do not always produce different amino acid sequences.
What data are used to summarise quantitative variation within a species?
Measurements from a sample of individuals.
What makes a sample of individuals random?
Individuals are selected without deliberately favouring particular characteristics, giving all eligible individuals an equal chance of selection.
How does random sampling help a sample represent its population?
It reduces selection bias.
Why might a random sample still differ from its population?
It may differ by chance.
What does the mean summarise in a set of measurements?
The central value of the measurements.
How is the mean of a set of measurements calculated?
Divide the sum of the values by the number of values.
What does standard deviation indicate about a set of measurements?
Their spread around the mean: a larger standard deviation indicates greater spread, while a smaller one indicates tighter clustering.
Why is the mean alone insufficient to compare quantitative variation between groups within a species?
Groups with similar means can differ in spread, so the mean alone does not show how much individuals differ.