Genetic Diversity and Adaption

Question 1

What is genetic diversity?

Answer 1

Number of different alleles of a gene within a population

Question 2

How can genetic diversity within a population increase?

Answer 2

• Mutations in the DNA, forming new alleles
• Gene flow (new alleles introduced when individuals from another population migrate in and reproduce)

Question 3

What is a genetic bottleneck?

Answer 3

An event that causes a big reduction in population, reducing the number of different alleles in the gene pool

Question 4

The founder effect

Answer 4

• Few organisms migrate from a population and start a new colony
• Few alleles in the gene pool
• Higher incidence of genetic disease

Question 5

Natural selection

Answer 5

• Individuals of a population best suited to their environment survive and reproduce
• Beneficial alleles likely to pass on to next generation
• Frequency of the beneficial allele in the population increases over time (evolution)
• Results in species being better adapted to their environment

Question 6

What is evolution?

Answer 6

The gradual change in allele frequency over time

Question 7

Types of adaptations

Answer 7

• Behavioural (eg. Mating dances)
• Physiological (eg. Hibernation)
• Anatomical (eg. Streamlined shape)

Question 8

Directional selection

Answer 8

• Individuals with an extreme type of characteristic are more likely to survive and reproduce
• Parent population exposed to environmental change
• Those with beneficial allele survive and reproduce
• Mean increases or decreases

Question 9

Stabilising selection

Answer 9

• Individuals with an extreme type of characteristic are less likely to survive and reproduce
• Those in middle range survive and reproduce
• Mean remains the same

Question 10

Investigating the effect of antimicrobial substances on microbial growth

Answer 10

• Evenly distribute bacteria on agar plate (lawn spreading)
• Use a range of at least 5 different compounds
• Keep other variables the same (single species of bacteria)
• Use aseptic technique
• Incubate at 25° for 24 hours
• Measure clear zone of inhibition

Question 11

Aseptic techniques

Answer 11

• Disinfect bench
• Flame inoculating loop before and after transferring microorganisms
• Flame mouth of glass bottles
• Don’t put bottle top on bench
• Replace lid quickly