10.4

Question 1

observable characteristic

Answer 1

determined by genes
variety within depends on number and variety of alleles plus environmental influences

Question 2

2 limitations of comparing observable characteristics

Answer 2

1. large number of them are coded by more than one gene
   not discrete but vary continuously
   - difficult to distinguish from one another
2. they can be modified by environmental conditions

Question 3

comparison of DNA base sequences

Answer 3

dna sequencing is done by automatic machines and data is produced is analysed by computers
each nucleotide base is tagged with different coloured fluorescent dye
measures genetic diversity between species, and evolutionary relationships

Question 4

bases dye colours

Answer 4

adenine- green
thymine- red
guanine-yellow
cytosine-blue

Question 5

interspecific variation

Answer 5

if one species differs from another

Question 6

intraspecific variation

Answer 6

members of the same species differ from each other

Question 7

random sampling disadvantages

Answer 7

1. sampling bias - selection process is biased
2. chance- sample isn’t representative

Question 8

How to minimise chance from sampling process

Answer 8

1. use a large sample size
2. analysis of data- statistical tests can determine extent chance has influenced

Question 9

standard deviation

Answer 9

width of normal distribution curve

square root of (sum of(value - mean)^2 / total number of values-1

Question 10

DNA comparison evolutionary relaitonship

Answer 10

species more closely related show more similarity in DNA base sequences than species more distantly related
- mutations over time cause changes in nucleotide bases of new species

Question 11

Two other ways to compare genetic diversity

Answer 11

• mRNA
• amino acid sequences in proteins