4.4: Genetic diversity and adaptation

Question 1

Define genetic diversity

Answer 1

the number of different alleles of genes in a population

Question 2

Describe natural selection: stabilising and directional

Answer 2

1) New alleles for a gene created by random mutations
2) If new alleles increase survival rate they will survive and reproduce
3) Reproduction passes on advantageous allele onto the next generation
4) Over many generations the new alleles frequency increases within the population

Question 3

Features of directional selection (3)

Answer 3

1) One extreme has selective advantage
2) Occurs when there’s a change of environment
3) moda; trait changes

Question 4

Describe directional selection in antibiotic resistance (6)

Answer 4

1) Variation due to mutation to create new advantageous allele that give antibiotic resistance
2) Selection for advantageous phenotype of antibiotic resistance
3) Antibiotic resistant bacteria are more likely to survive and reproduce
4) Alleles for antibiotic resistance is passed on to future generations
5) Overtime frequency of allele coding for antibiotic resistance increases
6) Increase in antibiotic resistant bacteria in population

Question 5

Features of stabilising selection (3)

Answer 5

1) Modal trait has selective advantage
2) No change in environment
3) Modal trait stays the same

Question 6

Describe stabilising selection in birth weight in humans (5)

Answer 6

1) Selection against both extremes, low and high birthweight
2) Phenotype of medium birthweight more likely to survive and reproduce successfully
3) Alleles for medium birthweight passed onto future generations
4) frequency of allele coding for medium birthweight increases
5) Alleles for both extremes, high and low weights decrease.