4.7 Investigating diversity Flashcards
What could variation within a species could be the result of?
- Genetic factors i.e. different alleles
- Environmental factors
- Or a combination of both
What is discontinuous variation?
- Distinct, discrete categories
- Data tends to be qualitative
- Controlled by a single gene or a few genes
- Unaffected / not strongly influenced by the environment
Example; blood groups
What is continuous variation?
- No distinct categories
- Data teds to be quantitative
- Controlled by many genes
- Strongly influenced by the environment
- Example: heigh
What is continuous variation?
- No distinct categories
- Data teds to be quantitative
- Controlled by many genes
- Strongly influenced by the environment
- Example: heigh
How can genetic diversity within, or between species can be made by comparing…
The frequency of measurable / observable characteristics
- Indicates genetic diversity because is based on the fact that different alleles determine different characteristics
- So the higher the variety of a characteristic, the higher the variety of alleles of that gene and hence the higher the genetic diversity
The base sequence of DNA and mRNA
The amino acid sequence of the proteins encoded by DNA and mRNA
What are the limitations of using observable characteristics in a population as an estimate of genetic diversity?
- Many observable characteristics coded for by more than one gene (polygenic)→ vary continuously→difficult to distinguish one from another
- Characteristics could be modified by the environment so differences may be as a result of different environmental conditions rather than different alleles
What makes a sample representative?
Random sample - eliminates bias
Large sample size:
- Minimise effects of chance
- Anomalies have less influence and can be identified
Analyse results with a statistical test
What does standard deviation show?
Shows the spread of values around the mean
What are the limitations of using the mean?
- Can show if there is variation / differences between samples
- Useful for comparison, but provides no info about the range
