4.7 Investigating Diversity

Question 1

How can genetic diversity within or between species be measured?

Answer 1

• Comparing frequency of measurable or observable characteristics
• Comparing base sequence of DNA
• Comparing basic sequences of mRNA
• Comparing amino acid sequences of specific protein encoded by DNA and mRNA

Question 2

Explain how comparing DNA, mRNA and amino acid sequences can indicate relationships between organisms within a species and between species

Answer 2

• More differences in sequences –> more distantly related/earlier common ancestor
• As mutations (changes in DNA basic sequences) and build up overtime, more mutations cause more changes in amino acid sequences

Question 3

Explain the changes in methods of investigating in genetic diversity overtime

Answer 3

• Early estimates made by inferring DNA sequences from measurable or observable characteristics
  
  • Many coded for by more than one gene –> difficult to distinguish one from another
  • Many influenced by environment –> differences due to environment not genes
• Gene technologies allow this to be replaced by direct investigation of DNA sequences

Question 4

Explain how data should be collected when investigating variation within a species quantitively

Answer 4

• Collect data from random samples to remove bias
  
  • Use a grid/divide area into square
  • Use a random number generator to obtain random coordinates
• use same method of measurement each time
• use a large sample size/measure a large number of organisms so it’s representative of population
• Calculate running mean and sample until number becomes fairly constant
• Where applicable ensure sampling is ethical –> must not harm organism/must allow release unchanged

Question 5

Explain how data should be processed and analysed when investigated in variation within a species quantitatively

Answer 5

• Calculate a value of collective data and standard deviation of that mean
• Standard deviation shows spread of values about the mean so a higher standard deviation = higher variation
• If standard deviation is overlaps, causing values of two sets of data to be shared, any difference between the two maybe due to chance/not significant
• Used statistical tests to analyse whether there is a significant difference between populations